Search results for: hemicellulose glycosidic bonds

Authors: Aniekan James Akpan, Inemesit Akpan Umoren, Uduak Iwok

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From prehistoric and primitive cultures, education was seen as a process of culture transmission by way of guiding children into becoming good members of their local communities. Even in modern cultures, education is seen as a systematic discipline aimed at cultivating genuine values to improve oneself and society. Without education, the chances of realizing the desired vision are marred as it is believed that nations that invest much in education are able to reap the desired benefits technologically, economically, socially, politically, and otherwise. In this sense, the moulding of character is considered the primary purpose of education, and until the audience of mass media through its various vehicles is seen as tools for improving the overall development of society. It is believed that a media-friendly person is likely to perform better than someone who is less friendly. This work, therefore, examines the role media play in educational development. As highlighted by the study, a summary of the functions of media shows that they widen horizon by acting as a liberating force, breaking distance, bonds, and transforming a traditional society into a modern one. With the use of technological development theory, agenda-setting theory as well as uses and gratification theory and multiple intelligence theory, the work identifies different ways in which mass media help in educational development and draws attention to the audience’s perception of media functions in terms of educational development. With a survey method and a population of 6,903,321 people, the work sampled 220 respondents using purposive technique drawn from rural communities in the South-South region of Nigeria. The work concludes that mass media are potent vehicles for teaching and learning and therefore recommends that government should provide basic infrastructures to the rural communities to aid full utilization of media potentials in educational development and equally urge media owners and practitioners to as a matter of urgency increase coverage time on issues bordering on education as it is done for political and other issues.

Keywords: educational, development, media usage, perception

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Authors: Anshu Gupta, Charu Gupta

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Background: Punjab, a border state in India has achieved notoriety world over for its drug abuse problem. People right from school kids to elderly are hooked to drugs. This pattern of substance abuse is prevalent in both cities and villages alike. Excess of younger population in India has further aggravated the situation. It is feared that the benefits of India’s economic growth may well be negated by the rising substance abuse especially in this part of the country. It is quite evident that the pattern of substance abuse tends to change over time which is an impediment in the formulation of effective strategies to tackle this issue. Aim: Purpose of the study was to ascertain the change in the pattern of drug abuse for two consecutive years in the out patient department (OPD) population. Method: The study population comprised of all the patients reporting for deaddiction to the psychiatry outpatient department over a period of twelve months for two consecutive years. All the patients were evaluated by the International Classification of Diseases; 10 criteria for substance abuse/dependence. Results: A considerably high prevalence of substance abuse was present in the Indian population. In general, there was an increase in prevalence from first to the second year, especially among the female population. Increase in prevalence of substance abuse appeared to be more prominent among the younger age group of both the sexes. A significant increase in intravenous drug abuse was observed. Peer pressure and parental imitation were the major factors fueling substance abuse. Precipitation or fear of withdrawal symptoms was the major factor preventing abstinence. Substance abuse had a significant effect on the health and interpersonal relations of these patients. Summary/Conclusion: Drug abuse and addiction are on the rise throughout India. Changing cultural values, increasing economic stress and dwindling supportive bonds appear to be leading to initiation of substance abuse. Need of the hour is to formulate a comprehensive strategy to bring about an overall reduction in the use of drugs.

Keywords: deaddiction, peer pressure, parental imitation, substance abuse/dependance

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Authors: S. M. Chabane sari S. Zargou, A.R. Senoudi, F. Benmouna

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Immobilization of nano particles (NPs) is the subject of numerous studies pertaining to the design of polymer nano composites, supported catalysts, bioactive colloidal crystals, inverse opals for novel optical materials, latex templated-hollow inorganic capsules, immunodiagnostic assays; “Pickering” emulsion polymerization for making latex particles and film-forming composites or Janus particles; chemo- and biosensors, tunable plasmonic nano structures, hybrid porous monoliths for separation science and technology, biocidal polymer/metal nano particle composite coatings, and so on. Particularly, in the recent years, the literature has witnessed an impressive progress of investigations on polymer coatings, grafts and particles as supports for anchoring nano particles. This is actually due to several factors: polymer chains are flexible and may contain a variety of functional groups that are able to efficiently immobilize nano particles and their precursors by dispersive or van der Waals, electrostatic, hydrogen or covalent bonds. We review methods to prepare polymer-immobilized nano particles through a plethora of strategies in view of developing systems for separation, sensing, extraction and catalysis. The emphasis is on methods to provide (i) polymer brushes and grafts; (ii) monoliths and porous polymer systems; (iii) natural polymers and (iv) conjugated polymers as platforms for anchoring nano particles. The latter range from soft bio macromolecular species (proteins, DNA) to metallic, C60, semiconductor and oxide nano particles; they can be attached through electrostatic interactions or covalent bonding. It is very clear that physicochemical properties of polymers (e.g. sensing and separation) are enhanced by anchored nano particles, while polymers provide excellent platforms for dispersing nano particles for e.g. high catalytic performances. We thus anticipate that the synergetic role of polymeric supports and anchored particles will increasingly be exploited in view of designing unique hybrid systems with unprecedented properties.

Keywords: gold, layer, polymer, macromolecular

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Authors: Mohamed dammak

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Great attention has been paid to the design and synthesis of novel organic-inorganic compounds in recent decades because of their structural variety and the large diversity of atomic arrangements. In this work, the structure for the novel dimethyl aminopyridine tetrachlorocobaltate (C₇H₁₁N₂)₂CoCl₄ prepared by the slow evaporation method at room temperature has been successfully discussed. The X-ray diffraction results indicate that the hybrid material has a triclinic structure with a P space group and features a 0D structure containing isolated distorted [CoCl₄]2- tetrahedra interposed between [C7H11N²⁻]+ cations forming planes perpendicular to the c axis at z = 0 and z = ½. The effect of the synthesis conditions and the reactants used, the interactions between the cationic planes, and the isolated [CoCl4]2- tetrahedra are employing N-H...Cl and C-H…Cl hydrogen bonding contacts. The inspection of the Hirshfeld surface analysis helps to discuss the strength of hydrogen bonds and to quantify the inter-contacts. A phase transition was discovered by thermal analysis at 390 K, and comprehensive dielectric research was reported, showing a good agreement with thermal data. Impedance spectroscopy measurements were used to study the electrical and dielectric characteristics over a wide range of frequencies and temperatures, 40 Hz–10 MHz and 313–483 K, respectively. The Nyquist plot (Z" versus Z') from the complex impedance spectrum revealed semicircular arcs described by a Cole-Cole model. An electrical circuit consisting of a link of grain and grain boundary elements is employed. The real and imaginary parts of dielectric permittivity, as well as tg(δ) of (C₇H₁₁N₂)₂CoCl₄ at different frequencies, reveal a distribution of relaxation times. The presence of grain and grain boundaries is confirmed by the modulus investigations. Electric and dielectric analyses highlight the good protonic conduction of this material.

Keywords: organic-inorganic, phase transitions, complex impedance, protonic conduction, dielectric analysis

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Authors: T. P. Sathishkumar, P. Navaneethakrishnan

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The research work investigates the variation of tensile properties for the sansevieria ehrenbergii fiber (SEF) and SEF reinforced polyester composites respect to various water absorption time. The experiments were conducted according to ATSM D3379-75 and ASTM D570 standards. The percentage of water absorption for composite specimens was measured according to ASTM D570 standard. The fiber of SE was cut in to 30 mm length for preparation of the composites. The simple hand lay-up method followed by compression moulding process adopted to prepare the randomly oriented SEF reinforced polyester composites at constant fiber weight fraction of 40%. The surface treatment was done on the SEFs with various chemicals such as NaOH, KMnO4, Benzoyl Peroxide, Benzoyl Chloride and Stearic Acid before preparing the composites. NaOH was used for pre-treatment of all other chemical treatments. The morphology of the tensile fractured specimens studied using the Scanning Electron Microscopic. The tensile strength of the SEF and SEF reinforced polymer composites were carried out with various water absorption time such as 4, 8, 12, 16, 20 and 24 hours respectively. The result shows that the tensile strength was drop off with increase in water absorption time for all composites. The highest tensile property of raw fiber was found due to lowest moistures content. Also the chemical bond between the cellulose and cementic materials such as lignin and wax was highest due to lowest moisture content. Tensile load was lowest and elongation was highest for the water absorbed fibers at various water absorption time ranges. During this process, the fiber cellulose inhales the water and expands the primary and secondary fibers walls. This increases the moisture content in the fibers. Ultimately this increases the hydrogen cation and the hydroxide anion from the water. In tensile testing, the water absorbed fibers shows highest elongation by stretching of expanded cellulose walls and the bonding strength between the fiber cellulose is low. The load carrying capability was stable at 20 hours of water absorption time. This could be directly affecting the interfacial bonding between the fiber/matrix and composite strength. The chemically treated fibers carry higher load and lower elongation which is due to removal of lignin, hemicellulose and wax content. The water time absorption decreases the tensile strength of the composites. The chemically SEF reinforced composites shows highest tensile strength compared to untreated SEF reinforced composites. This was due to highest bonding area between the fiber/matrix. This was proven in the morphology at the fracture zone of the composites. The intra-fiber debonding was occurred by water capsulation in the fiber cellulose. Among all, the tensile strength was found to be highest for KMnO4 treated SEF reinforced composite compared to other composites. This was due to better interfacial bonding between the fiber-matrix compared to other treated fiber composites. The percentage of water absorption of composites increased with time of water absorption. The percentage weight gain of chemically treated SEF composites at 4 hours to zero water absorption are 9, 9, 10, 10.8 and 9.5 for NaOH, BP, BC, KMnO4 and SA respectively. The percentage weight gain of chemically treated SEF composites at 24 hours to zero water absorption 5.2, 7.3, 12.5, 16.7 and 13.5 for NaOH, BP, BC, KMnO4 and SA respectively. Hence the lowest weight gain was found for KMnO4 treated SEF composites by highest percentage with lowest water uptake. However the chemically treated SEF reinforced composites is possible materials for automotive application like body panels, bumpers and interior parts, and household application like tables and racks etc.

Keywords: fibres, polymer-matrix composites (PMCs), mechanical properties, scanning electron microscopy (SEM)

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Authors: Muhammad Farooq

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The present article explores the woman's consent as a paramount element in contracting a Muslim marriage. Also, whether permission of the wali (guardian) is a condition per se for a valid nikah (marriage deed) in the eye of law and Sharia. The researcher attempts to treat it through the related issues, inter alia; the marriage guardian, the women's legal capacity to give consent whether she is a virgin or nonvirgin and how that consent is to be given or may be understood. Does her laugh, tears or salience needs a legal interpretation as well as other female manifestations of emotion explained by the Muslim jurists? The silence of Muslim Family Law Ordinance 1961 (hereafter; MFLO 1961) in this regard and the likely reasons behind such silence is also inquired in brief. Germane to the theme, the various cases in which the true notion of woman's consent is interpreted by courts in Pakistan are also examined. In order to address the issue in hand, it is proposed to provide a brief overview of a few contemporary writers' opinions in which the real place of woman's consent in Muslim marriage is highlighted. Key to the idea of young Muslim woman's marriage, the doctrine of kafa'a (equality or suitability) between the man and woman is argued here to be grounded in the patriarchal and social norms. It is, therefore, concluded that such concept was the result of analogical reasoning and has less importance in the present time. As such it is not a valid factor in current scenarios to validate or invalidate marital bonds. A standard qualitative convention is used for this research. Among primary and secondary sources; for examples, Qur'an, Sunnah, Books, Scholarly articles, texts of law and case law is used to point out the researcher's view. In summation, the article is concluded with a bold statement that a young woman being a party to the contract, is absolutely entitled to 'full and free' consent for the Muslim marriage contract. It is the woman, an indispensable partaker and her consent (not the guardian' permission) that does validate or invalidate the said agreement in the eye of contemporary personal law and in Sharia.

Keywords: consent of woman, ejab (declaration), Nikah (marriage agreement), qabol (acceptance), sui juris (of age; independent), wali (guardian), wilayah (guardianship)

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Authors: Stefano Ruggieri, Rubinia C. Bonfanti

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Research on leadership in sports organizations has proved extremely fruitful in recent decades, favoring the growing and diffusion of figures such as mental coaches, trainers, etc. Recent scholarly attention on organizations has been directed towards the phenomenon of leader self-sacrifice, wherein leaders who display such behavior are perceived by their followers as more effective, charismatic, and legitimate compared to those who prioritize self-interest. This growing interest reflects the importance of leaders who prioritize the collective welfare over personal gain, as they inspire greater loyalty, trust, and dedication among their followers, ultimately fostering a more cohesive and high-performing team environment. However, there is limited literature on the mechanisms through which self-sacrifice influences both group dynamics (such as cohesion and team identification) and individual factors (such as self-competence). The aim of the study is to analyze the impact of the leader self-sacrifice on cohesion, team identification and self-competence. Team identification is a crucial determinant of individual identity, delineated by the extent to which a team member aligns with a specific organizational team rather than broader social collectives. This association motivates members to synchronize their actions with the collective interests of the group, thereby fostering cohesion among its constituents, and cultivating a shared sense of purpose and unity within the team. In the domain of team sports, particularly soccer and water polo, two studies involving 447 participants (men = 238, women = 209) between 22 and 35 years old (M = 26.36, SD = 5.51) were conducted. The first study employed a correlational methodology to investigate the predictive capacity of self-sacrifice on cohesion, team identification, self-efficacy, and self-competence. The second study utilized an experimental design to explore the relationship between team identification and self-sacrifice. Together, these studies provided comprehensive insights into the multifaceted nature of leader self-sacrifice and its profound implications for group cohesion and individual well-being within organizational settings. The findings underscored the pivotal role of leader self-sacrifice in not only fostering stronger bonds among team members but also in enhancing critical facets of group dynamics, ultimately contributing to the overall effectiveness and success of the team.

Keywords: cohesion, leadership, self-sacrifice, sports organizations, team-identification

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Authors: Luiz Nolasco Jr. Rezende, Antonio Villar M. Sá, Claudia Marcia L. Pato

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The increasing urban violence in Brazil involves more and more infractions committed by children and youths. The challenges faced by the institutional environments responsible for the education and resocialization of adolescents in conflict with the law are enormous, especially of those deprived of their liberty. These institutions have an inadequate educational structure. They are characterized by a dirty and unhealthy environment without the minimum basic conditions for their activities, by frequent practices of degradation, humiliation, and the physical and psychological punishment of inmates. This mixed-method study investigated the personal values of adolescents with restriction of freedom in a socio-educational institutional environment aiming to contribute to the development of their morality through an educational process. For that, we used a survey and transdisciplinary play workshops involving thirty-two boys aged between 15 and 19 years old and at least two years out of school. To evaluate the survey the reduced version of the Portrait Questionnaire—PQ21—was used. The workshops happened once a week, lasting 80 minutes each, totaling twelve meetings. By using the game of chess and its metaphors, participants produced texts and engaged in critical brainstorming about their lives. The survey results pointed out that these young people showed a predominance of values of openness to change and self-transcendence, dissatisfaction with one's own reality and surroundings, not considering the consequences of their actions on themselves and others, difficulties in speaking and writing, and desire for changes in their lives. After the pedagogical interventions, these adolescents demonstrated an understanding of the implications of their actions for themselves, for their families, especially for the mothers, with whom they demonstrated stronger bonds. It was possible to observe evidence of improvement in the capacity of linguistic expression, more autonomy and critical vision, including about themselves and their respective contexts. These results demonstrated the educational potential of lively, symbolic, dynamic and playful activities that favor the mediation and identification of these adolescents with their lives, and contribute to the projection of dreams.

Keywords: adolescents arrested, human values, moral development, playful workshops

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Authors: Giulia Magi Meconi, Nicholas Ballard, José M. Asua, Ronen Zangi

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Experimental and computational studies are combined to elucidate the adsorption proprieties of ionic and nonionic surfactants on hydrophobic polymer surface such us poly(styrene). To present these two types of surfactants, sodium dodecyl sulfate and poly(ethylene glycol)-block-poly(ethylene), commonly utilized in emulsion polymerization, are chosen. By applying quartz crystal microbalance with dissipation monitoring it is found that, at low surfactant concentrations, it is easier to desorb (as measured by rate) ionic surfactants than nonionic surfactants. From molecular dynamics simulations, the effective, attractive force of these nonionic surfactants to the surface increases with the decrease of their concentration, whereas, the ionic surfactant exhibits mildly the opposite trend. The contrasting behavior of ionic and nonionic surfactants critically relies on two observations obtained from the simulations. The first is that there is a large degree of interweavement between head and tails groups in the adsorbed layer formed by the nonionic surfactant (PEO/PE systems). The second is that water molecules penetrate this layer. In the disordered layer, these nonionic surfactants generate at the surface, only oxygens of the head groups present at the interface with the water phase or oxygens next to the penetrating waters can form hydrogen bonds. Oxygens inside this layer lose this favorable energy, with a magnitude that increases with the surfactants density at the interface. This reduced stability of the surfactants diminishes their driving force for adsorption. All that is shown to be in accordance with experimental results on the dynamics of surfactants desorption. Ionic surfactants assemble into an ordered structure and the attraction to the surface was even slightly augmented at higher surfactant concentration, in agreement with the experimentally determined adsorption isotherm. The reason these two types of surfactants behave differently is because the ionic surfactant has a small head group that is strongly hydrophilic, whereas the head groups of the nonionic surfactants are large and only weakly attracted to water.

Keywords: emulsion polymerization process, molecular dynamics simulations, polymer surface, surfactants adsorption

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Authors: Afrouz Yousefi, Mohtada Sadrzadeh

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The widespread presence of poly- and perfluoroalkyl substances (PFAS) poses a significant concern due to their ability to accumulate in living organisms and their persistence in the environment, thanks to their robust carbon-fluorine (C-F) bonds, which require substantial energy to break (485 kJ/mol). The prevalence of toxic PFAS compounds can be highly detrimental to ecosystems, wildlife, and human health. Ongoing efforts are dedicated to investigating methods for fully breaking down and eliminating PFAS from the environment. Among the various techniques employed, advanced oxidation processes have shown promise in completely breaking down emerging contaminants in wastewater. However, the drawback lies in the relatively slow reaction rates of these processes and the substantial energy input required, which currently impedes their widespread commercial adoption. We developed a hybrid process, comprising electro-Fenton as an advanced oxidation process and membrane distillation, to simultaneously degrade organic PFAS pollutants and extract pure water from the mixture. In this study, environmentally persistent perfluorooctanoic acid (PFOA), as an emerging contaminant, was used to study the effectiveness of the electro-Fenton/membrane distillation hybrid system. The PFOA degradation studies were conducted in two modes: electro-Fenton and electro-Fenton coupled with membrane distillation. High-performance liquid chromatography with ultraviolet detection (HPLC-UV), ion-chromatography (measuring fluoride ion concentration), total organic carbon (TOC) decay, mineralization current efficiency (MCE), and specific energy consumption (SEC) were evaluated for a single EF and hybrid EF-MD processes. In contrast to a single EF reaction, TOC decay improved significantly in the EF-MD process. Overall, the MCE of hybrid processes surpassed 100% while it remained under 50% for a single EF reaction. Calculations of specific energy consumption (SEC) demonstrated a substantial decrease of nearly one-third in energy usage when integrating the EF reaction with the MD process.

Keywords: water treatment, PFAS, membrane distillation, electro-Fenton, advanced oxidation

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Authors: Uttam Kumar Ghorai, Madhupriya Samanta, Subhajit Saha, Swati Das, Nilesh Mazumder, Kalyan Kumar Chattopadhyay

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Organic semiconductors have gained potential interest in the last few decades for their significant contributions in the various fields such as solar cell, non-volatile memory devices, field effect transistors and light emitting diodes etc. The most important advantages of using organic materials are mechanically flexible, light weight and low temperature depositing techniques. Recently with the advancement of nanoscience and technology, one dimensional organic and inorganic nanostructures such as nanowires, nanorods, nanotubes have gained tremendous interests due to their very high aspect ratio and large surface area for electron transport etc. Among them, self-assembled organic nanostructures like Copper, Zinc Phthalocyanine have shown good transport property and thermal stability due to their π conjugated bonds and π-π stacking respectively. Field emission properties of inorganic and carbon based nanostructures are reported in literatures mostly. But there are few reports in case of cold cathode emission characteristics of organic semiconductor nanostructures. In this work, the authors report the field emission characteristics of chemically and physically synthesized Copper Phthalocyanine (CuPc) nanostructures such as nanowires, nanotubes and nanotips. The as prepared samples were characterized by X-Ray diffraction (XRD), Ultra Violet Visible Spectrometer (UV-Vis), Fourier Transform Infra-red Spectroscopy (FTIR), and Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscope (TEM). The field emission characteristics were measured in our home designed field emission set up. The registered turn-on field and local field enhancement factor are found to be less than 5 V/μm and greater than 1000 respectively. The field emission behaviour is also stable for 200 minute. The experimental results are further verified by theoretically using by a finite displacement method as implemented in ANSYS Maxwell simulation package. The obtained results strongly indicate CuPc nanostructures to be the potential candidate as an electron emitter for field emission based display device applications.

Keywords: organic semiconductor, phthalocyanine, nanowires, nanotubes, field emission

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Authors: Rehin Sulay, Anandhu Krishna, Jintumol Mathew, Vibin Ipe Thomas

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N-Nitrosodimethyl amine, the simplest member of the N-Nitrosoamine family, is a carcinogenic and mutagenic agent that has gained considerable research interest owing to its toxic nature. Ozonation of industrially important hydrazines such as unsymmetrical dimethylhydrazine (UDMH) or monomethylhydrazine (MMH) has been associated with NDMA formation and accumulation in the environment. UDMH/MMH - ozonation also leads to several other transformation products such as acetaldehyde dimethyl hydrazone (ADMH), tetramethyl tetra azene (TMT), diazomethane, methyl diazene, etc, which can be either precursors or competitors for NDMA formation.In this work, we explored the formation mechanism of ADMH and TMT from UDMH-ozonation and their further oxidation to NDMA using the second-order Moller Plesset perturbation theory employing the 6-311G(d) basis set. We have also investigated how MMH selectively forms methyl diazene and diazomethane under normal conditions and NDMA in the presence of excess ozone. Our calculations indicate that the reactions proceed via an initial H abstraction from the hydrazine –NH2 group followed by the oxidation of the generated N-radical species. The formation of ADMH from the UDMH-ozone reaction involves an acetaldehyde intermediate, which then reacts with a second UDMH molecule to generate ADMH. The preferable attack of ozone molecule on N=C bond of ADMH generates DMAN intermediate, which subsequently undergoes oxidation to form NDMA. Unlike other transformation products, TMT formation occurs via the dimerization of DMAN. Though there exist a N=N bonds in the TMT, which are preferable attacking sites for ozone, experimental studies show the lower yields of NDMA formation, which corroborates with the high activation barrier required for the process(42kcal/mol).Overall, our calculated results agree well with the experimental observations and rate constants. Computational calculations bring insights into the electronic nature and kinetics of the elementary reactions of this pathway, enabled by computed energies of structures that are not possible to access experimentally.

Keywords: reaction mechanism, ozonation, substituted hydrazine, transition state

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Authors: Salah Belaidi

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We have carried out extensive and in-depth research to search for bioactive compounds based on Algerian plants. A selection of 50 ligands from Algerian medicinal plants. Several compounds used in herbal medicine have been drawn using Marvin Sketch software. We determined the three-dimensional structures of the ligands with the MMFF94 force field in order to prepare these ligands for molecular docking. The 3D protein structure of the SARS-CoV-2 main protease was taken from the Protein Data Bank. We used AutoDockVina software to apply molecular docking. The hydrogen atoms were added during the molecular docking process, and all the twist bonds of the ligands were added using the (ligand) module in the AutoDock software. The COVID-19 main protease (Mpro) is a key enzyme that plays a vital role in viral transcription and mediating replication, so it is a very attractive drug target for SARS-CoV-2. In this work, an evaluation was carried out on the biologically active compounds present in these selected medicinal plants as effective inhibitors of the protease enzyme of COVID-19, with an in-depth computational calculation of the molecular docking using the Autodock Vina software. The top 7 ligands: Phloroglucinol, Afzelin, Myricetin-3-O- rutinosidTricin 7-neohesperidoside, Silybin, Silychristinthat and Kaempferol are selected among the 50 molecules studied which are Algerian medicinal plants, whose selection is based on the best binding energy which is relatively low compared to the reference molecule with binding affinities of -9.3, -9.3, -9, -8.9, -8 .5, 8.3 and -8.3 kcal mol-1 respectively. Then, we analyzed the ADME properties of the best7 ligands using the web server SwissADME. Two ligands (Silybin, Silychristin) were found to be potential candidates for the discovery and design of novel drug inhibitors of the protease enzyme of SARS-CoV-2. The stability of the two ligands in complexing with the Mpro protease was validated by molecular dynamics simulation; they revealed a stable trajectory in both techniques, RMSD and RMSF, by showing molecular properties with coherent interactions in molecular dynamics simulations. Finally, we conclude that the Silybin ligand forms a more stable complex with the Mpro protease compared to the Silychristin ligand.

Keywords: COVID-19, medicinal plants, molecular docking, ADME properties, molecular dynamics

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Authors: Mohamed Moussaoui, Mouna Baassi, Soukayna Baammi, Hatim Soufi, Mohammed Salah, Rachid Daoud, Achraf EL Allali, Mohammed Elalaoui Belghiti, Said Belaaouad

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The present study aims to investigate the quantitative structure-activity relationship (QSAR) of a series of Thiazole derivatives reported as anticancer agents (hepatocellular carcinoma), using principally the electronic descriptors calculated by the density functional theory (DFT) method and by applying the multiple linear regression method. The developed model showed good statistical parameters (R²= 0.725, R²ₐ𝒹ⱼ= 0.653, MSE = 0.060, R²ₜₑₛₜ= 0.827, Q²𝒸ᵥ = 0.536). The energy of the highest occupied molecular orbital (EHOMO) orbital, electronic energy (TE), shape coefficient (I), number of rotatable bonds (NROT), and index of refraction (n) were revealed to be the main descriptors influencing the anti-cancer activity. Additional Thiazole derivatives were then designed and their activities and pharmacokinetic properties were predicted using the validated QSAR model. These designed molecules underwent evaluation through molecular docking (MD) and molecular dynamic (MD) simulations, with binding affinity calculated using the MMPBSA script according to a 100 ns simulation trajectory. This process aimed to study both their affinity and stability towards Cyclin-Dependent Kinase 2 (CDK2), a target protein for cancer disease treatment. The research concluded by identifying four CDK2 inhibitors - A1, A3, A5, and A6 - displaying satisfactory pharmacokinetic properties. MDs results indicated that the designed compound A5 remained stable in the active center of the CDK2 protein, suggesting its potential as an effective inhibitor for the treatment of hepatocellular carcinoma. The findings of this study could contribute significantly to the development of effective CDK2 inhibitors.

Keywords: QSAR, ADMET, Thiazole, anticancer, molecular docking, molecular dynamic simulations, MMPBSA calculation

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Authors: Lianne M. Q. Lee, Mohammed Sharaf Shaiban

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The importance of bank liquidity management took center stage as policy makers promoted a more resilient global banking system after the market turmoil of 2007. The growing recognition of Islamic banks’ function of intermediating funds in the economy warrants the need to investigate its balance sheet structure which is distinct from its conventional counterparts. Given that asymmetric risk, transformation is inevitable; Islamic banks need to identify the liquidity risk within their distinctive balance sheet structure. Thus, there is a strong need to quantify and assess the liquidity position to ensure proper functioning of a financial institution. It is vital to measure bank liquidity because liquid banks face less liquidity risk. We examine this issue by using two alternative quantitative measures of liquidity creation “cat fat” and “cat nonfat” constructed by Berger and Bouwman (2009). “Cat fat” measures all on balance sheet items including off balance sheet, whilst the latter measures only on balance sheet items. Liquidity creation is measured over the period 2007-2014 in 14 countries where Islamic and conventional commercial banks coexist. Also, separately by bank size class as empirical studies have shown that liquidity creation varies by bank size. An interesting and important finding shows that all size class of Islamic banks, on average have increased creation of aggregate liquidity in real dollar terms over the years for both liquidity creation measures especially for large banks indicating that Islamic banks actually generates more liquidity to the economy compared to its conventional counterparts, including from off-balance sheet items. The liquidity creation for off-balance sheets by conventional banks may have been affected by the global financial crisis when derivatives markets were severely hit. The results also suggest that Islamic banks have the higher volume of assets and deposits and that borrowing/issues of bonds are less in Islamic banks compared to conventional banks because most products are interest-based. As Islamic banks appear to create more liquidity than conventional banks under both measures, it translates that the development of Islamic banking is significant over the decades since its inception. This finding is encouraging as, despite Islamic banking’s overall size, it represents growth opportunities for these countries.

Keywords: financial institution, liquidity creation, liquidity risk, policy and regulation

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Authors: Johannes Barlang

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Adhesive bonding plays a pivotal role in various industrial applications, ranging from automotive manufacturing to aerospace engineering. The peel strength of adhesives, a critical parameter reflecting the ability of an adhesive to withstand external forces, is crucial for ensuring the integrity and durability of bonded joints. This study provides a synopsis of the methodologies, influencing factors, and significance of peel testing in the evaluation of adhesive performance. Peel testing involves the measurement of the force required to separate two bonded substrates under controlled conditions. This study systematically reviews the different testing techniques commonly applied in peel testing, including the widely used 180-degree peel test and the T-peel test. Emphasis is placed on the importance of selecting an appropriate testing method based on the specific characteristics of the adhesive and the application requirements. The influencing factors on peel strength are multifaceted, encompassing adhesive properties, substrate characteristics, environmental conditions, and test parameters. Through an in-depth analysis, this study explores how factors such as adhesive formulation, surface preparation, temperature, and peel rate can significantly impact the peel strength of adhesively bonded joints. Understanding these factors is essential for optimizing adhesive selection and application processes in real-world scenarios. Furthermore, the study highlights the role of peel testing in quality control and assurance, aiding manufacturers in maintaining consistent adhesive performance and ensuring the reliability of bonded structures. The correlation between peel strength and long-term durability is discussed, shedding light on the predictive capabilities of peel testing in assessing the service life of adhesive bonds. In conclusion, this study underscores the significance of peel testing as a fundamental tool for characterizing adhesive performance. By delving into testing methodologies, influencing factors, and practical implications, this study contributes to the broader understanding of adhesive behavior and fosters advancements in adhesive technology across diverse industrial sectors.

Keywords: adhesively bonded joints, cleavage resistance, elastic adhesives, peel strength

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Authors: Rossella Marzullo

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Family plays a central role in the Calabrian criminal organization, which draws its strength from blood ties and gender stereotypes that still impose a strong verticalization of intra-family relationships for the benefit of men. However, female figures are of great importance in the organizational structure of the 'Ndrangheta families, despite the fact that they appear to be formally suffocated by the culture of gender subordination still strongly present in the archaic world of criminal organizations. And this is so much true that over time, the women of the 'Ndrangheta have added to the function of ‘internal containment’, the increasingly explicit function of intermediaries in the ‘external’ activities of the clan. But what happens in the 'Ndrangheta if women break the bond and decide to speak? The results are shocking. When a woman starts talking to ask the institutions for help, the system ‘goes crazy’, because the woman is considered the means of consolidating and transmitting family codes: she educates, forges, holds the structure together. If a woman from the 'Ndrangheta decides to speak out and get out of the family bottlenecks of the clan, she does not exclusively destroy the family; she destroys the system. This happens because, while not playing the same roles as men within organizations, women carry out support activities as intermediaries for the circulation of communications, thus ensuring the operability of the gang in practice and on a daily basis. Crossing the border means breaking the bonds of belonging, thus questioning one's own identity and reconstructing it according to other points of reference. How much these disruptive choices are feared by the men of the 'Ndrangheta has been seen in the dramatic stories of Lea Garofalo and Maria Concetta Cacciola: the fear of the breaking of the family pact, of the earthquake that arises from within, has marked their fate of death, useful both to stop the judicial action and to recompose the organization's estate under the aegis of terror. With physical, psychological violence, underhanded torture, and moral blackmail, the men of the mafia family tried to heal the shock caused by the voices of women, relying on violence and yet another attempt to subordinate them. This proves that the 'Ndrangheta is really afraid of them. The female voices of the 'Ndrangheta, who have shaken a consolidated and considered intangible system, represent the anti-'ndrangheta par excellence; in their choices, there is an even stronger desire to break with the mafia world.

Keywords: families, gender, ‘Ndrangheta, stereotypes

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Authors: Ariel Vilchez, Francisca Acevedo, Rodrigo Navia

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The wound healing process can be accelerated and improved by the action of antioxidants such as curcumin (Cur) over the tissues; however, the efficacy of curcumin used through the digestive system is not enough to exploit its benefits. Electrospinning presents an alternative to carry curcumin directly to the wounds, and polyhydroxybutyrate (PHB) is proposed as the matrix to load curcumin owing to its biodegradable and biocompatible properties. PHB is among 150 types of Polyhydroxyalkanoates (PHAs) identified, it is a natural thermoplastic polyester produced by microbial fermentation obtained from microorganisms. The proposed objective is to develop electrospun bacterial PHB-based microfibers containing curcumin for possible biomedical applications. Commercial PHB was solved in Chloroform: Dimethylformamide (4:1) to a final concentration of 7% m/V. Curcumin was added to the polymeric solution at 1%, and 7% m/m regarding PHB. The electrospinning equipment (NEU-BM, China) with a rotary collector was used to obtain Cur-PHB fibers at different voltages and flow rate of the polymeric solution considering a distance of 20 cm from the needle to the collector. Scanning electron microscopy (SEM) was used to determine the diameter and morphology of the obtained fibers. Thermal stability was obtained from Thermogravimetric (TGA) analysis, and Fourier Transform Infrared Spectroscopy (FT-IR) was carried out in order to study the chemical bonds and interactions. A preliminary curcumin release to Phosphate Buffer Saline (PBS) pH = 7.4 was obtained in vitro and measured by spectrophotometry. PHB fibers presented an intact chemical composition regarding the original condition (dust) according to FTIR spectra, the diameter fluctuates between 0.761 ± 0.123 and 2.157 ± 0.882 μm, with different qualities according to their morphology. The best fibers in terms of quality and diameter resulted in sample 2 and sample 6, obtained at 0-10kV and 0.5 mL/hr, and 0-10kV and 1.5 mL/hr, respectively. The melting temperature resulted near 178 °C, according to the bibliography. The crystallinity of fibers decreases while curcumin concentration increases for the studied interval. The curcumin release reaches near 14% at 37 °C at 54h in PBS adjusted to a quasi-Fickian Diffusion. We conclude that it is possible to load curcumin in PHB to obtain continuous, homogeneous, and solvent-free microfibers by electrospinning. Between 0% and 7% of curcumin, the crystallinity of fibers decreases as the concentration of curcumin increases. Thus, curcumin enhances the flexibility of the obtained material. HPLC should be used in further analysis of curcumin release.

Keywords: antioxidant, curcumin, polyhydroxybutyrate, wound healing

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Authors: Malik Sajjad Mehmood, Aisha Ali, Hamna Khan, Tariq Yasin, Masroor Ikram

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Ultra-high molecular weight polyethylene (UHMWPE) is one of the polymers belongs to polyethylene (PE) family having monomer –CH2– and average molecular weight is approximately 3-6 million g/mol. Due its chemical, mechanical, physical and biocompatible properties, it has been extensively used in the field of electrical insulation, medicine, orthopedic, microelectronics, engineering, chemistry and the food industry etc. In order to alter/modify the properties of UHMWPE for particular application of interest, certain various procedures are in practice e.g. treating the material with high energy irradiations like gamma ray, e-beam, and ion bombardment. Radiation treatment of UHMWPE induces free radicals within its matrix, and these free radicals are the precursors of chain scission, chain accumulation, formation of double bonds, molecular emission, crosslinking etc. All the aforementioned physical and chemical processes are mainly responsible for the modification of polymers properties to use them in any particular application of our interest e.g. to fabricate LEDs, optical sensors, antireflective coatings, polymeric optical fibers, and most importantly for radiation dosimetry applications. It is therefore, to check the feasibility of using UHMWPE for radiation dosimetery applications, the compressed sheets of UHMWPE were irradiated at room temperature (~25°C) for total dose values of 30 kGy and 100 kGy, respectively while one were kept un-irradiated as reference. Transmittance data (from 400 nm to 800 nm) of e-beam irradiated UHMWPE and its hybrids were measured by using Muller matrix spectro-polarimeter. As a result significant changes occur in the absorption behavior of irradiated samples. To analyze these (radiation induced) changes in polymer matrix Urbach edge method and modified Tauc’s equation has been used. The results reveal that optical activation energy decreases with irradiation. The values of activation energies are 2.85 meV, 2.48 meV, and 2.40 meV for control, 30 kGy, and 100 kGy samples, respectively. Direct and indirect energy band gaps were also found to decrease with irradiation due to variation of C=C unsaturation in clusters. We believe that the reported results would open new horizons for radiation dosimetery applications.

Keywords: electron beam, radiation dosimetry, Tauc’s equation, UHMWPE, Urbach method

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Authors: Salamatu Shaibu, Jan Hernning Sommer

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Integrating biodiversity conservation practices in mining landscapes ensures the continual provision of various ecosystem services to the dependent communities whilst serving as ecological insurance for corporate mining when purchasing reclamation security bonds. Climate hazards such as long dry seasons, erratic rainfall patterns, and extreme weather events contribute to biodiversity loss in addition to the impact due to mining. Both corporate mining and mine-fringe communities perceive the effect of climate on biodiversity from the context of the benefits they accrue, which motivate their conservation practices. In this study, pragmatic approaches including semi-structured interviews, field visual observation, and review were used to collect data on corporate mining employees and households of fringing communities in the southwestern mining hub. The perceived changes in the local climatic conditions and the consequences on environmental management practices that promote biodiversity conservation were examined. Using a thematic content analysis tool, the result shows that best practices such as concurrent land rehabilitation, reclamation ponds, artificial wetlands, land clearance, and topsoil management are directly affected by prolonging long dry seasons and erratic rainfall patterns. Excessive dust and noise generation directly affect both floral and faunal diversity coupled with excessive fire outbreaks in rehabilitated lands and nearby forest reserves. Proposed adaptive measures include engaging national conservation authorities to promote reforestation projects around forest reserves. National government to desist from using permit for mining concessions in forest reserves, engaging local communities through educational campaigns to control forest encroachment and burning, promoting community-based resource management to promote community ownership, and provision of stricter environmental legislation to compel corporate, artisanal, and small scale mining companies to promote biodiversity conservation.

Keywords: biodiversity conservation, climate hazards, corporate mining, mining landscapes

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Authors: Yi-Hao Pai, Wen-Feng Chen

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The planting area of Pomelo in Hualien, Taiwan amounts to thousands of hectares. Especially in the blooming season of Pomelo, it is an important producing area for Pomelo honey, and it is also a good test field for promoting the "Under-forest Economy". However, in the current Pomelo garden planting and management operations, the large amount of agricultural waste generated by the pruning of the branches causes environmental sanitation concerns, which can lead to the hiding of pests or the infection of the Pomelo tree, and indirectly increase the health risks of bees. Therefore, how to deal with the pruning of the branches and avoid open burning is a topic of social concern in recent years. In this research, afeasibility study evaluating energy conversion efficiency through agricultural waste gasification from the Pomelo garden, Taiwan, is demonstrated. we used a high-temperature gasifier to convert the pruning of the branches into syngas and biochar. In terms of syngas composition and calorific value assessment, we use the biogas monitoring system for analysis. Then, we used Raman spectroscopy and electron microscopy (EM) to diagnose the microstructure and surface morphology of biochar. The results indicate that the 1 ton of pruning of the branches can produce 1797.03m3 of syngas, corresponding to a calorific value of 9.1MJ/m3. The main components of the gas include CH4, H2, CO, and CO2, and the corresponding gas composition ratio is 16.8%, 7.1%, 13.7%, and 24.5%. Through the biomass syngas generator with a conversion efficiency of 30% for power generation, a total of 1,358kWh can be obtained per ton of pruning of the branches. In the research of biochar, its main characteristics in Raman spectroscopy are G bands and D bands. The first-order G and D bands are at 1580 and 1350 cm⁻¹, respectively. The G bands originates from the in-plane tangential stretching of the C−C bonds in the graphitic structure, and theD band corresponds to scattering from local defects or disorders present in carbon. The area ratio of D and G peaks (D/G) increases with the decrease of reaction temperature. The larger the D/G, the higher the defect concentration and the higher the porosity. This result is consistent with the microstructure displayed by SEM. The study is expected to be able to reuse agricultural waste and promote the development of agricultural and green energy circular economy.

Keywords: agricultural waste, gasification, energy conversion, pomelo garden

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Authors: Mateen A Khan, Taj Mohammad, Md. Imtaiyaz Hassan

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Alzheimer’s disease is characterized by the accumulation of the processing products of the amyloid beta peptide cleaved by amyloid precursor protein (APP). Iron increases the synthesis of amyloid beta peptides, which is why iron is present in Alzheimer's disease patients' amyloid plaques. Iron misregulation in the brain is linked to the overexpression of APP protein, which is directly related to amyloid-β aggregation in Alzheimer’s disease. The APP 5'-UTR region encodes a functional iron-responsive element (IRE) stem-loop that represents a potential target for modulating amyloid production. Targeted regulation of APP gene expression through the modulation of 5’-UTR sequence function represents a novel approach for the potential treatment of AD because altering APP translation can be used to improve both the protective brain iron balance and provide anti-amyloid efficacy. The molecular docking analysis of APP IRE RNA with eukaryotic translation initiation factors yields several models exhibiting substantial binding affinity. The finding revealed that the interaction involved a set of functionally active residues within the binding sites of eIF4F. Notably, APP IRE RNA and eIF4F interaction were stabilized by multiple hydrogen bonds with residues of APP IRE RNA and eIF4F. It was evident that APP IRE RNA exhibited a structural complementarity that tightly fit within binding pockets of eIF4F. The simulation studies further revealed the stability of the complexes formed between RNA and eIF4F, which is crucial for assessing the strength of these interactions and subsequent roles in the pathophysiology of Alzheimer’s disease. In addition, MD simulations would capture conformational changes in the IRE RNA and protein molecules during their interactions, illustrating the mechanism of interaction, conformational change, and unbinding events and how it may affect aggregation propensity and subsequent therapeutic implications. Our binding studies correlated well with the translation efficiency of APP mRNA. Overall, the outcome of this study suggests that the genomic modification and/or inhibiting the expression of amyloid protein by targeting APP IRE RNA can be a viable strategy to identify potential therapeutic targets for AD and subsequently be exploited for developing novel therapeutic approaches.

Keywords: Alzheimer's disease, Protein-RNA interaction analysis, molecular docking simulations, conformational dynamics, binding stability, binding kinetics, protein synthesis.

Procedia PDF Downloads 55

Authors: I. Belyamani, M. K. Hassan, J. U. Otaigbe, W. R. Fielding, K. A. Mauritz, J. S. Wiggins, W. L. Jarrett

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We have investigated the flame-retardant efficiency of special new phosphate glass (P-glass) compositions having different glass transition temperatures (Tg) on the processing conditions of polyamide 6,6 (PA6,6) and the final hybrid flame retardancy (FR). We have showed that the low Tg P glass composition (i.e., ILT 1) is a promising flame retardant for PA6,6 at a concentration of up to 15 wt. % compared to intermediate (IIT 3) and high (IHT 1) Tg P glasses. Cone calorimetry data showed that the ILT 1 decreased both the peak heat release rate and the total heat amount released from the PA6,6/ILT 1 hybrids, resulting in an efficient formation of a glassy char layer. These intriguing findings prompted to address several questions concerning the mechanism of action of the different P glasses studied. The general mechanism of action of phosphorous based FR additives occurs during the combustion stage by enhancing the morphology of the char and the thermal shielding effect. However, the present work shows that P glass based FR additives act during melt processing of PA6,6/P glass hybrids. Dynamic mechanical analysis (DMA) revealed that the Tg of PA6,6/ILT 1 was significantly shifted to a lower Tg (~65 oC) and another transition appeared at high temperature (~ 166 oC), thus indicating a strong interaction between PA6,6 and ILT 1. This was supported by a drop in the melting point and crystallinity of the PA6,6/ILT 1 hybrid material as detected by differential scanning calorimetry (DSC). The dielectric spectroscopic investigation of the networks’ molecular level structural variations (i.e. hybrids chain motion, Tg and sub-Tg relaxations) agreed very well with the DMA and DSC findings; it was found that the three different P glass compositions did not show any effect on the PA6,6 sub-Tg relaxations (related to the NH2 and OH chain end groups motions). Nevertheless, contrary to IIT 3 and IHT 1 based hybrids, the PA6,6/ILT 1 hybrid material showed an evidence of splitting the PA6,6 Tg relaxations into two peaks. Finally, the CPMAS 31P-NMR data confirmed the miscibility between ILT 1 and PA6,6 at the molecular level, as a much larger enhancement in cross-polarization for the PA6,6/15%ILT 1 hybrids was observed. It can be concluded that compounding low Tg P-glass (i.e. ILT 1) with PA6,6 facilitates hydrolytic chain scission of the PA6,6 macromolecules through a potential chemical interaction between phosphate and the alpha-Carbon of the amide bonds of the PA6,6, leading to better flame retardant properties.

Keywords: broadband dielectric spectroscopy, composites, flame retardant, polyamide, phosphate glass, sustainable

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Authors: Thembelihle Portia Lubisi, Malusi Ntandoyenkosi Mkhize, Jonas Kalebe Johakimu

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Fertilizers play an important role in maintaining the productivity and quality of plants. Inorganic fertilizers (containing nitrogen, phosphorus, and potassium) are largely used in South Africa as they are considered inexpensive and highly productive. When applied, a portion of the excess fertilizer will be retained in the soil, a portion enters water streams due to surface runoff or the irrigation system adopted. Excess nutrient from the fertilizers entering the water stream eventually results harmful algal blooms (HABs) in freshwater systems, which not only disrupt wildlife but can also produce toxins harmful to humans. Use of agro-chemicals such as pesticides and herbicides has been associated with increased antimicrobial resistance (AMR) in humans as the plants are consumed by humans. This resistance of bacterial poses a threat as it prevents the Health sector from being able to treat infectious disease. Archaeological studies have found that pyrolysis liquids were already used in the time of the Neanderthal as a biocide and plant protection product. Pyrolysis is thermal degradation process of plant biomass or organic material under anaerobic conditions leading to production of char, bio-oils and syn gases. Bio-oil constituents can be categorized as water soluble (wood vinegar) and water insoluble fractions (tar and light oils). Wood vinegar (pyro-ligneous acid) is said to contain contains highly oxygenated compounds including acids, alcohols, aldehydes, ketones, phenols, esters, furans, and other multifunctional compounds with various molecular weights and compositions depending on the biomass material derived from and pyrolysis operating conditions. Various researchers have found the wood vinegar to be efficient in the eradication of termites, effective in plant protection and plant growth, has antibacterial characteristics and was found effective in inhibiting the micro-organisms such as candida yeast, E-coli, etc. This study investigated characterisation of South African forestry product processing waste with intention of evaluating the potential of using the respective biomass waste as feedstock for boil oil production via pyrolysis process. Ability to use biomass waste materials in production of wood-vinegar has advantages that it does not only allows for reduction of environmental pollution and landfill requirement, but it also does not negatively affect food security. The biomass wastes investigated were from the popular tree types in KZN, which are, pine saw dust (PSD), pine bark (PB), eucalyptus saw dust (ESD) and eucalyptus bark (EB). Furthermore, the research investigates the possibility of mixing the different wastes with an aim to lessen the cost of raw material separation prior to feeding into pyrolysis process and mixing also increases the amount of biomass material available for beneficiation. A 50/50 mixture of PSD and ESD (EPSD) and mixture containing pine saw dust; eucalyptus saw dust, pine bark and eucalyptus bark (EPSDB). Characterisation of the biomass waste will look at analysis such as proximate (volatiles, ash, fixed carbon), ultimate (carbon, hydrogen, nitrogen, oxygen, sulphur), high heating value, structural (cellulose, hemicellulose and lignin) and thermogravimetric analysis.

Keywords: characterisation, biomass waste, saw dust, wood waste

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Authors: Yetti Marlida, Syukri Arif, Nadirman Haska

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Recently, alcohol fuels have been produced on industrial scales by fermentation of sugars derived from wheat, corn, sugar beets, sugar cane etc. The enzymatic hydrolysis of cellulosic materials to produce fermentable sugars has an enormous potential in meeting global bioenergy demand through the biorefinery concept, since agri-food processes generate millions of tones of waste each year (Xeros and Christakopoulos 2009) such as sugar cane baggase , wheat straw, rice straw, corn cob, and oil palm trunk. In fact oil palm trunk is one of the most abundant lignocellulosic wastes by-products worldwide especially come from Malaysia, Indonesia and Nigeria and provides an alternative substrate to produce useful chemicals such as bioethanol. Usually, from the ages 3 years to 25 years, is the economical life of oil palm and after that, it is cut for replantation. The size of trunk usually is 15-18 meters in length and 46-60 centimeters in diameter. The trunk after cutting is agricultural waste causing problem in elimination but due to the trunk contains about 42% cellulose, 34.4%hemicellulose, 17.1% lignin and 7.3% other compounds,these agricultural wastes could make value added products (Pumiput, 2006).This research was production of bioethanol from oil palm trunk via saccharafication by cocktail carbohydrases enzymes. Enzymatic saccharification of acid treated oil palm trunk was carried out in reaction mixture containing 40 g treated oil palm trunk in 200 ml 0.1 M citrate buffer pH 4.8 with 500 unit/kg amylase for treatment A: Treatment B: Treatment A + 500 unit/kg cellulose; C: treatment B + 500 unit/kgg xylanase: D: treatment D + 500 unit/kg ligninase and E: OPT without treated + 500 unit/kg amylase + 500 unit/kg cellulose + 500 unit/kg xylanase + 500 unit/kg ligninase. The reaction mixture was incubated on a water bath rotary shaker adjusted to 600C and 75 rpm. The samples were withdraw at intervals 12 and 24, 36, 48,60, and 72 hr. For bioethanol production in biofermentor of 5L the hydrolysis product were inoculated a loop of Saccharomyces cerevisiae and then incubated at 34 0C under static conditions. Samples are withdraw after 12, 24, 36, 48 and 72 hr for bioethanol and residual glucose. The results of the enzymatic hidrolysis (Figure1) showed that the treatment B (OPT hydrolyzed with amylase and cellulase) have optimum condition for glucose production, where was both of enzymes can be degraded OPT perfectly. The same results also reported by Primarini et al., (2012) reported the optimum conditions the hydrolysis of OPT was at concentration of 25% (w /v) with 0.3% (w/v) amylase, 0.6% (w /v) glucoamylase and 4% (w/v) cellulase. In the Figure 2 showed that optimum bioethanol produced at 48 hr after incubation,if time increased the biothanol decreased. According Roukas (1996), a decrease in the concentration of ethanol occur at excess glucose as substrate and product inhibition effects. Substrate concentration is too high reduces the amount of dissolved oxygen, although in very small amounts, oxygen is still needed in the fermentation by Saccaromyces cerevisiae to keep life in high cell concentrations (Nowak 2000, Tao et al. 2005). The results of the research can be conluded that the optimum enzymatic hydrolysis occured when the OPT added with amylase and cellulase and optimum bioethanol produced at 48 hr incubation using Saccharomyses cerevicea whereas 18.08 % bioethanol produced from glucose conversion. This work was funded by Directorate General of Higher Education (DGHE), Ministry of Education and Culture, contract no.245/SP2H/DIT.LimtabMas/II/2013

Keywords: oil palm trunk, enzymatic hydrolysis, saccharification

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Authors: Vedanki Khandenwal, Pawan Srivastava, Kartick Tarafder, Subhasis Ghosh

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We present here the experimental realization of controlled doping of graphene monolayers through charge transfer by trapping selected organic molecules between the graphene layer and underlying substrates. This charge transfer between graphene and trapped molecule leads to controlled n-type or p-type doping in monolayer graphene (MLG), depending on whether the trapped molecule acts as an electron donor or an electron acceptor. Doping controllability has been validated by a shift in corresponding Raman peak positions and a shift in Dirac points. In the transfer characteristics of field effect transistors, a significant shift of Dirac point towards positive or negative gate voltage region provides the signature of p-type or n-type doping of graphene, respectively, as a result of the charge transfer between graphene and the organic molecules trapped within it. In order to facilitate the charge transfer interaction, it is crucial for the trapped molecules to be situated in close proximity to the graphene surface, as demonstrated by findings in Raman and infrared spectroscopies. However, the mechanism responsible for this charge transfer interaction has remained unclear at the microscopic level. Generally, it is accepted that the dipole moment of adsorbed molecules plays a crucial role in determining the charge-transfer interaction between molecules and graphene. However, our findings clearly illustrate that the doping effect primarily depends on the reactivity of the constituent atoms in the adsorbed molecules rather than just their dipole moment. This has been illustrated by trapping various molecules at the graphene−substrate interface. Dopant molecules such as acetone (containing highly reactive oxygen atoms) promote adsorption across the entire graphene surface. In contrast, molecules with less reactive atoms, such as acetonitrile, tend to adsorb at the edges due to the presence of reactive dangling bonds. In the case of low-dipole moment molecules like toluene, there is a lack of substantial adsorption anywhere on the graphene surface. Observation of (i) the emergence of the Raman D peak exclusively at the edges for trapped molecules without reactive atoms and throughout the entire basal plane for those with reactive atoms, and (ii) variations in the density of attached molecules (with and without reactive atoms) to graphene with their respective dipole moments provides compelling evidence to support our claim. Additionally, these observations were supported by first principle density functional calculations.

Keywords: graphene, doping, charge transfer, liquid phase exfoliation

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Authors: Reza Ziaie Moayed, Saeideh Mohammadi

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Soft soil is used in many of civil engineering projects like coastal, marine and road projects. Because of low shear strength and stiffness of soft soils, large settlement and low bearing capacity will occur under superstructure loads. This will make the civil engineering activities more difficult and costlier. In the case of soft soils, improvement is a suitable method to increase the shear strength and stiffness for engineering purposes. In recent years, the artificial cementation of soil by cement and lime has been extensively used for soft soil improvement. Cement stabilization is a well-established technique for improving soft soils. Artificial cementation increases the shear strength and hardness of the natural soils. On the other hand, in soft soils, the use of piles to transfer loads to the depths of ground is usual. By using cement treated soil around the piles, high bearing capacity and low settlement in piles can be achieved. In the present study, lateral bearing capacity of short piles in cemented soils is investigated by numerical approach. For this purpose, three dimensional (3D) finite difference software, FLAC 3D is used. Cement treated soil has a strain hardening-softening behavior, because of breaking of bonds between cement agent and soil particle. To simulate such behavior, strain hardening-softening soil constitutive model is used for cement treated soft soil. Additionally, conventional elastic-plastic Mohr Coulomb constitutive model and linear elastic model are used for stress-strain behavior of natural soils and pile. To determine the parameters of constitutive models and also for verification of numerical model, the results of available triaxial laboratory tests on and insitu loading of piles in cement treated soft soil are used. Different parameters are considered in parametric study to determine the effective parameters on the bearing of the piles on cemented treated soils. In the present paper, the effect of various length and height of the artificial cemented area, different diameter and length of the pile and the properties of the materials are studied. Also, the effect of choosing a constitutive model for cemented treated soils in the bearing capacity of the pile is investigated.

Keywords: bearing capacity, cement-treated soils, FLAC 3D, pile

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Authors: Akanksha Singh, Mahesh Kumar, Shailesh N. Sharma

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Semiconductor quantum dots (QDs) such as CdSe, CdS, InP, etc. have gained significant interest in the recent years due to its application in various fields such as LEDs, solar cells, lasers, biological markers, etc. The interesting feature of the QDs is their tunable band gap. The size of the QDs can be easily varied by varying the synthesis parameters which change the band gap. One of the limitations with II-VI semiconductor QDs is their biological application. The use of cadmium makes them unsuitable for biological applications. III-V QD such as InP overcomes this problem as they are structurally robust because of the covalent bonds which do not allow the ions to leak. Also, InP QDs has large Bohr radii which increase the window for the quantum confinement effect. The synthesis of InP QDs is difficult and time consuming. Authors have synthesized InP using a novel, quick synthesis method which utilizes trioctylphosphine as a source of phosphorus. In this work, authors have made InP composites with P3HT(Poly(3-hexylthiophene-2,5-diyl))polymer(organic-inorganic hybrid material) and gold nanoparticles(metal-semiconductor composites). InP-P3HT shows FRET phenomenon whereas InP-Au shows charge transfer mechanism. The synthesized InP QDs has an absorption band at 397 nm and PL peak position at 491 nm. The band gap of the InP QDs is 2.46 eV as compared to the bulk band gap of InP i.e. 1.35 eV. The average size of the QDs is around 3-4 nm. In order to protect the InP core, a shell of wide band gap material i.e. ZnS is coated on the top of InP core. InP-P3HT composites were made in order to study the charge transfer/energy transfer phenomenon between them. On adding aliquots of P3HT to InP QDs solution, the P3HT PL increases which can be attributed to the dominance of Förster energy transfer between InP QDs (donor) P3HT polymer (acceptor). There is a significant spectral overlap between the PL spectra of InP QDs and absorbance spectra of P3HT. But in the case of InP-Au nanocomposites, significant charge transfer was seen from InP QDs to Au NPs. When aliquots of Au NPs were added to InP QDs, a decrease in the PL of the InP QDs was observed. This is due to the charge transfer from the InP QDs to the Au NPs. In the case of metal semiconductor composites, the enhancement and quenching of QDs depend on the size of the QD and the distance between the QD and the metal NP. These two composites have different phenomenon between donor and acceptor and hence can be utilized for two different applications. The InP-P3HT composite can be utilized for LED devices due to enhancement in the PL emission (FRET). The InP-Au can be utilized efficiently for photovoltaic application owing to the successful charge transfer between InP-Au NPs.

Keywords: charge transfer, FRET, gold nanoparticles, InP quantum dots

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Authors: Afifa Hafidh, Fathi Touati, Ahmed Hichem Hamzaoui, Sayda Somrani

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The objective of the present study has been to synthesize and to characterize silica hybrid materials using sol-gel technic and to investigate their properties. Silica materials were successfully fabricated using various bi-functional 1,3,4-thiadiazoles and tetraethoxysilane (TEOS) as co-precursors via a facile one-pot sol-gel pathway. TEOS was introduced at room temperature with 1,3,4-thiadiazole 2,5-difunctiunal adducts, in ethanol as solvent and using HCl acid as catalyst. The sol-gel process lead to the formation of monolithic, coloured and transparent gels. TEOS was used as a principal network forming agent. The incorporation of 1,3,4-thiadiazole molecules was realized by attachment of these later onto a silica matrix. This allowed covalent linkage between organic and inorganic phases and lead to the formation of Si-N and Si-S bonds. The prepared hybrid materials were characterized by Fourier transform infrared, NMR ²⁹Si and ¹³C, scanning electron microscopy and nitrogen absorption-desorption measurements. The optic and magnetic properties of hybrids are studied respectively by ultra violet-visible spectroscopy and electron paramagnetic resonance. It was shown in this work, that heterocyclic moieties were successfully attached in the hybrid skeleton. The formation of the Si-network composed of cyclic units (Q3 structures) connected by oxygen bridges (Q4 structures) was proved by ²⁹Si NMR spectroscopy. The Brunauer-Elmet-Teller nitrogen adsorption-desorption method shows that all the prepared xerogels have isotherms type IV and are mesoporous solids. The specific surface area and pore volume of these materials are important. The obtained results show that all materials are paramagnetic semiconductors. The data obtained by Nuclear magnetic resonance ²⁹Si and Fourier transform infrared spectroscopy, show that Si-OH and Si-NH groups existing in silica hybrids can participate in adsorption interactions. The obtained materials containing reactive centers could exhibit adsorption properties of metal ions due to the presence of OH and NH functionality in the mesoporous frame work. Our design of a simple method to prepare hybrid materials may give interest of the development of mesoporous hybrid systems and their use within the domain of environment in the future.

Keywords: hybrid materials, sol-gel process, 1, 3, 4-thiadaizole, TEOS

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Authors: William E. Bauta, Jennifer Rebeles, Reggie Jacob

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Porphyrins are noteworthy in biomedical science for their cancer tissue accumulation and photophysical properties. The preferential accumulation of some porphyrins in cancerous tissue has been known for many years. This, combined with their characteristic photophysical and photochemical properties, including their strong fluorescence and their ability to generate reactive oxygen species in vivo upon laser irradiation, has led to much research into the application of porphyrins as cancer diagnostic and therapeutic agents. Porphyrins have been used as dyes to detect cancer cells both in vivo and, less commonly, in vitro. In one example, human sputum samples from lung cancer patients and patients without the disease were dissociated and stained with the porphyrin TCPP (5,10,15,20-tetrakis-(4-carboxyphenyl)-porphine). Cells were analyzed by flow cytometry. Cancer samples were identified by their higher TCPP fluorescence intensity relative to the no-cancer controls. However, quantitative analysis of fluorescence in cell suspensions stained with multiple fluorophores requires particles stained with each of the individual fluorophores as controls. Fluorescent control particles must be compatible in size with flow cytometer fluidics and have favorable hydrodynamic properties in suspension. They must also display fluorescence comparable to the cells of interest and be stable upon storage amine-functionalized spherical polystyrene beads in the 5 to 20-micron diameter range that was reacted with TCPP and EDC in aqueous pH six buffer overnight to form amide bonds. Beads were isolated by centrifugation and tested by flow cytometry. The 10-micron amine-functionalized beads displayed the best combination of fluorescence intensity and hydrodynamic properties, such as lack of clumping and remaining in suspension during the experiment. These beads were further optimized by varying the stoichiometry of EDC and TCPP relative to the amine. The reaction was accompanied by the formation of a TCPP-related particulate, which was removed, after bead centrifugation, using a microfiltration process. The resultant TCPP-functionalized beads were compatible with flow cytometry conditions and displayed a fluorescence comparable to that of stained cells, which allowed their use as fluorescence standards. The beads were stable in refrigerated storage in the dark for more than eight months. This work demonstrates the first preparation of porphyrin-functionalized flow cytometry control beads.

Keywords: tetraaryl porphyrin, polystyrene beads, flow cytometry, peptide coupling

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