Search results for: melanocytic skin tumours
Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 1102

Search results for: melanocytic skin tumours

832 Successful Rehabilitation of Recalcitrant Knee Pain Due to Anterior Cruciate Ligament Injury Masked by Extensive Skin Graft: A Case Report

Authors: Geum Yeon Sim, Tyler Pigott, Julio Vasquez

Abstract:

A 38-year-old obese female with no apparent past medical history presented with left knee pain. Six months ago, she sustained a left knee dislocation in a motor vehicle accident that was managed with a skin graft over the left lower extremity without any reconstructive surgery. She developed persistent pain and stiffness in her left knee that worsened with walking and stair climbing. Examination revealed healed extensive skin graft over the left lower extremity, including the left knee. Palpation showed moderate tenderness along the superior border of the patella, exquisite tenderness over MCL, and mild tenderness on the tibial tuberosity. There was normal sensation, reflexes, and strength in her lower extremities. There was limited active and passive range of motion of her left knee during flexion. There was instability noted upon the valgus stress test of the left knee. Left knee magnetic resonance imaging showed high-grade (grade 2-3) injury of the proximal superficial fibers of the MCL and diffuse thickening and signal abnormality of the cruciate ligaments, as well as edema-like subchondral marrow signal change in the anterolateral aspect of the lateral femoral condyle weight-bearing surface. There was also notable extensive scarring and edema of the skin, subcutaneous soft tissues, and musculature surrounding the knee. The patient was managed with left knee immobilization for five months, which was complicated by limited knee flexion. Physical therapy consisting of quadriceps, hamstrings, gastrocnemius stretching and strengthening, range of motion exercises, scar/soft tissue mobilization, and gait training was given with marked improvement in pain and range of motion. The patient experienced a further reduction in pain as well as an improvement in function with home exercises consisting of continued strengthening and stretching.

Keywords: ligamentous injury, trauma, rehabilitation, knee pain

Procedia PDF Downloads 108
831 Phenotype of Cutaneous Squamous Cell Carcinoma in a Brazilian City with a Tropical Climate

Authors: Julia V. F. Cortes, Maria E. V. Amarante, Carolina L. Cerdeira, Roberta B. V. Silva

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Nonmelanoma skin cancer is more commonly diagnosed than all other malignancies combined. In that group, cutaneous squamous cell carcinoma stands out for having the highest probability of metastasis and recurrence after treatment, in addition to being the second most prevalent form of skin cancer. Its main risk factors include exposure to carcinogens, such as ultraviolet radiation related to sunlight exposure, smoking, alcohol consumption, and human papillomavirus (HPV) infection. Considering the increased risk of skin cancer in the Brazilian population, caused by the high incidence of solar radiation, and the importance of identifying risk phenotypes for the accomplishment of public health actions, an epidemiological study was conducted in a city with a tropical climate located in southeastern Brazil, aiming to identify the target population and assist in primary and secondary prevention. This study describes the profile of patients with cutaneous squamous cell cancer, correlating the variables, sex, age, and differentiation. The study used as primary data source the results of anatomopathological exams delivered from January 2015 to December 2019 for patients registered at one pathology service, which analyzes the results of biopsies, Thus, 66 patients with cutaneous squamous cell carcinoma were analyzed. The most affected age group was 60 years or older (78.79%), emphasizing that moderately differentiated (79.49%) and well-differentiated forms (66.67%) are prevalent in this age group, resulting in a difference of 12.82 percentage points between them. In addition, the predominant sex was male (58%), and it was found that half of the women and 65.79% of men had a moderately differentiated type, whereas the well-differentiated type was slightly more frequent in women. It is worth noting that the moderately differentiated subtype has a 59.20% prevalence among all cases. Thus, it was concluded that the most affected age group was 60 years or older and that men were more affected. As for the subtype, the moderately differentiated one, which is recognized for presenting the second-highest risk for metastasis, was prevalent in this study, affecting 6.6% more men and predominating in the elderly.

Keywords: cutaneous squamous cell carcinoma, epidemiology, skin cancer, spinal cell cancer

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830 Study of Three Channel Electrode Position to Detect Optimum Myoelectric Signal on Five Type Grasp Movement

Authors: Ilham Priadythama, Pringgo Widyo Laksono, Agung Pamungkas

Abstract:

Myoelectric is prosthetic, flexible, and offered industrial application has been highly developed and widely used. Myoelectric hand use myoelectric signal from muscle to activate and control the membrane part of hand. Commonly myoelectric signal is detected on human arm from skin surface. So that it only small magnitude signal captured. Detecting myoelectric signal on the skin surface takes proper and consistent procedure. This paper provides preliminary study of electrodes position which gives best signal strength for five basic grasping. Two-position scenario used to place three channel electrodes set. A bi-potential amplifier based on AD620 used to amplify the signal. Finally, the signal was analyzed using DSSF3 software. From this study, we found that grasp type was stronger using first scenario electrode placement while the rest type better with another scenario.

Keywords: myoelectric signal, basic grasp, DSSF3, electrode, bi-potential amplifier

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829 Calculation of Organs Radiation Dose in Cervical Carcinoma External Irradiation Beam Using Day’s Methods

Authors: Yousif M. Yousif Abdallah, Mohamed E. Gar-Elnabi, Abdoelrahman H. A. Bakary, Alaa M. H. Eltoum, Abdelazeem K. M. Ali

Abstract:

The study was established to measure the amount of radiation outside the treatment field in external beam radiation therapy using day method of dose calculation, the data was collected from 89 patients of cervical carcinoma in order to determine if the dose outside side the irradiation treatment field for spleen, liver, both kidneys, small bowel, large colon, skin within the acceptable limit or not. The cervical field included mainly 4 organs which are bladder, rectum part of small bowel and hip joint these organ received mean dose of (4781.987±281.321), (4736.91±331.8), (4647.64±387.1) and (4745.91±321.11) respectively. The mean dose received by outfield organs was (77.69±15.24cGy) to large colon, (93.079±12.31cGy) to right kidney (80.688±12.644cGy) to skin, (155.86±17.69cGy) to small bowel. This was more significant value noted.

Keywords: radiation dose, cervical carcinoma, day’s methods, radiation medicine

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828 Preparation and Quality Control of a Novel Radiolabeled Complex of 166ho for the Treatment of Somatostatin Receptor Expressing Tumours

Authors: H. Yousefnia, A. Golabi Dezfuli, S. Zolghadri, M. Hosntalab

Abstract:

Peptide receptor radionuclide therapy is nowadays used for the treatment of various abnormalities with somatostatin receptors. In this study, 166Ho-DOTATOC was prepared and the best conditions for its radiolabeling was obtained. For this purpose, a certain of DOTATOC was added to a vial containing 166Ho. various experiments by varying ligand concentration, pH, temperature and time were performed to determine the best conditions. Radiochemical purity of the complex was assessed by instant thin layer chromatography method utilizing 0.9% NaCl as the mobile phase. 166Ho-DOTATOC was prepared with radiochemical purity of higher than 95% at the optimized condition (pH=4, temperature: 95° C, time:30 min). In 0.9% NaCl, free Ho cation was developed at Rf of 0.8 while the complex was remained at the front of the paper.

Keywords: Ho-166, neuroendocrine, octreotide, quality control

Procedia PDF Downloads 386
827 Ulnar Parametacarpal Flap for Coverage of Fifth Finger Defects: Propeller Flap Concept

Authors: Ahmed M. Gad, Ahmed S. Hweidi

Abstract:

Background: Defects of the little finger and adjacent areas are not uncommon. It could be a traumatic, post-burn, or after contracture release. Different options could be used for resurfacing these defect, including skin grafts, local or regional flaps. Ulnar para-metacarpal flap described by Bakhach in 1995 based on the distal division of the dorsal branch of the ulnar artery considered a good option for that. In this work, we applied the concept of propeller flap for better mobilization and in-setting of the ulnar para-metacarpal flap. Methods: The study included 15 cases with 4 females and 11 male patients. 10 of the patients had severe post-burn contractures of little finger, and 5 had post-traumatic little finger defects. Contractures were released and resulting soft tissue defects were reconstructed with propeller ulnar para-metacarpal artery flap. The flap based on two main perforators communicating with the palmar system, it was raised based on one of them depending on the extent of the defect and rotated 180 degrees after judicious dissection of the perforator. Results: 13 flaps survived completely, one of the cases developed partial skin loss, which healed by dressing, another flap was completely lost and covered later by a full-thickness skin graft. Conclusion: Ulnar para-metacarpal flap is a reliable option to resurface the little finger as well as adjacent areas. The application of the propeller flap concept based on whether the proximal or distal communicating branch makes the rotation and in-setting of the flap easier.

Keywords: little finger defects, propeller flap, regional hand defects, ulnar parametacarpal flap

Procedia PDF Downloads 197
826 Evaluation of the Radiolabelled 68GA-DOTATOC Complex in Adenocarcinoma Breast Cancer

Authors: S. Zolghadri, M. Naderi, H. Yousefnia, B. Alirzapour, A. R. Jalilian, A. Ramazani

Abstract:

Nowadays, 68Ga-DOTATOC has been known as a potential agent for the detection of neuroendocrine tumours and it has indicated higher sensitivity compared with the 111In-Octeroetide. The aim of this study was to evaluate the effectiveness of this new agent in the diagnosis of adenocarcinoma breast cancer. 68Ga-DOTATOC was prepared with the radiochemical purity of higher than 98% and by the specific activity of 39.6 TBq/mmol. 37 MBq of the complex was injected intravenously into the BULB/c mice with adenocarcinoma breast cancer. PET/CT images were acquired after 30, 60 and 90 min post injection demonstrated significant accumulation in the tumour sites. Also, considerable activity was observed in the kidney and bladder as the main routs of excretion. Generally, the results showed that 68Ga-DOTATOC can be considered as a suitable complex for diagnosis of the adenocarcinoma breast cancer using PET procedure.

Keywords: adenocarcinoma breast cancer, 68Ga, octreotide, imaging

Procedia PDF Downloads 341
825 An Amended Method for Assessment of Hypertrophic Scars Viscoelastic Parameters

Authors: Iveta Bryjova

Abstract:

Recording of viscoelastic strain-vs-time curves with the aid of the suction method and a follow-up analysis, resulting into evaluation of standard viscoelastic parameters, is a significant technique for non-invasive contact diagnostics of mechanical properties of skin and assessment of its conditions, particularly in acute burns, hypertrophic scarring (the most common complication of burn trauma) and reconstructive surgery. For elimination of the skin thickness contribution, usable viscoelastic parameters deduced from the strain-vs-time curves are restricted to the relative ones (i.e. those expressed as a ratio of two dimensional parameters), like grosselasticity, net-elasticity, biological elasticity or Qu’s area parameters, in literature and practice conventionally referred to as R2, R5, R6, R7, Q1, Q2, and Q3. With the exception of parameters R2 and Q1, the remaining ones substantially depend on the position of inflection point separating the elastic linear and viscoelastic segments of the strain-vs-time curve. The standard algorithm implemented in commercially available devices relies heavily on the experimental fact that the inflection time comes about 0.1 sec after the suction switch-on/off, which depreciates credibility of parameters thus obtained. Although the Qu’s US 7,556,605 patent suggests a method of improving the precision of the inflection determination, there is still room for nonnegligible improving. In this contribution, a novel method of inflection point determination utilizing the advantageous properties of the Savitzky–Golay filtering is presented. The method allows computation of derivatives of smoothed strain-vs-time curve, more exact location of inflection and consequently more reliable values of aforementioned viscoelastic parameters. An improved applicability of the five inflection-dependent relative viscoelastic parameters is demonstrated by recasting a former study under the new method, and by comparing its results with those provided by the methods that have been used so far.

Keywords: Savitzky–Golay filter, scarring, skin, viscoelasticity

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824 A Study on Relationship of Lifestyle and Socio-Economic Status with Obesity in Indian Children

Authors: Sushma Ghildyal, Sanjay Kumar Singh

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The present study was undertaken with the purpose to understand the relationship of lifestyle and Socio-Economic status with child obesity among 1000 boys aged from 16 to 18 years of Varanasi District of Uttar Pradesh State in India. The study was conducted in both urban and rural area of the District. Ten schools i.e. five from urban area and five from rural area were selected by using purposive sampling. Healthy boys of class 10th, 11th and 12th were taken as subjects for the study. Prior consent was obtained from school authority. Anthropometric measurements were taken from each subject. Anthropometric measurements were Standing Height, Weight, Biceps skin folds, Triceps skin folds, Sub-scapular skin folds and Supra-iliac skin folds taken by Lange’s skin fold caliper. Lifestyle and Socio-Economic Status were obtained by questionnaires. In order to assess the BMI, Body fat %, Lifestyle and Socio-Economic Status; descriptive analyses were done. To find out the significant association of obesity with lifestyle and Socio-Economic Status Chi-square test was used. To find out significant difference between obesity of Urban and Rural children t-test was applied. Level of significance was set at 0.05 level. The conclusions drawn were: (1) The result showed that in urban area Varanasi District of Uttar Pradesh 0.6% children were in very high level adaptive lifestyle, 6.2% were in high level adaptive lifestyle, 25.4% above average level adaptive lifestyle, 47.8% moderately adaptive lifestyle, 3.6% and 0.4% low and very low level adaptive lifestyle. (2) In rural area Varanasi District of Uttar Pradesh 0.00% children were in very high level adaptive lifestyle, 9.4% were in high level adaptive lifestyle, 24.8% average level adaptive lifestyle, 47.0% moderately adaptive lifestyle, 15.2% below average and 3.0% very low level adaptive lifestyle.(3) In urban area 12.8% were in upper class Socio-Economic Status, 56.6% in upper middle class Socio-Economic Status, 30.2% in middle class Socio-Economic Status and 0.2% in lower middle class Socio-Economic Status. (4) In rural area 1.4% were in upper class Socio-Economic Status, 15.2% in upper middle class Socio-Economic Status, 51.6% in middle class Socio-Economic Status and 0.8% in lower middle class Socio-Economic Status. (5) In urban area 21.2% children of 16-18 years were obese. (6) In rural area 0.2% children of 16-18 years were obese. (7) In overall Varanasi District of Uttar Pradesh 10.7% children of 16-18 years were obese. (8) There was no significant relationship of obesity with Lifestyle of urban area children of 16-18 years. (9) There was significant relationship of obesity with Socio-Economic Status of urban area children of 16-18 years (10) There was no significant relationship of obesity with Lifestyle of rural area children of 16-18 years of Varanasi District Uttar Pradesh. (11) There was significant relationship of obesity with Socio-Economic Status of rural area children of 16-18 years. (12) Results showed significant difference between urban and rural area children of 16-18 years in respect to obesity of Varanasi District of Uttar Pradesh.

Keywords: lifestyle, obesity, rural area, socio-economic status, urban area

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823 Wind Load Reduction Effect of Exterior Porous Skin on Facade Performance

Authors: Ying-Chang Yu, Yuan-Lung Lo

Abstract:

Building envelope design is one of the most popular design fields of architectural profession in nowadays. The main design trend of such system is to highlight the designer's aesthetic intention from the outlook of building project. Due to the trend of current façade design, the building envelope contains more and more layers of components, such as double skin façade, photovoltaic panels, solar control system, or even ornamental components. These exterior components are designed for various functional purposes. Most researchers focus on how these exterior elements should be structurally sound secured. However, not many researchers consider these elements would help to improve the performance of façade system. When the exterior elements are deployed in large scale, it creates an additional layer outside of original façade system and acts like a porous interface which would interfere with the aerodynamic of façade surface in micro-scale. A standard façade performance consists with 'water penetration, air infiltration rate, operation force, and component deflection ratio', and these key performances are majorly driven by the 'Design Wind Load' coded in local regulation. A design wind load is usually determined by the maximum wind pressure which occurs on the surface due to the geometry or location of building in extreme conditions. This research was designed to identify the air damping phenomenon of micro turbulence caused by porous exterior layer leading to surface wind load reduction for improvement of façade system performance. A series of wind tunnel test on dynamic pressure sensor array covered by various scale of porous exterior skin was conducted to verify the effect of wind pressure reduction. The testing specimens were designed to simulate the typical building with two-meter extension offsetting from building surface. Multiple porous exterior skins were prepared to replicate various opening ratio of surface which may cause different level of damping effect. This research adopted 'Pitot static tube', 'Thermal anemometers', and 'Hot film probe' to collect the data of surface dynamic pressure behind porous skin. Turbulence and distributed resistance are the two main factors of aerodynamic which would reduce the actual wind pressure. From initiative observation, the reading of surface wind pressure was effectively reduced behind porous media. In such case, an actual building envelope system may be benefited by porous skin from the reduction of surface wind pressure, which may improve the performance of envelope system consequently.

Keywords: multi-layer facade, porous media, facade performance, turbulence and distributed resistance, wind tunnel test

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822 An Exploratory Study on Newborns Using Massage Oil to Induce Miliaria

Authors: Chia-Feng Chen, Wan-Yi Lin, Chia-En Liu

Abstract:

Background: There are approximately 600 newborns that stay four weeks in our postpartum agency every year. As we all know, newborn’s skin is 40-60% thinner than adult skin, newborn skin has a higher trans epidermal water loss, so many postpartum agencies use massage oil every day, no matter which seasons. In fact, neonatal miliaria or prickly heat is the most common condition from two to three -week- old newborns. According to research, about 80 percent of two to three -week- old baby are diagnosed with prickly heat because nurses apply massage oil to their faces every day. In China, we can use honeysuckle to wipe the newborn's face for treatment. Purpose: the purpose of the study is to discuss that using massage oil will be induced neonatal miliaria among two or three-week-old newborns and the aim of the study is to assess the protocol of miliaria condition with the face. Methods: a quasi-experimental design was used to evaluated the result between massage oil and non massage oil. A total of 22 participants were recruited randomly and analyzed from August to September in the south of China and collected for about 2 week long. The 22 participants were randomly selected and live in the stable air condition belong, 24 to 26℃. Results: the 64% of participants were diagnosed with miliaria using massage oil, the 2/8 of participants were diagnosed with miliaria no using massage oil. The pearson correction was0.67. The result of 22 participants, including massage oil, and diagnosed with miliaris. Besides, in our study, 9 of participants with miliaria for 3 to 6 days on the face, were treatment with honey-suckle wipe 3days through pediatric doctor suggestion. The effect of honey-suckle were useful in improving miliaria and decreasing the anxiety of parents. Conclusions: Miliaria is a common condition in newborns, especially in summer. The authors postulate that the massage oil did not find suitable for newborn in summer, and the study provides evidence that honey-suckle effectively control miliaria on using massage oil of participants.

Keywords: massage oil, miliaria, newborn, honey suckle

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821 A Rare Atypical Presentation of Iichthyosis Follicularis, Alopecia, and Photophobia Syndrome

Authors: D. R. Apoorva

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Ichthyosis follicularis, alopecia, and photophobia (IFAP) syndrome is a rare oculocutaneous disorder of genetic origin. This disorder results from mutations in the membrane-bound transcription factor protease site, two genes that impair cholesterol homeostasis, and the ability to cope with endoplasmic reticulum stress. We report a rare case of IFAP syndrome with an atypical presentation, and it was interesting to note that the child had patchy non-scarring alopecia over the scalp along with unilateral madarosis. To our best knowledge, this unique presentation has not been described earlier. The child presented with photophobia and unilateral ptosis. The child also had short stature and intellectual disability. Skin histopathology was nonspecific and consisted of dilated hair follicles with keratin plugs extending above the skin surface. This rare oculocutaneous disorder requires proper documentation so that identification of its variants may be possible in the future. Early recognition of atypical presentations can help in preventing cardiovascular complications, which remain the major cause of death.

Keywords: alopecia, photophobia, ichthyosis follicularis, IFAP syndrome

Procedia PDF Downloads 79
820 Immune Disregulation in Inflammatory Skin Diseases with Comorbid Metabolic Disorders

Authors: Roman Khanferyan, Levon Gevorkyan, Ivan Radysh

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Skin barrier dysfunction induces multiple inflammatory skin diseases. Epidemiological studies clearly support the link between most dermatological pathologies, immune disorders and metabolic disorders. Among them most common are psoriasis (PS) and Atopic dermatitis (AD). Psoriasis is a chronic immune-mediated inflammatory skin disease that affects 1.5 to 3.0% of the world's population. Comorbid metabolic disorders play an important role in the progression of PS and AD, as well. It is well known that PS, AD and overweight/obesity are associated with common pathophysiological mechanisms of mild chronic inflammation. The goal of the study was to study the immune disturbances in patients with PS, AD and comorbid metabolic disorders. To study the prevalence of comorbidity of PS and AD (data from 1406 patient’s histories of diseases) were analyzed. The severity of the disease is assessed using the PASI index (Psoriasis Area and Severity Index). 59 patients with psoriasis of different localizations of lesions and severity, as well as with different body mass index (BMI), were examined. The determination of the concentration of pro-inflammatory cytokines (IL-6, IL-8, IFNγ, IL-17, L-18 and TNFa) and chemokines (RANTES, IP-10, MCP-1 and Eotaxin) in sera and supernatants of 48h-cultivated peripheral blood mononuclear cell (PBMC) of psoriasis patients and healthy volunteers (36 adults) have been carried out by multiplex assay (Luminex Corporation, USA). It has been demonstrated that 42% of PS patients had comorbidity with different types of atopies. The most common was bronchial asthma and allergic rhinitis. At the same time, the prevalence of AD in PS patients was determined in 8.7% of patients. It has been shown that serum levels of all studied cytokines (IL-6, IL-8, IFNγ, IL-17, L-18 and TNF) in most of the studied patients were higher in PS patients than in those with AD and healthy controls (p<0.05). An in vitro synthesis of the IL-6 and IFNγ by PBMC demonstrated similar results to those determined in blood sera. There was a high correlation between BMI, immune mediators and the concentrations of adipokines and chemokines (p<0.05). The concentrations of Leptin and Resistin in obese psoriatic patients were greater by 28.6% and 17%, respectively, compared to non-obese psoriatic patients. In obese patients with psoriasis the serum levels of adiponectin were decreased up to 1.3-fold. The mean serum RANTES, IP-10, MCP-1, EOTAXIN levels in obese psoriatic patients were decreased by up to 13.1%, 21.9%, 40.4% and 28.2%, respectively. Similar results have been demonstrated in AD patients with comorbid overweight and obesity. Thus, the study demonstrated the important role of cytokines and chemokines dysregulation in inflammatory skin diseases, especially in patients with comorbid obesity and overweight. Metabolic disorders promote the severity of PS and AD, highly increase immune dysregulation, and synthesis of adipokines, which correlates with the production of proinflammatory immune mediators in comorbid obesity and overweight.

Keywords: psoriasis, atopic dermatitis, pro-inflammatory cytokines, chemokines, comorbid obesity

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819 Soil Arching Effect in Columnar Embankments: A Numerical Study

Authors: Riya Roy, Anjana Bhasi

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Column-supported embankments provide a practical and efficient solution for construction on soft soil due to the low cost and short construction times. In the recent years, geosynthetic have been used in combination with column systems to support embankments. The load transfer mechanism in these systems is a combination of soil arching effect, which occurs between columns and membrane effect of the geosynthetic. This paper aims at the study of soil arching effect on columnar embankments using finite element software, ABAQUS. An axisymmetric finite element model is generated and using this model, parametric studies are carried out. Thus the effects of various factors such as height of embankment fill, elastic modulus of pile and tensile stiffness of geosynthetic, on soil arching have been studied. The development of negative skin friction along the pile-soil interface have also been studied and the results obtained from this study are compared with the current design methods.

Keywords: ABAQUS, geosynthetic, negative skin friction, soil arching

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818 Emperical Correlation for Measurement of Thermal Diffusivity of Spherical Shaped Food Products under Forced Convection Environment

Authors: M. Riaz, Inamur Rehman, Abhishek Sharma

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The present work is the development of an experimental method for determining the thermal diffusivity variations with temperature of selected regular shaped solid fruits and vegetables subjected to forced convection cooling. Experimental investigations were carried on the sample chosen (potato and brinjal), which is approximately of spherical geometry. The variation of temperature within the food product is measured at several locations from centre to skin, under forced convection environment using a deep freezer, maintained at -10°C.This method uses one dimensional Fourier equation applied to regular shapes. For this, the experimental temperature data obtained from cylindrical and spherical shaped products during pre-cooling was utilised. Such temperature and thermal diffusivity profiles can be readily used with other information such as degradation rate, etc. to evaluate thermal treatments based on cold air cooling methods for storage of perishable food products.

Keywords: thermal diffusivity, skin temperature, precooling, forced convection, regular shaped

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817 Application of MRI in Radioembolization Imaging and Dosimetry

Authors: Salehi Zahabi Saleh, Rajabi Hosaien, Rasaneh Samira

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Yttrium-90 (90Y) radioembolisation(RE) is increasingly used for the treatment of patients with unresectable primary or metastatic liver tumours. Image-based approaches to assess microsphere distribution after RE have gained interest but are mostly hampered by the limited imaging possibilities of the Isotope 90Y. Quantitative 90Y-SPECT imaging has limited spatial resolution because it is based on 90Y Bremsstrahlung whereas 90Y-PET has better spatial resolution but low sensitivity. As a consequence, new alternative methods of visualizing the microspheres have been investigated, such as MR imaging of iron-labelled microspheres. It was also shown that MRI combines high sensitivity with high spatial and temporal resolution and with superior soft tissue contrast and thus can be used to cover a broad range of clinically interesting imaging parameters.The aim of the study in this article was to investigate the capability of MRI to measure the intrahepatic microsphere distribution in order to quantify the absorbed radiation dose in RE.

Keywords: radioembolisation, MRI, imaging, dosimetry

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816 Comparative Evaluation of Ultrasound Guided Internal Jugular Vein Cannulation Using Measured Guided Needle and Conventional Size Needle for Success and Complication of Cannulation

Authors: Devendra Gupta, Vikash Arya, Prabhat K. Singh

Abstract:

Background: Ultrasound guidance could be beneficial in placing central venous catheters by improving the success rate, reducing the number of needle passes, and decreasing complications. Central venous cannulation set has a single puncture needle of a fixed length of 6.4 cm. However, the average distance of midpoint of IJV to the skin is around 1 cm to 2 cm. The long length needle has tendency to go in depth more than required and this is very common during learning period of any individual. Therefore, we devised a long needle with a guard which can be adjusted according to the required length. Methods: After approval from the institute ethics committee and patient’s written informed consent, a prospective, randomized, single-blinded controlled study was conducted. Adult patient aged of both sexes with ASA grade 1-2 undergoing surgery requiring internal jugular venous (IJV) access was included. After intubation, the head was rotated to the contralateral side at 30 degree head rotation on the position of the right IJV. The transducer probe a 6.5 to 13-MHz linear transducer (Sonosite, USA) had been placed at the apex of triangle with minimal pressure to avoid IJV compression. The distance from skin to midpoint of the right IJV and skin to anterior wall of Common Carotid Artery (CCA) had been done using B-mode duplex sonography with a 6.5 to 13-MHz linear transducer. Depending upon the results of randomization 420 patients had been divided into two groups of equal numbers (n=210). Group 1. USG guided right sided IJV cannulation was done with conventional (6.4 cm) needle; and Group 2. USG guided right sided IJV cannulation was done with conventional (6.4 cm) needle with guard fixed to a required length (length between skin and midpoint of IJV) by an experienced anesthesiologist. Independent observer has noted the number of attempts and occurrence of complications (CCA puncture, pneumothorax or adjacent tissue damage). Results: Demographic data were similar in both the group. The groups were comparable when considered for relationship of IJV to CCA. There was no significant difference between groups as regard to distance of midpoint of IJV to the skin (p<0.05). IJV cannulation was successfully done in single attempts in 180 (85.7%), in two attempts in 27 (12.9%) and three attempts in 3 (1.4%) in group I, whereas in single attempt in 207 (98.6%) and second attempts in 3 (1.4%) in group II (p <0.000). Incidence of carotid artery puncture was significantly more in group I (7.1%) compared to group II (0%) (p<0.000). Incidence of adjacent tissue puncture was significantly more in group I (8.6%) compared to group II (0%) (p<0.000). Conclusion: Therefore IJV catheterization using guard over the needle at predefined length with the help of real-time ultrasound results in better success rates and lower immediate complications.

Keywords: ultrasound guided, internal jugular vein cannulation, measured guided needle, common carotid artery puncture

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815 In vivo Wound Healing Activity and Phytochemical Screening of the Crude Extract and Various Fractions of Kalanchoe petitiana A. Rich (Crassulaceae) Leaves in Mice

Authors: Awol Mekonnen, Temesgen Sidamo, Epherm Engdawork, Kaleab Asresb

Abstract:

Ethnopharmacological Relevance: The leaves of Kalanchoe petitiana A. Rich (Crassulaceae) are used in Ethiopian folk medicine for treatment of evil eye, fractured surface for bone setting and several skin disorders including for the treatment of sores, boils, and malignant wounds. Aim of the Study: In order to scientifically prove the claimed utilization of the plant, the effects of the extracts and the fractions were investigated using in vivo excision, incision and dead space wound models. Materials and Method: Mice were used for wound healing study, while rats and rabbit were used for skin irritation test. For studying healing activity, 80% methanolic extract and the fractions were formulated in strength of 5% and 10%, either as ointment (hydroalcoholic extract, aqueous and methanol fractions) or gel (chloroform fraction). Oral administration of the crude extract was used for dead space model. Negative controls were treated either with simple ointment or sodium carboxyl methyl cellulose xerogel, while positive controls were treated with nitrofurazone (0.2 w/v) skin ointment. Negative controls for dead space model were treated with 1% carboxy methyl cellulose. Parameters, including rate of wound contraction, period of complete epithelializtion, hydroxyproline contents and skin breaking strength were evaluated. Results: Significant wound healing activity was observed with ointment formulated from the crude extract at both 5% and 10% concentration (p<0.01) compared to controls in both excision and incision models. In dead space model, 600 mg/kg (p<0.01), but not 300 mg/kg, significantly increased hydroxyproline content. Fractions showed variable effect, with the chloroform fraction lacking any significant effect. Both 5% and 10% formulations of the aqueous and methanolic fractions significantly increased wound contraction, decreased epithelializtion time and increased hydroxyproline content in excision wound model (p<0.05) as compared to controls. These fractions were also endowed with higher skin breaking strength in incision wound model (p<0.01). Conclusions: The present study provided evidence that the leaves of Kalanchoe petitiana A. Rich possess remarkable wound healing activities supporting the folkloric assertion of the plant. Fractionation revealed that polar or semi-polar compound may play vital role, as both aqueous and methanolic fractions were endowed with wound healing activity.

Keywords: wound healing, Kalanchoae petitiana, excision wound, incision wound, dead space model

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814 Appropriate Depth of Needle Insertion during Rhomboid Major Trigger Point Block

Authors: Seongho Jang

Abstract:

Objective: To investigate an appropriate depth of needle insertion during trigger point injection into the rhomboid major muscle. Methods: Sixty-two patients who visited our department with shoulder or upper back pain participated in this study. The distance between the skin and the rhomboid major muscle (SM) and the distance between the skin and rib (SB) were measured using ultrasonography. The subjects were divided into 3 groups according to BMI: BMI less than 23 kg/m2 (underweight or normal group); 23 kg/m2 or more to less than 25 kg/m2 (overweight group); and 25 kg/m2 or more (obese group). The mean ±standard deviation (SD) of SM and SB of each group were calculated. A range between mean+1 SD of SM and the mean-1 SD of SB was defined as a safe margin. Results: The underweight or normal group’s SM, SB, and the safe margin were 1.2±0.2, 2.1±0.4, and 1.4 to 1.7 cm, respectively. The overweight group’s SM and SB were 1.4±0.2 and 2.4±0.9 cm, respectively. The safe margin could not be calculated for this group. The obese group’s SM, SB, and the safe margin were 1.8±0.3, 2.7±0.5, and 2.1 to 2.2 cm, respectively. Conclusion: This study will help us to set the standard depth of safe needle insertion into the rhomboid major muscle in an effective manner without causing any complications.

Keywords: pneumothorax, rhomboid major muscle, trigger point injection, ultrasound

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813 Causes of Jaundice and Skin Rashes Amongst Children in Selected Rural Communities in the Gambia

Authors: Alhage Drammeh

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The research is on the occurrence of certain diseases among children in rural and far-flung parts of the Gambia and the extent to which they are caused by lack of access to clean water. A baseline survey was used to discover, describe, and explain the actual processes. The paper explains the purpose of the research, which is majorly to improve the health condition of children, especially those living in rural communities. The paper also gives a brief overview of the socio-economic situation of The Gambia, emphasizing its status as a Least Developed Country (LDC) and the majority of its population living below the poverty line, with women and children hardest hit. The research used as case studies of two rural communities in the Gambia -Basse Dampha Kunda Village and Foni Besse. Data was collected through oral interviews and medical tests conducted among people in both villages, with an emphasis on children. The demographic detail of those tested is tabulated for a clearer understanding. The results were compared, revealing that skin rashes, hepatitis, and certain other diseases are more prevalent in communities lacking access to safe drinking water. These results were also presented in a tabular form. The study established how some policy failures and neglect on the part of the Government of The Gambia are imperiling the health of many rural dwellers in the country, the most glaring being that the research team was unable to test water samples collected from the two communities, as there are no laboratory reagents for testing water anywhere in The Gambia. Many rural communities lack basic amenities, especially clean and potable water, as well as health facilities. The study findings also highlighted the need for healthcare providers and medical NGOs to voice the plight of rural dwellers and collaborate with the government to set up health facilities in rural areas of The Gambia.

Keywords: jaundice, skin rashes, children, rural communities, the Gambia, causes

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812 Simulation Analysis and Control of the Temperature Field in an Induction Furnace Based on Various Parameters

Authors: Sohaibullah Zarghoon, Syed Yousaf, Cyril Belavy, Stanislav Duris, Samuel Emebu, Radek Matusu

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Induction heating is extensively employed in industrial furnaces due to its swift response and high energy efficiency. Designing and optimising these furnaces necessitates the use of computer-aided simulations. This study aims to develop an accurate temperature field model for a rectangular steel billet in an induction furnace by leveraging various parameters in COMSOL Multiphysics software. The simulation analysis incorporated temperature dynamics, considering skin depth, temperature-dependent, and constant parameters of the steel billet. The resulting data-driven model was transformed into a state-space model using MATLAB's System Identification Toolbox for the purpose of designing a linear quadratic regulator (LQR). This controller was successfully implemented to regulate the core temperature of the billet from 1000°C to 1200°C, utilizing the distributed parameter system circuit.

Keywords: induction heating, LQR controller, skin depth, temperature field

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811 Animal Modes of Surgical or Other External Causes of Trauma Wound Infection

Authors: Ojoniyi Oluwafeyekikunmi Okiki

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Notwithstanding advances in disturbing wound care and control, infections remain a main motive of mortality, morbidity, and financial disruption in tens of millions of wound sufferers around the sector. Animal models have become popular gear for analyzing a big selection of outside worrying wound infections and trying out new antimicrobial techniques. This evaluation covers experimental infections in animal models of surgical wounds, pores and skin abrasions, burns, lacerations, excisional wounds, and open fractures. Animal modes of external stressful wound infections stated via extraordinary investigators vary in animal species used, microorganism traces, the quantity of microorganisms carried out, the dimensions of the wounds, and, for burn infections, the period of time the heated object or liquid is in contact with the skin. As antibiotic resistance continues to grow, new antimicrobial procedures are urgently needed. Those have to be examined using popular protocols for infections in external stressful wounds in animal models.

Keywords: surgical wounds, animals, wound infections, burns, wound models, colony-forming gadgets, lacerated wounds

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810 Characterization of Hyaluronic Acid-Based Injections Used on Rejuvenation Skin Treatments

Authors: Lucas Kurth de Azambuja, Loise Silveira da Silva, Gean Vitor Salmoria, Darlan Dallacosta, Carlos Rodrigo de Mello Roesler

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This work provides a physicochemical and thermal characterization assessment of three different hyaluronic acid (HA)-based injections used for rejuvenation skin treatments. The three products analyzed are manufactured by the same manufacturer and commercialized for application on different skin levels. According to the manufacturer, all three HA-based injections are crosslinked and have a concentration of 23 mg/mL of HA, and 0.3% of lidocaine. Samples were characterized by Fourier-transformed infrared (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) techniques. FTIR analysis resulted in a similar spectrum when comparing the different products. DSC analysis demonstrated that the fusion points differ in each product, with a higher fusion temperature observed in specimen A, which is used for subcutaneous applications, when compared with B and C, which are used for the middle dermis and deep dermis, respectively. TGA data demonstrated a considerable mass loss at 100°C, which means that the product has more than 50% of water in its composition. TGA analysis also showed that Specimen A had a lower mass loss at 100°C when compared to Specimen C. A mass loss of around 220°C was observed on all samples, characterizing the presence of hyaluronic acid. SEM images displayed a similar structure on all samples analyzed, with a thicker layer for Specimen A when compared with B and C. This series of analyses demonstrated that, as expected, the physicochemical and thermal properties of the products differ according to their application. Furthermore, to better characterize the crosslinking degree of each product and their mechanical properties, a set of different techniques should be applied in parallel to correlate the results and, thereby, relate injection application with material properties.

Keywords: hyaluronic acid, characterization, soft-tissue fillers, injectable gels

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809 Appearance and Magnitude of Dynamic Pressure in Micro-Scale of Subsonic Airflow around Symmetric Objects

Authors: Shehret Tilvaldyev, Jorge Flores-Garay, Alfredo Villanueva, Erwin Martinez, Lazaro Rico

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The efficiency of modern transportation is severely compromised by the prevalence of turbulent drag. The high level of turbulent skin-friction occurring, e.g., on the surface of an aircraft, automobiles or the carriage of a high-speed train, is responsible for excess fuel consumption and increased carbon emissions. The environmental, political, and economic pressure to improve fuel efficiency and reduce carbon emissions associated with transportation means that reducing turbulent skin-friction drag is a pressing engineering problem. The dynamic pressure of subsonic airflow around solid objects creates lift, but also induces drag force. This paper is presenting the results of laboratory experiments, investigating appearance and magnitude of dynamic pressure in micro scale of subsonic air flow around right cylinder and symmetrical airfoil.

Keywords: airflow, dynamic pressure, micro scale, symmetric object

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808 A One-Dimensional Model for Contraction in Burn Wounds: A Sensitivity Analysis and a Feasibility Study

Authors: Ginger Egberts, Fred Vermolen, Paul van Zuijlen

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One of the common complications in post-burn scars is contractions. Depending on the extent of contraction and the wound dimensions, the contracture can cause a limited range-of-motion of joints. A one-dimensional morphoelastic continuum hypothesis-based model describing post-burn scar contractions is considered. The beauty of the one-dimensional model is the speed; hence it quickly yields new results and, therefore, insight. This model describes the movement of the skin and the development of the strain present. Besides these mechanical components, the model also contains chemical components that play a major role in the wound healing process. These components are fibroblasts, myofibroblasts, the so-called signaling molecules, and collagen. The dermal layer is modeled as an isotropic morphoelastic solid, and pulling forces are generated by myofibroblasts. The solution to the model equations is approximated by the finite-element method using linear basis functions. One of the major challenges in biomechanical modeling is the estimation of parameter values. Therefore, this study provides a comprehensive description of skin mechanical parameter values and a sensitivity analysis. Further, since skin mechanical properties change with aging, it is important that the model is feasible for predicting the development of contraction in burn patients of different ages, and hence this study provides a feasibility study. The variability in the solutions is caused by varying the values for some parameters simultaneously over the domain of computation, for which the results of the sensitivity analysis are used. The sensitivity analysis shows that the most sensitive parameters are the equilibrium concentration of collagen, the apoptosis rate of fibroblasts and myofibroblasts, and the secretion rate of signaling molecules. This suggests that most of the variability in the evolution of contraction in burns in patients of different ages might be caused mostly by the decreasing equilibrium of collagen concentration. As expected, the feasibility study shows this model can be used to show distinct extents of contractions in burns in patients of different ages. Nevertheless, contraction formation in children differs from contraction formation in adults because of the growth. This factor has not been incorporated in the model yet, and therefore the feasibility results for children differ from what is seen in the clinic.

Keywords: biomechanics, burns, feasibility, fibroblasts, morphoelasticity, sensitivity analysis, skin mechanics, wound contraction

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807 Studying Medicinal Plants of Rajasthan Used by Tribes for Different Diseases

Authors: Rekha Vijayvergia

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Around seven percent of tribal population of India lives in Rajasthan. Rajasthan has rich cultural diversity and biodiversity. Ethno-botany can be defined as the total natural and traditional relationship and the interactions between man and his surrounding plant wealth from times immemorial, due to sheer, necessity, intuition, observation, and experimentation. Medicinal plants are valuable and are used for the production of various drugs. These plants produce a high diversity of natural products or secondary metabolites like Mahanimbicine, Andrographine, murrayaline, lupeol, and limonin etc. with a prominent function in the protection against diseases like diabetes, kidney stones, osteoporosis, tumours, opthalmia, leucorrhoea, bronchial asthma, diarrhea, cancer, etc. The present report gives an account of traditional medicinal uses of common medicinal plants of Rajasthan. A total of 18 plant species belonging to 13 families are reported, that are being used for various purposes.

Keywords: ethno botany, Rajasthan, secondary metabolites, traditional medicines

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806 Carbon Based Wearable Patch Devices for Real-Time Electrocardiography Monitoring

Authors: Hachul Jung, Ahee Kim, Sanghoon Lee, Dahye Kwon, Songwoo Yoon, Jinhee Moon

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We fabricated a wearable patch device including novel patch type flexible dry electrode based on carbon nanofibers (CNFs) and silicone-based elastomer (MED 6215) for real-time ECG monitoring. There are many methods to make flexible conductive polymer by mixing metal or carbon-based nanoparticles. In this study, CNFs are selected for conductive nanoparticles because carbon nanotubes (CNTs) are difficult to disperse uniformly in elastomer compare with CNFs and silver nanowires are relatively high cost and easily oxidized in the air. Wearable patch is composed of 2 parts that dry electrode parts for recording bio signal and sticky patch parts for mounting on the skin. Dry electrode parts were made by vortexer and baking in prepared mold. To optimize electrical performance and diffusion degree of uniformity, we developed unique mixing and baking process. Secondly, sticky patch parts were made by patterning and detaching from smooth surface substrate after spin-coating soft skin adhesive. In this process, attachable and detachable strengths of sticky patch are measured and optimized for them, using a monitoring system. Assembled patch is flexible, stretchable, easily skin mountable and connectable directly with the system. To evaluate the performance of electrical characteristics and ECG (Electrocardiography) recording, wearable patch was tested by changing concentrations of CNFs and thickness of the dry electrode. In these results, the CNF concentration and thickness of dry electrodes were important variables to obtain high-quality ECG signals without incidental distractions. Cytotoxicity test is conducted to prove biocompatibility, and long-term wearing test showed no skin reactions such as itching or erythema. To minimize noises from motion artifacts and line noise, we make the customized wireless, light-weight data acquisition system. Measured ECG Signals from this system are stable and successfully monitored simultaneously. To sum up, we could fully utilize fabricated wearable patch devices for real-time ECG monitoring easily.

Keywords: carbon nanofibers, ECG monitoring, flexible dry electrode, wearable patch

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805 Induction of Cellular and Humoral Immune Responses in BALB/c Mice Immunized With rB2L and rF1L Proteins of Orf Virus Adjuvanted With Alumina Nanoparticles

Authors: Alhaji Modu Bukar, Faez Firdaus Abdullah Jesse, Che Azurahanim Che Abdullah, Mustapha M. Noordin, Mohd-Lila Mohd Azmia

Abstract:

Orf virus (ORFV) is the causative agent of a proliferative skin lesion known as contagious ecthyma in sheep and goats. Currently used live attenuated vaccines against ORFV infection have been reported to cause severe outbreaks in vaccinated animals. In this study, we investigated the immunogenicity of the B2L and F1L proteins of the virus, which are thought to elicit a protective immune response The 6-week-old 50 female mice were divided into 8 groups: seven experimental groups and one control group. Each animal in the experimental group received an initial immunisation with the nanoparticles or proteins coated with the nanoparticles, followed by two booster immunizations with the same products 14 days apart. Ten days after the last booster inoculation, the mice were either humanely killed or lethally challenged with UPM /HSN-2-ORFV at a dose of 106 TCID50/mL in a volume of 50 μl. The spleen was examined for histopathological changes and quantification of T cells by flow cytometry. On the other hand, the degree of protection of mice from the lethal virus was evaluated by lesion size, weight loss, and histopathological examination of skin and liver. The results showed that mice immunised with rB2L alone, rB2L-Al₂O₃-NPs, rB2L/rF1L, and rB2L/rF1L-Al₂O₃-NPs elicited statistically higher levels of anti-rB2L and/or rF1L-specific IgA/IgG and CD4/CD8 cell immune responses than mice in the control groups (p < 0.01). The vaccine candidate did not exhibit severe skin damage after monitoring histopathology, morbidity, and mortality. Overall, the results suggest that recombinant rB2L and rF1L antigens may be useful universal vaccine candidates against ORFV infections.

Keywords: orf virus, antigen nanoparticles, virus, nanoparticles

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804 Design and Evaluation of a Prototype for Non-Invasive Screening of Diabetes – Skin Impedance Technique

Authors: Pavana Basavakumar, Devadas Bhat

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Diabetes is a disease which often goes undiagnosed until its secondary effects are noticed. Early detection of the disease is necessary to avoid serious consequences which could lead to the death of the patient. Conventional invasive tests for screening of diabetes are mostly painful, time consuming and expensive. There’s also a risk of infection involved, therefore it is very essential to develop non-invasive methods to screen and estimate the level of blood glucose. Extensive research is going on with this perspective, involving various techniques that explore optical, electrical, chemical and thermal properties of the human body that directly or indirectly depend on the blood glucose concentration. Thus, non-invasive blood glucose monitoring has grown into a vast field of research. In this project, an attempt was made to device a prototype for screening of diabetes by measuring electrical impedance of the skin and building a model to predict a patient’s condition based on the measured impedance. The prototype developed, passes a negligible amount of constant current (0.5mA) across a subject’s index finger through tetra polar silver electrodes and measures output voltage across a wide range of frequencies (10 KHz – 4 MHz). The measured voltage is proportional to the impedance of the skin. The impedance was acquired in real-time for further analysis. Study was conducted on over 75 subjects with permission from the institutional ethics committee, along with impedance, subject’s blood glucose values were also noted, using conventional method. Nonlinear regression analysis was performed on the features extracted from the impedance data to obtain a model that predicts blood glucose values for a given set of features. When the predicted data was depicted on Clarke’s Error Grid, only 58% of the values predicted were clinically acceptable. Since the objective of the project was to screen diabetes and not actual estimation of blood glucose, the data was classified into three classes ‘NORMAL FASTING’,’NORMAL POSTPRANDIAL’ and ‘HIGH’ using linear Support Vector Machine (SVM). Classification accuracy obtained was 91.4%. The developed prototype was economical, fast and pain free. Thus, it can be used for mass screening of diabetes.

Keywords: Clarke’s error grid, electrical impedance of skin, linear SVM, nonlinear regression, non-invasive blood glucose monitoring, screening device for diabetes

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803 Poly(Methyl Methacrylate) Degradation Products and Its in vitro Cytotoxicity Evaluation in NIH3T3 Cells

Authors: Lesly Y Carmona-Sarabia, Luisa Barraza-Vergara, Vilmalí López-Mejías, Wandaliz Torres-García, Maribella Domenech-Garcia, Madeline Torres-Lugo

Abstract:

Biosensors are used in many applications providing real-time monitoring to treat long-term conditions. Thus, understanding the physicochemical properties and biological side effects on the skin of polymers (e. g., poly(methyl methacrylate), PMMA) employed in the fabrication of wearable biosensors is crucial for the selection of manufacturing materials within this field. The PMMA (hydrophobic and thermoplastic polymer) is commonly employed as a coating material or substrate in the fabrication of wearable devices. The cytotoxicityof PMMA (including residual monomers or degradation products) on the skin, in terms of cells and tissue, is required to prevent possible adverse effects (cell death, skin reactions, sensitization) on human health. Within this work, accelerated aging of PMMA (Mw ~ 15000) through thermal and photochemical degradation was under-taken. The accelerated aging of PMMA was carried out by thermal (200°C, 1h) and photochemical degradation (UV-Vis, 8-15d) adapted employing ISO protocols (ISO-10993-12, ISO-4892-1:2016, ISO-877-1:2009, ISO-188: 2011). In addition, in vitro cytotoxicity evaluation of PMMA degradation products was performed using NIH3T3 fibroblast cells to assess the response of skin tissues (in terms of cell viability) exposed with polymers utilized to manufacture wearable biosensors, such as PMMA. The PMMA (Mw ~ 15000) before and after accelerated aging experiments was characterized by thermal gravimetric analysis (TGA), differential scanning calorimetric (DSC), powder X-ray diffractogram (PXRD), and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) to determine and verify the successful degradation of this polymer under the specific conditions previously mention. The degradation products were characterized through nuclear magnetic resonance (NMR) to identify possible byproducts generated after the accelerated aging. Results demonstrated a percentage (%) weight loss between 1.5-2.2% (TGA thermographs) for PMMA after accelerated aging. The EDS elemental analysis reveals a 1.32 wt.% loss of carbon for PMMA after thermal degradation. These results might be associated with the amount (%) of PMMA degrade after the accelerated aging experiments. Furthermore, from the thermal degradation products was detected the presence of the monomer and methyl formate (low concentrations) and a low molecular weight radical (·COOCH3) in higher concentrations by NMR. In the photodegradation products, methyl formate was detected in higher concentrations. These results agree with the proposed thermal or photochemical degradation mechanisms found in the literature.1,2 Finally, significant cytotoxicity on the NIH3T3 cells was obtained for the thermal and photochemical degradation products. A decrease in cell viability by > 90% (stock solutions) was observed. It is proposed that the presence of byproducts (e.g. methyl formate or radicals such as ·COOCH₃) from the PMMA degradation might be responsible for the cytotoxicity observed in the NIH3T3 fibroblast cells. Additionally, experiments using skin models will be employed to compare with the NIH3T3 fibroblast cells model.

Keywords: biosensors, polymer, skin irritation, degradation products, cell viability

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