Describing Polymers Synthesized from Reducing Sugars and Ammonia Employing FTIR Spectroscopy

          يمكن تشخيص الميلانويد باستخدام تقنية مطيافية الأشعة تحت الحمراء (FTIR) . أن UV/Vis هي أداة فعالة للتحليل النوعي والكمي للمكونات الكيميائية في بوليمرات الميلانودين. تتطابق الميزات الهيكلية والاهتزازية للميلانويدات المُصنَّعة من D-Glucose و D-Fructose ، وفقًا لأطياف FTIR ، مع الاختلاف الوحيد في شدة القمم. باستخدام أطياف FTIR ، ينقسم الهيكل التركيبي للميلانودين إلى سبع مناطق رئيسية. تم تأكيد وجود مجموعات C = C و C = N و C = O في جميع الميلانويدات المكونة من الفركتوز والجلوكوز مع الأمونيا من خلال المناطق التي تتراوح من 1600 إلى 1690 سم -1 ، ويتضح النطاق إلى حد كبير على أنه نطاق واسع. يحتوي كل من الميلانويدات على كربوكسيل أو كربونيل في المنطقة تقريبا 1700 سم -1. في جميع الميلانويدينات، اختفت مجموعة +NH في نطاق 3080 سم-1. ومع ذلك ، فإن كثافة اللون تعتمد على نوع السكر المستخدم في تخليق الميلانويدين. علاوة على ذلك، بالمقارنة مع ميلانويدين المخلق من الأمونيا و الكلوكوز Glc-ammoina ، التي تحتوي على نسبة أعلى من الكربون المهجن sp3 ، فإن الميلانويدين المخلق من الأمونيا و الفركتوز Fru-ammonia لديها نسبة أعلى من الكربون المهجن sp2 على أساس تحليل الأشعة فوق البنفسجية / المرئية و FTIR وأطياف المشتق الثاني. علاوة على ذلك ، تمت محاكاة البيانات بأستخدام تحليل المكون الرئيسي (PCA). تم استخدام تحليل المكون الرئيسي (PCA) لتفسير البيانات.          Melanoidins can be diagnosed using the Fourier transform infrared (FTIR) technique. UV/Vis is an effective tool for both qualitative and quantitative analysis of chemical components in melanoidin polymers. The structural and vibrational features of melanoidin synthesized from D-glucose and D-fructose are identical, according to FTIR spectra, with the only difference being the intensity of bands.  Using FTIR spectra, the skeleton of melanoidin is divided into seven major regions. The existence of the C=C, C=N, and C=O groups in all melanoidins formed from fructose and glucose with ammonia is confirmed by the areas ranging from 1600 to 1690 cm-1, and the band is largely evident as a broad shoulder. Both melanoidins have a carboxyl or carbonyl extending around 1700 cm-1. In all melanoidins, the NH+ group has vanished in the 3080 cm-1 range. However, the color intensity depends on the type of sugar employed in melanoidin synthesis. Furthermore, in comparison to Glc-ammonia, which has a higher proportion of sp3 hybridized carbon, Fru-ammonia has a higher proportion of sp2 hybridized carbon based on UV/Vis, FTIR and second-derivative spectra. Moreover, the data were simulated using principal component analysis. Principal component analysis (PCA) was used to interpret the data

Brasures composites architecturés sans plomb pour les modules électroniques de puissance

National audienceGénéralement, un module électronique de puissance utilisé pour les véhicules électriques et hybrides (EV/HEV) est un assemblage de plusieurs composants électroniques en silicium (transistors et diodes) brasés sur un substrat en cuivre. La brasure, qui est souvent un alliage riche en plomb de type PbSn, assure le transfert thermique et la conduction électrique entre les différents composants électroniques et le substrat. En fonctionnement, les modules de puissance sont soumis à des cycles thermiques. Sous l'effet de flux thermiques dissipés, l'assemblage de différents éléments dans un module de puissance génère des contraintes importantes dans la brasure. Elles sont essentiellement dues à des propriétés de dilatabilité différentes des matériaux qui constituent l'assemblage qui peuvent conduire à des défaillances caractérisées par l'amorçage puis la propagation de fissures au niveau de la brasure. D'autre part, pour des raisons environnementales, l'élimination du plomb dans les alliages de brasage électronique est devenue une priorité industrielle. En effet, les nouvelles règlementations telle que la directive REACH, vont progressivement imposer l'élimination du plomb pour de telles applications. Toutefois, les alliages sans plomb utilisés à ce jour souffrent d'une faible résistance au vieillissement thermique. Sous l'effet de la chaleur, la microstructure initiale de la brasure peut évoluer en donnant naissance à des intermétalliques. Ces dernières peuvent se développer sous la forme de plaquettes aciculaires (aiguilles) qui constituent des sites privilégiés à la concentration de contraintes. Ce phénomène de concentration réduit alors drastiquement la durée de vie du module électronique. L'objectif principal de cette étude est de développer une brasure sans plomb mais relativement réfractaire présentant des conductivités thermique et électrique élevées associées à une dilatabilité la plus proche possible de celle du silicium (CTE~5.10-6K-1). De plus, la microstructure de la brasure doit prendre en compte la maîtrise de croissance des intermétalliques lors du vieillissement

Substrat architecturé pour une gestion thermique efficace dans les modules électroniques de puissance

National audienceLes modules électroniques de puissance sont des composants essentiels pour le développement de nombreuses fonctions dans les véhicules électriques et hybrides. Ces modules sont des assemblages de composants électroniques en silicium (transistor et diode) sur un substrat généralement en cuivre. Le substrat assure le maintien mécanique et le transfert de la chaleur pour obtenir une température de fonctionnement convenable (<175°C) du silicium. En fonctionnement, une partie de la puissance est dissipée sous forme d'un flux de chaleur à cause de la résistance interne des semi-conducteurs. Ce flux diffuse de la face inferieure des composants électroniques vers le substrat et engendre l'échauffement de l'assemblage. Du fait que cet assemblage comprend divers matériaux, les dilatations thermiques différentes génèrent des contraintes de cisaillement dans la zone de liaison (brasure) en provoquant l'endommagement des modules électroniques. Pour résoudre ce problème, le substrat doit avoir un compromis entre des caractéristiques électriques et thermiques proches de celles du substrat actuel (Cu) et un coefficient de dilatation linéique proche de celui du semi-conducteur (Si). Une des solutions alternatives consiste à développer un matériau composite architecturé. Nous proposons d'atténuer les effets mécaniques de la dilatation différentielle à l'aide d'un substrat architecturé. Le substrat proposé est un matériau composite métallique dont les paramètres de forme ont été optimisés par simulation numérique et validés expérimentalement afin d'accroître au mieux la conductivité du substrat et d'en réduire la dilatation macroscopique. De plus, nous avons validé la mise en oeuvre du substrat proposé par des procédés conventionnels de colaminage, de pliage et de découpe

Review Article p16 INK4A and p14 ARF Gene Promoter Hypermethylation as Prognostic Biomarker in Oral and Oropharyngeal Squamous Cell Carcinoma: A Review

Head and neck squamous cell carcinoma is a heterogeneous group of tumors with each subtype having a distinct histopathological and molecular profile. Most tumors share, to some extent, the same multistep carcinogenic pathways, which include a wide variety of genetic and epigenetic changes. Epigenetic alterations represent all changes in gene expression patterns that do not alter the actual DNA sequence. Recently, it has become clear that silencing of cancer related genes is not exclusively a result of genetic changes such as mutations or deletions, but it can also be regulated on epigenetic level, mostly by means of gene promoter hypermethylation. Results from recent studies have demonstrated that DNA methylation patterns contain tumor-type-specific signatures, which could serve as biomarkers for clinical outcome in the near future. The topic of this review discusses gene promoter hypermethylation in oral and oropharyngeal squamous cell carcinoma (OSCC). The main objective is to analyse the available data on gene promoter hypermethylation of the cell cycle regulatory proteins p16 INK4A and p14 ARF and to investigate their clinical significance as novel biomarkers in OSCC. Hypermethylation of both genes seems to possess predictive properties for several clinicopathological outcomes. We conclude that the methylation status of p16 INK4A is definitely a promising candidate biomarker for predicting clinical outcome of OSCC, especially for recurrence-free survival

Founder effect in the Horn of Africa for an insulin receptor mutation that may impair receptor recycling.

AIMS/HYPOTHESIS: Genetic insulin receptoropathies are a rare cause of severe insulin resistance. We identified the Ile119Met missense mutation in the insulin receptor INSR gene, previously reported in a Yemeni kindred, in four unrelated patients with Somali ancestry. We aimed to investigate a possible genetic founder effect, and to study the mechanism of loss of function of the mutant receptor. METHODS: Biochemical profiling and DNA haplotype analysis of affected patients were performed. Insulin receptor expression in lymphoblastoid cells from a homozygous p.Ile119Met INSR patient, and in cells heterologously expressing the mutant receptor, was examined. Insulin binding, insulin-stimulated receptor autophosphorylation, and cooperativity and pH dependency of insulin dissociation were also assessed. RESULTS: All patients had biochemical profiles pathognomonic of insulin receptoropathy, while haplotype analysis revealed the putative shared region around the INSR mutant to be no larger than 28 kb. An increased insulin proreceptor to β subunit ratio was seen in patient-derived cells. Steady state insulin binding and insulin-stimulated autophosphorylation of the mutant receptor was normal; however it exhibited decreased insulin dissociation rates with preserved cooperativity, a difference accentuated at low pH. CONCLUSIONS/INTERPRETATION: The p.Ile119Met INSR appears to have arisen around the Horn of Africa, and should be sought first in severely insulin resistant patients with ancestry from this region. Despite collectively compelling genetic, clinical and biochemical evidence for its pathogenicity, loss of function in conventional in vitro assays is subtle, suggesting mildly impaired receptor recycling only

Expression of a glycosylphosphatidylinositol-anchored ligand, growth hormone, blocks receptor signalling

We have investigated the interaction between GH (growth hormone) and GHR (GH receptor). We previously demonstrated that a truncated GHR that possesses a transmembrane domain but no cytoplasmic domain blocks receptor signalling. Based on this observation we investigated the impact of tethering the receptor's extracellular domain to the cell surface using a native lipid GPI (glycosylphosphatidylinositol) anchor. We also investigated the effect of tethering GH, the ligand itself, to the cell surface and demonstrated that tethering either the ecGHR (extracellular domain of GHR) or the ligand itself to the cell membrane via a GPI anchor greatly attenuates signalling. To elucidate the mechanism for this antagonist activity, we used confocal microscopy to examine the fluorescently modified ligand and receptor. GH–GPI was expressed on the cell surface and formed inactive receptor complexes that failed to internalize and blocked receptor activation. In conclusion, contrary to expectation, tethering an agonist to the cell surface can generate an inactive hormone receptor complex that fails to internalize

Behavioural Lifestyle Intervention Study (BLIS) in patients with type 2 diabetes in the United Arab Emirates: A randomized controlled trial

BACKGROUND: Lifestyle modification is a cornerstone of the management of type 2 diabetes. However, in the United Arab Emirates, a country where type 2 diabetes is highly prevalent, non-compliance with a healthy lifestyle has been reported in many diabetic Emirati patients. The use of behavioural theories in lifestyle counselling is believed to facilitate behavioural changes, nevertheless, there are no published data regarding the use of structured behavioural lifestyle programmes tailored to suit Emirati culture. The primary objective of this study was to develop a behavioural lifestyle programme and to evaluate its effectiveness in improving glycaemic control in Emirati patients with type 2 diabetes. METHODS: The Behavioural Lifestyle Intervention Study (BLIS) was a translational randomized controlled trial in which patients (n = 35) were randomly assigned to the intervention or control group. Patients in the intervention group went through a six-month behavioural lifestyle programme composed of 8 sessions, whereas patients in the control group received standard care. Cognitive behavioural theory was the underpinning theory for the lifestyle intervention. HbA1c levels were the trial’s primary outcome measure, and the main dietary factor targeted for change was carbohydrate intake. They were measured at baseline, 3 months and 6 months and were assessed using one-way ANOVA at a significance level of P < 0.05. All of the patients were then followed up at 1 year on all outcome measures. RESULTS: At 6 months, the HbA1c levels of the patients (n = 18) in the intervention group were significantly reduced (−1.56 ± 1.81, P < 0.05), whereas no significant change was observed in the patients of the control group. Similarly, both carbohydrate intake from cereals and total carbohydrate intake (in grams) were reduced (p < 0.05) in the intervention group, by 32.92 ± 54.34 and 20.94 ± 56.73, respectively. At 1 year, the patients in the intervention group maintained a significant reduction in HbA1c levels (−1.12 ± 1.46, p < 0.05), whereas no change was observed in the control group. CONCLUSION: The behavioural lifestyle intervention programme was effective in improving glycaemic control and compliance with carbohydrate intake goals in Emirati patients with type 2 diabetes. Larger randomized controlled trials are needed to validate these results and to identify key behavioural strategies that will improve compliance to lifestyle modifications in real life. TRIAL REGISTRATION: Clinicaltrials.gov trial identifier NCT0238693

La comunicazione interculturale e l’approccio comunicativo: dall’idea allo strumento

il saggio si inserisce in un filone di ricerca aperto nel 199 e proseguito con saggi e volumi: in questo caso di descrive e discute la progettazione di un passo fondamentale, dall'elaborazione teorica del modello di riferimento alla traduzione di tale modello in strumento operativo per la consultazione e la didattica

Factors affecting the motivation of healthcare professionals providing care to Emiratis with type 2 diabetes

OBJECTIVE: We aimed to identify facilitators of and barriers to healthcare professionals' motivation in a diabetes centre in the United Arab Emirates (UAE). DESIGN: A qualitative research approach was employed using semistructured interviews to assess perception of and attitudes regarding healthcare professionals' motivation in providing good quality diabetes care. SETTING: A diabetes centre located in Abu-Dhabi, UAE. PARTICIPANTS: Healthcare professionals including specialist physicians, dieticians, podiatrists, health educators and nurses were recruited through purposive sampling. MAIN OUTCOME MEASURES: After data collection, the audiotaped interviews were transcribed verbatim and subjected to content analysis. RESULTS: Nine semistructured interviews were conducted with healthcare professionals of various professional backgrounds. Important facilitators and barriers related to patient, professional, organization and cultural factors were identified. Barriers that related to heavy workload, disjointed care, lack of patient compliance and awareness, and cultural beliefs and attitudes about diabetes were common. Key facilitators included the patient's role in achieving therapeutic outcomes as well as compliance, cooperation and communication. CONCLUSION: This qualitative study provides some unique insights about factors affecting healthcare professionals' motivation in providing good quality care. To improve the motivation of healthcare professionals in the management of diabetes and therefore the quality of diabetes care, several steps are needed. Importantly, the role of primary care should be reinforced and strengthened regarding the management of type 2 diabetes mellitus, privacy of the consultation time should be highly protected and regulated, and awareness of the Emirate culture and its impact on health should be disseminated to the healthcare professionals providing care to Emirates with diabetes. Also, greater emphasis should be placed on educating Emiratis with diabetes on, and involving them in, the management of their condition