Photoemission studies of ex-situ and in-situ surface cleaning and electronic properties of ZnO surfaces

The aim of this research project was to undertake the surface characterisation of (0001)- Zn, (000-1)-O polar and (10-10), (11-20) non-polar ZnO surfaces by x-ray photoelectron spectroscopy (XPS) and to develop surface cleaning procedures to make these surfaces suitable for subsequent device processing. Conventional XPS and synchrotron radiation based photoelectron spectroscopy (SRPES) were used to undertake binding energy calibrations, estimations of surface contamination, stoichiometric analysis and electronic band alignment measurements for the different ZnO surfaces. A wide range of cleaning procedures including ex-situ organic solvent cleaning, in-situ ultra-high vacuum (UHV) annealing, in-situ atomic hydrogen and atomic oxygen cleaning as well as in-situ high temperate molecular oxygen annealing treatments were systematically investigated and evaluated as to their effectiveness at preparing contamination free surfaces. The ex-situ wet chemical cleaning resulted in only a small reduction in the carbon contamination signal and a corresponding increase in the surface hydroxide signal. On all ZnO surfaces investigated, the contamination was reduced at different rates, depending on the surface termination. The in-situ surface cleaning studies showed that while in general it is possible to remove the carbon contamination by a variety of methods, the surface hydroxide species cannot be removed, due to the bond strength of O-H. It was found that the effective carbon removal temperature for the ZnO surfaces using atomic hydrogen cleaning was 600 °C, using molecular oxygen thermal cleaning it was 700 °C and for atomic oxygen, the cleaning temperature was 400 °C. As the result of removing carbon contamination on all ZnO surfaces, the natural surface downward banding was reversed into upward band bending

COMPARISON OF THE EFFICACY AND SAFETY OF TRAMADOL VERSUS TAPENTADOL IN ACUTE OSTEOARTHRITIC KNEE PAIN: A RANDOMIZED, CONTROLLED TRIAL

Objectives: Osteoarthritis of knee, a common disorder of elderly, has multifaceted pain mechanisms. Newer opioids such as tramadol and tapentadoltarget those multiple pain mechanisms, with few studies that compare them. We compared the efficacy and safety of tramadol versus tapentadol inacute episodes of osteoarthritic knee pain on 100 patients, 50 in each group.Methods: Group A received tramadol 50 mg twice daily for a period of 1-week, and Group B received tablet tapentadol 50 mg twice daily for aperiod of 1-week. Pain and function were evaluated by numerical pain rating scale (NPRS) and Western Ontario and McMaster Universities (WOMAC)questionnaire and scored during the initial baseline visit before the start of treatment. The efficacy of the drugs was evaluated at the end of 1 weekfollow-up by repeating the NPRS and WOMAC questionnaire. Adherence to medication was emphasized, and side effects of the drugs were evaluatedby Naranjo's scale. The data were analyzed statistically using descriptive statistics, namely, mean, standard deviation, and median. Non-parametrictests, namely, Mann–Whitney test, Wilcoxon signed rank test, and parametric tests such as unpaired t-test and paired t-test were used whereverapplicable. All patients completed the study.Results: There was no statistically significant difference in the total WOMAC scoring between the two groups: Tramadol and tapentadol. However,tapentadol provided statistically significant pain relief compared to tramadol as measured by the NPRS. Both the groups tolerated the drugs well.There was no incidence of any adverse effects.Conclusion: Hence, both the drugs are efficacious in treating an acute painful episode of osteoarthritic knee pain and can be safely prescribed to thepatients.Keywords: Tapentadol, Tramadol, Newer opioids.s

Microscopic origins of the surface exciton photoluminescence peak in ZnO nanostructures

We report photoluminescence (PL) studies of the surface exciton peak in ZnO nanostructures at ∼3.367 eV aimed at elucidation of the nature and origin of the emission and its relationship to the nanostructure morphology. PL spectra in conjunction with localized voltage application in high vacuum and different gas atmospheres show a consistent variation (and recovery), allowing an association of the PL to a bound excitonic transition at the ZnO surface, which is modified by an adsorbate. PL studies of samples treated by plasma and of samples exposed to UV light under high vacuum conditions, both well-known processes for desorption of surface adsorbed oxygen, show no consistent effects on the surface exciton peak indicating the lack of involvement of oxygen species. X-ray photoelectron spectroscopy data strongly suggest involvement of adsorbed OH species. X-ray diffraction, scanning, and transmission electronmicroscopy data are presented also, and the relationship of the surface exciton peak to the nanostructure morphology is discussed

Modulation of glucose transporter proteins by polyphenolic extract of Ichnocarpus frutescens (L.) W. T. Aiton in experimental type 2 diabetic rats

172-180Traditionally, in India, the decoction of Black creeper, Ichnocarpus frutescens (L.) W. T. Aiton leaves is used to treatment diabetes mellitus. However, its molecular mechanisms of antihyperglycemic effects have not been completely studied. Due to the potential antidiabetic effect of I. frutescens, we hypothesized that the polyphonic extract might add to glucose uptake through improvement in the expression of genes of the glucose transporter (GLUT) family messenger RNA (mRNA) in the liver and adipose tissues. Experimentally, diabetes mellitus was induced in Wistar rats through i.p. injection of freshly prepared solution of streptozotocin (45 mg/kg). This was done 15 minutes after the administration of nicotinamide (120 mg/kg, ip). Serum level of insulin and C-peptide were analyzed using standard methods. Glucose metabolism by the hepatocytes and adipocytes were also analyzed by quantitative RT-PCR mRNA expression levels of phosphoenolpyruvate carboxykinase 1 (PCK1), GLUT2 in the hepatocytes, and GLUT4 in the adipocytes. The hemidiaphragm were also isolated and processed to study in-vitro peripheral glucose utilization. Results of the present investigation suggest that STZ-NA induced diabetes is associated with hyperglycemia, altered levels of PCK1 and glucose transporters gene expression as well as decreased levels of insulin and C-peptide. On the other hand, the outcome of the daily oral administration of PPE to STZ-NA induced diabetic rats at different doses (150 and 300 mg/kg bodywt.) for 30 days supports our hypothesis by showing significant improvement of insulin levels, C-peptide level, downregulation of PCK1 and upregulation of GLUT (2, 4) mRNA expression levels when compared to those of diabetic rats. The administration of PPE had also increased the uptake of glucose by rat hemidiaphragm significantly. Findings from this study demonstrate that PPE enhances peripheral glucose uptake through glycogenesis pathway, mediated by upregulation of GLUT2 and GLUT4, and downregulation of PCK1. Our study suggests that the leaf of I. frutescens is a rich source of polyphenolic compounds, including those with an insulin-sensitizing function that may have the potential for treating or managing diabetes or insulin resistance

Anti-Urolithiatic Activity of Melia Azedarach Linn Leaf Extract in Ethylene Glycol-Induced Urolithiasis in Male Albino Rats

Purpose: To investigate the anti-urolithiatic activity of the aqueous and alcoholic extracts of Melia azedarach Linn leaves in calcium oxalate urolithiasis in male albino rats.Methods: The effect of oral administration of aqueous and ethanol extracts of Melia azedarach Linn leaves on calcium oxalate urolithiasis has been investigated. Lithiasis was induced by oral adminstration of ethylene glycol (0.75 %v/v) in male albino rats for 28 days. Each of the extract (250 mg/kg) was administered orally day 0 as a prophylactic regimen and from day 15 as a curative regimen. Regular administration of ethylene glycol caused hyperoxaluria in ethylene glycol-fed animals, leading to increased renal retention and excretion of oxalate, calcium and phosphate. Histopathological study, urine microscopy, serum analysis and biochemical analysis of kidney homogenate were performed.Results: Oxalate and calcium excretion in urine increased (p < 0.01) to 3.68 ± 0.01 and 4.5 ± 0.01 mg/24 h, respectively, in lithiatic control animals compared to (0.37 ± 0.01 and 1.27 ± 0.12 mg/24 h) for the normal control group. Treatment with aqueous or ethanol extract (250 mg/kg, p.o.) significantly (p <0.01) reduced the elevated levels of calcium, oxalate and phosphate excretion in urine to 0.79 ± 0.01 and 1.09 ± 0.04 mg/24 h, respectively. Following treatment with the ethanol extract (250mg/kg), serum creatinine excretion was restored from 0.95 ± 0.01 mg/24 h to the normal level of 0.87 ± 0.01 mg/24 h. The results were comparable to those of the standard drug, allopurinol (50 mg/kg p.o.).Histopathological data for the kidney supported the foregoing results.Conclusions: The results demonstrate that the aqueous and ethanol extracts of Melia azedarach Linn leaves have potent antiurolithiatic activity against ethylene glycol-induced calcium oxalate urolithiasis in male albino rats.Keywords: Melia azedarach, Antiurolithiatic, Ethylene glycol, Urolithiasis, Excretion, Kidne

INVESTIGATION ON ANTIDIARRHOEAL ACTIVITY OF ARISTOLOCHIA INDICA LINN. ROOT EXTRACTS IN MICE

Background: The present study aimed at investigating the effect of ethanolic extract (EtAI), and aqueous extract (AqAI) of Aristolochia indica Linn roots on castor oil-induced diarrhoea and study on small intestinal transit. Phytochemical analysis of extracts was performed as per standard procedure. Materials and Methods: The oral toxicity study using Swiss albino mice was performed in accordance with OECD guidelines. The EtAI and AqAI extracts of Aristolochia indica Linn were studied for antidiarrhoeal property using castor oil-induced diarrhoeal model and charcoal-induced gastrointestinal motility test in Swiss albino mice. Results: Among the tested doses of 200 and 400 mg/kg body weight, the extracts reduced the frequency and severity of diarrhoea in test animals throughout the study period. At the same doses, the extract delayed the intestinal transit of charcoal meal in test animals as compared to the control and the results were statistically significant. Conclusion: Experimental findings showed that ethanol extract of Aristolochia indica Linn root possess significant antidiarrheal activity and may be a potent source of anti-diarrhoeal drug in future

Appraising the therapeutical potentials of Alchornea laxiflora (Benth.) Pax & K. Hoffm., an underexplored medicinal herb: A systematic review

Ethnopharmacological relevance:Alchornea laxiflora (Benth.) Pax & K. Hoffm. (Euphorbiaceae) is an important traditional medicinal plant grown in tropical Africa. The stem, leaves, and root have been widely used in the folk medicine systems in Nigeria, Cameroon, South Africa, and Ghana to treat various ailments, including inflammatory, infectious, and central nervous system disorders, such as anxiety and epilepsy.Material and methods: The scientific name of the plant was validated using the “The Plant List,” “Kew Royal Botanic Gardens,” and Tropicos Nomenclatural databases. The literature search on A. laxiflora was performed using electronic search engines and databases such as Google scholar, ScienceDirect, PubMed, AJOL, Scopus, and Mendeley.Results: To the best of our knowledge, no specific and detailed review has been reported on A. laxiflora. Consequently, this review provides an up-to-date systematic presentation on ethnobotany, phytoconstituents, pharmacological activities, and toxicity profiles of A. laxiflora. Phytochemical investigations disclosed the presence of important compounds, such as alkaloids, flavonoids, phenolics, terpenoids, and fatty acids. Furthermore, various pharmacological activities and traditional uses reported for this botanical drug were discussed comprehensively.Conclusion: This systemic review presents the current status and perspectives of A. laxiflora as a potential therapeutic modality that would assist future researchers in exploring this African botanical drug as a source of novel drug candidates for varied diseases

Therapeutic implications of current Janus kinase inhibitors as anti-COVID agents: A review

Severe cases of COVID-19 are characterized by hyperinflammation induced by cytokine storm, ARDS leading to multiorgan failure and death. JAK-STAT signaling has been implicated in immunopathogenesis of COVID-19 infection under different stages such as viral entry, escaping innate immunity, replication, and subsequent inflammatory processes. Prompted by this fact and prior utilization as an immunomodulatory agent for several autoimmune, allergic, and inflammatory conditions, Jakinibs have been recognized as validated small molecules targeting the rapid release of proinflammatory cytokines, primarily IL-6, and GM-CSF. Various clinical trials are under investigation to evaluate Jakinibs as potential candidates for treating COVID-19. Till date, there is only one small molecule Jakinib known as baricitinib has received FDA-approval as a standalone immunomodulatory agent in treating critical COVID-19 patients. Though various meta-analyses have confirmed and validated the safety and efficacy of Jakinibs, further studies are required to understand the elaborated pathogenesis of COVID-19, duration of Jakinib treatment, and assess the combination therapeutic strategies. In this review, we highlighted JAK-STAT signalling in the pathogenesis of COVID-19 and clinically approved Jakinibs. Moreover, this review described substantially the promising use of Jakinibs and discussed their limitations in the context of COVID-19 therapy. Hence, this review article provides a concise, yet significant insight into the therapeutic implications of Jakinibs as potential anti-COVID agents which opens up a new horizon in the treatment of COVID-19, effectively

SIMS characterisation of ZnO and MgO thin films

Poster Presented in the BOC Gases Postgraduate Poster Competition,  held by School of Physical Sciences, Dublin City University in 2009.</p