WS2-Nanosheet-Modified Electrodes as an Efficient Electrochemical Sensing Platform for the Nonenzymatic Detection of the Insecticide Imidacloprid.

Imidacloprid (IMI) is a systemic insecticide, which is widely used for seed treatment and pest control in vegetables. The unwarranted presence of traces of IMI in vegetables and groundwater is a matter of grave concern which needs to be detected and quantified in order to effect remedial measures for the sake of food safety. In this work, we communicate the fabrication of tungsten sulfide (WS2) nanosheets and the construction of an amperometric sensor for the precise determination of IMI. The sensor performances were evaluated by using cyclic voltammetry (CV). The presence of surface-active sites and the fast electron transfer on WS2/GCE favored the electrochemical reduction of the aromatic nitro group in IMI. The developed IMI sensor displayed a linear range of IMI detection from 10 to 90 µM with a detection limit of 0.28 µM. The developed WS2/GCE sensor also displayed good sensitivity, with a value of 3.98 µA µM-1 cm-2. The electrochemical measurements demonstrated the superior selectivity of the constructed WS2/GCE sensor for IMI detection, which makes it suitable for practical applications.

Determination and quantification of related substances and degradation products in bictegravir by full factorial design evaluated HPLC and mass spectrometry.

Determining and quantifying novel impurities and degraded impurities of a drug product is always a continuous challenge to enhancing the drug quality for patients' safety. Herein, our work deals with (i) developing a rapid, accurate, and reliable high-performance liquid chromatographic validation method to quantify the bictegravir drug (integrase inhibitors of antiretroviral drugs) and its novel related impurities at low levels, and (ii) the liquid chromatography-mass spectrometry (LC-MS) method to identify degraded impurities. Separation of bictegravir acid (impurity-I) and methyl bictegravir (impurity-II) impurities which are identified by LC-MS in the bictegravir drug was executed by developing a method and the same method performance evaluated by using full factorial design. This developed analytical technique gave a well-separated peak of bictegravir and related analytes such as bictegravir acid (impurity-I) and methyl bictegravir (impurity-II), adequate with the peak properties as per USP guidelines. The method's sensitivity and linearity are demonstrated by its detection and quantification limits at low levels with a correlation coefficient of 0.998. The method's repeatability, specificity, and accuracy suggest that this developed technique is a reliable determination strategy for the bictegravir drug substance and its related impurities (impurity-I and impurity-II) in a simple, feasible, and affordable way.

Identification and validation of potential genotoxic impurities, 1,3-dichloro-2-propanol, and 2,3-dichloro-1-propanol, at subtle levels in a bile acid sequestrant, colesevelam hydrochloride, using hyphenated GC-MS technique.

Potential genotoxic impurities (PGI) and N-nitrosamine impurities in active pharmaceutical ingredients (APIs) and their determination at low levels are substantial challenges for cholesterol-lowering agents in recent years. Herein we developed a robust, reliable, rapid, accurate and validated technique of gas chromatography equipped with a mass spectrometer (GC-MS) for quantifying subtle levels of 1,3-dichloro-2-propanol (PGI-I) and 2,3-dichloro-1-propanol (PGI-II) in colesevelam hydrochloride drug substance (bile acid sequestrant). The separation of colesevelam hydrochloride, PGI-I and PGI-II was executed with chromatographic technique using a capillary column, DB-624 measuring with 30 m × 0.32 mm × 1.8 µm specification of 6% cyanopropylphenyl-94% dimethylpolysiloxane copolymer and helium carrier gas. This developed technique gave a good intensity peak without any interference and extra masses at the retention times of 11.17 min for PGI-I and 11.59 min for PGI-II, which was adequate, with mass spectra (m/z) of 79 and 62, respectively. The method's sensitivity and linearity are demonstrated by its detection and quantification limits at subtle levels with correlation coefficients of 0.9965 for PGI-I and 0.9910 for PGI-II. The determination is mainly focused on improving sensitivity with the limits of detection and quantitation far below the specifications, which can support tighter limits. This results in a cost-effective and easily adoptable methodology having precise and accurate results in colesevelam hydrochloride API at subtle levels.

Stress and Strain Created Around Miniscrews during En Masse Retraction - A Finite Element Method.

Background: En masse retraction of the anterior teeth may create anchorage problems. The effective means of obtaining anchorage in en masse retraction is by the usage of temporary anchorage devices. Aims and Objectives: The purpose of this study is focused on stress and strain created around miniscrew during en masse retraction using the cone beam computed tomography (CBCT) data obtained at two intervals and by the finite element analysis done using the CBCT data obtained. This will show us the stress and strain created around miniscrews and the withstanding capacity of miniscrews. Conclusion: Stress and strain was higher in TADs as compared to cortical and alveolar bone.

Eco-Friendly Synthesis of MnO2 Nanorods Using Gmelina arborea Fruit Extract and Its Anticancer Potency Against MCF-7 Breast Cancer Cell Line.

INTRODUCTION: Cancer disease is known due to its unregulated proliferation of cells that have evolved from the body's regular cells. The disease develops as a result of epigenetic and genetic modifications, tumor suppressor gene inactivation, and oncogene activation. The present work describes an environmentally benign approach for the synthesis of manganese oxide nanoparticles (MnO2 NPs) using Gmelina arborea fruit extract (GAE) in an aqueous medium. METHODS: The study evaluated the formation of MnO2 NPs and their anticancer efficacy against MCF-7 breast cancer cell line. RESULTS: The formation of MnO2 NPs was confirmed through powder X-ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HR-TEM). The crystalline nature of as-prepared MnO2 NPs was evident from XRD pattern. The morphology of the material was studied using SEM analysis, which suggested a rod-like nature with an average diameter of 50 nm. Further, the TEM and HR-TEM images confirmed the rod shape of the as-prepared MnO2 NPs with an interplanar distance of 0.271 nm. In addition, the concentric rings from selected area electron diffraction (SAED) analysis show the crystalline nature of the as-prepared material, which further supports the obtained XRD pattern. The anticancer efficacy of MnO2 NPs was evaluated against MCF-7 breast cancer cell line, which showed up to 96% inhibition of the cells at 400 µg/mL concentration. CONCLUSION: Bio-conjugation of MnO2 NPs can provide enough scope for the therapeutic use of Gmelina arborea, assuming appropriate mechanistic evaluations are conducted.

Functional Outcome of Open Latarjet Procedure in Non-Athletic Middle-Aged Patients.

INTRODUCTION: The movement and steadiness of the shoulder joint is due to both the dynamic and static stabilisers. Recurrent anterior shoulder instability is common due to the Bankart lesion or the Hill Sachs lesion. The bone loss and soft tissue failure due to these lesions causing instability is well compensated by Latarjet procedure which acts by triple blocking effect of the bone graft, the sling effect of the conjoint tendon of subscapularis and the ligament of the coracoacromial ligament stump. MATERIALS AND METHODS: Middle-aged patients with recurrent anterior shoulder dislocation and a mid-range instability on clinical assessment with an isolated glenoid bone loss of 20% or Bankart lesion with engaging Hill Sachs lesion were selected for the study. The surgical procedure included a subscapularis split to expose the glenoid. The coracoid graft harvested was prefixed with Kirschner wires and placed flush over the glenoid ensuring no medial or lateral overhang and fixed with 4.0mm cancellous screws with the washer. The functional outcome was measured with the ROWE score and ASES score and the movements were evaluated. RESULTS: A total of 24 patients fulfilled the inclusion criteria. Post-operatively at final follow-up, the mean ROWE score was 97.08 ±8.45 and the mean ASES score was 94.4±9.10. One patient had screw breakage as a complication and another had restriction of movement which was managed with physiotherapy. CONCLUSION: Open Latarjet is an effective procedure for recurrent anterior shoulder instability in non-athletic middle-aged patients as a excellent functional outcome was achieved with this technique. We therefore recommend open Latarjet as an alternative to arthroscopic treatment in developing countries where patient affordability and the availability of the resources are the issues.

A randomized, double-blind, parallel-group, single-dose comparative pharmacokinetic study of DRL_TZ, a candidate biosimilar of trastuzumab, with Herceptin® (EU) in healthy adult males.

BACKGROUND & OBJECTIVES: Trastuzumab (TZ) is a recombinant DNA-derived humanized monoclonal antibody approved for human epidermal growth factor receptor 2 positive early breast cancer, metastatic breast and gastric cancers. For the development of TZ biosimilars, establishing pharmacokinetic equivalence is required. The primary objective of this study was to compare the pharmacokinetics (PK) of Dr Reddy's Laboratories TZ (DRL_TZ) with that of EU-approved Reference Medicinal Product (RMP), Herceptin® in healthy adult male subjects. METHODS: In this double-blind, parallel-group, phase I study (TZ-01-003), healthy male subjects aged 18-55 yr were randomized 1:1 to receive a single intravenous infusion of 6 mg/kg of TZ as DRL_TZ or RMP. Similarity for primary PK parameters was defined as the 90 per cent confidence intervals (CIs) for the geometric mean ratios (GMRs) falling within 75-133 per cent limits. Primary endpoints included area under the concentration-time curve - from time zero (pre-dose) to the last quantifiable concentration [AUC(0-t)] and from time zero (pre-dose) extrapolated to infinity [AUC(0-∞)], and maximum observed serum concentration (Cmax). Secondary objectives were to compare the safety and immunogenicity of DRL_TZ with that of the RMP. RESULTS: Thirty two subjects were dosed (DRL_TZ, 16; RMP, 16). Primary PK parameters were found to be comparable with their 90 per cent CIs for the GMR falling within the usual more stringent limits of 80-125 per cent. The number of subjects reporting at least one TEAE in both the arms was similar. No serious adverse events were reported. Fifteen subjects, eight in DRL_TZ arm and seven in Herceptin® arm, tested positive for anti-drug antibodies (ADAs), none of the ADAs were neutralizing in nature. INTERPRETATION & CONCLUSIONS: In this study, DRL_TZ demonstrated PK equivalence with the RMP and had comparable safety and immunogenicity profiles in healthy adult male subjects.

Molecular mechanisms in grass-Epichloë interactions: towards endophyte driven farming to improve plant fitness and immunity.

All plants harbor many microbial species including bacteria and fungi in their tissues. The interactions between the plant and these microbes could be symbiotic, mutualistic, parasitic or commensalistic. Mutualistic microorganisms are endophytic in nature and are known to play a role in plant growth, development and fitness. Endophytes display complex diversity depending upon the agro-climatic conditions and this diversity could be exploited for crop improvement and sustainable agriculture. Plant-endophyte partnerships are highly specific, several genetic and molecular cascades play a key role in colonization of endophytes in host plants leading to rapid changes in host and endophyte metabolism. This results in the accumulation of secondary metabolites, which play an important role in plant defense against biotic and abiotic stress conditions. Alkaloids are one of the important class of metabolites produced by Epichloë genus and other related classes of endophytes and confer protection against insect and mammalian herbivory. In this context, this review discusses the evolutionary aspects of the Epichloë genus along with key molecular mechanisms determining the lifestyle of Epichloë endophytes in host system. Novel hypothesis is proposed to outline the initial cellular signaling events during colonization of Epichloë in cool season grasses. Complex clustering of alkaloid biosynthetic genes and molecular mechanisms involved in the production of alkaloids have been elaborated in detail. The natural defense and advantages of the endophyte derived metabolites have also been extensively discussed. Finally, this review highlights the importance of endophyte-arbitrated plant immunity to develop novel approaches for eco-friendly agriculture.

In situ reversible redox switching of first hyperpolarizability of bimetallic ruthenium complexes.

In this article we report the reversible redox switching of first hyperpolarizability of bimetallic ruthenium complexes bridged by bipyridyl tetrazine (bptz) ligands by second harmonic light scattering experiments (SHLS). We have synthesised [RuII(acac)2(CH3CN)2] and [(acac)2Ru-bptz-Ru(acac)2] complexes and measured their first hyperpolarizabilities as a function of in situ electrochemical oxidation/reduction of the metal centres. As a result of the oxidation of ruthenium centre from Ru(ii) to Ru(iii), the molecular hyperpolarizability of the complexes went up. The mixed-valence intermediate bimetallic complex and not the fully oxidized complex exhibit the highest ß value of 780 × 10-30 esu. We also demonstrated that the hyperpolarizability is reversible with the change of the oxidation state of the metal and both the complexes are stable for several cycles of redox switching. The experimental results are also supported by calculations.

Efficacy of Alpha Glucosidase Inhibitor from Marine Actinobacterium in the Control of Postprandial Hyperglycaemia in Streptozotocin (STZ) Induced Diabetic Male Albino Wister Rats.

The current study was carried out to evaluate the in-vitro and in-vivo efficiency of alpha glucosidase inhibitor of marine actinobacteria in the control of postprandial hyperglycaemia. Soil samples were collected from salterns, coastal area in Kothapatnam, Ongole, Andhra Pradesh, India. Among the actinobacterial isolates tested for yeastα-glucosidase inhibitory activity, only three isolates showed prominent inhibition. The patient isolate was selected and identified as Streptomyces coelicoflavus SRBVIT13 using 16S r-RNA gene sequencing. In in-vitro studies, the chloroform extract of Streptomyces coelicoflavus SRBVIT13 showed significant enzyme inhibitory activity against yeast and mammalian α-glucosidaseenzymes. In animal studies, the oral ingestion of chloroform extract (600 mg/kg) of S. coelicoflavus SRBVIT13 in maltose and sucrose loaded diabetic rats, showed significant regulation of postprandial blood glucose by 82.25% and a 77.25% reduction, respectively. The lead compound from S. coelicoflavusSRBVIT13 was isolated, purified, characterized, and identified by stranded analytical techniques as 2-t-butyl-5-chloromethyl-3-methyl-4-oxoimidazolidine-1-carboxylic acid, t-butyl ester. The results obtained in the present study are promising and the bioactive compound from S. coelicoflavusSRBVIT13 may be considered as a potential agent in regulating the postprandial hyperglycaemia.

An immunoinformatics approach to define T cell epitopes from polyketide and non-ribosomal peptide synthesis proteins of Mycobacterium tuberculosis as potential vaccine candidates.

The role of polyketide and non-ribosomal proteins from the class of small molecule metabolism of Mycobacterium tuberculosis is well documented in envelope organization, virulence, and pathogenesis. Consequently, the identification of T cell epitopes from these proteins could serve to define potential antigens for the development of vaccines. Fourty-one proteins from polyketide and non-ribosomal peptide synthesis of small molecule metabolism proteins of M tuberculosis H37Rv were analyzed computationally for the presence of HLA class I binding nanomeric peptides. All possible overlapping nanomeric peptide sequences from 41 small molecule metabolic proteins were generated through in silico and analyzed for their ability to bind to 33 alleles belonging to A, B, and C loci of HLA class I molecule. Polyketide and non-ribosomal protein analyses revealed that 20% of generated peptides were predicted to bind HLA with halftime of dissociation T1/2  ≥ 100 minutes, and 77% of them were mono-allelic in their binding. The structural bases for recognition of nanomers by different HLA molecules were studied by structural modeling of HLA class I-peptide complexes. Pathogen peptides that could mimic as self-peptides or partially self-peptides in the host were excluded using a comparative study with the human proteome; thus, subunit or DNA vaccines will have more chance of success.

Physician's advice on quitting smoking in HIV and TB patients in south India: a randomised clinical trial.

Setting: National Institute for Research in Tuberculosis, Madurai, India. Objective: To determine the efficacy of physician's advice on quitting smoking compared with standard counselling in patients with tuberculosis (TB) and patients with human immunodeficiency virus (HIV) infection. Design/Methods: This was a clinical trial conducted in Madurai, south India, among 160 male patients (80 with TB and 80 with HIV), randomised and stratified by nicotine dependence (low/high according to the Fagerström scale), who received physician's advice with standard counselling or standard counselling alone for smoking cessation. Abstinence at 1 month was assessed by self-report and carbon monoxide breath analysis. Results: The patients' mean age was 39.4 years (SD 8.5). Overall, 35% of the patients had high nicotine dependence. Most patients (41%) smoked both cigarettes and bidis. In a combined analysis including both the HIV and the TB groups, quit rates were 41% of the 68 patients in the physician group and 35% of the 68 patients in the standard counselling arm. Conclusions: Physician's advice to quit smoking delivered to patients with TB or HIV is feasible and acceptable. Smoking cessation could easily be initiated in TB patients in programme settings. Future studies should assess long-term abstinence rates with a larger sample size to demonstrate the efficacy of physician's advice.

Contexte : National Institute for Research in Tuberculosis (NIRT), Madurai, Inde.Objectif : Déterminer l'efficacité des conseils d'un médecin comparés aux conseils standard d'arrêt du tabac chez des patients atteints de tuberculose (TB) et chez des patients infectés par le virus de l'immunodéficience humaine (VIH).Schéma/Méthodes : Cet essai clinique a été réalisé à Madurai, dans le sud de l'Inde. Cent soixante patients masculins (80 TB et 80 VIH) ont été randomisés, stratifiés en fonction de leur dépendance à la nicotine (faible/élevée selon l'échelle de Fagerström) pour bénéficier soit des conseils d'un médecin avec des conseils standard ou des conseils standard seuls pour l'arrêt du tabac. L'abstinence à un mois a été évaluée par déclaration des patients et analyse du monoxyde de carbone dans l'air expiré.Résultats : L'âge moyen (DS) a été de 39,4 (±8,5) ans. Dans l'ensemble, 35% des patients avaient une dépendance élevée à la nicotine. La majorité des patients (41%) fumait à la fois des cigarettes et des bidis (cigarettes indiennes). En analyse combinée (à la fois le groupe VIH et TB), les taux de cessation ont été de 41% sur 68 patients dans le groupe « médecin ¼ et de 35% de 68 patients dans le bras « conseil standard ¼ (non significatif).Conclusions: Les conseils d'un médecin en matière d'arrêt de tabac délivrés aux patients atteints de TB ou de VIH sont faisables et acceptables. L'arrêt du tabac pourrait bien être mis en œuvre dans le contexte des programmes chez les patients TB. De futures études devraient évaluer le taux d'abstinence à long terme avec des échantillons de plus grande taille afin de démontrer l'efficacité des conseils d'un médecin.

Marco de referencia: El Instituto Nacional de Investigación en Tuberculosis de Madurai, en la India.Objetivo: Comparar la eficacia de los consejos que da el médico con el asesoramiento corriente sobre el abandono del tabaco, en pacientes aquejados de tuberculosis (TB) o infección por el virus de la inmunodeficiencia humana (VIH).Métodos: El ensayo clínico inicial se llevó a cabo en Madurai, en el sur de la India. Se escogieron de manera aleatoria 160 pacientes de sexo masculino (80 con diagnóstico de TB y 80 de infección por el VIH), se estratificaron en función de la dependencia de la nicotina (baja y alta, según la escala de Fagerström) y se asignaron a un grupo que recibiría consejos del médico además del asesoramiento corriente sobre el abandono del tabaco o un grupo que solo recibiría el asesoramiento corriente. Al cabo de un mes, se evaluó la abstinencia a partir de la información proporcionada por los pacientes y la medición de monóxido de carbono en el aire espirado.Resultados: El promedio de edad de los participantes fue 39,4 años (desviación estándar 8,5 años). En general, el 35% de los participantes exhibía una alta dependencia de la nicotina. La mayoría fumaba cigarrillos y también bidis (41%). En el análisis conjunto (ambos grupos: TB y VIH), las tasas de abandono fueron 41% en los 68 pacientes del grupo que recibió consejo médico y 35% en los 68 pacientes del grupo que obtuvo asesoramiento corriente (diferencia no significativa).Conclusión: El consejo sobre el abandono del tabaco ofrecido por el médico a los pacientes con diagnóstico de TB o infección por el VIH es factible y bien aceptado. Es posible iniciar intervenciones de abandono del tabaco con los pacientes TB en el marco programático. Futuros estudios podrían evaluar las tasas de abstinencia a largo plazo con muestras más grandes, a fin de demostrar la eficacia del consejo dado por los médicos.

Programmed death ligand 1 is expressed in canine B cell lymphoma and downregulated by MEK inhibitors.

Programmed death ligand 1 (PD-L1) expression in antigen-presenting cells and tumors can inhibit T cell-mediated immunity. In this study, PD-L1 mRNA and protein expression was evaluated in canine B cell lymphoma (CLL17-71), large T-cell leukemia (CLGL-90), B cell leukemia (GL-1) and primitive leukocyte round cell neoplasia (CLL-1390). Variable PD-L1 mRNA and protein were observed in these cells with high endogenous expression present in CLL17-71 cells. PD-L1 protein was also observed in canine patient B cell lymphoma tissues using immunostaining. PD-L1 and signal transducer and activator of transcription 1 ( STAT1 ) mRNA expression were reduced in the presence of mitogen-activated protein kinase kinase 1.2 (MEK1/2) inhibitors RDEA119 and AZD6244 in CLL 17-71 cells. RDEA119 had similar effect on PD-L1 and STAT-1 in IFN-γ activated CLL-1390 cells. Overall, these results indicate that PD-L1 is expressed in canine B cell lymphoma. Its inhibition by MEK1/2 inhibitors suggests a possible treatment strategy using targeted drugs which likely could enhance antitumor immune response.

Magnetic assembly of 3D cell clusters: visualizing the formation of an engineered tissue.

OBJECTIVES: Contactless magnetic assembly of cells into 3D clusters has been proposed as a novel means for 3D tissue culture that eliminates the need for artificial scaffolds. However, thus far its efficacy has only been studied by comparing expression levels of generic proteins. Here, it has been evaluated by visualizing the evolution of cell clusters assembled by magnetic forces, to examine their resemblance to in vivo tissues. MATERIALS AND METHODS: Cells were labeled with magnetic nanoparticles, then assembled into 3D clusters using magnetic force. Scanning electron microscopy was used to image intercellular interactions and morphological features of the clusters. RESULTS: When cells were held together by magnetic forces for a single day, they formed intercellular contacts through extracellular fibers. These kept the clusters intact once the magnetic forces were removed, thus serving the primary function of scaffolds. The cells self-organized into constructs consistent with the corresponding tissues in vivo. Epithelial cells formed sheets while fibroblasts formed spheroids and exhibited position-dependent morphological heterogeneity. Cells on the periphery of a cluster were flattened while those within were spheroidal, a well-known characteristic of connective tissues in vivo. CONCLUSIONS: Cells assembled by magnetic forces presented visual features representative of their in vivo states but largely absent in monolayers. This established the efficacy of contactless assembly as a means to fabricate in vitro tissue models.

Effect of embelin against 3-nitropropionic acid-induced Huntington's disease in rats.

3-Nitropropionic acid (3-NP) causes severe neurotoxicity in animals, which depicts Huntington's disease (HD) in humans. Embelin, the main active constituent of Embelia ribes, has been reported to possess various pharmacological actions, mainly anti-inflammatory, antioxidant, anticonvulsant and neuroprotective. The aim of the present study was to evaluate the neuroprotective effect of embelin against 3-NP induced experimental HD in rats. Adult Wistar rats were pretreated with vehicle/embelin (10 and 20mg/kg p.o.) for 7 days. From 8th day onwards, embelin was co-treated with 3-NP (15mg/kg, i.p.) for 7 days. At the end of the treatment schedule, animals were evaluated for behavioral alterations and brain homogenates were used for estimation of oxidative stress parameters (lipid peroxidation, reduced glutathione, catalase and glutathione-S-transferase). 2,3,5-Triphenyl tetrazolium chloride (TTC) stained brain slices were used for lesion size measurement. Administration of 3-NP significantly altered the behavioral and neuronal antioxidant status and caused significant neuronal damage in striatal region. Embelin, at both the tested doses, caused a significant reversal of behavioral and antioxidant status alterations and reversed the striatal neuronal damage induced by 3-NP. These findings suggest the neuroprotective effect of embelin against HD. The observed protective effect might be attributed to the antioxidant properties of embelin.

Identification, Isolation, and Characterization of a New Degradation Impurity in Nafcillin Sodium.

A new degradant of Nafcillin Sodium was found at a level of 1.8% w/w during the gradient reversed-phase HPLC analysis in stability storage samples. This impurity was identified by LC-MS and was characterized by (1)H-NMR, (13)C-NMR, LC/MS/MS, elemental analysis, and IR techniques. Based on the structural elucidation data, this impurity was named as N-[(2S)-2-carboxy-2-{[(2-ethoxynaphthalen-1-yl)carbonyl]amino}ethylidene]-3-({N-[(2-ethoxynaphthalen-1-yl)carbonyl]glycyl}sulfanyl)-D-valine. This impurity was prepared by isolation and was co-injected into the HPLC system to confirm the retention time. To the best of our knowledge, this impurity has not been reported elsewhere. The identification and structural elucidation of this degradant impurity has been discussed in detail.

Development and validation of a gas chromatography method for the trace level determination of allylamine in sevelamer hydrochloride and sevelamer carbonate drug substances.

A capillary gas chromatography method using a flame ionization detector has been developed for the trace analysis of allylamine (AA) in sevelamer hydrochloride (SVH) and sevelamer carbonate (SVC) drug substances. The method utilized a mega bore capillary column DB-CAM (30 m × 0.53 mm × 1.0 µm) with a bonded and cross-linked, base-deactivated polyethylene glycol stationary phase and was validated for specificity, sensitivity, precision, linearity, and accuracy. The detection and quantitation limits obtained for allylamine were 2 µg/g and 6 µg/g, respectively. The method was found to be linear in the range between 6 µg/g and 148 µg/g with a correlation coefficient of 0.9990. The average recoveries obtained in SVH and SVC were 93.9% and 99.1%, respectively. The developed method was found to be robust for the determination of AA in sevelamer drug substances and also the specificity was demonstrated with a gas chromatograph coupled with a mass spectrometer.

Biochemical markers assisted screening of Fusarium wilt resistant Musa paradisiaca (L.) cv. puttabale micropropagated clones.

An efficient protocol was standardized for screening of panama wilt resistant Musa paradisiaca cv. Puttabale clones, an endemic cultivar of Karnataka, India. The synergistic effect of 6-benzyleaminopurine (2 to 6 mg/L) and thidiazuron (0.1 to 0.5 mg/L) on MS medium provoked multiple shoot induction from the excised meristem. An average of 30.10 +/- 5.95 shoots was produced per propagule at 4 mg/L 6-benzyleaminopurine and 0.3 mg/L thidiazuron concentrations. Elongation of shoots observed on 5 mg/L BAP augmented medium with a mean length of 8.38 +/- 0.30 shoots per propagule. For screening of disease resistant clones, multiple shoot buds were mutated with 0.4% ethyl-methane-sulfonate and cultured on MS medium supplemented with Fusarium oxysporum f. sp. cubense (FOC) culture filtrate (5-15%). Two month old co-cultivated secondary hardened plants were used for screening of disease resistance against FOC by the determination of biochemical markers such as total phenol, phenylalanine ammonia lyase, oxidative enzymes like peroxidase, polyphenol oxidase, catalase and PR-proteins like chitinase, beta-1-3 glucanase activities. The mutated clones of M. paradisiaca cv. Puttabale cultured on FOC culture filtrate showed significant increase in the levels of biochemical markers as an indicative of acquiring disease resistant characteristics to FOC wilt.

High temperature thermoelectric properties of strontium titanate thin films with oxygen vacancy and niobium doping.

We report the evolution of high temperature thermoelectric properties of SrTiO3 thin films doped with Nb and oxygen vacancies. Structure-property relations in this important thermoelectric oxide are elucidated and the variation of transport properties with dopant concentrations is discussed. Oxygen vacancies are incorporated during growth or annealing in Ar/H2 above 800 K. An increase in lattice constant due to the inclusion of Nb and oxygen vacancies is found to result in an increase in carrier density and electrical conductivity with simultaneous decrease in carrier effective mass and Seebeck coefficient. The lattice thermal conductivity at 300 K is found to be 2.22 W m(-1) K(-1), and the estimated figure of merit is 0.29 at 1000 K.