Development and Characterisation of Nanoclays from Indian Clays

Indian clays are known for their smecticity. One such clay sample collected from Bhuj (Gujarat)was characterised and modified by successive sedimentation processes for different time intervals.The non-plastic components of clay, viz., quartz, illite, iron oxide, CaO, MgO, and organic matterwere removed in different steps, as the heavy impurities in the clay-water suspensions, settledown during sedimentation. The free iron oxide present in clay suspension was reduced bygiving sodium citrate-bicarbonate-dithionite treatment and iron content was further reducedfrom 12Œ15 per cent to 5Œ7 per cent respectively. The organic matter was removed by sodiumacetate-H2O2 treatment. The modified clay so obtained was characterised by thermal analysis,FTIR, and XRD,  SEM and TEM. The cation exchange capacities of original and modified clayswere determined both by methylene blue method and ammonium acetate method. The cationex change capacity is found to enhance from 120Œ130 meq/100 g to 135Œ145 meq/100 g. Usingthe above procedure, 92 per cent smecticity was obtained. Organo philisation of purified clay(smectite) was carried out by intercalation with alkyl ammonium salt. The  XRD  analysis show edenhancement of interlamellar spacing from 1.294 nm to 2.855 nm.Defence Science Journal, 2008, 58(4), pp.517-524, DOI:http://dx.doi.org/10.14429/dsj.58.167

The Influence of Handgrip and Pedal Cadence During Sustained Cycling Power Outputs

In cycling performance, there has been interest in contribution the upper body (i.e. handgrip) provides during cycling efforts as well as power output during varying cadences. Little has been done pertaining to cardiovascular responses with the aforementioned during sustained power. PURPOSE: To determine the cardiovascular reactions to isometric hand-grip and different pedal cadences during sustained cycling efforts. METHODS: Subjects were nine (n=9) experienced cyclists. Each signed a medical-health and physical readiness questionnaire, and IRB approved informed consent. Resting values of heart rate (b*min.-1), blood pressure (mmHg), height (cm), weight (kg) and age (years) were assessed. A MonarkTM bicycle ergometer was used for testing. Grip was substantiated through the use of a hand grip dynamometer at 20 kg of tension. An exercise test of 20 minutes at 150 Watts was performed four times with random assignment through a Latin Squares Design. Protocols were distinguished by grip/no grip; 50/100 RPM; 3kp/1.5kp resistance. During the 20 minute exercise test, heart rate, blood pressure and calculated Rate Pressure Product (HR * SBP)*100-1 were recorded every minute. Statistical measures included group means (SD) between protocols and use of a Repeated Measures ANOVA to examine variable differences between grip/ no-grip and cadence/resistance protocols. Significance was set at p \u3c 0.05. RESULTS: Statistically significant differences were reported for the variables of heart rate, systolic blood pressure and work of the heart for the following protocols: high cadence/low resistance-grip HR=147.72 (3.24); SBP= 164.59 (6.42); WH=242.58 (23.99) and high cadence/low resistance-no grip HR=150.83 (6.49); SBP=166.05 (5.60); WH=245.57 (25.70). The following protocols showed no significant differences: low cadence/high resistance-grip HR=132.50 (3.24); SBP=160.29 (4.95); WH=211.54 (12.22) and low cadence/high resistance-no grip HR=130.51 (3.36); SBP=156.66 (5.17); WH=204.63 (11.45). Conclusion: This research demonstrated that grip appears to be a transient influence during sustained work. Cadence was a more influential factor on cardiovascular responses during sustained cycling performance

Rewriting Nature’s Assembly Manual for a ssRNA Virus

Satellite Tobacco Necrosis Virus (STNV) is one of the smallest viruses known. Its genome encodes only its coat protein (CP) subunit relying on the polymerase of its helper virus TNV for replication. The genome contains a cryptic set of dispersed assembly signals in the form of stem-loops that each present a minimal CP binding motif -A.X.X.A- in the loops. The genomic fragment encompassing nucleotides 1-127 is predicted to contain five such Packaging Signals (PSs). We have used mutagenesis to determine the critical assembly features in this region. These include the CP binding motif, the relative placement of PS stem-loops, their number and their folding propensity. CP binding has an electrostatic contribution but assembly nucleation is dominated by the recognition of the folded PSs in the RNA fragment. Mutation to remove all –A.X.X.A- motifs in PSs throughout the genome yields an RNA that is unable to assemble efficiently. In contrast, when a synthetic 127nt fragment encompassing improved PSs is swapped onto the RNA otherwise lacking CP recognition motifs assembly is partially restored although the virus-like particles created are incomplete, implying that PSs outside this region are required for correct assembly. Swapping this improved region into the wild-type STNV1 sequence results in a better assembly substrate than the viral RNA, producing complete capsids and outcompeting the wild-type genome in head-to-head competition. These data confirm details of the PS-mediated assembly mechanism for STNV, and identify an efficient approach for production of stable viruslike particles encapsidating non-native RNAs or other cargoes

An Intracellular Model of Hepatitis B Viral Infection: An In Silico Platform for Comparing Therapeutic Strategies

Hepatitis B virus (HBV) is a major focus of antiviral research worldwide. The International Coalition to Eliminate HBV, together with the World Health Organisation (WHO), have prioritised the search for a cure, with the goal of eliminating deaths from viral hepatitis by 2030. We present here a comprehensive model of intracellular HBV infection dynamics that includes all molecular processes currently targeted by drugs and agrees well with the observed outcomes of several clinical studies. The model reveals previously unsuspected kinetic behaviour in the formation of sub-viral particles, which could lead to a better understanding of the immune responses to infection. It also enables rapid comparative assessment of the impact of different treatment options and their potential synergies as combination therapies. A comparison of available and currently developed treatment options reveals that combinations of multiple capsid assembly inhibitors perform best

Revealing the density of encoded functions in a viral RNA

Nikesh Patel, et al, ‘Revealing the density of encoded functions in a viral RNA’, Proceedings of the National Academy of Sciences of the United States of America (PNAS), Vol. 112 (7): 2227-2232, February 2015, doi: http:dx.doi.org/10. 1073/pnas.1420812112. This article is freely available online through the PNAS open access option.We present direct experimental evidence that assembly of a single-stranded RNA virus occurs via a packaging signal-mediated mechanism. We show that the sequences of coat protein recognition motifs within multiple, dispersed, putative RNA packaging signals, as well as their relative spacing within a genomic fragment, act collectively to influence the fidelity and yield of capsid self-assembly in vitro. These experiments confirm that the selective advantages for viral yield and encapsidation specificity, predicted from previous modeling of packaging signal-mediated assembly, are found in Nature. Regions of the genome that act as packaging signals also function in translational and transcriptional enhancement, as well as directly coding for the coat protein, highlighting the density of encoded functions within the viral RNA. Assembly and gene expression are therefore direct molecular competitors for different functional folds of the same RNA sequence. The strongest packaging signal in the test fragment, encodes a region of the coat protein that undergoes a conformational change upon contact with packaging signals. A similar phenomenon occurs in other RNA viruses for which packaging signals are known. These contacts hint at an even deeper density of encoded functions in viral RNA, which if confirmed, would have profound consequences for the evolution of this class of pathogensPeer reviewedFinal Published versio

Dataset of high-throughput ligand screening against the RNA Packaging Signals regulating Hepatitis B Virus nucleocapsid formation

Multiple ssRNA viruses which infect bacteria, plants or humans use RNA Packaging Signal (PS)-mediated regulation during assembly to package their genomes faithfully and efficiently [1], [2], [3], [4], [5]. PSs typically comprise short nucleotide recognition motifs, most often presented in the unpaired region of RNA stem-loops, and often bind their cognate coat proteins (CPs) with nanomolar affinity. PSs identified to date are resilient in the face of the typical error prone replication of their virus-coded polymerases, making them potential drug targets [1], [2], [3]. An immobilised array of small molecular weight, drug-like compounds was panned [6] against a fluorescently-labelled oligonucleotide encompassing the most conserved Hepatitis B Virus (HBV) PS, PS1 [3], known to be a major determinant in nucleocapsid formation [7]. This identified > 70 compounds that bind PS1 uniquely in the array. The commercially available 66 of these were tested for their potential effect(s) on HBV nucleocapsid-like particle (NCP) assembly in vitro [8], which identified potent assembly inhibitors. Here, we describe a high-throughput screen for such effects using employing fluorescence anisotropy in a 96-well microplate format. HBV genomic RNAs (gRNA) and short oligonucleotides encompassing PS1 were 5ʹ labelled with an Alexa Fluor 488 dye. Excess (with respect to stoichiometric T=4 NCP formation [9]) HBV core protein (Cp) dimers were titrated robotically into solutions containing each of these RNAs stepwise, using a Biomek 4000 liquid handling robot. The anisotropy values of these mixtures were monitored using a POLARstar microplate reader. NCP-like structures were challenged with RNase A to identify reactions that did not result in complete NCP formation [10]. The results imply that ∼50 % of the compounds prevent complete NCP formation, highlighting both PS-meditated assembly and the PS-binding compounds as potential directly-acting anti-virals with a novel molecular target. Importantly, this method allows high-throughput in vitro screening for assembly inhibitors in this major human pathogen

Identification of robust cardiac reference genes in a mouse model of cardiometabolic disease

Cardiovascular disease is linked to obesity, the metabolic syndrome, and altered 24hour (circadian) rhythms. Although the underlying mechanisms remain undefined, transcriptome analysis in the heart is beginning to provide important insights into the cardiometabolic pathogenesis. The reliability and accuracy of real-time quantitative PCR generated gene expression data is largely dependent on the selection of suitable reference genes (RG), which must be constitutively expressed regardless of cardio-metabolic disease state and time of day. However, many studies do not employ the appropriate selections strategies. In this study we determined the expression stability of seven candidate RGs (GAPDH, YWHAZ, B2M, EIF4A2, ATP5?, ACTB and CYC1) in a mouse model of diet-induced metabolic syndrome in both the day and night, using geNorm qBasePLUS software. RG expression varied in hearts of normal fed versus high fat fed mice, and was also dependant on the time of day. When all experimental variables were considered YWHAZ and ACTB were ranked the most stable and therefore the most suitable genes for generating comparative gene expression data in heart tissue from murine models of cardiometabolic disease. This study provides important information for reference gene selection, and will aid further transcriptome investigations into heart organ functio

Modification of Physicochemical Properties of Active Pharmaceutical Ingredient by Pharmaceutical Co-Crystals

The oral drug delivery is widely used and accepted routes of administration, but it fails to provide the therapeutic effectiveness of drugs due to low solubility, poor compression and oral bioavailability. Crystal engineering is the branch where the modification of API is of great importance. Co-crystallization of API using a co-former is a hopeful and emerging approach to improve the performance of pharmaceuticals, such as micromeritic properties, solubility, dissolution profile, pharmacokinetics and stability. Pharmaceutical co-crystals are multicomponent systems in which one component is an active pharmaceutical ingredient and the others are pharmaceutically acceptable ingredients that are of GRAS category. In multidrug co-crystals one drug acts as API and other drug acts as coformer. This chapter illustrates the guidance for more efficient design and manufacture of pharmaceutical co-crystals with the desired physicochemical properties and applications

Antipsychotic use in children and adolescents from 1996 to 2001: epidemiology, prescribing practices, and relationships with service utilization

textThe purpose of this study was to examine prevalence rates of antipsychotic use in children and adolescents from 1996 to 2001 in three state Medicaid programs and one private managed care organization; prescriber types and diagnoses associated with antipsychotic prescribing; and, trends in service utilization of youths receiving antipsychotic treatment. Prescription claims were used to evaluate total, age-specific, and genderspecific prevalence of antipsychotic use. Prescription claims from the Texas Medicaid system were used to examine prescriber types, and data from the Texas Department of Mental Health and Mental Retardation from 1998 to 2001 were used to examine diagnoses and service utilization of children and adolescents receiving antipsychotic treatment. From 1996 to 2001, the prevalence of total antipsychotic use increased in each insurance program (Ohio Medicaid: 4.7 to 14.3 per 1,000; Texas Medicaid: 6.3 to 15.5; California Medi-Cal: 4.5 to 6.9; and, Managed Care Organization: 1.5 to 3.4). The prevalence of atypical antipsychotic use dramatically increased (Ohio Medicaid: 1.4 to 13.1 per 1,000; Texas Medicaid: 2.5 to 14.9; California Medi-Cal: 0.3 to 6.2; and, Managed Care Organization: 0.4 to 2.7). Across all systems, the use of antipsychotics increased in children and adolescents above the age of five years, and in both males and females. In the Texas Medicaid system, psychiatrists accounted for the highest number of antipsychotic prescriptions for children and adolescents. Disruptive behavioral disorders were most commonly associated with antipsychotic prescribing. The mean number of inpatient psychiatric hospitalizations per child or adolescent receiving antipsychotic treatment and mental health care services from TDMHMR increased, as the mean number of hospital days per hospitalized youth decreased. Utilization of assessment services, counseling and psychotherapy, medication-related services, service coordination, and skills training increased. The mean duration of enrollment in assessment services, medication-related services, and skills training decreased, while the mean duration of enrollment in crisis intervention and service coordination increased. Given the limited efficacy and safety data with antipsychotics in children and adolescents, additional studies of atypical antipsychotics and other treatment modalities are needed on what, how, and when the best treatments can be provided to children and adolescents across health care settings.Pharmac