Multiwall carbon nanotube polyvinyl alcohol-based saturable absorber in passively Q-switched fiber laser

In this work, we demonstrated a compact Q-switched erbium-doped fiber laser capable of generating high-energy pulses using a newly developed multiwall carbon nanotube (CNT) polyvinyl alcohol (PVA) thin film based saturable absorber. Q-switched pulse operation is obtained by sandwiching the thin film between two fiber ferrules forming a saturable absorber. A saturable absorber with 1.25 wt. % of PVA concentration shows a consistency in generating pulsed laser with a good range of tunable repetition rate, shortest pulse width, and produces a high pulse energy and peak power. The pulse train generated has a maximum repetition rate of 29.9 kHz with a corresponding pulse width of 3.49 μs as a function of maximum pump power of 32.15 mW. The maximum average output power of the Q-switched fiber laser system is 1.49 mW, which translates to a pulse energy of 49.8 nJ. The proposed method of multiwall CNT/PVA thin film fabrication is low in cost and involves uncomplicated processes.

Hemoglobin fructation promotes heme degradation through the generation of endogenous reactive oxygen species

Protein glycation is a cascade of nonenzymatic reactions between reducing sugars and amino groups of proteins. It is referred to as fructation when the reducing monosaccharide is fructose. Some potential mechanisms have been suggested for the generation of reactive oxygen species (ROS) by protein glycation reactions in the presence of glucose. In this state, glucose autoxidation, ketoamine, and oxidative advance glycation end products (AGEs) formation are considered as major sources of ROS and perhaps heme degradation during hemoglobin glycation. However, whether fructose mediated glycation produces ROS and heme degradation is unknown. Here we report that ROS (H2O2) production occurred during hemoglobin fructation in vitro using chemiluminescence methods. The enhanced heme exposure and degradation were determined using UV-Vis and fluorescence spectrophotometry. Following accumulation of ROS, heme degradation products were accumulated reaching a plateau along with the detected ROS. Thus, fructose may make a significant contribution to the production of ROS, glycation of proteins, and heme degradation during diabetes.

Cyclic nucleotide phosphodiesterases: important signaling modulators and therapeutic targets

By catalyzing hydrolysis of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), cyclic nucleotide phosphodiesterases are critical regulators of their intracellular concentrations and their biological effects. As these intracellular second messengers control many cellular homeostatic processes, dysregulation of their signals and signaling pathways initiate or modulate pathophysiological pathways related to various disease states, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication, chronic obstructive pulmonary disease, and psoriasis. Alterations in expression of PDEs and PDE-gene mutations (especially mutations in PDE6, PDE8B, PDE11A, and PDE4) have been implicated in various diseases and cancer pathologies. PDEs also play important role in formation and function of multimolecular signaling/regulatory complexes, called signalosomes. At specific intracellular locations, individual PDEs, together with pathway-specific signaling molecules, regulators, and effectors, are incorporated into specific signalosomes, where they facilitate and regulate compartmentalization of cyclic nucleotide signaling pathways and specific cellular functions. Currently, only a limited number of PDE inhibitors (PDE3, PDE4, PDE5 inhibitors) are used in clinical practice. Future paths to novel drug discovery include the crystal structure-based design approach, which has resulted in generation of more effective family-selective inhibitors, as well as burgeoning development of strategies to alter compartmentalized cyclic nucleotide signaling pathways by selectively targeting individual PDEs and their signalosome partners.

Comprehensive gene expression analysis of the DNA (cytosine-5) methyltransferase family in rice (Oryza sativa L.)

Cytosine DNA methylation is a conserved epigenetic regulatory mechanism in both plants and animals. DNA methyltransferases (DNA MTases) not only initiate (de novo) but also maintain the process of DNA methylation. Here, we characterized the genome-wide expression profiles of 10 cytosine DNA MTase genes belonging to 4 subfamilies, MET1, CMT, DNMT2, and DRM, in rice. Tissue-specific gene expression analysis showed that all family members varied widely in their expression and specificities and might be involved in some basic metabolic pathways. Similarly, the expression of all rice cytosine DNA MTase genes was not regulated by plant hormones except OsDRM1a and OsDRM1b, which were downregulated by jasmonic acid. The transcription level of 10 genes in rice shoots and roots was also measured under salt and osmotic stress. Meanwhile, quantitative polymerase chain reaction data of the japonica and indica rice cultivars revealed that there is large variation in the expression activities of all genes. The results provide a foundation to further explore the roles of DNA MTases and the epigenetic regulation of abiotic stress responses in rice.

Germline de novo mutations and linkage markers vs. DNA sequencing for carrier detection in von Willebrand disease

Linkage analysis in autosomal inherited von Willebrand disease (VWD) is important to diagnose the carriers and reduce the burden of severe type VWD. The study was designed to identify the carriers and estimate the frequency of variable number of tandem repeats (VNTR) instability in VWD families. Carrier detection was performed in eight recessive type 3 VWD (VWD3) families using VNTRs VWF1 and VWF2, RsaI (789Thr/Ala) linkage markers, multimer analysis and DNA sequencing. Moreover, five dominant VWD families were studied through DNA sequencing and multimer analysis. Frequency of VWF VNTR instability was investigated in 20 VWD families. In VWD3 families, a total of 22 (81.5%) carriers were identified using VWF1 and VWF2 markers. However, only 13(48.1%) carriers were identified through RsaI markers. Mutation screening revealed 22(81.5%) carriers in VWD3 and 4 (33.3%) carriers in VWD2 families. In comparison to DNA sequencing, the accuracy of VWF1 and VWF2 markers in VWD3 was 85.7% while RsaI could identify 68.2% carriers accurately. Mutations p.R1205H and p.C1272R were identified as de novo in families. Multimer analysis confirmed the identified carriers in VWD2 families. Three VWD families were found to be carrying VNTR instability for VWF1 and VWF2 locus. VNTRs could be an effective linkage markers for carrier detection in VWD3 families. However, in the event of germline de novo mutations and VNTR instability, it may confound risk of misdiagnosis of carriers. Multimer analysis could be an alternative way of carrier detection in dominant type 2A and type 2B VWD families.

Effect of bacterial growth period on the sensitivity of the MTT assay for silver

Respiratory activity inhibition by toxic compounds in bacteria and yeast has been used to detect toxic compounds in the environment. Often the age of culture contributes towards the sensitivity of detection. In the present work, the effect of growth period on the sensitivity of an inhibitive assay for heavy metals using bacterial respiratory assay system based on the reduction of the water soluble tetrazolium dye MTT is reported. A silver-sensitive isolate was discovered to exhibit different sensitivities towards silver at different growth periods. An exponential decay model adequately described the inhibition due to silver. Analysis using ANOVA with post-hoc Tukey's test showed that the IC50 obtained by strain DRYS8 grown at the 12 hr- period in nutrient broth at 28 degrees C gave the lowest value compared to other growth periods. This study highlights the importance of taking into accounts growth conditions and age of culture in developing cellular-based bioassays.

Histological scoring and associated risk factors of non-alcoholic fatty liver disease

Non alcoholic steatohepatitis is a hepatic disorder with histological features of alcohol induced liver disease that occurs in individual who do not consume significant alcohol. Liver biopsy is an important part of the evaluation in term of both grade & stage. A cross sectional study was carried out in the department of Pathology, Dhaka Medical College, Dhaka & department of Hepatology, Bangabandhu Sheikh Mujib Medical University (BSMMU) from July 2007 to June 2009. Total 55 adult subjects of both sex were included on the basis of predefined inclusion & exclusion criteria in this study to evaluate the histological pattern of non alcoholic fatty liver disease (NAFLD) and its correlation with risk factors. Liver biopsy was done and H & E and Masson's Trichrome stain slides were examined to evaluate the grade and stage of NAFLD. Scoring and semiquantitative assessment of steatosis and NAFLD severity was done according to Kleiner scale known as NAFLD activity score (NAS). The results of Pearson correlation showed only BMI and triglyceride level significantly correlated with NAS score. The results of Spearman's rank correlation showed that BMI, central obesity, triglyceridaemia and age significantly correlated with staging of fibrosis. The results of multiple regression analysis showed that variation of NAS depend on BMI and triglyceride level. The study also revealed that risk factors contributed about 29% risk for the occurrence of non alcoholic steatohepatitis.

Metallic sewing needle ingestion presenting as acute abdomen

We reported an unusual case of a 26-year-old man presenting to surgical emergency as generalized peritonitis following an ingestion of multiple metallic sewing needles. The X-ray of his abdomen showed pneumoperitoneum and multiple metallic foreign bodies in the abdominal cavity. An ultrasonogram of his abdomen showed multiple metallic foreign bodies in the abdominal cavity and urinary bladder. Emergency exploratory laparotomy was performed. On laparotomy, gastric and duodenal perforation was found through which metallic sewing needles were protruding out. A peritoneal lavage was done, and all the sewing needles were extracted from the perforation site, paracolic gutter, liver parenchyma, and urinary bladder. The primary repair of the perforation with omental patching was done with the drainage of subhepatic space and pelvic cavity. These multiple ingested sewing needles led to the perforation of the stomach and the duodenum, which resulted in perforation peritonitis.

Use of a tissue expander as a radio-protective spacer with a latissimus dorsi flap in the management of a peripheral primitive neuroectodermal tumour (pPNET)

Peripheral primitive neuroectodermal tumours (pPNET) are aggressive neoplasms that require radical surgical resection with adjuvant chemotherapy and radiotherapy. A pPNET of the posterior chest wall was resected with wide soft tissue margins in a 14 year old male. Following tumour excision a spacer device was positioned in the retroperitoneum adjacent to the ipsilateral left kidney displacing it from the planned radiotherapy field. A pedicled latissimus dorsi myocutaneous flap was used to achieve robust soft tissue cover. Ultrasound demonstrated anteromedial displacement of the left kidney with no hydronephrosis and renal function remained normal during subsequent radiotherapy. This report highlights the usefulness of a tissue expander in providing protection for vital structures during radiotherapy.

Energetic domains and conformational analysis of human serum albumin upon co-incubation with sodium benzoate and glucose

Sodium benzoate (SB), a powerful inhibitor of microbial growth, is one of the most commonly used food preservative. Here, we determined the effects of SB on human serum albumin (HSA) structure in the presence or absence of glucose after 35 days of incubation under physiological conditions. The biochemical, biophysical, and molecular approaches including free amine content assay (TNBSA assay), fluorescence, and circular dichroism spectroscopy (CD), differential scanning calorimetry (DSC), and molecular docking and LIGPLOT studies were utilized for structural studies. The TNBSA results indicated that SB has the ability to bind Lys residues in HSA through covalent bonds. The docking and LIGPLOT studies also determined another specific site via hydrophobic interactions. The CD results showed more structural helicity for HSA incubated with SB, while HSA incubated with glucose had the least, and HSA incubated with glucose + SB had medium helicity. Fluorescence spectrophotometry results demonstrated partial unfolding of HSA incubated with SB in the presence or absence of glucose, while maximum partial unfolding was observed in HSA incubated with glucose. These results were confirmed by DSC and its deconvoluted thermograms. The DSC results also showed significant changes in HSA energetic structural domains due to HSA incubation with SB in the presence or absence of glucose. Together, our studies showed the formation of three different intermediates and indicate that biomolecular investigation are effective in providing new insight into safety determinations especially in health-related conditions including diabetes.

First report of blood parasites in fishes from Kashmir and their effect on the haematological profile

Cyprinus carpio communis Linnaeus, Carassius carassius Linnaeus, Schizothorax curvifrons Heckel and Triplophysa marmorata species of fishes were captured from Anchar Lake and river Jhelum of Kashmir Himalaya for hematological and parasitological analysis. During the investigation haemoflagellates from the genus Babesiosoma and Trypanosoma were recorded in the blood smears. Trypanosomes were present in all the species except C. carpio, whereas Babesiosoma were only found in T. marmorata. Haematological analysis revealed a significant (p<0.01) reduction in red blood cell count in the fishes infected with Babesiosoma and Trypanosoma. A significant decrease (p<0.05) was recorded in haemoglobin value and packed cell volume in the infected fishes in comparison to the non-infected fishes.

Cyclic nucleotide phosphodiesterase 3 signaling complexes

The superfamily of cyclic nucleotide phosphodiesterases is comprised of 11 gene families. By hydrolyzing cAMP and cGMP, PDEs are major determinants in the regulation of intracellular concentrations of cyclic nucleotides and cyclic nucleotide-dependent signaling pathways. Two PDE3 subfamilies, PDE3A and PDE3B, have been described. PDE3A and PDE3B hydrolyze cAMP and cGMP with high affinity in a mutually competitive manner and are regulators of a number of important cAMP- and cGMP-mediated processes. PDE3B is relatively more highly expressed in cells of importance for the regulation of energy homeostasis, including adipocytes, hepatocytes, and pancreatic β-cells, whereas PDE3A is more highly expressed in heart, platelets, vascular smooth muscle cells, and oocytes. Major advances have been made in understanding the different physiological impacts and biochemical basis for recruitment and subcellular localizations of different PDEs and PDE-containing macromolecular signaling complexes or signalosomes. In these discrete compartments, PDEs control cyclic nucleotide levels and regulate specific physiological processes as components of individual signalosomes which are tethered at specific locations and which contain PDEs together with cyclic nucleotide-dependent protein kinases (PKA and PKG), adenylyl cyclases, Epacs (guanine nucleotide exchange proteins activated by cAMP), phosphoprotein phosphatases, A-Kinase anchoring proteins (AKAPs), and pathway-specific regulators and effectors. This article highlights the identification of different PDE3A- and PDE3B-containing signalosomes in specialized subcellular compartments, which can increase the specificity and efficiency of intracellular signaling and be involved in the regulation of different cAMP-mediated metabolic processes.

Preparation and physical properties of (PVA)0.7(NaBr)0.3(H3PO4) x M solid acid membrane for phosphoric acid - Fuel cells

A solid acid membranes based on poly (vinyl alcohol) (PVA), sodium bromide (NaBr) and phosphoric acid (H₃PO₄) were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA)_0.7(NaBr)_0.3(H₃PO₄)_xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM) studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H₃PO₄ concentration which it has been achieved to be of the order 4.3 × 10⁻³ S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA)_0.7(NaBr)_0.3(H₃PO₄)_xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications.

Prevalence of Cryptosporidium species among HIV positive asymptomatic and symptomatic immigrant population in Kashmir, India

BACKGROUND AND OBJECTIVES

Cryptosporidiosis has not been reported as an endemic disease in Kashmir, but high prevalence of Cryptosporidium sp. has been found among asymptomatic (non-diarrheic) HIV positive immigrants in present study. Due to increasing number of HIV positive immigrants in Kashmir, Cryptosporidium may become a public health problem in Kashmir.

MATERIALS AND METHODS

A total of 45 stool samples were obtained from symptomatic (diarrheic n = 9) and asymptomatic (non-diarrheic n = 36) patients infected with HIV. The stool samples were concentrated using formalin ethyl acetate concentration technique, stained with modified Kinyoun's cold stain and oocysts were identified by microscopy under 1000 x magnification. It was confirmed by detection of antigens in stool samples by ELISA.

RESULTS

It was established that all the patients studied were carriers of Cryptosporidium. In present study though 80% of patients were asymptomatic (non-diarrheic) and HIV positive which involved non-Kashmiri army personals and travelers (immigrants) but were carriers of Cryptosporidium and 20% of HIV positive patients were emigrants (local Kashmiri traders) who travelled different states of India were having diarrhea (symptomatic) as well as carrier of Cryptosporidium.

CONCLUSION

Though Cryptosporidium infection causes chronic diarrhea but in present study all HIV positive patients screened whether diarrheic or non-diarrheic were positive for Cryptosporidium. To prevent the transmission of Cryptosporidium oocyst in environment and endemic spread of cryptosporidiosis as non-diarrheic HIV positive population may be potential source of infection, obligatory laboratory testing for Cryptosporidium in HIV positive immigrant population like traders and travelers is highly recommended in order to have a better understanding of the cause of spread Cryptosporidium infection in Kashmir.

Presentation and clinical course of Wolfram (DIDMOAD) syndrome from North India

AIMS

Wolfram syndrome, also known as DIDMOAD, is a relatively rare inherited neurodegenerative disorder, first evident in childhood as an association of juvenile-onset diabetes mellitus and optic atrophy, followed by diabetes insipidus and deafness. The aim of the study was to examine the clinical profile of patients with DIDMOAD syndrome presenting to a tertiary care hospital in north India.

METHODS

Clinical presentation of juvenile-onset diabetes mellitus fulfilling the diagnosis of Wolfram syndrome was studied using a prepared standardized form.

RESULTS

Subjects with juvenile-onset non-autoimmune diabetes mellitus attending the diabetic clinic at a tertiary care centre in north India were followed for 10 years and a diagnosis of fully developed Wolfram syndrome was confirmed in seven individuals. The series consisted of five male and two female patients with a mean age of 17.5 ±7.34 years. Two subjects had consanguinity and none had any other family member affected. Optic atrophy was present in all, sensorineural hearing loss in 4/7, central diabetes insipidus in 4/7 and nephrogenic diabetes insipidus in 2/7 subjects. The new associations found were: spastic myoclonus, short stature with pancreatic malabsorption, nephrogenic diabetes insipidus, cyanotic heart disease and choledocholithiasis with cholangitis. Genetic analysis revealed mutation in exon 8 of the WFS1 gene in all the cases studied.

CONCLUSIONS

The present clinical series of Wolfram syndrome reveals a varied clinical presentation of the syndrome and some new associations.