Selectivity of Sol-Gel and Hydrothermal TiO2 Nanoparticles towards Photocatalytic Degradation of Cationic and Anionic Dyes.

Titanium dioxide (TiO2) nanoparticles have been extensively studied for catalyzing the photo-degradation of organic pollutants, the photocatalyst being nonselective to the substrate. We, however, found that TiO2 nanoparticles prepared via the sol-gel and hydrothermal synthetic routes each possess a definite specificity to the charge of the substrate for photodegradation. The nanoparticles were characterized by SEM, FTIR, XRD, TGA, and UV-visible spectra, and the photocatalytic degradation under UV-B (285 nm) irradiation of two model compounds, anionic methyl Orange (MO) and cationic methylene blue (MB) was monitored by a UV-visible spectrophotometer. Untreated sol-gel TiO2 nanoparticles (Tsg) preferentially degraded MO over MB (90% versus 40% in two hours), while after calcination at 400 °C for two hours (Tsgc) they showed reversed specificity (50% MO versus 90% MB in one hour). The as-prepared hydrothermal TiO2 nanoparticles (Tht) behaved in the opposite sense of Tsg (41% MO versus 91% MB degraded in one and a half hours); calcination at 400 °C (Thtc) did not reverse the trend but enhanced the efficiency of degradation. The study indicates that TiO2 nanoparticles can be made to degrade a specific class of organic pollutants from an effluent facilitating the recycling of a specific class of pollutants for cost-effective effluent management.

Assessment of Healthcare Waste Management Paradigms and Its Suitable Treatment Alternative: A Case Study.

The management and treatment of healthcare waste (HCW) are of great concern owing to its potential hazard to human health and the environment, particularly in developing countries. Nowadays, various technological alternatives are gaining momentum as efficient and favorable waste management options across the world. However, selecting a suitable technology as well as an effective waste management approach for the treatment of HCW is still a challenging task for the municipal authorities. This study renders a comprehensive analysis of healthcare waste management (HCWM) practices and the technological options for its better management through a case study in Khulna, the southwestern division of Bangladesh. A number of healthcare establishments (HCEs) in the study area were selected and a questionnaire survey, as well as field investigations, was performed to find out the present status of HCWM and its limitations. An assessment of different technological alternatives was also carried out using Sustainability Assessment of Technologies (SAT) methodology which could pave the way for treating hazardous waste more efficiently in the Khulna metropolitan area. The study revealed that the overall HCW generation rate and hazardous HCW generation rate in Khulna city were 0.90 kg bed-1 day-1 and 0.18 kg bed-1 day-1, respectively. Assessment of management system revealed that 56% (n = 38) of workers did not receive any form of training in the handling of hazardous waste. Around 54% (n = 47) of them did not use any safety equipment or clothing. It has been found from the study that, among different technological alternatives based on the final score, incineration was the most suitable option for the treatment of hazardous waste in Khulna. Finally, some guidelines have been put forward to improve its existing management practices.

Antioxidant, cytotoxic and antineoplastic effects of Carissa carandas Linn. leaves.

For scientific clarification of some traditional uses, this study was designed to explore the antioxidant, cytotoxic and antineoplastic properties of leaf extract of Carissa carandas Linn., a traditional medicinal plant of Bangladesh. The methanol extract of Carissa carandas leaves (MELC) was applied on DPPH and ABTS experiments to determine its antioxidant activity. In vitro the cytotoxic effect of MELC was evaluated against colonic adenocarcinoma cell lines (SW-480 and SW-48) whereas in vivo its antineoplastic property was tested against Ehrlich ascites carcinoma (EAC). The DPPH and ABTS assays revealed the antioxidant activity of MELC with IC50 10.5±1.2 and 1.75±0.3µg/ml that was comparable to L-ascorbic acid. In vitro cytotoxic study, MELC reduced the viability of adenocarcinoma cells in dose dependent manner and in vivo, administration of MELC (25mg/kg) resulted in a significant (p<0.05) decrease in viable EAC cell count thereby increasing the life span of the EAC cell bearing mice. Restoration of hematological parameters such as red blood cells (RBC), hemoglobin and white blood cells (WBC) to normal levels in MELC-treated mice was also observed. Moreover, treatment with MELC induced apoptosis of EAC cells as observed in fluorescence microscopic view of DAPI (4,6-diamidino-2-phenylindole) stained cells and also increased p53 gene expression MELC-treated cells in respect to untreated EAC control. In addition, the MELC was rich in polyphenol content and its GC-MS chromatogram confirmed the presence of some compounds all of which showed anticancer and cytotoxic activities in previous studies. In a word, this study supports the use of Carissa carandas in traditional medicine as well as highlights the need to further explore the potentials of MELC as an antineoplastic agent.

Detection of anammox activity and 16S rRNA genes in ravine paddy field soil.

An anammox assay involving a ¹5N tracer and gas chromatography-mass spectrometry revealed that the potential anammox activity accounted for 1 to 5% of total N2 production in a ravine paddy field, Japan. Among four 4-cm-deep layers, the top layer showed the highest activity. Clone libraries showed that the DNA in the top layer contained sequences related to those of Candidatus 'Brocadia fulgida', Ca. 'B. anammoxidans', and Ca. 'Kuenenia stuttgartiensis'. These results suggest that a specific population of anammox bacteria was present in paddy soils, although a small part of dinitrogen gas was emitted from the soil via anammox.

Effect of heavy oil exposure on antibacterial activity and expression of immune-related genes in Japanese flounder Paralichthys olivaceus.

Heavy oil (HO) pollution is one of the most important environmental issues globally. However, little is known about the immunotoxicity of HO in fish. We therefore investigated the effects of HO exposure on immunocompetence and expression of immune-related genes in Japanese flounder, Paralichthys olivaceus. To test immunocompetency, serum collected from the fish was mixed with Edwardsiella tarda, plated, and the resultant numbers of bacterial colonies were counted. Plates with serum from HO-exposed fish (5 d postexposure [dpe]) had significantly higher numbers of colonies than those of the untreated control group, suggesting that HO exposure suppresses immunocompetency. Downregulation of the immunoglobulin light chain (IgM) gene in HO-exposed fish at 5 dpe was detected by real-time polymerase chain reaction. These results suggest that IgM-mediated immunity is suppressed by HO exposure. We measured polycyclic aromatic hydrocarbon (PAH) concentrations in the liver of the fish. Low molecular weight PAHs were found to be taken up at high concentrations in fish liver; therefore, they are likely the cause of immune suppression in the fish.

Fuel ethanol production from sweet sorghum using repeated-batch fermentation.

Ethanol was efficiently produced from three varieties of sweet sorghum using repeated-batch fermentation without pasteurization or acidification. Saccharomyces cerevisiae cells could be recycled in 16 cycles of the fermentation process with good ethanol yields. This technique would make it possible to use a broader range of sweet sorghum varieties for ethanol production.

Analysis of B-genome chromosome introgression in interspecific hybrids of Brassica napus × B. carinata.

Brassica carinata, an allotetraploid with B and C genomes, has a number of traits that would be valuable to introgress into B. napus. Interspecific hybrids were created between B. carinata (BBCC) and B. napus (AACC), using an advanced backcross approach to identify and introgress traits of agronomic interest from the B. carinata genome and to study the genetic changes that occur during the introgression process. We mapped the B and C genomes of B. carinata with SSR markers and observed their introgression into B. napus through a number of backcross generations, focusing on a BC(3) and BC(3)S(1) sibling family. There was close colinearity between the C genomes of B. carinata and B. napus and we provide evidence that B. carinata C chromosomes pair and recombine normally with those of B. napus, suggesting that similar to other Brassica allotetraploids no major chromosomal rearrangements have taken place since the formation of B. carinata. There was no evidence of introgression of the B chromosomes into the A or C chromosomes of B. napus; instead they were inherited as whole linkage groups with the occasional loss of terminal segments and several of the B-genome chromosomes were retained across generations. Several BC(3)S(1) families were analyzed using SSR markers, genomic in situ hybridization (GISH) assays, and chromosome counts to study the inheritance of the B-genome chromosome(s) and their association with morphological traits. Our work provides an analysis of the behavior of chromosomes in an interspecific cross and reinforces the challenges of introgressing novel traits into crop plants.

Increasing the flow of carbon into seed oil.

The demand for vegetable oils for food, fuel (bio-diesel) and bio-product applications is increasing rapidly. In Canada alone, it is estimated that a 50 to 75% increase in canola oil production will be required to meet the demand for seed oil in the next 7-10years. Plant breeding and genetics have demonstrated that seed oil content is a quantitative trait based on a number of contributing factors including embryo genetic effects, cytoplasmic effects, maternal genetic effects, and genotype-environment interactions. Despite the involvement of numerous quantitative trait loci in determining seed oil content, genetic engineering to over-express/repress specific genes encoding enzymes and other proteins involved in the flow of carbon into seed oil has led to the development of transgenic lines with significant increases in seed oil content. Proteins encoded by these genes include enzymes catalyzing the production of building blocks for oil assembly, enzymes involved in oil assembly, enzymes regulating metabolic carbon partitioning between oil, carbohydrate and secondary metabolite fractions, and transcription factors which orchestrate metabolism at a more general level.

Gross anatomical study of spleenic length.

The aim of the present study was to establish the standard length of the normal spleen in Bangladeshi people. One hundred and twenty human cadavers of which eighty-seven male and thirty-three female were dissected to remove spleen with associated structures in the morgue of Forensic Medicine Department of Mymensingh Medical College. Collected specimens were tagged with specific identification number, divided into five groups according to age and height of the individual. Gross and fine dissections were carried out after fixing the specimen in 10% formol saline solution. Length of the spleen was measured by measuring tape and expressed in cm and findings of the present study were compared with the findings of national and international studies. This was a cross sectional descriptive study carried out in the Department of Anatomy of Mymensingh Medical College, Mymensingh. The mean length of spleen was maximum as 11.20 cm in male in group C (31-45 years), and as 11.80 cm in female in group B(16-30 years) and mean length of spleen was minimum as 10.06 cm in male and 9.53 cm in female in group A (upto 15 years). Difference between group A and B, A and C, A and D were statistically significant. There were no significant differences in between other groups. According to height of individual the mean length of spleen was maximum 11.42 cm in 165.01 to 180 cm height group and minimum 10.30 cm in 0-120 cm height group which indicate that length of the spleen increases with height of the individual. This was observed that length of the spleen depends on the age, sex and body height of the individual.

Aggregation of conjugated polymers in aromatic solvent.

Segments of conjugated polymers display the propensity to aggregate in solutions with common organic solvents. Here we revealed that the segmental aggregation of a conjugated polymer, poly(9,9-bis(2-ethylhexyl)fluorene-2,7-diyl), (PF2/6), in toluene was stabilized by the polymer-solvent complex formation through pi-pi stacking induction of solvent molecules and polymer segments. In this case, a portion of the solvent was trapped inside the aggregate domains upon bringing the system to the subambient temperatures. The residence time of these associated solvent molecules became long enough to yield a separate upfield-shifted NMR resonance. The line-shape of this resonance revealed alignment of the polymer segments in the aggregates. A portion of the solvent was frozen in the compact structure due to the formation of strong polymer-solvent complex.

Spectrum of organisms causing peritonitis in peritoneal dialysis patients--experience from Bangladesh.

In the present study, organisms responsible for peritonitis and their sensitivity to antibiotics were evaluated in peritoneal dialysis (PD) patients in Bangladesh. We collected PD effluent from 100 peritonitis cases and sent samples to the laboratory for Gram stain and cytology. Cultures used direct inoculation of PD fluid in plate media and broth media simultaneously. Organisms were isolated by Gram stain in 60% of cases. Cell counts showed a mean of 700 (range: 90-7000) white blood cells per milliliter Plate media yielded 33% growth, and broth media, 67% growth. In continuous ambulatory PD, 77% samples were culture-positive; the organisms isolated were gram-positive bacteria in 41% of cases, gram-negative bacteria in 52%, and fungus in 7%. In intermittent PD, only 43% samples were culture-positive; the isolated organisms were gram-positive bacteria in 18% cases and gram negative bacteria in 82%. Gram-positive organisms (Staphylococcus and Streptococcus species) were sensitive to vancomycin and rifampicin; moderately sensitive to ciprofloxacin, ceftriaxone, and ceftazidime; and resistant to ampicillin, cloxacillin, and cephalexin. Gram-negative organisms (Escherichia coli, Klebsiella species) were sensitive to imipenem and aztreonam, and moderately sensitive to ciprofloxacin, ceftriaxone, ceftazidime, and gentamicin. Pseudomonas species were sensitive to aztreonam and ceftazidime, and moderately sensitive to ciprofloxacin, ceftriaxone, and gentamicin. Gram-negative organisms were predominantly responsible for peritonitis in PD patients, and before culture results are received, combined empiric therapy with vancomycin and imipenem or aztreonam may be started.

Occurrence of two genotypes of tetracycline (TC) resistance gene tet(M) in the TC-resistant bacteria in marine sediments of Japan.

The tetracycline (TC) resistance gene tet(M) was monitored in bacteria isolated from Japanese coastal and off-shore marine sediments. The high rate of occurrence of TC resistant (TC(r)) bacteria (120 microg mL(-1) TC) was observed at frequency ranges between 0.0-0.08% in Tokyo Bay, 1.67-1.82% in Sagami Bay and 0.0-4.35% in the open Pacific Ocean. The tet(M) gene was PCR amplified from the TC(r) isolates, showing 127 of 209 isolates (60.8%) as positive. The rate of occurrence of tet(M) was between 32.0-96.0%, 21.1 -28.0% and 0.0-83.3% in the isolates from Tokyo Bay, Sagami Bay and the open Pacific Ocean, respectively. The tet(M) positive isolates belonged to 4 orders of bacteria. Bacillales was the most dominant order (121 strains) among tet(M) possessing bacteria, followed by Actinomycetales (three strains), Flavobacteriales (one strain) and Pseudomonadales (one strain). This indicates that tet(M) is present in various bacterial species and suggests that marine sediments are a natural reservoir of the tet(M) gene. Nucleotide sequence of the tet(M) revealed that two genotypes of tet(M) were found in the bacteria. The two genotypes were placed in genetically distant branches of the phylogenetic tree, suggesting that the two tet(M)s have different origins.

Condensed multilamellar structure of a complex of DNA with an amphiphilic block copolymer.

Deoxyribonucleic acid (DNA) is an attractive building block for self-assembled nanostructures, because the anionic phosphate group and the base moiety allow it to bind with a broad spectrum of organic and inorganic species through ionic and hydrogen bonding. Here we present a hierarchical structure formed by the ionic complex of DNA with an amphiphilic block copolymer comprising a cationic block. Upon the complexation the cationic block chains wrap around DNA for charge matching and the microphase separation between the hydrophobic block and the hydrophilic component yields a multilamellar structure with liquid crystalline ordering of the DNA chains condensed in the hydrophilic microdomains. Each hydrophilic lamellar domain is found to contain two DNA sublayers separated by a thin water gap, with each sublayer comprising two rows of densely packed DNA chains to lower the interfacial free energy for the present system with strong polar-nonpolar repulsion.

Deterioration of water quality of Surma river.

Surma River is polluted day by day by human activities, poor structured sewerage and drainage system, discharging industrial and household wastes. The charas (natural channels) are responsible for surface runoff conveyance from its urban catchments to the receiving Surma River. Water samples have been collected from a part of Surma River along different points and analyzed for various water quality parameters during dry and monsoon periods. Effects of industrial wastes, municipal sewage, and agricultural runoff on river water quality have been investigated. The study was conducted within the Chattak to Sunamganj portion of Surma River, which is significant due to the presence of two major industries--a paper mill and a cement factory. The other significant feature is the conveyors that travel from India to Chattak. The river was found to be highly turbid in the monsoon season. But BOD and fecal coliform concentration was found higher in the dry season. The water was found slightly acidic. The mean values of parameters were Conductivity 84-805 micros; DO: dry-5.52 mg/l, monsoon-5.72 mg/l; BOD: dry-1mg/l, monsoon-0.878 mg/l; Total Solid: dry-149.4 mg/l, monsoon-145.7 mg/l. In this study, an effort has been taken to investigate the status of concentration of phosphate (PO(-4)) and ammonia-nitrogen (NH4-N) at four entrance points of Malnichara to the city, Guali chara, Gaviar khal and Bolramer khal. Data has been collected from March-April and September-October of 2004. Concentrations have been measured using UV Spectrophotometer. Although the phosphate concentration has been found within the limit set by DOE for fishing, irrigation and recreational purposes, however ammonia-nitrogen has been found to exceed the limit.

Outcome of peritoneal dialysis and hemodialysis in elderly patients with diabetes: early experience from Bangladesh.

In the present study, we analyzed the short-term outcome of continuous ambulatory peritoneal dialysis (PD) and hemodialysis (HD) in a group of elderly Bangladeshi patients with diabetes. Over a period of 2 years, we tracked various parameters in 60 patients on maintenance dialysis (25 on PD, 35 on HD). Mean age of the patients was 62 +/- 12 years (PD) and 57 +/- 8 years (HD), p < 0.03. Pre-dialysis systolic blood pressures (SBP) were 156 +/- 12 mmHg and 160 +/- 15 mmHg, and diastolic blood pressures (DBP) were 86 +/- 7 mmHg and 84 +/- 6 mmHg, both p = nonsignificant (NS). Pre-dialysis serum creatinine (SCr) levels were 1036 +/- 139 micromol/L and 1028 +/- 408 micromol/L, and daily urine volumes (UV) were 1.1 -/+ 0.4 L and 1 +/- 0.1 L, both also p=NS. At the end of the 2 years, durations of dialysis were 14 +/- 8 months (PD) and 13 +/- 12 months (HD), p=NS; SBPs were 142 +/- 15 mmHg and 155 +/- 18 mmHg, p < 0.004; DBPs were 81 +/- 6 mmHg and 80 +/- 7 mmHg, p=NS; and SCr levels were 538 +/- 154 micromol/L and 578 +/- 195 micormol/L, p=NS. The daily UVs had declined to 0.7 +/- 0.3 L and 0.3 +/- 0.3 L (p < 0.001) after periods of 12 +/- 7 months and 7 +/- 5 months (p < 0.001) respectively. During the study period, mortality in the PD group was 60% and in the HD group was 43% (p=NS). We conclude that elderly diabetic patients on PD have better control of blood pressure and maintain residual renal function longer than do similar patients on HD; at the same time, mortality in the two groups is comparable.

Outcome of continuous ambulatory peritoneal dialysis in a group of elderly patients from Bangladesh.

In the present study, we evaluated the clinical course and outcome of chronic peritoneal dialysis (PD) in a group of elderly patients. We enrolled 60 elderly patients (37 men, 23 women) starting PD over a 4-year study period and assessed outcomes. The mean age of our patients was 61 +/- 7 years; mean PD duration was 16 months (range: 3 - 40 months). Primary diseases were mainly diabetic nephropathy (54%) and glomerulonephritis (20%). In most patients, the PD modality was chosen because of cardiac instability. Complications during PD included peritonitis (1 episode per 9 patient-months) and exit-site infection (1 episode per 26 patient-months). Technique survival was 89% at 1 year. Patient survival was 83% and 32% at 1 and 4 years respectively. The most frequent causes of death were cerebrovascular accident, cardiac complications, and sepsis. We also compared predialysis parameters to final parameters for 20 deceased patients. Mean age in this group was 62 +/- 8 years, and mean PD duration was 13 +/- 8 months. Body mass index (BMI) was 23 +/- 3 kg/m2 predialysis versus 22 +/- 3 kg/m2 at the end of dialysis (p < 0.01); residual renal creatinine clearance was 4.4 +/- 2 mL/min versus 2.3 +/- 2 mL/min (p < 0.003), and weekly total Kt/V was 2.1 +/- 0.3 versus 1.8 +/- 0.3 (p < 0.002). Albumin showed positive correlations with BMI (r = 0.40, p < 0.02) and with creatinine (r = 0.40, p < 0.01). We conclude that survival of elderly patients on continuous ambulatory peritoneal dialysis is reasonable in the first year, and that further improvement may be achieved by initiating dialysis early, by increasing the dialysis dose, and by improving the patients' nutrition status.