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1.
J Clin Tuberc Other Mycobact Dis ; 36: 100450, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38770156

ABSTRACT

Objectives: Several studies suggested that diabetes mellitus (DM) worsens the tuberculosis (TB) treatment outcome. But information regarding the association of DM with retreatment of TB is very scarce in Bangladesh. Present study aimed to assess the effects of DM on retreatment of TB. Methods: This case-control study was conducted among 254 patients (127 cases and 127 controls) from January 2022 - December 2022. Patients were recruited by purposive sampling from 92 centers of the Diabetic Association of Bangladesh (BADAS). Data were collected by face-to-face interview and record reviewing with the help of semi-structured questionnaire and checklist respectively. Quality of data was maintained in all stages of the study. Data were analyzed by using IBM SPSS software. Informed written consent was taken from each patient prior to the study. Ethical issues were maintained strictly. Results: Present study matched the age and sex of cases and controls. The study revealed that majority of case (89.0) and controls (97.6) were married. Among cases 78.0 % had DM and among controls 64.6 % had DM. Among diabetic patients, 78.8 % cases' and 64.6 % controls' HbA1C level was not within normal range. The study found that, the number of episodes of previous TB (AOR = 3.088, ρ = 0.019), presence of DM (AOR = 2.817, ρ = 0.012) and uncontrolled HbA1C level (AOR = 2.500, ρ = 0.028) were independently associated with retreatment of TB. Conclusion: The study found that presence of DM, uncontrolled HbA1C level and multiple episodes of previous TB were the risk factors for retreatment of TB. So, a separate guideline for treatment of TB-DM patients should be established to prevent retreatment cases.

2.
Discov Nano ; 19(1): 2, 2024 Jan 02.
Article in English | MEDLINE | ID: mdl-38168725

ABSTRACT

Polypropylene (PP) is a versatile polymer with numerous applications that has undergone substantial changes in recent years, focusing on the demand for next-generation polymers. This article provides a comprehensive review of recent research in PP and its advanced functional applications. The chronological development and fundamentals of PP are mentioned. Notably, the incorporation of nanomaterial like graphene, MXene, nano-clay, borophane, silver nanoparticles, etc., with PP for advanced applications has been tabulated with their key features and challenges. The article also conducts a detailed analysis of advancements and research gaps within three key forms of PP: fiber, membrane, and matrix. The versatile applications of PP across sectors like biomedical, automotive, aerospace, and air/water filtration are highlighted. However, challenges such as limited UV resistance, bonding issues, and flammability are noted. The study emphasizes the promising potential of PP while addressing unresolved concerns, with the goal of guiding future research and promoting innovation in polymer applications.

3.
ACS Omega ; 8(31): 28355-28366, 2023 Aug 08.
Article in English | MEDLINE | ID: mdl-37576688

ABSTRACT

Regardless of the adverse effects of Bisphenol A (BPA), its use in industry and in day-to-day life is increasing at a higher rate every year. In the present study, a simple and reliable chemical approach was used to develop an efficient BPA sensor based on a Co-Ru-based heterometallic supramolecular polymer (polyCoRu). Surface morphology and elemental analysis were examined using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Furthermore, functional group analysis was accomplished by Fourier transform infrared spectroscopy (FT-IR). UV-vis spectroscopy was used to confirm the complexation in the ratio of 0.5:0.5:1 (metal 1/metal 2/ligand). Electrochemical characterization of the synthesized polyCoRu was conducted using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) analyses. The study identified two distinct linear dynamic ranges for the detection of BPA, 0.197-2.94 and 3.5-17.72 µM. The regression equation was utilized to determine the sensitivity and limit of detection (LOD), resulting in values of 0.6 µA cm-2 µM-1 and 0.02 µM (S/N = 3), respectively. The kinetics of BPA oxidation at the polyCoRu/GCE were investigated to evaluate the heterogeneous rate constant (k), charge transfer coefficient (α), and the number of electrons transferred during the oxidation and rate-determining step. A probable electrochemical reaction mechanism has been presented for further comprehending the phenomena occurring at the electrode surface. The practical applicability of the fabricated electrode was analyzed using tap water, resulting in a high percentage of recovery ranging from 96 to 105%. Furthermore, the reproducibility and stability data demonstrated the excellent performance of polyCoRu/GCE.

4.
Indian Heart J ; 73(5): 612-616, 2021.
Article in English | MEDLINE | ID: mdl-34627578

ABSTRACT

BACKGROUND: Percutaneous transvenous mitral commissurotomy (PTMC) is the standard of treatment for symptomatic severe rheumatic mitral stenosis (MS). PTMC has the standard Inoue technique, but we have to modify the procedure in many technically challenging cases, especially to cross the mitral valve. METHODOLOGY: Two over-the-wire strategies to enter the LV were taken in 80 complex cases of PTMC. The first one was done by exchanging the J-shaped wire from the balloon, introducing the spring wire into it, and pushing it into LV. The second one-removal of balloon keeping the spring wire in LA and the Mullin's sheath was introduced, and the tip of the wire was pushed into LV, and the balloon was introduced over the wire. We also changed the left atrium (LA) graphy in the RAO view instead of the AP view to facilitating entry into LV. RESULTS: We succeeded in 76 (95 %) cases. Strategy one was applied to all but successful in only 25 cases (31 %), and strategy 2 was applied in the remaining. Strategy 1 required less procedural time and fluoroscopic time in comparison to strategy 2 (40 ± 10 vs 60 ± 16 min, 25 ± 7 vs 35 ± 8 min). After modification of taking the LA graphy in RAO view, our rate of facing the difficulties decreased from 21 % to 9 %. Critical MS (31 %) and the giant LA (30 %) were the topmost causes of difficulties. No major complications were recorded. CONCLUSION: Over-the-wire entry into LV is cost-effective, requiring no new equipment and is safe and can be used in complex cases.


Subject(s)
Mitral Valve Stenosis , Mitral Valve , Catheterization , Heart Atria , Heart Ventricles/diagnostic imaging , Heart Ventricles/surgery , Humans , Mitral Valve/diagnostic imaging , Mitral Valve/surgery , Mitral Valve Stenosis/diagnosis , Mitral Valve Stenosis/surgery
5.
Glob Pediatr Health ; 7: 2333794X20967585, 2020.
Article in English | MEDLINE | ID: mdl-33195743

ABSTRACT

Due to lack of robust data on childhood cystic fibrosis (CF) in Bangladesh we sought to evaluate their clinico-epidemiology. A cross-sectional observation was conducted adopting CF-foundation consensus-panel-diagnostic criteria in 3 tertiary-care-hospitals in Bangladesh from 2000 to 2017. Clinically suspected 95 CF-cases were subjected to sweat-chloride testing using locally-developed a fast, cheap and effective indigenously body-wrapped sweating technique measured by US-Easy Lyte-automated microprocessor-controlled analyzer marking ≥60 mmol/L as positive. Mean-age of CF-cases at disease-onset was 16.9 ± 26.6 months that significantly differed with age-at-diagnosis (P < .02). Pulmonary syndromes included chronic wet cough in 100%, respiratory distress in 90.5%, digital-clubbing in 78%, mucopurulent-sputum in 74%-cases, and crepitation in 82%. Radio-imaging revealed bronchiectasis in 60%, hyperinflation/peribronchial-thickening in 22% and, pan-sinusitis in 89%-cases. While 37% had history-of malabsorption, high-fecal-fat revealed in 53%-cases. Malnutrition prevailed as severe-underweight in 87%-cases and all CF-cases (100%) had high sweat-chloride (mean = 118 ± 53.34 mmol/L). Thus, children with pulmonary features coupled with severe malnutrition and associated radio-imaging bronchiectasis should be screened for CF with a fast, cheap and effective sweat test in resource poor settings.

6.
ACS Omega ; 5(22): 12882-12891, 2020 Jun 09.
Article in English | MEDLINE | ID: mdl-32548472

ABSTRACT

Here, we report a semiempirical quantum chemistry computational approach to understanding the electrocatalytic reaction mechanism (ERM) of a metallic supramolecular polymer (SMP) with nitrite through UV/vis spectral simulations of SMP with different metal oxidation states before and after interactions with nitrite. In one of our recent works, by analyzing the electrochemical experimental data, we showed that computational cyclic voltammetry simulation (CCVS) can be used to predict the possible ERM of heterometallo-SMP (HMSMP) during electrochemical oxidation of nitrite (Islam T.ACS Appl. Polym. Mater.2020, 2( (2), ), 273-284). However, CCVS cannot predict how the ERM happens at the molecular level. Thus, in this work, we simulated the interactions between the repeating unit (RU) of the HMSMP polyNiCo and nitrite to understand how the oxidation process took place at the molecular level. The RU for studying the ERM was confirmed through comparing the simulated UV/vis and IR spectra with the experimental spectra. Then, the simulations between the RU of the polyNiCo and various species of nitrite were done for gaining insights into the ERM. The simulations revealed that the first electron transfer (ET) occurred through coordination of NO2 - with either of the metal centers during the two-electron-transfer oxidation of nitrite, while the second ET followed a ligand-ligand charge transfer (LLCT) and metal-ligand charge transfer (MLCT) pathway between the NO2 species and the RU. This ET pathway has been proposed by analyzing the transition states (TSs), simulated UV/vis spectra, energy of the optimized systems, and highest occupied molecular orbital-lowest occupied molecular orbital (HOMO-LUMO) interactions from the simulations between the RU and nitrite species.

7.
Int J Infect Dis ; 92: 56-61, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31926354

ABSTRACT

BACKGROUND: Data are scarce regarding the prevalence of diabetes mellitus (DM) among tuberculosis (TB) patients in Bangladesh. This study was undertaken to estimate the number needed to screen (NNS) to identify a case of DM among those with TB symptoms and those with confirmed TB disease, and to identify factors predicting treatment outcomes of TB patients with and without DM. METHODS: Persons attending public-private model screening centres in urban Dhaka for the evaluation of TB were offered free blood glucose testing in addition to computer-aided chest X-ray and sputum Xpert MTB/RIF. RESULTS: Among 7647 people evaluated for both TB and DM, the NNS was 35 (95% confidence interval (CI) 31-40) to diagnose one new case of DM; among those diagnosed with TB, the NNS was 21 (95% CI 17-29). Among those with diagnosed TB, patients with DM were more likely to have cavitation on chest X-ray compared to those without DM (31% vs 22%). Treatment failure (odds ratio (OR) 18.9, 95% CI 5.43-65.9) and death (OR 2.08, 95% CI 1.11-3.90) were more common among TB patients with DM than among TB patients without DM. DM was the most important predictor of a poor treatment outcome in the classification analysis for TB patients aged 39 years and above. CONCLUSIONS: A considerable burden of DM was found among patients accessing TB diagnostics through a public-private model in urban Bangladesh, and DM was associated with advanced TB disease and a high rate of poor treatment outcome.


Subject(s)
Diabetes Mellitus/diagnosis , Mass Screening , Tuberculosis/complications , Adult , Aged , Bangladesh/epidemiology , Diabetes Complications/diagnosis , Diabetes Mellitus/epidemiology , Female , Humans , Male , Middle Aged , Prevalence , Treatment Outcome , Tuberculosis/diagnosis , Young Adult
8.
Int J Biol Macromol ; 138: 13-20, 2019 Oct 01.
Article in English | MEDLINE | ID: mdl-31279061

ABSTRACT

The present study suggests the formation of polyvinyl alcohol (PVA)-Azadirachta indica (neem)-chitosan blend nanofibrous mat (PNCNM) by bi-layered technique under optimum processing conditions. The antibacterial activity against Staphylococcus aureus (S. aureus) bacteria, morphology, bonding behavior, thermal stability, tensile behavior and moisture management properties of the developed sample had been investigated. The scanning electron microscopy (SEM) images revealed the homogeneous and smooth fibers produced having average diameter of 213.52nm (nm) with the minimum and maximum diameter of 152nm and 298nm respectively. Besides, it showed 91% porosity which is indicative of porous structure. The presence of PVA, neem constituents and chitosan was established by Fourier Transform Infrared Spectroscopy (FTIR) indicating the formation of hydrogen bonding among them. The addition of neem extracts led to enhanced thermal stability and moisture management properties. In addition, the developed mat showed a tensile strength of 18.78N corresponding to the elongation value of 4.98mm. Besides, the incorporation of neem extract into the nanofiber mat exhibited a significant synergistic antibacterial activity against bacterial cells through the formation of inhibition zone. Thus, the newly developed nanofibrous mat could turn out to be a suitable material for the wound dressing purpose.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Azadirachta/chemistry , Chitosan/chemistry , Nanofibers/chemistry , Plant Extracts/chemistry , Polyvinyl Alcohol/chemistry , Microbial Sensitivity Tests , Plant Leaves/chemistry , Porosity , Staphylococcus aureus/drug effects , Tensile Strength
9.
Trop Med Health ; 46: 5, 2018.
Article in English | MEDLINE | ID: mdl-29507506

ABSTRACT

BACKGROUND: Violence affects 15-75% of women across the globe and has a significant impact on their health, well-being, and rights. While quantitative research links it to poor mental health, there is a lack of qualitative enquiry in how women experience it, and how it is related to the mental disorders in Bangladesh. This information is important in understanding the situation and structuring a locally appropriate and culturally sensitive program. METHODS: We adopted a phenomenological approach and conducted 16 in-depth interviews, three informal interviews, one focus group discussion, and one key informant interview. We also reviewed published reports and documents. We followed criterion sampling in selecting women with mental disorders who experienced violence. We explored their experiences and understanding of the issues and described the phenomenon. RESULTS: We found that Bangladesh society was largely controlled by men, and marriage was often forced on women. Women often were blamed for any mishap in the family and married women were under social and emotional pressure to keep the marital relationship going even when painful. We found all forms of violence (physical, emotional, sexual etc.) and most of the time found more than one type in women with mental disorders. Sexual violence is a reality for some women but rarely discussed. We found the society very tolerant with mental disorder patients and those who resorted to violence against them.We identified four theoretical understandings about the role of violence in mental disorders. Sometimes the violence predisposed the mental illness, sometimes it precipitated it, while other times it maintained and was a consequence of it. Sometimes the violence may be unrelated to the mental illness. The relationships were complex and depended on both the type of mental disorder and the nature and intensity of the violence. We found most of the time that more than one type of violence was involved and played more than one role, which varied across different types of mental disorders. Interestingly, not all violence that mentally disordered women faced was because they were women, but because of mental disorders, which brought violence to them as a consequence. CONCLUSIONS: The findings of this first ever qualitative study into the experiences of violence by women with mental disorder in Bangladesh can be used in developing a culturally specific intervention to reduce both violence and mental disorders in women.

10.
Bioconjug Chem ; 27(10): 2307-2314, 2016 Oct 19.
Article in English | MEDLINE | ID: mdl-27580353

ABSTRACT

Water-soluble helical Fe(II)-based metallosupramolecular polymers ((P)- and (M)-polyFe) were synthesized by 1:1 complexation of Fe(II) ions and bis(terpyridine)s bearing a (R)- and (S)-BINOL spacer, respectively. The binding affinity to calf thymus DNA (ct-DNA) was investigated by titration measurements. (P)-PolyFe with the same helicity as B-DNA showed 40-fold higher binding activity (Kb = 13.08 × 107 M-1) to ct-DNA than (M)-polyFe. The differences in binding affinity were supported by electrochemical impedance spectroscopy analysis. The charge-transfer resistance (Rct) of (P)-polyFe increased from 2.5 to 3.9 kΩ upon DNA binding, while that of (M)-polyFe was nearly unchanged. These results indicate that ionically strong binding of (P)-polyFe to DNA chains decreased the mobility of ions in the conjugate. Unique rod-like images were obtained by atomic force microscopy measurement of the DNA conjugate with (P)-polyFe, likely because of the rigid binding between DNA chains and the polymer. Differences in polymer chirality lead to significantly different cytotoxicity levels in A549 cells. (P)-PolyFe showed higher binding affinity to B-DNA and much higher cytotoxicity than (M)-polyFe. The helicity in metallosupramolecular polymer chains was important not only for chiral recognition of DNA but also for coordination to a biological target in the cellular environment.


Subject(s)
Antineoplastic Agents/pharmacology , DNA/metabolism , Polymers/chemistry , Polymers/metabolism , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Apoptosis/drug effects , Chemistry Techniques, Synthetic , Dielectric Spectroscopy/methods , Drug Screening Assays, Antitumor/methods , Fluoresceins/metabolism , Humans , Iron Compounds/chemistry , Mice , Microscopy, Atomic Force , NIH 3T3 Cells/drug effects , Polymers/pharmacology , Solubility , Water/chemistry
11.
BMC Res Notes ; 9: 100, 2016 Feb 16.
Article in English | MEDLINE | ID: mdl-26879846

ABSTRACT

BACKGROUND: Melioidosis is endemic in tropical Australia and Southeast Asian countries and its causative organism Burkholderia pseudomallei is a recognized cause of pneumonia in these regions. Recent isolation of the organism in the soil of Kapasia, Gazipur, Bangladesh has proven its exposure among the population residing in endemic areas of our country. Pneumonia is the most common presentation of melioidosis. Acute, subacute and chronic pneumonia due to B. pseudomallei can present as primary or secondary pneumonia. Treatment of such cases are challenging as well. Till date, few cases of acute and chronic pneumonia due to melioidosis occurring in local Bangladeshis as well as in returning travelers to Europe have been reported. To the best of our knowledge, this is the first reported case of primary melioidosis pneumonia declared cured after a 27 weeks of treatment regimen from Bangladesh. CASE PRESENTATION: A 43-year-old Bangladeshi gentleman, known diabetic, hypertensive, smoker, presented with the complaints of recurrent episodes of low to high grade intermittent fever, productive cough with occasional haemoptysis and 10 kg weight loss over one and half months. Poorly responding to conventional antibiotics, he was suspected as a case of pulmonary tuberculosis. Examination and investigations revealed left sided consolidation with cavitary lesion, hepato-splenomegaly and sputum analysis confirmed growth of Burkholderia pseudomallei. The patient was successfully treated as a case of primary melioidosis pneumonia. CONCLUSION: Often misdiagnosed and empirically treated as tuberculosis, untreated melioidosis pneumonia may even lead to death. Therefore, melioidosis should be suspected in appropriate clinical scenario in patients with a history of residing in or traveling to endemic areas. In Bangladesh, time has come to explore whether melioidosis should be considered as an emerging infectious disease.


Subject(s)
Melioidosis/complications , Melioidosis/drug therapy , Pneumonia/complications , Pneumonia/drug therapy , Adult , Bangladesh , Burkholderia pseudomallei/physiology , Hospitalization , Humans , Male , Melioidosis/diagnostic imaging , Melioidosis/microbiology , Pneumonia/diagnostic imaging , Pneumonia/microbiology , Radiography, Thoracic , Treatment Outcome
12.
ACS Appl Mater Interfaces ; 7(34): 19034-42, 2015 Sep 02.
Article in English | MEDLINE | ID: mdl-26285226

ABSTRACT

A platinum(II)-based, luminescent, metallo-supramolecular polymer (PolyPtL1) having an inherent dipole moment was synthesized via complexation of Pt(II) ions with an asymmetric ligand L1, containing terpyridyl and pyridyl moieties. The synthesized ligand and polymer were well characterized by various NMR techniques, optical spectroscopy, and cyclic voltammetry studies. The morphological study by atomic force microscopy revealed the individual and assembled polymer chains of 1-4 nm height. The polymer was specifically attached on Au-electrodes to produce two types of film (films 1 and 2) in which the polymer chains were aligned with their dipoles in opposite directions. The Au-surface bounded films were characterized by UV-vis, Raman spectroscopy, cyclic voltammetry, and atomic force microscopy study. The quantum mechanical calculation determined the average dipole moment for each monomer unit in PolyPtL1 to be about 5.8 D. The precise surface derivatization permitted effective tuning of the direction dipole moment, as well as the direction of rectification of the resulting polymer-attached molecular diodes. Film 1 was more conductive in positive bias region with an average rectification ratio (RR = I(+4 V)/I(-4 V)) ≈ 20, whereas film 2 was more conducting in negative bias with an average rectification ratio (RR = I(-4 V)/I(+4 V)) ≈ 18.

13.
Chem Commun (Camb) ; 51(55): 11012-4, 2015 Jul 14.
Article in English | MEDLINE | ID: mdl-26051550

ABSTRACT

High proton conduction (8.5 × 10(-2) mS cm(-1)) was observed in a Mo(vi)-based metallo-supramolecular polymer with carboxylic acids at 95%RH. The integration of OH groups into the polymer was analysed using FTIR spectroscopy and found to be crucial for the proton transport in the polymer.

15.
Waste Manag ; 32(11): 2096-105, 2012 Nov.
Article in English | MEDLINE | ID: mdl-22088960

ABSTRACT

The aim of this research was to determine appropriate treatment technique for effective treatment of heavily polluted landfill leachate. We accomplished several treatment experiments: (i) aerobic biological treatment, (ii) chemical coagulation, (iii) advanced oxidation process (AOP) and (iv) several combined treatment strategies. Efficiency of these treatment procedures were monitored by analysing COD and colour removal. Leachate used for this study was taken from Matuail landfill site at Dhaka city. With extended aeration process which is currently used in Matuail landfill site for leachate treatment, maximum COD and colour removal of 36% and 20%, respectively could be achieved with optimum retention period of 7 days. With optimum aluminium sulphate dose of 15,000 mg/L and pH value of 7.0, maximum COD and colour removals of 34% and 66%, respectively were observed by using chemical coagulation. With optimum pH of 5.0 and optimum dosages of reagents having H(2)O(2)/Fe(2+) molar ratio of 1.3 the highest removal of COD and colour were found 68% and 87%, respectively with sludge production of 55%. Fenton treatment which is an advanced oxidation process was the most successful between these three separate treatment procedures. Among the combined treatment options performed, extended aeration followed by Fenton method was the most suitable one.


Subject(s)
Refuse Disposal/methods , Water Pollutants, Chemical , Water Purification/methods , Aerobiosis , Ammonia/isolation & purification , Bangladesh , Biological Oxygen Demand Analysis , Color , Developing Countries , Hydrogen Peroxide/chemistry , Hydrogen-Ion Concentration , Iron/chemistry , Wastewater , Water Pollutants, Chemical/chemistry , Water Pollutants, Chemical/metabolism
16.
J Health Popul Nutr ; 29(2): 92-102, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21608418

ABSTRACT

The study assessed the achievements in, critically reviewed the relevant issues of, and put forward recommendations for achieving the target of the Millennium Development Goal relating to mortality of children aged less than five years (under-five mortality) in Bangladesh within 2015. To materialize the study objectives, a thorough literature review was done. Mortality of under-five children and infants decreased respectively to 65 from 151 and to 52 from 94 per 1,000 livebirths during 1990-2006. The immunization coverage increased from 54% to 81.9% during the same period. The projection shows that Bangladesh will achieve targeted reduction in under-five mortality and infant mortality within the time limit, except immunization coverage. Neonatal mortality contributed to the majority of childhood deaths. Contribution of neonatal mortality to child mortality was the highest. There were remarkable differences in child mortality by sex, division, and residence. To progress further for achieving the target of MDG relating to child mortality, some issues, such as lower use of maternal healthcare services, hazardous environmental effects on childhood illness, high malnutrition among children, shorter duration of exclusive breastfeeding practices, various child injuries leading to death, low healthcare-use of children, probable future threat of financial shortage, and strategies lacking area-wise focus on child mortality, need to be considered. Without these, the achievement of MDG relating to child mortality may not be possible within 2015.


Subject(s)
Child Mortality , Infant Mortality , Maternal Health Services/organization & administration , Bangladesh , Child, Preschool , Humans , Infant
17.
Chemistry ; 16(1): 368-75, 2010 Jan 04.
Article in English | MEDLINE | ID: mdl-19918809

ABSTRACT

pi-Extended silafluorenes and spirobisilafluorenes bearing electron-donating aminostyryl substituents at the 2,7- or 3,6-positions were synthesized by a Horner-Wadsworth-Emmons reaction. The electronic influence of spirocyclic structure and substitution mode of the aminostyryl substituents was investigated by UV/Vis spectroscopy, which indicated the existence of a spiroconjugation effect in the 3,6-substituted spirobisilafluorene. They exhibited moderate to strong fluorescence emission, and the fluorescence properties were compatible with the UV/Vis absorption characteristics, except for the 3,6-substituted spirobisilafluorene, which showed relatively large enhancement of fluorescence quantum yield and Stokes shift. The influence of the spirocyclic structure and substitution mode on the photophysical properties of the silicon compounds was investigated by DFT calculations.

18.
Chem Commun (Camb) ; (44): 6762-4, 2009 Nov 28.
Article in English | MEDLINE | ID: mdl-19885471

ABSTRACT

A phosphoniafluorene and a spirobiphosphoniafluorene bearing 4-(diethylamino)styryl groups were synthesized. These compounds exhibited bathochromically shifted absorption and emission, compared with their silicon analogues, because of the strong acceptor property of the phosphonium core. They also showed enhanced two-photon absorptions at around 930 nm.


Subject(s)
Fluorenes/chemistry , Photons , Absorption , Spectrum Analysis , Spiro Compounds/chemistry , Styrenes/chemistry
19.
Environ Monit Assess ; 154(1-4): 127-33, 2009 Jul.
Article in English | MEDLINE | ID: mdl-18553146

ABSTRACT

The physical, chemical and biological characteristics of the wastewater of Natural Gas Fertilizer Factory Ltd. Fenchuganj, Sylhet were determined through extensive laboratory tests in the months of March, July, October and December of the year 2005. Concentration of Suspended Solids was within the range of 445 to 950 mg/L. Bangladesh Industrial Effluent Standards for Suspended Solids is 100 mg/L. Suspended Solids were found above the limit in all the samples. Concentration of Dissolved Solids was found to vary from 576 to 1,456 mg/L. Bangladesh Industrial Effluent Standards, for Dissolved Solids is 2,100 mg/L. Dissolved Solids were found within the limit. Concentration of BOD(5) was found to vary from 4.5 to 8.4 mg/L. Bangladesh Industrial Effluent Standards for BOD(5) is 50 mg/L. For the year 2005, the BOD(5) was found below the limit in all the samples. Dissolved Oxygen of the wastewater was found to be between 2.0 to 3.0 mg/L, which do not satisfy the standard (4.5-8 mg/L). Oil and grease concentration were found in the range of 28 to 68 mg/L, whereas the standard is 10 mg/L for discharge into the inland surface water. In 2005, concentration of Cr(+ 6) was found to vary from 0.01 to 0.156 mg/L in the wastewater. Bangladesh Industrial Effluent Standards, for Cr(+6) is 0.1 mg/L. The concentration of chromium was found above the limit in three samples. Concentration of NO(3) was found to vary from 4.5 to 15.2 mg/L in the wastewater. Bangladesh Industrial Effluent Standards for nitrate is 10 mg/L. The nitrate was found above the limit in three samples. Maximum concentration of ammonia in lagoon 1 was found 1,710 mg/L in month of December. Bangladesh Industrial Effluent Standards for ammonia nitrogen is 100 mg/L. For the year 2005, the ammonia nitrogen was found above the limit in all samples.


Subject(s)
Environmental Monitoring , Sewage/analysis , Waste Disposal, Fluid , Ammonia/analysis , Bangladesh , Chromium Compounds/analysis , Nitrates/analysis , Rivers , Water Pollutants, Chemical/analysis
20.
J Org Chem ; 71(26): 9903-5, 2006 Dec 22.
Article in English | MEDLINE | ID: mdl-17168620

ABSTRACT

Diaryliodonium triflates have been directly prepared by reaction of arenes with elemental iodine in good yields by using K2S2O8 and TFA, followed by treatment with NaOTf. This procedure avoids the use of high temperature and severe reaction conditions.


Subject(s)
Benzene Derivatives/chemistry , Hydrocarbons, Iodinated/chemical synthesis , Iodine/chemistry , Potassium Compounds/chemistry , Sulfates/chemistry , Trifluoroacetic Acid/chemistry , Hydrocarbons, Iodinated/chemistry
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