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1.
Mymensingh Med J ; 32(3): 833-840, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37391982

ABSTRACT

When performing infra-umbilical procedures, caudal epidural analgesia with bupivacaine is frequently used to provide both intra- and post-operative analgesia. Dexmedetomidine, an alpha 2 agonistsare extensively used in neuraxial blocks and peripheral nerve blocks to prolong the action of bupivacaine. To find out the effects of dexmedetomidine as an adjuvant to bupivacaine for caudal analgesia in children undergoing infra-umbilical surgery. This was a randomized, controlled double-blinded prospective observational study and was performed from July 2019 to December 2019. A total of 60 (Sixty) patients with different infra-umbilical surgical problems underwent different procedure under caudal anaesthesia in different operation theatre in Bangabandhu Sheikh Mujib Medical University, Dhaka were enrolled in this study. Elaborate personal history, meticulous clinical examinations and relevant laboratory investigations was done. Post-operative adverse effects also were monitored. All information from history of illness, clinical, laboratory findings, duration of analgesia and post-operative adverse effects were recorded in a preformed data sheet (Appendix-I) and statistical analysis was done by SPSS 22.0. Mean age of the children in Group A (dexmedetomidine + bupivacaine) was 5.50±2.61 years and in Group B (bupivacaine) was 5.66±2.75. Mean weight of the children in Group A was 19.22±8.58 kg and in Group B was 19.70±8.94 kg in this study. Mean duration of anaesthesia was 27.5±6.5 minute in Group A and 28.5±5.5 minute in Group B. The mean duration of analgesia was 4.32±0.54 hours for Group A and 2.12±0.32 hours in Group B. In Group A, 46.7% patients required 1 and 3.3% required 2 rescue analgesic but in Group B, 43.3% patients required single rescue analgesic and 33.3% required two rescue analgesics (p<0.05). In Group A, 6.7% patients had nausea/ vomiting and in Group B, 16.7% patients had nausea/ vomiting (p>0.05). It can be concluded that dexmedetomidine with bupivacaine for caudal analgesia in infra-umbilical surgery significantly prolongs the duration of postoperative analgesia when compared to bupivacaine alone without any side-effects.


Subject(s)
Analgesia , Dexmedetomidine , Drug-Related Side Effects and Adverse Reactions , Humans , Child , Child, Preschool , Bupivacaine/therapeutic use , Dexmedetomidine/therapeutic use , Bangladesh , Nausea
2.
Mymensingh Med J ; 26(2): 395-405, 2017 04.
Article in English | MEDLINE | ID: mdl-28588178

ABSTRACT

This study was aimed at finding the parameters for prediction of difficulty in endotracheal intubation, that are easy to examine and that could better predict difficulty. The current observational prospective, cross sectional study was conducted in the department of Anaesthesia, Analgesia and Intensive Care Medicine, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh from March 2015 to September 2015 comprising 180 patient of both sexes requiring endotracheal intubation were arranged into two groups, Group A: Modified Mallampati test Group and Group B: Modified Mallampati & upper lip bite test group (combined) Assessment of difficulty in intubation was done by Cormack & Lehane direct Laryngoscopic grading. Outcome was measured as no difficulty or difficulty in intubation. In Group A 33 cases were true positive, 15 false negative, 26 false positive, 16 true negative. In Group B 53 cases were true positive, 1 false positive, 8 false negative, 28 true negative. The validity tests for Group A for evaluation of difficult intubation were indicated by sensitivity 55.9%, Specificity 51.6%, Accuracy 54.41%, Positive predictive value 68.8% and Negative predictive value 38.1%. The values for Group-B were 86.9%, 96.6%, 90.0%, 98.1% and 77.8% respectively. Combined modified Mallampati & Upper Lip Bite Test has definite value in the diagnosis of difficulty in intubation and can be regarded as sensitive & specific test for operative discrimination of the patient.


Subject(s)
Bite Force , Intubation, Intratracheal , Bangladesh , Cross-Sectional Studies , Female , Humans , Intubation, Intratracheal/methods , Laryngoscopy , Lip , Male , Prospective Studies
3.
Clin Microbiol Infect ; 22(8): 733.e9-733.e19, 2016 Aug.
Article in English | MEDLINE | ID: mdl-27208430

ABSTRACT

Hepatitis B e-antigen negative (e(-)) chronic HBV infection (CHI) encompasses a heterogeneous clinical spectrum ranging from inactive carrier (IC) state to e(-) chronic hepatitis B (CHB), cirrhosis and hepatic decompensation. In the backdrop of dysfunctional virus-specific T cells, natural killer (NK) cells are emerging as innate effectors in CHI. We characterized CD3(-) CD56(+) NK cells in clinically well-defined, treatment-naive e(-) patients in IC, e(-)CHB or decompensated liver cirrhosis (LC) phase to appraise their role in disease progression. The NK cell frequencies increased progressively with disease severity (IC 8.2%, e(-)CHB 13.2% and LC 14.4%). Higher proportion of NK cells from LC/e(-)CHB expressed CD69, NKp46, NKp44, TRAIL and perforin, the last two being prominent features of CD56(bright) and CD56(dim) NK subsets, respectively. The frequencies of CD3(-) CD56(+) NK cells together with TRAIL(+) CD56(bright) and Perforin(+) CD56(dim) NK cells correlated positively with serum alanine transaminase levels in e(-)CHB/LC. K562 cell-stimulated NK cells from e(-)CHB/LC exhibited significantly greater degranulation but diminished interferon-γ production than IC. Further, Perforin(+) NK cell frequency inversely correlated with autologous CD4(+) T-cell count in e(-) patients and ligands of NK receptors were over-expressed in CD4(+) T cells from e(-)CHB/LC relative to IC. Co-culture of sorted CD56(dim) NK cells and CD4(+) T cells from e(-)CHB showed enhanced CD4(+) T-cell apoptosis, which was reduced by perforin inhibitor, concanamycin A, suggesting a possible perforin-dependent NK cell-mediated CD4(+) T-cell depletion. Moreover, greater incidence of perforin-expressing NK cells and decline in CD4(+) T cells were noticed intrahepatically in e(-)CHB than IC. Collectively, NK cells contribute to the progression of e(-)CHI by enhanced TRAIL- and perforin-dependent cytolytic activity and by restraining anti-viral immunity through reduced interferon-γ secretion and perforin-mediated CD4(+) T-cell lysis.


Subject(s)
Hepatitis B e Antigens/immunology , Hepatitis B virus/immunology , Hepatitis B, Chronic/immunology , Hepatitis B, Chronic/virology , Killer Cells, Natural/immunology , Biomarkers , Cell Degranulation/immunology , Cytokines/biosynthesis , Disease Progression , Female , Granzymes/genetics , Granzymes/metabolism , Hepatitis B, Chronic/diagnosis , Humans , Immunophenotyping , Killer Cells, Natural/metabolism , Liver Function Tests , Lymphocyte Activation/immunology , Lymphocyte Count , Male , Perforin/genetics , Perforin/metabolism , Severity of Illness Index , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolism
4.
J Phys Condens Matter ; 25(38): 385501, 2013 Sep 25.
Article in English | MEDLINE | ID: mdl-23988867

ABSTRACT

The effect of 6 MeV H(+) irradiation on hydrothermally grown ZnO single crystal has been investigated using high resolution x-ray diffraction (HRXRD) and optical absorption (ultraviolet-visible) spectroscopy. The increase of the diffuse scattering in the reciprocal space maps measured using HRXRD indicates an increase of the point defect density upon irradiation. Within the penetration depth of x-rays of several micrometres, the defect density increased with increasing distance from the sample surface. On the other hand, the near band gap optical absorption became sharper for the irradiated crystal. This reflects enhanced band to band absorption and reduced sub-band gap absorption due to defects. Temperature dependent photoluminescence spectra of the pristine sample show negative thermal quenching (NTQ) of the luminescence which is due to the presence of two or more donor related defects. Upon irradiation, a single dominant donor bound transition can be found without any temperature induced NTQ. Enhancement of the band edge luminescence and reduction of the defect related luminescence is observed at 10 K. Such changes have been discussed in the light of the hydrogen present in the as-grown state of hydrothermal ZnO.

5.
Rev Sci Instrum ; 84(3): 033301, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23556809

ABSTRACT

Radioactive ion beams (RIB) have been produced on-line, using a gas-jet recoil transport coupled Electron Cyclotron Resonance (ECR) ion-source at the VECC-RIB facility. Radioactive atoms∕molecules carried through the gas-jet were stopped in a catcher placed inside the ECR plasma chamber. A skimmer has been used to remove bulk of the carrier gas at the ECR entrance. The diffusion of atoms∕molecules through the catcher has been verified off-line using stable isotopes and on-line through transmission of radioactive reaction products. Beams of (14)O (71 s), (42)K (12.4 h), (43)K (22.2 h), and (41)Ar (1.8 h) have been produced by bombarding nitrogen and argon gas targets with proton and alpha particle beams from the K130 cyclotron at VECC. Typical measured intensity of RIB at the separator focal plane is found to be a few times 10(3) particles per second (pps). About 3.2 × 10(3) pps of 1.4 MeV (14)O RIB has been measured after acceleration through a radiofrequency quadrupole linac. The details of the gas-jet coupled ECR ion-source and RIB production experiments are presented along with the plans for the future.

6.
Malays J Nutr ; 19(1): 121-9, 2013 Apr.
Article in English | MEDLINE | ID: mdl-24800390

ABSTRACT

INTRODUCTION: Essential fatty acids (EFAs) play a vital role in the human body and need to be taken through a regular diet. EFAs are susceptible to autoxidation, hence the stability of the EFAs and their products is a matter of concern. METHODS: Margarine containing sunflower oil as a carrier of EFAs was prepared and the effects of water content, incorporation of EFAs, emulsifiers and antioxidants on the physical properties of margarine, that is, slipping point, dropping point and spreadability were studied. The oxidative stability of the formulated margarine was also evaluated after incorporation of EFAs and antioxidants. RESULTS: The incorporation of EFAs in the form of sunflower oil resulted in improved physical properties especially spreadability. The study revealed that up to 45% sunflower oil can be incorporated using glycerol monostearate as an emulsifier with total fat to water ratio of 85:15. Lecithin imparted better spreadability and grainy structure but is known to be susceptible to microbial attack. The capsicum oleoresin showed good activity as an antioxidant. Further addition of kalonji seeds ethanol extract (KEE) as well as curcuminoids resulted in improved spreadability but showed a decrease in oxidation stability. CONCLUSION: A stable and nutritional margarine was developed with the addition of natural antioxidants. Consumers can avail the benefits of both the EFAs and natural antioxidants in the margarine.


Subject(s)
Antioxidants/analysis , Emulsifying Agents/analysis , Food Technology/methods , Margarine/analysis , Plant Oils/analysis , Chemical Phenomena , Food Analysis/methods , Food Analysis/statistics & numerical data , Food Technology/statistics & numerical data , Sunflower Oil
7.
Mymensingh Med J ; 21(3): 533-40, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22828556

ABSTRACT

The most common problem associated with subarachnoid block (SAB) for caesarean section remains the rapid onset of profound hypotension. This study was designed to compare the incidence of hypotension after preloading with Ringer's Lactate, Hydroxyethylstarch and combination prior to SAB in caesarean section. Ninety non-labouring ASA grade 1 and 2, aged 20-35 years, weight and height was 45-60kg and 153-165cm respectively divided randomly into three groups. Group-RL received Ringer's Lactate 20ml/kg as preloading fluid. Group-H received Hydroxyethylstarch-6% 8ml/kg and Group-RLH received preloading fluid with combination of Ringer's Lactate 10ml/kg and Hydroxyethylstarch-6% 4ml/kg. Blood pressure (Systolic, Diastolic & Mean arterial pressure) was measured every 5 minute for 20 minute and every 10 minutes thereafter. Hypotension was less in Group-RLH (6.7%) whereas in Group-H and Group-RL hypotension was 20% and 47.7% respectively. Systolic blood pressure decreased significantly in all three groups. But the decreasing was less in Group-RLH than other two groups. Less IV fluid was required in Group-RLH (403ml) and Group-H (577ml) in comparison to Group-RL (1032ml) to prevent and treat peroperative hypotension. No ephedrine was needed in Group-RLH. Variation in Pulse rate was not significant in Group-RLH (p=0.061). But in other two groups it was highly significant (Group RL p≤0.001 and Group H p=0.004). There was no significant difference in neonatal outcome between three groups. Preloading with low volume colloid (4ml/kg) plus crystalloid (10ml/kg) is superior to crystalloid or colloid alone.


Subject(s)
Anesthesia, Obstetrical , Anesthesia, Spinal , Cesarean Section , Fluid Therapy/adverse effects , Hypotension/epidemiology , Adult , Female , Heart Rate , Humans , Hydroxyethyl Starch Derivatives/adverse effects , Isotonic Solutions/adverse effects , Pregnancy , Ringer's Lactate
8.
J Phys Condens Matter ; 24(32): 325503, 1-9, 2012 Aug 15.
Article in English | MEDLINE | ID: mdl-22790024

ABSTRACT

Low temperature photoluminescence and room temperature positron annihilation spectroscopy have been employed to investigate the defects incorporated by 6 MeV H(+) ions in a hydrothermally grown ZnO single crystal. Prior to irradiation, the emission from donor bound excitons is at 3.378 eV (10 K). The irradiation creates an intense and narrow emission at 3.368 eV (10 K). The intensity of this peak is nearly four times that of the dominant near band edge peak of the pristine crystal. The characteristic features of the 3.368 eV emission indicate its origin as a 'hydrogen at oxygen vacancy' type defect. The positron annihilation lifetime measurement reveals a single component lifetime spectrum for both the unirradiated (164 ± 1 ps) and irradiated crystal (175 ± 1 ps). It reflects the fact that the positron lifetime and intensity of the new irradiation driven defect species are a little higher compared to those in the unirradiated crystal. However, the estimated defect concentration, even considering the high dynamic defect annihilation rate in ZnO, comes out to be ∼4 × 10(17) cm(-3) (using SRIM software). This is a very high defect concentration compared to the defect sensitivity of positron annihilation spectroscopy. A probable reason is the partial filling of the incorporated vacancies (positron traps), which in ZnO are zinc vacancies. The positron lifetime of ∼175 ps (in irradiated ZnO) is consistent with recent theoretical calculations for partially hydrogen-filled zinc vacancies in ZnO. Passivation of oxygen vacancies by hydrogen is also reflected in the photoluminescence results. A possible reason for such vacancy filling (at both Zn and O sites) due to irradiation has also been discussed.

9.
Prep Biochem Biotechnol ; 42(3): 249-66, 2012.
Article in English | MEDLINE | ID: mdl-22509850

ABSTRACT

Vegetable edible oils and fats are mainly used for frying purposes in households and the food industry. The oil undergoes degradation during frying and hence has to be replaced from time to time. Rhamnolipids are produced by microbial cultivation using refined vegetable oils as a carbon source and Pseudomonas aeruginosa (ATCC 10145). The raw material cost accounts for 10-30% of the overall cost of biosurfactant production and can be reduced by using low-cost substrates. In this research, attention was focused on the preparation of rhamnolipids, which are biosurfactants, using potential frying edible oils as a carbon source via a microbial fermentation technique. The use of low-cost substrates as a carbon source was emphasized to tilt the cost of production for rhamnolipids. The yield was 2.8 g/L and 7.5 g/L from waste frying oil before and after activated earth treatment, respectively. The crude product contained mainly dirhamnolipids, confirmed by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), liquid chromatography-mass spectroscopy (LC-MS), and (1)H-nuclear magnetic resonance (NMR). Hence, the treatment can be used to convert waste frying oil as a low-cost substrate into a cost-effective carbon source.


Subject(s)
Glycolipids/biosynthesis , Plant Oils/chemistry , Pseudomonas aeruginosa/chemistry , Biodegradation, Environmental , Carbon/chemistry , Chromatography, High Pressure Liquid , Chromatography, Thin Layer , Fermentation , Helianthus/chemistry , Hot Temperature , Linoleic Acid/chemistry , Magnetic Resonance Spectroscopy , Peroxides/analysis , Peroxides/chemistry , Plant Oils/analysis , Pressure , Pseudomonas aeruginosa/growth & development , Sunflower Oil , Surface Tension , Surface-Active Agents/chemistry , Time Factors , Viscosity , Waste Products/analysis
10.
Prep Biochem Biotechnol ; 42(2): 125-42, 2012.
Article in English | MEDLINE | ID: mdl-22394062

ABSTRACT

Biosurfactants are microbially synthesized surfactants that are environmental friendly due to low toxicity. Sophorolipid is one of the simplest biosurfactants with well-defined structure produced by Starmerella bombicola(ATCC 22214) on glucose and vegetable oil as the carbon source. The raw material cost accounts for 10-30% of the overall cost. Glycerol is readily available from a commercial fat-splitting process as sweetwater at a very low cost. Sophorolipids was synthesized using glycerol and sweetwater as a cost-effective carbon source. The glycerol was further replaced with sweetwater as a source of glycerol. Optimum glycerol concentration was 15% w/v with 10% w/v sunflower oil, giving 6.6 g/L of sophorolipids. The crude sophorolipid contains two major components; both of them were lactonic sophorolipids as analyzed by reverse-phase high-performance liquid chromatography (RP-HPLC), liquid chromatography-mass spectroscopy (LC-MS), and nuclear magnetic resonance ((1)H-NMR).


Subject(s)
Candida/metabolism , Glycerol/metabolism , Glycolipids/metabolism , Industrial Microbiology/methods , Surface-Active Agents/metabolism , Carbon/metabolism , Chromatography, High Pressure Liquid , Industrial Microbiology/economics , Water/metabolism
11.
J Phys Condens Matter ; 23(15): 155801, 2011 Apr 20.
Article in English | MEDLINE | ID: mdl-21460421

ABSTRACT

The room temperature positron annihilation lifetime for single crystalline ZnO has been measured as 164 ± 1 ps. The single component lifetime value is very close to but higher than the theoretically predicted value of ~154 ps. Photoluminescence study (at 10 K) indicates the presence of hydrogen and other defects, mainly acceptor related, in the crystal. Defects related to a lower open volume than zinc vacancies, presumably a complex with two hydrogen atoms, are the major trapping sites in the sample. The bulk positron lifetime in ZnO is expected to be a little less than 164 ps.

12.
Mymensingh Med J ; 20(1): 93-7, 2011 Jan.
Article in English | MEDLINE | ID: mdl-21240170

ABSTRACT

In a randomised case control study in children undergoing elective subumbilical surgery, we have assessed the clinical value of bupivacaine and bupivacaine-clonidine mixture for caudal analgesia. Sixty children aged 2-10 years, were allocated randomly to two equal groups (n=30) to receive 0.25% bupivacaine 1ml/kg (Group I) and 0.25% bupivacaine 1ml/kg with clonidine 2µg/kg (Group II). The baseline haemodynamic parameters, heart rate and blood pressure were recorded. Intraoperatively children in both groups maintained haemodynamic stability and required less amount of muscle relaxant. Duration of analgesia in minutes was assessed by the time interval between the caudal extradural injection and the first analgesic demand by the patient. It was significantly longer (p=0.000) in Group II (712 ± 15.30 minutes) as compared with Group I (246 ± 8.74 minutes). Group II required significantly less supplementary analgesia after operation. There was no significant difference in the incidence of side effects between the two groups. Group I received more doses of diclofenac suppository in first 24 postoperative hours. We conclude that, when added to bupivacaine, clonidine improves the duration of caudal analgesia in children undergoing subumbilical surgery.


Subject(s)
Anesthesia, Caudal , Anesthetics, Local/administration & dosage , Bupivacaine/administration & dosage , Clonidine/administration & dosage , Pain, Postoperative/drug therapy , Case-Control Studies , Child , Child, Preschool , Humans , Prospective Studies
13.
J Appl Microbiol ; 106(6): 2006-16, 2009 Jun.
Article in English | MEDLINE | ID: mdl-19245405

ABSTRACT

AIM: Characterization of an anaerobic thermophilic bacterium and subcellular localization of its Cr(VI)-reducing activity for potential bioremediation applications. METHODS AND RESULTS: 16S rRNA gene sequence-based analyses of bacterial strains isolated from sediment samples of a Bakreshwar (India) hot spring, enriched anaerobically in iron-reducing medium, found them to be 86-96% similar to reported Thermoanaerobacter strains. The most efficient iron reducer among these, BSB-33, could also reduce Cr(VI) at an optimum temperature of 60 degrees C and pH 6.5. Filtered culture medium could reduce Cr(VI) but not Fe(III). Cell-free extracts reduced Cr(VI) inefficiently under aerobic conditions but efficiently anaerobically. Fractionation of the cell-free extracts showed that chromium reduction activity was present in both the cytoplasm and membrane. CONCLUSIONS: BSB-33 reduced Fe(III) and Cr(VI) anaerobically at 60 degrees C optimally. After fractionation, the reducing activity of Cr(VI) was found in both cytoplasmic and membrane fractions. SIGNIFICANCE AND IMPACT OF THE STUDY: To the best of our knowledge, this is the first systematic study of anaerobic Cr(VI) reduction by a gram-positive thermophilic micro-organism and, in contrast to our results, none of the earlier reports has mentioned Cr(VI)-reducing activity to be present both in the cytoplasm and membrane of an organism. The strain may offer itself as a potential candidate for bioremediation.


Subject(s)
Chromium/metabolism , Soil Pollutants/metabolism , Thermoanaerobacter/isolation & purification , Thermoanaerobacter/metabolism , Cell Membrane/metabolism , Cytoplasm/metabolism , DNA, Ribosomal/genetics , Hot Springs , Hot Temperature , India , Iron/metabolism , Microscopy, Electron , Oxidoreductases/analysis , RNA, Ribosomal, 16S/genetics , Soil Microbiology , Thermoanaerobacter/genetics
14.
Transplant Proc ; 39(3): 750-2, 2007 Apr.
Article in English | MEDLINE | ID: mdl-17445589

ABSTRACT

INTRODUCTION: Steroid-induced osteoporosis is a major problem after organ transplantation. There is considerable evidence that bisphosphonates are effective in decreasing osteoporosis. AIM: This prospective study was carried out to see the effects of bisphosphonates on bone mineral density (BMD) after successful renal transplantation. MATERIAL AND METHODS: Fifty consecutive patients of successful renal transplantation were randomized into two groups. Group A (n = 27) received 35 mg/wk of Alendronate for 6 months after transplantation. Group B (n = 23) did not receive Alendronate and served as a control. Both groups underwent a pretransplant baseline dual-energy X-ray absorptiometry (DEXA) scan of their hips and lumber spines. Both groups received oral calcium and vitamin D supplement. Both groups were matched for the regimen and dose of immunosuppressive drugs. BMD was measured at 3 months and 6 months after transplantation. RESULTS: Both groups showed a decline in BMD in early months posttransplantation. However, the 6-month DEXA scans showed a significant rise in BMD in group A as compared to group B. CONCLUSION: Bisphosphonates appear to have a beneficial effect on steroid-induced bone loss.


Subject(s)
Alendronate/adverse effects , Bone Density Conservation Agents/therapeutic use , Bone Density/drug effects , Kidney Transplantation/physiology , Absorptiometry, Photon , Adrenal Cortex Hormones/adverse effects , Femur/drug effects , Humans , Patient Selection , Prospective Studies , Spine/drug effects
16.
Int J Dev Neurosci ; 17(3): 239-53, 1999 Jun.
Article in English | MEDLINE | ID: mdl-10452367

ABSTRACT

Morphological effects of prenatal sound attenuation and sound overstimulation by species specific and music sounds on the brainstem auditory nuclei of chick have been evaluated quantitatively. Changes in length, volume, neuron number, size of neuronal nuclei and glial numbers of second and third order auditory nuclei, n. magnocellularis (NM) and n. laminaris (NL), were determined from thionine-stained serial sections of control and experimental groups on posthatch day 1 using stereological methods. Significant increase in volume of both auditory nuclei attributable to increase in length of nucleus, number and size of neurons, number of glia as well as neuropil was observed in response to both species specific and music overstimulation given during the critical period of development. The enhanced development of auditory nuclei in response to enriched environment prenatally indicates a positive effect of activity on neurons which may have clinical implications in addition to providing explanation for preference to auditory cues in the postnatal life. Reduction in neuron number with a small increase in proportion of cell nuclei of large size as well as an increase in glial numbers was seen in both NM and NL of the prenatally sound attenuated chicks. The increase in size of some neuronal nuclei may probably be evidence of enhanced synthesis of proteins involved in cell death or an attempt at recovery. The dissociated response of neurons and glia under sound attenuated and auditory stimulated conditions suggests that they are independently regulated by activity-dependent signals with glia also being under influence of other signals for a role in removal of dead cell debris.


Subject(s)
Auditory Pathways/physiology , Brain Mapping , Brain Stem/physiology , Chick Embryo/growth & development , Music , Neuronal Plasticity/physiology , Acoustic Stimulation , Animals , Cell Count , Cell Size , Neurons/cytology , Organ Size/physiology , Species Specificity
17.
J Colloid Interface Sci ; 196(1): 53-61, 1997 Dec 01.
Article in English | MEDLINE | ID: mdl-9441649

ABSTRACT

The solubilities of methane, carbon dioxide, ethane, and propane have been determined experimentally at 1 atm partial pressure and 25°C in aqueous solutions of sodium dodecyl sulfate and cetyltrimethylammonium bromide. For this purpose a specially developed apparatus is used, which is relatively simple compared to those reported in the literature hitherto. Above the CMC, the solubility of each gas increases linearly with surfactant concentration indicating micellar solubilization. The degree of solubilization is greatest for propane and decreases in the order propane > ethane > carbon dioxide > methane. Both the length of the alkyl chain and the properties of the head-group region (i.e., the micelle-water interfacial tension) are observed to determine the intramicellar solubility. A method for estimating the solubilities is also proposed based on the rationale that the micellar phase may be represented by a droplet of a "model solvent" into which the solubilizate molecule dissolves as it would in a bulk solvent. The mixture of the solute species and the model solvent is assumed to behave as a regular solution. Accordingly, a characteristic solubility parameter is estimated for the model solvent from the interaction potential between two adjacent surfactant molecules in a micelle. The solubility computed using the regular solution approximation is further corrected for the Laplace pressure that acts across the curved micelle-water interface and generally reduces the intramicellar solubility. It is concluded that for small nonpolar solutes, micellar solubilities may be reasonably well predicted by assuming that the model solvent has a solubilizing capacity (i.e., solubility parameter) close to that of a bulk equivalent alkane. Copyright 1997 Academic Press. Copyright 1997Academic Press

18.
19.
Phys Rev D Part Fields ; 46(3): 914-920, 1992 Aug 01.
Article in English | MEDLINE | ID: mdl-10015007
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