Oxygen vacancy-enriched Zn2SnO4 for aliphatic alcohol sensing and enhanced selectivity towards n-butanol.

The sensitive detection of toxic flammable volatile organics using low cost efficient sensors is important for ensuring both indoor and outdoor safety. It is essential for chemical sensors to exhibit a significantly stronger response to target analytes compared to equivalent amounts of analogous competing chemicals. In line with this importance, current work evaluated the performance of Zn2SnO4, a n-type semiconducting metal oxide, for sensing n-butanol in comparison to methanol, ethanol, and propanol vapours. These vapours fall within the category of aliphatic alcohols but vary in characteristics such as molecular weight, vapour pressure, volatility, and diffusivity. In this work we have explored the sensor's performance by adjusting the operating temperature over the range of 225-300 °C while detecting 1000 ppm of each of these vapours. Efforts were made to establish a correlation between the sensor's responses with the interactions of these vapours on the sensor's surface. Prior to assessing the sensing characteristics of the solid-state-route-derived Zn2SnO4, its structural characteristics, including phase purity, crystalline structure, bonding patterns, morphology, and defect characteristics, were studied. This comprehensive analysis sheds light on the potential of Zn2SnO4 as an effective sensor for detecting n-butanol.

Autocombustion Route Derived Zinc Ferrite Nanoparticles as Chemiresistive Sensor for Detection of Alcohol Vapors.

Prolonged exposure to alcohol vapors can have detrimental effects on human health, potentially leading to eye irritation, dizziness, and in some cases, damage to the nervous system. The present article aims to provide a comprehensive understanding on the synthesis and characterization of zinc ferrite (ZnFe2O4) nanoparticles, as well as their interactions with a range of alcohol vapors, including methanol, ethanol, n-propanol, and isopropanol. These alcohols differ in their molecular weight, boiling points, diffusivity, and other properties. The study reveals the semiconducting ZnFe2O4 nanoparticulate sensor's capability for reversible, repeatable, and sensitive detection of alcohol vapors. The sensor exhibits the highest response to ethanol within operating temperature range (225-300 °C). An attempt is made to establish a correlation between the properties of the target analytes and the observed sensing signals. Additionally, the response conductance transients of ZnFe2O4 under the exposure to the studied alcohol vapors are modeled based on the Langmuir-Hinshelwood adsorption mechanism. The characteristic time constants obtained from this modeling are justified with respect to the properties of the analytes.

Probing the p-type Chemiresistive Response of NiFe2 O4 Nanoparticles for Potential Utilization as Ethanol Sensor.

Detection of gas molecules and volatile organic compounds (VOCs) using efficient, low cost sensors has fetched significant attention in environmental monitoring, safety measures and medical diagnosis. In the present work, nickel ferrite (NFO) nanoparticles are explored as p-type semiconducting metal oxide (SMO) sensor for detection of five different organic vapors namely methanol, ethanol, n-propanol, iso-propanol and acetone which often cause severe damage to human body under prolonged exposure. The sensing studies in presence of the aforementioned five vapors are carried out by varying the sensor operating temperature (225-300 °C) and vapor concentrations (10-1000 ppm). Developed NFO sensor demonstrated best performance in terms of sensing (~10 ppm), response time (<10 s), excellent repeatability and selectivity towards ethanol among all other considered gas species. The repeatability of the sensor response is verified and the underlying reasons for the variation in the response of NFO sensor due to the change of operating temperature, analyte type and concentrations has been discussed. The synthesis of NFO through auto combustion method and study on their formation behaviour, oxygen vacancy evolution, band gap calculation, crystalline nature as well as microstructural features provides here the comprehensive information about the potential application of NFO nanoparticles as gas sensor.

Bacterial vaginosis in early pregnancy and adverse pregnancy outcome.

OBJECTIVE: To assess the prevalence of bacterial vaginosis (BV) in asymptomatic pregnant women and its association with preterm birth (PTB) and premature rupture of membranes (PROM). METHODS: In a cohort study 1,006 pregnant women between 16-28 weeks' gestation were screened for BV (Nugent's criteria) and for lower genital tract infection. Women were followed to confirm pregnancy outcome. Data were analyzed using STATA software. Univariate and multivariate methods were used to investigate the association between bacterial vaginosis and adverse pregnancy outcome. RESULTS: Prevalence of BV was 11.53%. Baseline characteristics were similar for both groups, 6.8% women were lost to follow-up. Incidence of PTB was higher in BV positive women compared to BV negative women (p = 0.001). On multiple logistic regression (MLR), BV was associated with an increased risk of PTB (p = 0.001) and PROM (p = 0.001), other correlates being previous PTB (p = 0.003) and the presence of enteropharyangeal organisms in vagina (p = 0.03). BV accounted for 82.53% of the attributable risk for PTB. CONCLUSION: Presence of BV in early pregnancy is associated with an increased risk of PTB and PROM. Multicentric interventional study is recommended.

Atypical presentations of falciparum malaria.

To identify the uncommon presentations of falciparum malaria in an endemic area and to assess the outcome of treatment, a study was carried out on 35 proved cases whose clinical presentations were either dominated by features other than fever or the history of fever was totally absent. Both urban and rural patients were included. Seventeen cases (48.3%) presented with features of cerebral malaria. Acute abdomen, urticaria, and unexplained shock were the other atypical presentations. Five cases (14.3%) of cerebral malaria died. We conclude that awareness of atypical presentations is important to detect cases of falciparum malaria in an endemic area. Intravenous quinine may need to be given promptly even when cerebral malaria is diagnosed empirically.

Identification of calmodulin-dependent protein kinase III and its major Mr 100,000 substrate in mammalian tissues.

A major substrate, Mr 100,00 (100 kDa), for a Ca2+/calmodulin (CaM)-dependent protein kinase found in many mammalian tissues has been purified from rat pancreas. The purified substrate was used to identify and partially purify a CaM-dependent protein kinase (CaM kinase III) from rat pancreas. The physical properties and substrate specificity of CaM kinase III were distinct from those of all known CaM-dependent protein kinases. Only CaM kinase III was able to phosphorylate the 100-kDa protein; synapsin I, phosphorylase b, myosin light chain, and histone were poor substrates for this enzyme. Polyclonal antibodies, raised against the purified 100-kDa protein, recognized the protein in a variety of mammalian tissues and cell lines. Immunoassay revealed that the 100-kDa protein made up 0.3-1.7% of the total cytosolic protein in these samples. Analysis of CaM kinase III revealed that the enzyme had a similar widespread tissue distribution. These results demonstrate the existence of a fifth CaM-dependent protein phosphorylation system present in high levels in animal cells.

Insulin-induced enhancement of uptake of noradrenaline in atrial strips.

1 Addition of insulin to the organ bath increased the force of contraction of guinea-pig left atrial strips driven electrically at 1 Hz. 2 The positive inotropic response to insulin remained unaltered in atria depleted of catecholamine or when beta-adrenoceptors were blocked by addition of propranolol to the organ bath. 3 The response os isolated atria to noradrenaline was significantly reduced in the presence of insulin. 4 Insulin affected neither the calcium accumulating abilities of the heart sarcolemma, mitochondria or microsomes, nor the cyclic adenosine 3',5'-monophosphate (cyclic-AMP)-protein kinase-induced stimulation of microsomal calcium uptake. 5 Addition of insulin to the organ bath enhanced significantly the ability of the cardiac tissue to take up [3H]-noradrenaline as well as [3H]-metaraminol. The activities of monoamine oxidase and catechol-O-methyl transferase were not changed after addition of insulin to homogenates of the heart. 6 The ability of insulin to facilitate uptake of noradrenaline would be expected to cause a decrease in the amount of the amine reaching the receptors, thus leading to a diminished response to this amine. This may explain, at least in part, insulin-induced subsensitivity to noradrenaline. 7 This view is supported by the observation that after blockade of amine uptake by destruction of nerve terminals, insulin failed to reduce the positive inotropic response to noradrenaline.

Role of catecholamines in the genesis of arrhythmias.

Catecholamines play a major role in the induction of cardiac rhythm disorders. The effects of catecholamines are caused by activation of beta-receptors in the heart and appear to be mediated by the cyclic AMP/protein kinase system. Increased rate of spontaneous diastolic depolarization of cardiac fibers on exposure to endogenous or exogenous catecholamine activity leads to tachyarrhythmias. Because of non-uniform distribution of sympathetic nerve endings, activation of the sympathetic nerve system may result in non-uniform reduction in the refractory period leading to re-entrant excitation. Under abnormal conditions myocardium may become more sensitive to catecholamines. In ischemia, sympathetic stimulation causes more local differences in refractory period and a greater tendency to fibrillate. Following acute coronary ligation there is a direct relationship between rhythm disturbance and levels of myocardial catecholamines. Catecholamines not only cause arrhythmia but also contribute to the development of digitalis-induced arrhythmias. The role of catecholamines in the genesis of certain cardiac arrhythmias is further supported by the fact that beta-blocking drugs which antagonize sympathetic activity are effective for treating various types of acute arrhythmias and for prevention of recurrent arrhythmias.

Contractility of endotoxic atria.

Previous studies showed that atria of guinea pigs pretreated with endotoxin had a reduced sensitivity to norepinephrine. Since accumulation of [3H]norepinephrine was reduced in atria from endotoxin-treated guinea pigs, the reduced responsiveness of such atria to norepinephrine cannot be explained on the basis of endotoxin effect on the uptake of the amine. In the present study, the relative enhancement of the contractile force of the atria during paired stimulation in endotoxic and control animals was of equal magnitude. The results indicate that reduced sensitivity to norepinephrine may not be related only to endotoxin effect on the contractility of the myocardium. Endotoxin treatment may induce certain changes in the sequence of steps involved in the process of excitation-contraction coupling in the myocardium. The most likely locus of endotoxin action appears to be the heart cell membrane.

The effect of epinephrine on phenylethanolamine N-methyltransferase in cultured explants of adrenal medulla.

The investigation reported here was designed to gain further insight into the mechanisms by which phenylethanolamine N-methyltransferase (PNMT) is regulated. Explants of adrenal medullae were cultured in defined media for up to 48 h, during which time the tissue remained histologically intact. Addition of epinephrine to the medium led to a diminution in the activity of PNMT, measurable in the dialyzed homogenates of the cultured tissue. The enzyme activity was inversely proportional to the concentration of epinephrine present in the culture medium. A diminution in the amount of PNMT protein also resulted from incubation of the explants in the presence of epinephrine. The extent of loss of PNMT, measured by immunochemical titration, corresponded to the degree of loss in PNMT activity under the same conditions. None of the metabolites of epinephrine, including 3,4-dihydroxy- or 3-methoxy-4-hydroxymandelate, or metanephrine, had an effect on PNMT. Tyrosine hydroxylase and catechol O-methyltransferase activities were also diminished, whereas tyrosine transaminase, acid phosphatase, and monoamine oxidase activities were not affected by addition of epinephrine to the medium. Ascorbic acid added to the medium prolonged the lifetime of epinephrine but did not alter the degree of diminution of PNMT. The results obtained are consistent with the view that epinephrine is rapidly assimilated into the cytoplasm of medullary cells and plays an important role in regulating the concentration of PNMT in the adrenal gland.

Effect of dopamine on renal blood flow of baboon in endotoxin shock.

Renal vasodilation observed in canine endotoxemia did not occur during endotoxin shock in the baboon: in fact, renal artery blood flow was markedly reduced. Infusion of dopamine in the baboon restored the renal artery blood flow.

Domiciliary management of simple femoral fractures in children.

Twenty-six children with a simple fracture of one femur were nursed at home while on gallows traction, under the supervision of health visitors. The average stay in hospital before they were allowed home on traction was 8,5 days. A control group of 28 children with similar fractures, who were nursed only in hospital, spent an average of 34 days in hospital. No complications of treatment were encountered in either group. It is suggested that when there is an efficient health visiting service, children with uncomplicated fractures of the femur can be nursed at home, with benefit to the hospital, the child, and his family.

Effect of dopamine infusion on the hemodynamics of normal and sympathectomized rhesus monkeys in endotoxin shock.

Infusion of endotoxin in chemically sympathectomized monkeys caused a fall in the mean aortic pressure, but the cardiac output, stroke volume, and central venous pressure were well maintained. Endotoxin-induced tachycardia in monkeys with functional sympathetics was not seen in the sympathectomized animals. Infusion of dopamine improved the hemodynamic and cardiovascular status, probably by causing vasoconstriction of the splenic and hepatic artery where the pooling of blood is believed to occur in endotoxin shock. However, these beneficial effects were not apparent when dopamine was administered in the chemically sympathectomized animal infused with endotoxin. Since chemical sympathectomy did not affect the endotoxin-induced decline in the systolic and mean aortic pressure or the severity of the endotoxin shock, it is suggested that catecholamines may not be the primary initiator or trigger substances in endotoxin shock.