This article extensively reviews the recent development of semiconductor metal oxide gas sensors for environmentally hazardous gases including NO2, NO, N2O, H2S, CO, NH3, CH4, SO2 and CO2. The gas sensing properties of differently-prepared metal oxides and loaded metal oxides towards nine environmentally hazardous gases have been individually compared and digested. Promising materials for sensitive and selective detection of each hazardous gas have been identified. For instance, unloaded WO3 nanostructures are the most promising candidates for NO2 sensing while metal catalyst loaded WO3 and gold-loaded SnO2 sensors are among the most effective for NO and N2O sensing, respectively. Moreover, related gas-sensing mechanisms are comprehensively discussed.

Semiconducting metal oxides as sensors for environmentally hazardous gases

Xin Zhou,†,‡ Songyi Lee,† Zhaochao Xu,* and Juyoung Yoon*,† †Department of Chemistry and Nanoscience, Ewha Womans University, Seoul 120-750, Republic of Korea ‡Research Center for Chemical Biology, Department of Chemistry, Yanbian University, Yanjii 133002, People’s Republic of China Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Shahekou, Dalian, Liaoning, People’s Republic of China

Recent Progress on the Development of Chemosensors for Gases.

Background Asymptomatic bacteriuria is a bacterial infection of the urine without any of the typical symptoms that are associated with a urinary infection, and occurs in 2% to 15% of pregnancies. If left untreated, up to 30% of mothers will develop acute pyelonephritis. Asymptomatic bacteriuria has been associated with low birthweight and preterm birth. This is an update of a review last published in 2015. Objectives To assess the effect of antibiotic treatment for asymptomatic bacteriuria on the development of pyelonephritis and the risk of low birthweight and preterm birth. Search methods For this update, we searched the Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) on 4 November 2018, and reference lists of retrieved studies. Selection criteria Randomised controlled trials (RCT) comparing antibiotic treatment with placebo or no treatment in pregnant women with asymptomatic bacteriuria found on antenatal screening. Trials using a cluster-RCT design and quasi-RCTs were eligible for inclusion, as were trials published in abstract or letter form, but cross-over studies were not. Data collection and analysis Two review authors independently assessed trials for inclusion and risk of bias, extracted data, and checked for accuracy. We assessed the quality of the evidence using the GRADE approach. Main results We included 15 studies, involving over 2000 women. Antibiotic treatment compared with placebo or no treatment may reduce the incidence of pyelonephritis (average risk ratio (RR) 0.24, 95% confidence interval (CI) 0.13 to 0.41; 12 studies, 2017 women; low-certainty evidence). Antibiotic treatment may be associated with a reduction in the incidence of preterm birth (RR 0.34, 95% CI 0.13 to 0.88; 3 studies, 327 women; low-certainty evidence), and low birthweight babies (average RR 0.64, 95% CI 0.45 to 0.93; 6 studies, 1437 babies; low-certainty evidence). There may be a reduction in persistent bacteriuria at the time of delivery (average RR 0.30, 95% CI 0.18 to 0.53; 4 studies; 596 women), but the results were inconclusive for serious adverse neonatal outcomes (average RR 0.64, 95% CI 0.23 to 1.79, 3 studies; 549 babies). There were very limited data on which to estimate the effect of antibiotics on other infant outcomes, and maternal adverse effects were rarely described. Overall, we judged only one trial at low risk of bias across all domains; the other 14 studies were assessed as high or unclear risk of bias. Many studies lacked an adequate description of methods, and we could only judge the risk of bias as unclear, but in most studies, we assessed at least one domain at high risk of bias. We assessed the quality of the evidence for the three primary outcomes with GRADE software, and found low-certainty evidence for pyelonephritis, preterm birth, and birthweight less than 2500 g. Authors' conclusions Antibiotic treatment may be effective in reducing the risk of pyelonephritis in pregnancy, but our confidence in the effect estimate is limited given the low certainty of the evidence. There may be a reduction in preterm birth and low birthweight with antibiotic treatment, consistent with theories about the role of infection in adverse pregnancy outcomes, but again, the confidence in the effect is limited given the low certainty of the evidence. Research implications identified in this review include the need for an up-to-date cost-effectiveness evaluation of diagnostic algorithms, and more evidence to learn whether there is a low-risk group of women who are unlikely to benefit from treatment of asymptomatic bacteriuria.

Antibiotics for asymptomatic bacteriuria in pregnancy.

Symptomatic and asymptomatic bacteriuria is common in pregnant women A history of previous urinary tract infections and low socioeconomic status are risk factors for bacteriuria in pregnancy Escherichia coli is the most common aetiologic agent in both symptomatic and asymptomatic infection and quantitative culture is the gold standard for diagnosis Treatment of asymptomatic bacteriuria has been shown to reduce the rate of pyelonephritis in pregnancy and therefore screening for and treatment of asymptomatic bacteriuria has become a standard of obstetrical care Antibiotic treatment of asymptomatic bacteriuria is associated with a decrease in the incidence of low birth weight, but the methodological quality of the studies limits the strength of the conclusions that can be drawn Debate exists in the literature as to whether treated pyelonephritis is associated with adverse fetal outcomes There is no clear consensus in the literature on antibiotic choice or duration of therapy for infection With increasing antibiotic resistance, consideration of local resistance rates is necessary when choosing therapy

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1365-2362.2008.02009.x

Asymptomatic bacteriuria and symptomatic urinary tract infections in pregnancy

Peste des petits ruminants

Considering the short-term exposure limit of SO2 to be 5 ppm, we first time report that semiconductor sensors based on vanadium doped SnO2 can be used for SO2 leak detection because of their good sensitivity towards SO2 at concentrations down to 5 ppm. Such sensors are quite selective in presence of other gases like carbon monoxide, methane and butane. The high sensitivity of vanadium doped tin dioxide towards SO2 may be understood by considering the oxidation of sulfur dioxide to sulfur trioxide on SnO2 surface through redox cycles of vanadium-sulfur-oxygen adsorbed species.

Vanadium doped tin dioxide as a novel sulfur dioxide sensor (vol 75, pg 385, 2008)

Bimal K. Bhattacharya*, Robert O. Green, Sadasiva Rao, M. Saxena, Shweta Sharma, K. Ajay Kumar, P. Srinivasulu, Shashikant Sharma, D. Dhar, S. Bandyopadhyay, Shantanu Bhatwadekar and Raj Kumar Space Applications Centre, Indian Space Research Organisation, Ahmedabad 380 015, India Jet Propulsion Laboratory, California Institute of Technology, CA 91109, USA National Remote Sensing Centre, Indian Space Research Organisation, Hyderabad 500 625, India Earth Observation Science Directorate, Indian Space Research Organisation, Bengaluru 560 231, India

/pdf/an-overview-of-aviris-ng-airborne-hyperspectral-science-98j1qdrwq0.pdf

An Overview of AVIRIS-NG Airborne Hyperspectral Science Campaign Over India

Urinary tract infections (UTI) are the most common bacterial infections encountered among pregnant patients Despite the fact that most women with bacteriuria of pregnancy have a benign course it has been clearly established that untreated bacteriuria can have serious implications for both mother and foetus Approximately one-third to one-half of women with untreated infections progresses to pyelonephritis Besides it has also been implicated as a risk factor for adverse perinatal outcomes like premature birth low birth weight and perinatal deaths In addition associations have been documented between antepartum UTI and a variety of maternal complications of pregnancy including hypertension pre-eclampsia anaemia amnionitis and endometritis Prevalence of asymptomatic bacteriuria in the obstetric population ranges from 3-10% It is generally accepted that 11-40% of women who have bacteriuria in early pregnancy and 1-3% of those who do not will develop overt infection before delivery Studies have also shown that only 30-50% of women with clinical symptoms have infected urine Observations suggest but do not prove that a proportion of patients with asymptomatic bacteriuria go on to develop symptomatic infection It is also conceivable that the development of symptomatic disease may ultimately protect the patients from complications since symptomatic disease leads to treatment Although these observations offer an attempt to delineate those at risk at present it seems safest to make a sweeping recommendation to screen all pregnant women and to treat bacteriuria when detected regardless of symptomatology of the patient (excerpt)

High prevalence of bacteriuria in pregnancy and its screening methods in north India.

Nucleocapsid (N), matrix (M) and hemagglutinin (H) genes-based simplex PCRs and an N and M genes-based multiplex PCR were developed for detection of Peste-des-petits-ruminants virus (PPRV). The M gene PCR was the most sensitive, followed by N, H and an already described fusion (F) gene PCRs, as they could detect the virus in samples with titers of 101, 102, 104and 105 TCID50/ml, respectively. The multiplex PCR was as sensitive as the M gene PCR, but it had the advantage of differentiating PPRV from Rinderpest virus (RPV).

The M and N genes-based simplex and multiplex PCRs are better than the F or H gene-based simplex PCR for Peste-des-petits-ruminants virus.

In the history of mankind, there was a time when women dominated the world. In due course of time, as the patriarchal societies evolved, the status of women gradually declined. Sons were preferred to daughters. In India, the Brahmin community promoted such customs and rituals, which gave more and more importance to sons eg. Lighting the funeral pyre of the father was told to be a pre-condition for salvation of his spirit. Similarly, in western civilization also women were considered to be weak. In consonance with such a mind-set man has been trying various techniques for sex-selection since antiquity eg. for acquiring a son choosing a special day, time and posture for sexual intercourse, special diet, charms and amulet and prayers etc. In Vedas also punsavana karma has been described as a technique for acquiring a son. Apart from these techniques, female infanticide has also been used as a way to create a male dominated, son-worshipping society. On development of the technique of ultrasonography as an example of progress of science and technology, man has devised a new way of killing females in womb itself, which has resulted in continuous decline in female: male sex ratio in India. To stop this, Indian Govt. promulgated PNDT Act 1994. But considering the widely prevalent practice of use of various regimen of sex-pre-selection by people as well as unscrupulous medical practitioners, Govt. of India has amended this Act (2002). Still, as authors have found in one of their studies, sex-selection drugs are being used widely by north Indians for getting a son. Here, it should be noted that sex-selection methods are being used in west also. But the perspective is different. There, it is not used for female feticide or for acquiring a son. Rather, it is more an effort towards demonstrating the control of man over the NATURE.

S. K. Bandyopadhyay

Papers

Vanadium doped tin dioxide as a novel sulfur dioxide sensor (vol 75, pg 385, 2008)

An Overview of AVIRIS-NG Airborne Hyperspectral Science Campaign Over India

High prevalence of bacteriuria in pregnancy and its screening methods in north India.

The M and N genes-based simplex and multiplex PCRs are better than the F or H gene-based simplex PCR for Peste-des-petits-ruminants virus.

History of son preference and sex selection in India and in the west