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Aquaculture has the potential to meet the need of growing demand of fish in an affordable price. But in capture and in culture fisheries the fishes face diseases that interfere in the production of fish. The occurrence of disease causes the reduced production in aquaculture or reduce the marketable value of fish because of change of flesh quality, thus hampering the production. Freshwater fishes whether they are cultured or wild face different types of diseases in their skin, gills, fins, blood, and internal organs. The parasites that cause the diseases may be protozoans or metazoans.The main protozoan freshwater fish diseases are ichthyophthiriasis, trichodiniasis, costiosis, chilodonellosis. The most common metazoan parasitic diseases of freshwater fishes are dactylogyrusis, gyrodactylosis, argulosis, myxosporidiasis, ligulosis, ergasilosis, lernaesis, etc. The focus of this review is to screen the research studies that takes place on freshwater fish parasites of West Bengal. The review also aims to study the diversity of freshwater fish parasites in West Bengal, so that it will helps the researcher to get an idea about the freshwater fish parasites and their mode of infection in the fishes. The research work that takes place in different regions of West Bengal. Some of them reveal new species of parasites in fishes. Protozoan, cnidarian, acanthocephalan, nematode, cestode, trematode, crustacean parasites are identified in freshwater fishes of West Bengal. Among the protozoans cailiates, flagellates are identified. Trichodinids are very common protozoan fish parasites in most districts. Parasites under genus Myxobolus, Dactylogyrus, Gyrodactylus, Argulus, Lernea are common among the metazoans.

Micro/nano sensors based on oxide semiconductors have received much interest worldwide due to their remarkable electrical conductivity, good stability, wide range of dimensional structures, large-scale production potential, and cost effectiveness. The present review extensively investigates the physics behind the nanostructure growth, gas sensing, and selectivity mechanisms of different micro/nano-based devices. Mainly, planar, vertical, heterojunction, and thin film devices are discussed along with their pros and cons in relation to gas sensing and transport mechanisms. The sensing behaviours of such devices have been explained considering nanostructure morphology (particles and pore sizes), surface states (type of defect states and defect concentrations), and interfaces (intra- and inter-grain boundaries). Further, nanostructures with different dimensions, such as nanoparticles, nanowires, nanorods, nanoplates/nanosheets, nanotubes, hollow spheres, and nanoflowers, have also been taken under consideration.

The influence of the electrode position in devices based on nanocrystalline TiO2 thin film for sensing of isopropyl alcohol has been investigated. Two types of device structure, viz. planar and vertical, with similar dimensions (length and width) were fabricated, employing Al metal electrodes. Both sensors were tested in the concentration range from 20 ppm to 400 ppm in the temperature range of 50°C to 200°C. The comparative study revealed that both sensors (planar and vertical) exhibited an optimum operating temperature of 150°C, with an optimum response of 77% and 33.08%, respectively. The response time and recovery time were found to be faster for the vertical device compared with its planar counterpart. The dissimilar sensor response of the planar and vertical devices can be understood based on the surface states and interface kinetics of the TiO2 sensing layer. An electrical model describing the modulation of the barrier height, the effect of grain boundaries (GBs), and carrier trapping at interface states at GBs was applied to understand the response time and recovery time.

This paper reports highly sensitive and selective ethanol sensing performance of ZnO thin films in a resistive configuration. ZnO thin films were grown by RF sputtering on a Si substrate at room temperature under a controlled environment. The grown film was characterized by x-ray diffraction analysis (XRD), field emission scanning electron microscopy (FESEM) and atomic force microscopy. XRD analysis reveals a crystalline size of ∼ 73 nm with preferential (002) plane growth along the c-axis, and FESEM confirms a uniform film with nanoplate like structures. Ethanol sensing performance of the ZnO based device with Al as contacts were carried out in the temperature range of 50–200°C for concentrations of 1–400 ppm. The highest response magnitude of ∼ 95% was obtained at 200°C with fast response and recovery time of ∼ 27 s and ∼ 25 s, respectively. Sensor responses of other similar volatile organic compounds confirms the high selectivity of ZnO nanoplates towards ethanol sensing. The ethanol sensing mechanism of the ZnO thin film is discussed considering adsorption–desorption kinetics under different ambient conditions and defect states.

In the present chapter, some notable features (epidemiology, pathogenesis, and clinical characteristics) regarding recent outbreak COVID-19 have been reviewed. Most significant features related to COVID-19 such as (i) roots of infection and disease manifestation, (ii) shape and structure of viral S-protein, (iii) genome sequence study and replication in host cell, (iv) role of environmental factors, (v) diagnosis tools and (vi) role of biosensor have been critically investigated. The biological and behavioral risk factors for pregnant women before and after child birth have been dictated clearly. Pulmonary abnormalities due to COVID-19 of the patient having diabetes, cancer etc. history have been clarified with help of CT imaging. Finally, prevention and cure strategies adopted by many health professionals based on the existing drugs are mentioned with their side effects.

First branchial cleft anomalies are embryological defect account for 8-10% of all branchial cleft defects. Approximately 17% of all Paediatric cervical masses are due to branchial anomalies. Despite of the fact that these anomalies are benign, secondary infection, positional effect and complication of treatment like surgery account for morbidity. Here one such case of 30 years old lady who presented to us with one discharging sinus in the floor of the right external auditory canal with a swelling in the upper neck for about 20 years. On examination showed one discharging sinus opening in the floor of right external auditory canal (EAC) and a cystic swelling in upper neck between sternomastoid and mandible. While compression over the swelling cheesy discharge comes out from EAC. MRI showed oval shaped fluid signal intensity lesion measuring about 4 × 2.1 × 1.6cm in right infra auricular region with slit like curvilinear tract about 10mm extending from upper part of the lesion opening into the antero-inferior part of external auditory canal at the junction of bony and cartilaginous part. Histopathology report showed a cyst lined by stratified squamous epithelium; wall is composed of fibrocollagenous tissue with mucous gland. The wall is densely infiltrated with lymphocytes forming lymphoid follicles at places. This paper presents a case report of collaural sinus from Otology unit, Department of Otolaryngology-HeadNeck Surgery, Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh.

Composite materials especially graphene and metal oxides received much interest recently in chemical sensor applications. Metal oxide like TiO2, SnO2, ZnO etc. in composite form with graphene or graphene derivates offer excellent gas sensing property. Pure graphene has very weak gas adsorption capability whereas derivatives of graphene i.e. graphene oxide (GO) or reduced graphene oxide (rGO) offer efficient adsorption capability and hence offer higher gas sensitivity. A comprehensive study of synthesis, characterization, gas sensing study and sensing mechanism towards various gases has been carried out in the present article. Role of graphene and metal oxide composite junction for gas sensing improvement have been discussed with light of energy band model and carrier transport kinetics.

In this paper, an efficient room temperature ethanol sensor device based on p-n homojunction of p-TiO2 nanoparticles (NPs) and n-TiO2 nanotubes (NTs) is reported. p-TiO2 NPs were prepared by low-temperature sol–gel method and coated on n-TiO2 NTs (NPs) grown by electrochemical anodization. Field emission scanning electron microscopy and X-ray diffraction authenticated the formation of stable homojunction between p-type anatase TiO2 NPs and n-type anatase TiO2 NTs. Current–voltage characteristics of the device, in the lower voltage range (0–1.26 V) for 30 °C, followed nonlinear characteristics (Schottky). With increase in voltages (>1.26 V) and temperature (40 °C–100 °C) such nonlinear behavior moves toward more linear ones. The gas sensing performance of the homojunction device was studied at room temperature with alcohols as the test species. The device offered the maximum response magnitude of ~57% (toward ethanol) at 100 ppm with appreciably fast response time and recovery time of ~30 and ~16 s, respectively. Dramatic increase in the effective depletion region area distributed throughout the nanotubular voids and the associated localized electric filed originated from the electrostatic charge separation therein (which helps in easy dissociation of target species) is possibly responsible for such efficient room temperature sensing performance.

The aim of this study was to evaluate the level of knowledge about gestational diabetes mellitus (GDM) in Bangladeshi people.Cross-sectional study.This study involving 1374 participants was conducted in 15 outpatient clinics of Diabetic Association of Bangladesh and its affiliated associations, Bangabandhu Sheikh Mujib Medical University and four medical college hospitals in Bangladesh from August 2015 to December 2015. A pretested interviewer-administered questionnaire was used to obtain information related to sociodemographic status, level of education, types of profession, and medical history. The questionnaire included eight questions on GDM. Level of knowledge (mean ± 1 standard deviation [SD]) was categorized as poor, average, and good. Descriptive, Chi-squared, and regression analysis were performed to express the results.Of total knowledge score of 8, participants' mean knowledge score (±SD) was 2.7 ± 1.5. The levels of good, average, and poor knowledge were 26.3%, 63.1%, and 10.6%, respectively. In multivariate analysis, participants aged below 30 years (P 0.001), male gender (P 0.001), high-income group (P 0.001), having university education (P 0.001), health professionals (P 0.001), capital Dhaka city residents (P 0.001), those with family history of diabetes (P = 0.007), and participants with diabetes (P = 0.007) were found to be significantly associated with the good knowledge score.Participants in this study had average knowledge about GDM. New innovative strategies should be developed to improve the knowledge of GDM among health professionals and general population.

Selective detection of vapor species, especially belonging to the same group, is a crucial bottleneck for resistive sensor devices. In this paper, methanol, ethanol, and 2-propanol detection by Pd/TiO2 nanorod array/Ti device in capacitive mode was achieved, with improved selectivity, employing a resonant frequency tuning technique. The optimal capacitive response of the device was obtained by identifying the resonant frequency over the frequency range of 0.01–200 kHz. The imaginary part of the impedance (−| Z | sinθ as a function of frequency) in air and in alcohols revealed a shift in resonant frequency towards lower frequency regime upon exposure to alcohols. Moreover, the difference in the resonant frequencies (Δ f ) from one alcohol to another were found to be almost constant which facilitated the frequency-selective sensing even for varying concentrations of target species (1, 50, and 100 ppm in present case). Such frequency selective nature of the device possibly originated from different degree of polarization of different alcohol molecules at different frequencies which was duly correlated to the corresponding equivalent circuit model. However, for real selective detection, when the target species is unknown, the proposed device does not work properly and an array of devices is necessary.

Systematic optimization of the surface attributes (structural and morphological) as well as the defect states [oxygen vacancies (OVs)], for achieving efficient alcohol sensing by TiO2 nanosheets, is the central focus of this paper. Variation in the surface roughness and the OVs of hydrothermally grown TiO2 nanosheets were achieved by varying the ethanol and water content in stepwise manner, keeping the NaOH concentrations in the electrolyte unchanged. Structural, morphological, and optical characterizations, such as field emission scanning electronmicroscopy and X-ray photoelectronspectroscopy, revealed that with increase in ethanol concentrations, surface roughness increased (at a particular water concentration), while at a fixed ethanol concentration, OVs increased with decrease in water concentrations. The sensor derived through the minimum water content and the maximum ethanol content offered the most promising sensor response owing to availability of the maximum amount of OVs with the highest surface roughness.

Low temperature (90 °C) gas sensing performance, with ethanol as a test case, of TiO2 nanoflowers in the presence of humidity, was investigated. It was revealed that the sensor resistance in air and in ethanol was reduced in the presence of humidity. However, such variations in sensor resistance in the humid and in the nonhumid environment are more pronounced for baseline case (in air) than that in target species exposure (in ethanol). Interaction probability of the target species, in the presence of humidity, with the TiO2 nanoflower surface was governed by the proton hopping model. For quantitative understanding of the subsequent electron generation and transport phenomenon, a space charge model, corelating the influence of mutually competing and interdependent factors like oxygen vacancies, adsorbed O– species, dissociation of water and ethanol molecules on TiO2 nanoflower surface, has been demonstrated. It was found that decrease in base line resistance (Δ R ) gradually becomes saturated with increase in relative humidity level, possibly owing to proton hopping in the physisorbed water layers which hinders the chemisorption of water molecules at the nanoflower surfaces leading toward relatively insignificant change in space charge region.

The dimensionality of the nanostructures plays a pivotal role in determining the sensing performance of metal oxide semiconductors. In this paper, 2-D TiO2 nanosheets were assembled to form hierarchical 3-D nanoflowers by a low-temperature hydrothermal process and tested for volatile organic compound (VOC) sensing. Structural characterization, such as X-ray diffraction, revealed the anatase crystallinity of the TiO2 nanoflowers. The chemical composition of the nanoflowers was confirmed through energy dispersive spectroscopy and X-ray mapping techniques. Field emission scanning electron microscopy results demonstrated the 3-D nanoflower like structure, consisting of 2-D nanosheets of length 120 nm and a thickness of 12–23 nm. A suitable growth mechanism for hierarchical nanoflowers has been proposed. The nanoflowers were found to offer promising sensing performance toward VOCs, such as acetone, methanol, 2-butanone, toluene, and 2-propanol at relatively low optimum operating temperature of 60 °C, 90 °C, 60 °C, 120 °C, and 60 °C, respectively. The sensor appreciably showed fast response ( $\sim 6$ –15 s) and recovery ( $\sim 15$ –39 s) characteristics. Furthermore, the sensor offered high selectivity toward acetone. The sensing performance of the nanoflowers has been correlated with a space charge model at the grain boundary.

1-D oxide nanostructures-based metal-insulator–metal structures represent potential gas sensor devices, owing to their vertical electron transport feature. In this paper, we demonstrate that for achieving optimum gas sensing by a TiO2 nanotube (NT) array in vertical mode, tuning of NTs (1-D) surface area as well as carrier transport path length by tailoring the NT length can be a valuable approach. For anodization times of 1, 4, 8, 12, and 16 h, the corresponding NT length was found to be 280–320, 506–514, 1730–1790, 2000–2200, and 2380–2420 nm, respectively, with almost no variation in tube diameters or separations. The carrier concentrations of the NTs were found to be decreasing with increasing tube length. The vertical device structure, employing NT arrays of different lengths as the sensing layer, was investigated in the temperature range of 50 °C–250 °C for sensing acetone, as a test gas/vapor, in the concentration range of 10–1000 ppm. The response magnitude of the sensor was increased with increased NT length, possibly owing to the availability of larger amounts of gas interaction sites due to higher surface area at increased length. The response time and recovery time of the developed sensor also increased with increasing tube length and became excessively sluggish after the critical tube length exceeded 2250 nm owing to slower adsorption/desorption and diffusion kinetics.

This paper concerns the tuning of the operating temperatures, selectivity, and repeatability of a resistive acetone sensor based on TiO 2 nanotubes (NTs) through surface modifications (of NTs) using Pd and Ni nanoparticles. Three sets of sensor devices, which employ unmodified, Ni-modified, and Pd-modified TiO 2 NT arrays as the sensing layer, were tested for acetone detection in the temperature range of 50 °C–250 °C, targeting 10–1000 ppm. It was found that both the modified (Pd and Ni) sensors offered a lower optimum operating temperature (100 °C) compared with its unmodified counterpart (150 °C), possibly owing to the requirement of lower activation energy in the case of modified systems. The cross sensitivity toward other interfering species, viz., ethanol, methanol, 2-butanone, and toluene, was investigated. Both the modified sensors were found to offer better selectivity toward acetone than the unmodified sensor. However, the response and selectivity improvement of the modified sensors was achieved at the expense of poor repeatability. Possibly owing to the increased structural defects and the nonidentical oxygen spill over in the repeated cycles, the modified sensors offered relatively poor repeatability. Among the two types of modifications, the Pd-modified sensor offered better response magnitude and transient characteristics (the response time and the recovery time) than the Ni-modified sensor. The underlying mechanism for such improvement has been also highlighted.

In this paper, sol-gel derived undoped p-type nano-titania thin films particularly aimed to detect low ppm (5–100 ppm) methanol at low temperature (75–150 °C) is reported. Anantase TiO2 thin film was deposited by sol-gel technique and p-type conductivity of the film was confirmed by Hall measurement. Nanocrystalline structure (12–15 nm) of the TiO2 film was confirmed by X-ray diffraction study and field emission scanning electron microscopy, respectively. Photoluminance spectroscopy and X-ray photoelectron spectroscopy were employed to characterize the defect structure. Methanol sensor study was carried for detecting the concentration range of 5 to 100 ppm in the temperature range of 75 to 150 °C. Highly promising sensing performance was observed at an optimum operating temperature of only 100 °C with 102% response magnitude (in 100 ppm methanol) and appreciably fast response and recovery time (∼18 and ∼21 s, respectively). The possible mechanism behind the origin of p-type conductivity has been correlated with the defect distribution model. Detailed sensing mechanism of the p-nano-titania has been explained using Schottky barrier model.

Highly stable, low temperature (27–175 °C) alcohol (ethanol, methanol and 2-propanol) sensing performance of a hydrothermally grown tetragonal TiO2 nanorod array, targeting the detection level of 1–100 ppm, is reported in this paper. Synthesized titania nanorods were characterized by X-ray diffraction, energy dispersive spectroscopy (EDS) and field emission scanning electron microscopy (FESEM) to investigate the crystallinity, chemical compositions and surface morphology, respectively. Photoluminescence spectroscopy (PL spectra) was employed to find out the surface oxygen vacancies and band gap of the material. An alcohol sensing study, in resistive mode, was carried out and the optimum temperature for alcohol sensing was found to be 75 °C with the corresponding maximum response magnitude of ∼69%, ∼75% and ∼80% towards 100 ppm ethanol, methanol and 2-propanol, with corresponding response time/recovery time of ∼13 s/24 s, ∼11/21 s and ∼9/18 s, respectively. The sensor also offered efficient detection (response magnitude of 29%, 37% and 40%) of 1 ppm alcohol(s) with fast response time and recovery time of ∼12–14 s and ∼4–5 s, respectively. The minimal cross sensitivity, with other interfering species like acetone, benzene, xylene and 2-butanone, and appreciable long term stability showed the potential of the developed sensor for commercial applications.

In this paper, we report on the development of a highly sensitive, relatively low-temperature ethanol sensor based on sol-gel derived p-TiO 2 thin film. The p-type anatase TiO 2 thin film was deposited by sol-gel technique on a thermally oxidized p-Si (resistivity 5 Ω cm) substrate. Anatase TiO 2 phase with nanocrystallinity was confirmed with an average particle size of ~11 nm from X-ray diffraction and field emission scanning electron microscopic study. Ethanol sensor study, in the resistive mode, was carried out at a relatively low operating temperature range (75 °C-175 °C) for sensing low concentrations of ethanol in air (5-100 ppm). Response magnitude of ~146% was observed at 150 °C toward 100-ppm ethanol (in air) with corresponding response time and recovery time of 39 and 15 s, respectively. The sensor showed appreciably high-response magnitude (129%) even at low ethanol concentration (5 ppm) with acceptable response and recovery time (54 and 22 s, respectively) at the same operating temperature (150 °C). At a particular temperature, for all the ethanol concentrations, sensor showed minimal base line resistance drift, thereby offering highly repeatable and stable sensing performance. Ethanol selectivity study against other volatile organic compounds, such as methanol, acetone, and 2-butanone, was also investigated and was found to be quite promising. Ethanol sensing mechanism for such p-type TiO 2 has also been discussed in the light of corresponding oxygen vacancy model.

The oxygen vacancy (OV) variation of the electrochemically grown $\hbox{TiO}_{2}$ nanotube (NT) was achieved through stoichiometry variation by varying the volume of water in the electrolyte ( $\hbox{NH}_{4}\hbox{F}$ with ethylene glycol) during anodization. By varying the water content (0%, 2%, and 10% by volume) in the mixed electrolyte, the morphology and stoichiometry of NTs were found to be varied dramatically. After detailed structural and morphological characterization by X-ray diffraction and field-emission scanning electron microscope and photoluminescence spectroscopy, the room-temperature acetone sensing was investigated by employing three distinct nanoforms derived through anodization. The reliability (i.e., repeatability and stability) of the sensors, as well as their response magnitude, was found to be greatly influenced by the variation in stoichiometry. The NTs derived with 2 volume percent $\hbox{H}_{2}\hbox{O}$ was found to offer the most promising response magnitude with excellent repeatability, whereas the best stability was ensured in the case of the NTs derived with 10 volume percent $\hbox{H}_{2}\hbox{O}$ . It was observed that an optimization of stoichiometry (OVs) and the surface-to-volume ratio is important in determining the response magnitude and repeatability. On the contrary, the stability is mainly governed by the stoichiometry only.

Undoped nanocrystalline anatase p-type TiO2 thin film was deposited by sol–gel method on thermally oxidized p-Si (2–5 Ω cm, 〈1 0 0〉) substrates. The thin film was characterized by X-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) to confirm the formation of nanocrystalline anatase titania and to determine the crystallite size (∼7 nm). The resistive sensor structure was fabricated employing two lateral Pd electrodes on top of the TiO2 sensing layer. The developed sensor was tested in the temperature range of 50–200 °C for the detection of low ppm acetone (0.5–50 ppm). The maximum response of ∼115% was obtained at 150 °C with response/recovery time of 14 s/22 s at 50 ppm acetone (in air). Moreover, the sensors were capable of detecting acetone as low as 0.5 ppm with acceptable response magnitude. As titania acetone sensors are mostly n-TiO2 based, the acetone sensing mechanism for p-TiO2 is yet to be established authentically. To address the issue, an equivalent circuit model, based on the corresponding band diagram of nanocrystalline p-TiO2 with Pd electrode, was developed to describe the electron transfer mechanism through grain, grain boundary and Pd electrode under the influence of acetone vapor.

A TiO2 nanotube array was grown electrochemically by using single and mixed electrolyte/s with 20 V constant potential at room temperature. Anodization was carried out for 120 min using five different electrolytes, e.g., H3PO4, NH4F, HF, NH4F with H3PO4 and HF with H3PO4. Structural characterizations of the grown titania nanotubes were conducted by using x-ray diffraction and field emission scanning electron microscopy. Optical properties of the grown nanotubes were investigated through photoluminescence (PL) spectroscopy. In the case of the 4 M H3PO4 electrolyte, no perceptible growth of nanotubes was observed. The individual electrolytes of 0.3 M NH4F and 1 M HF resulted into the formation of the wall-connected nanotubes. In contrast, the mixed electrolytes comprising the strong (NH4F, HF) and weak (H3PO4) electrolytes have been found to be efficient for the growth of wall-separated titania nanotubes. The results of the PL spectroscopy have demonstrated that the free-standing nanotubes offer low PL intensity compared to its connected counterpart owing to the lower carrier recombination rate of free-standing nanotubes.

Selective detection of vapor species, specially belonging to the same group, is a major constraint for resistive sensor devices. In this paper, selective alcohol (methanol, ethanol and 2-propanol) detection of Pd/TiO 2 nanorod array/Ti (Metal-Insulator-Metal) device in capacitive mode was achieved by a resonant frequency tuning technique. The resonant frequency, for optimal sensing, is identified through the imaginary part of the impedance (−|Z|sinθ as a function of frequency) in air and in alcohols. This revealed a shifting in resonant frequency towards lower frequency regime upon exposure to alcohols. Moreover, the difference in the resonant frequencies (Δf) from one alcohol to another were found to be almost constant which facilitated the frequency selective sensing even for varying concentrations of target species (1 ppm, 50 ppm and 100 ppm in present case). Such frequency selective nature of the device possibly originated from different degree of polarization of different alcohol molecules at different frequencies which was duly correlated to the corresponding equivalent circuit model.

In this paper we propose an experimental study model S3P2 of a fast fully dynamic programming algorithm design technique in finite directed graphs with few distinct nonnegative real edge weights. The Bellman-Ford’s approach for shortest path problems has come out in various implementations. In this paper the approach once again is re-investigated with adjacency matrix selection in associate least running time. The model tests proposed algorithm against arbitrarily but positive valued weighted digraphs introducing notion of Prograph that speeds up finding the shortest path over previous implementations. Our experiments have established abstract results with the intention that the proposed algorithm can consistently dominate other existing algorithms for Single Source Shortest Path Problems. A comparison study is also shown among Dijkstra’s algorithm, Bellman-Ford algorithm, and our algorithm.

Anisotropic Bianchi Type-I cosmological models have been studied on the basis of Lyra’s geometry. Two types of models, one with constant deceleration parameter and the other with variable deceleration parameter have been derived by considering a time-dependent displacement field.

The Mass of the ∧° - Hyperon

ANISOTROPIC BRANS-DICKE COSMOLOGY

On the K - Spectra of Elements (11Na - 15P) and Conduction Electrons Part I

INFLATIONARY KALUZA — KLEIN COSMOLOGY WITH VARIABLE G AND Λ AND DIMINISHING ANISOTROPY

Electrochemical anodization, in potentiostatic mode, with two different applied voltages (20 V and 60 V) has been carried out with Ti foil as anode and graphite rod as cathode. Viscous electrolyte with slight elevated temperature (37°C) was incorporated for dissolution of unwanted byproduct. XRD technique authenticates the purity of grown sample whereas FESEM images evolve a unique difference between two types of TiO 2 sample. Sensor study towards xylene reveals improved sensing behavior in case of 60 V anodization process. Reason behind the higher response is correlated with effective surface area by approximation through simple geometrical model.

Nanostructured semiconducting metal oxides have been slotted as the potential material for its applications in gas/vapor sensing systems. During the last couple of decades, extensive efforts have been devoted in maximizing the parameters like sensitivity and selectivity and minimizing the response and recovery times. The efforts are essentially directed towards modification of chemical, dimensional and morphological attributes of the metal oxides. The evolution started with the optimization of particles size and thickness of the thin films, but was accelerated, particularly since last decade, with the incorporation of several unprecedented interesting nanoforms of metal oxides like nanorods, nanowires, nanosheets, nanohollowspheres and nanotubes. It has been established that the vapour/gas sensing characteristics (e.g., operating temperature, sensitivity, response time and recovery time) of the semiconducting oxides improved dramatically if the nanostructure is changed from three dimensional to two dimensional and then to one dimensional. Thus, the domain calls for basketting of the state of knowledge with the contemporary relevance. In view of the above, the present article aims to discuss the underlying mechanisms governing the formation of metal oxide nanoforms under different process routes and correlation of the structural attributes with the semiconducting behavior with special reference to the sensing of acetone vapor. The beginning of the chapter elaborates the necessity of nanoforms in improving the sensing performance with the help of grain surface/boundary model. Subsequently, different semiconducting oxide nanostructure/nanoform (like nanorods, nanowires, nanosheets, nanohollowspheres and nanotubes) synthesis and their sensing properties with emphasis on their respective advantages and bottlenecks have been discussed. The chapter concludes with the salient features of the advancement of oxide nanoform based acetone sensors and predicting the future direction of research.

Present paper concerns, ethanol sensing performance of n-TiO 2 /p-Si heterojunction devices under different operating temperatures. The heterojunction was fabricated by growing TiO 2 oxide layer on p-Si (100) substrate by a dip coating method. Structural characterization like XRD and AFM was carried out to investigate the crystallinity and surface roughness of the grown film. Current-voltage characteristics of Au/n-TiO 2 /p-Si/Ti heterojunction were found to offer the ideality factor and cut in voltage of ∼2.86 and 1.9V, respectively. Static rectification ratio (R R /R F ) was found to be 32, 33 and 46, whereas dynamic rectification ratio were 22, 27 and 31 at 30°C, 50°C and 70°C, respectively. Gas sensing performance towards ethanol showed appreciable response magnitude of ∼64% at only 125°C.

Transvaginal sonography is superior to transabdominal sonography in most cases of pelvic pathology. A cross sectional study was done with forty patients to evaluate the clinical usefulness of transvaginal ultrasonography (TVS) in pre, peri and post menopausal women suspected to have endometrial hyperplasia.. The study was carried out January 2007 to November 2008 for a period of two years. The patients having endometrial hyperplasia diagnosed by TVS were correlated with histopathological diagnosis. Of total 40 cases, 18(45.0%) cases were endometrial hyperplasia and 22(55.0%) were negative for endometrial hyperplasia respectively in TVS findings. Only 2 cases were found as negative for endometrial hyperplasia in histopathology among the all suspected endometrial hyperplasia, which were diagnosed by TVS. On the other hand 17(42.5%) cases were endometrial hyperplasia and 23(57.5%) cases were negative for endometrial hyperplasia in histopathological findings. Among 22 negative for endometrial hyperplasia cases which were diagnosed by TVS, 1 case was endometrial hyperplasia and the rest 21 cases were negative for endometrial hyperplasia in histopathological findings. The validity of TVS in diagnosis of endometrial hyperplasia were studied by calculating sensitivity, specificity, accuracy, positive predictive value, which were 94%, 92%, 93%, 89% and 96% respectively. As the TVS findings of the present study correlated well with the histopathology findings and the validity test values were higher than observed by others, it can be concluded that TVS is sensitive and accurate modality in the evaluation of endometrial hyperplasia.

A nanocolloidal dispersion of lead chromate (PbCrO4) has been prepared in H2O/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/n-heptane water-in-oil (w/o) microemulsion medium. The formation of the PbCrO4 in the water pool of the microemulsion has been established by Fourier transform infrared measurements. The absorbance and fluorescence behaviors of the colloidal PbCrO4 have been investigated with varying water pool size, i.e., varying [water]/[AOT] mole ratio, ω. The dimension of the lead chromate encapsulated microemulsion droplets has also been determined by the dynamic light scattering method under varied ω. The dimension and shape of the colloidal dispersions in microemulsion have been examined by transmission and scanning electron microscopic measurements.

The absorption and fluorescence spectra of 3,3'-dioctadecyloxacarbocyanine [DiOC18(3)], a cationic oxacarbocyanine dye have been studied in aqueous and nonaqueous media containing egg phosphatidylcholine (PC) as well as in different solvents of diverse nature. The results show the evidence of complex formation of the dye in the ground and in the excited states with PC. The excited state interaction of the dye with PC suggests the electron transfer from PC to dye and this is supported by photovoltage generation in a photoelectrochemical cell consisting of dye and PC in aqueous medium. An attempt has been made to determine the polarity of the microenvironment of the dye in PC liposome or PC reverse micelle from the spectral studies of the dye in different solvents of known polarity.

Colloidal dispersions of Cu2[Fe (CN)6] have been prepared in the nanodomain water pools of water/AOT/n-heptane water-in-oil microemulsion at various [water]/[AOT] mole ratios, ω, by reacting CuSO4 with K4[Fe(CN)6]. The UV−visible absorption spectra of the isotropic molecular aggregates of Cu2[Fe(CN)6] surrounded by a layer of amphiphile AOT have been measured. The hydrodynamic diameter, diffusion coefficient, and the polydispersity index of the colloidal dispersions prepared in the absence and presence of gelatin at different ω have been determined by the dynamic light scattering method; the static light scattering method has been employed to estimate the average particle weight of the dispersion. The formation of Cu2[Fe(CN)6] in the dispersion has been established by X-ray diffraction measurements. The size and shape of the colloidal dispersions and the isolated particles have been examined by the transmission electron microscopy and scanning electron microscopy methods. The enthalpies of formation of Cu...