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The paper proposes low-voltage current mirrors namely low-voltage current mirror (LVCM) and flipped voltage follower based low-voltage current mirror (FVFLVCM) with high bandwidth. The stability of the proposed circuits has been performed by time-domain approach and frequency domain approach using Routh–Hurwitz stability criteria and phase margin calculations, respectively. The bandwidth of the proposed FVFLVCM has also been enhanced using resistive compensation technique. The proposed LVCM and FVFLVCM have wide input current range of 0–100 µA and 0–150 µA, low DC error of 5.9% and 4.9%, low DC power dissipation of 110.39 µW and 99 µW, high bandwidth of 367 MHz and 624 MHz, low input impedance of 16.3 KΩ and 12.3 KΩ, low THD of 0.26% and 1% and low output noise of 2.25 nA and 2.83 nA over 100 MHz, respectively. The results have been simulated using SPICE in the TSMC 0.18 µm CMOS technology and are presented to validate the effectiveness of the proposed current mirrors.

In this paper, quasi-floating gate MOSFET (QFGMOS) based current divider and pseudo-exponential function generator circuits are proposed. The use of QFGMOS makes the proposed circuits suitable for low voltage/low power operation. The proposed circuits have lower power supply voltage requirement, lower power dissipation and lower THD than the existing circuits available in literature. Both the circuits have been designed and simulated in Cadence virtuoso analog design environment using 180 nm CMOS technology. The simulation results have also been presented to validate the performance of the proposed circuits.

Many scholars have advocated for the use of empirical evidence to assess resilience across scales and over time. Accordingly, we conduct a case study using survey data on individual perceptions of disaster relief that were gathered each month from August to December 2015, shortly after the 2015 Nepal earthquake. We construct a scale-specific resilience index (SSRI) based on a set of variables that are validated separately at different spatial scales and over time against the survey data. The regression results show that the variables related to household structure, industrial diversity, community capital, and accessibility and emergency services are validated against the survey data at both the district and sub-district levels, the variables related to ethnic diversity and the capacity of emergency camps are validated only at the district level, and the earthquake experiences variable is validated only at the sub-district level. Consequently, to achieve optimal models, we use six validated variables to construct an SSRI at the district level and seven variables, including those related to the vulnerability of household property and the average elevation, to construct an SSRI at the sub-district level. The SSRI scores are validated via multilevel regression models against the surveyed relief scores after the 2015 Nepal earthquake. The results show that the SSRI scores based on the validated variables correlate favorably and as expected against the survey data at both district and sub-district levels, and outperform the composite resilience index, which considers all of the variables regardless of their individual validation results. The method used to construct the SSRI helps to identify the contributions of multidimensional resilience indicators across spatial scales and over time in real cases, and also provides index scores of scale-specific resilience that are easily understood and applicable to multi-scale decision-making processes.

This paper investigates implications of male labour migration in gender roles and identity of women, and household food security outcome in the Kaligandaki Basin, Nepal. The study covers three stud...

The state of food (in)security in rural communities of different ecological zones of the Kaligandaki Basin, Nepal, is assessed using a Household Food Insecurity Access Scale (HFIAS). The data were collected from 360 households using face‐to‐face interviews. The results show poor availability of food from subsistence production in the Middle‐Mountains and Trans‐Himalaya, whereas most households with sufficient purchasing power are able to access additional food from the market. Net food security is poor, with the highest level of insecurity in the Middle‐Mountains, followed by the Trans‐Himalaya and the Tarai. Although weaknesses were found in application of the HFIAS method due to respondent bias in subjective assessments of food insecurity in producer–consumer rural households, the method was found to be effective for rapidly incorporating utilization and stability elements into appraisals. Although not comprehensive, this approach has the potential to complement other forms of knowledge for designing targeted food policy in Nepal.

The paper proposes low-voltage current mode winner takes all (WTA)/loser takes all (LTA) circuit which detects maximum and minimum values from the given current inputs simultaneously. The circuit is developed using high swing self-biased cascode current mirror and a subtractor circuit. The cascode current mirror is used to improve the accuracy of current mirroring action over a wide input current range and subtractor circuit is used to compute the difference of two input currents. The proposed circuit operates at supply voltage of 1.1 V with high precision. The output current is mirrored with transfer error of 0.03% while input current is varying from 0 to 40 μA. Simulations have been performed using SPICE level 53 (TSMC) parameters in 0.18 μm CMOS technology. Some of the applications of the proposed WTA/LTA circuit such as half wave rectifier, full wave rectifier and modulus circuit have also been presented to show the effectiveness of the proposed circuit.

Graphene oxide (GO)/MnO2 nanocomposites were synthesized by adding KMnO4 in a solution of water and ethanol (3:1), containing 10 mg of GO. Brown precipitates were obtained after a continuous stirring for 1 hr. The precipitates were then washed with deionized water (DI) water and dried to obtain the MnO2-GO nanocomposites. Pure MnO2 was also synthesized using the same method without GO for the comparison. X-ray diffraction pattern confirm δ-MnO2 type of MnO2 with birnessite type MnO2 structure. The TEM images show the average diameter of MnO2 nanorods as 15 nm. Electrochemical characterizations were carried out in an aqueous solution of 3M KOH. Charge-discharge studies were carried out between 1A/g to 20 A/g current range. The MnO2-GO nanocomposites showed improved electrochemical performances. The capacitance of MnO2 and MnO2-GO electrodes was found to be as 300 F/g, and 350 F/g, respectively at a current of 0.5 A/g.

The paper presents a low supply voltage CMOS voltage reference with low line sensitivity and high PSRR. Generally, the reference voltage is obtained using both complementary-to-absolute-temperature (CTAT) current and proportional-to-absolute-temperature (PTAT) current. This technique increases the complexity and area of the reference circuit. To overcome these drawbacks, the temperature compensated reference voltage has been proposed using only CTAT currents. Mostly, the CTAT current generators are simple, power-efficient, and area-efficient as compared to the PTAT current generators. The negative feedback loop has been formed in the proposed design to obtain a supply independent CTAT current and to avoid the use of startup drivers. The proposed circuit has been designed using Cadence virtuoso analog design environment in BSIM3V3 180[Formula: see text]nm CMOS technology. The simulation results of the proposed circuit show a reference voltage of 312[Formula: see text]mV with a temperature coefficient (TC) of 38.85[Formula: see text]ppm/∘C over a wide temperature range of [Formula: see text]C to 125∘C with a supply voltage of 0.8[Formula: see text]V. The line sensitivity is 0.027% [Formula: see text] with a supply voltage ranging from 0.8[Formula: see text]V to 3[Formula: see text]V. The power supply rejection ratio (PSRR) without using any capacitive filter is observed as [Formula: see text] and [Formula: see text][Formula: see text]dB at 100[Formula: see text]Hz and 100[Formula: see text]kHz frequency, respectively. The circuit is simple and occupies a chip area of 0.0027[Formula: see text]mm2.

Here we present a ratiometric intensity analysis of the Raman spectrum in the HWN region of three breast tissue conditions, namely adipose, fibrous and malignant in a broad sampling of lumpectomy specimens. We demonstrate that these intensity ratios can be used as a “molecular barcode” in breast cancer pathology. Our ratiometric-based approach in HWN is simple, interpretable and exhibits distinct barcodes for different tissue types.

Acute lymphoblastic leukemia (ALL) is one of the most common malignancies which account for nearly one-third of all pediatric cancers. The current diagnostic assays are time-consuming, labor-intensive, and require expensive reagents. Here, we report a label-free approach featuring diffraction phase imaging and Raman microscopy that can retrieve both morphological and molecular attributes for label-free optical phenotyping of individual B cells. By investigating leukemia cell lines of early and late stages along with the healthy B cells, we show that phase image can capture subtle morphological differences among the healthy, early, and late stages of leukemic cells. By exploiting its biomolecular specificity, we demonstrate that Raman microscopy is capable of accurately identifying not only different stages of leukemia cells, but also individual cell lines at each stage. Overall, our study provides a rationale for employing this hybrid modality to screen leukemia cells using the widefield QPI and using Raman microscopy for accurate differentiation of early and late-stage phenotypes. This contrast-free and rapid diagnostic tool exhibits great promise for clinical diagnosis and staging of leukemia in the near future.

Leukocyte differential test is a widely performed clinical procedure for screening infectious diseases. Existing hematology analyzers require labor-intensive work and a panel of expensive reagents. Here we report an artificial-intelligence enabled reagent-free imaging hematology analyzer (AIRFIHA) modality that can accurately classify subpopulations of leukocytes with minimal sample preparation. AIRFIHA is realized through training a two-step residual neural network using label-free images of isolated leukocytes acquired from a custom-built quantitative phase microscope. By leveraging the rich information contained in quantitative phase images, we not only achieved high accuracy in differentiating B and T lymphocytes, but also classified CD4 and CD8 cells, therefore outperforming the classification accuracy of most current hematology analyzers. We validated the performance of AIRFIHA in a randomly selected test set and cross-validated it across all blood donors. Owing to its easy operation, low cost, and accurate discerning capability of complex leukocyte subpopulations, we envision AIRFIHA is clinically translatable and can also be deployed in resource-limited settings, e.g., during pandemic situations for the rapid screening of infectious diseases. Corresponding author(s) Email: rjzhou@cuhk.edu.hk, rishikesh.pandey@uconn.edu

In this work, the effect of gate misalignment towards the source and drain ends for 20 nm recessed double gate junctionless field-effect-transistor (R_DGJLFET) have been studied on various digital and analog performance parameters from device to circuit level while setting the simulation set-up using 2D Silvaco ATLAS technology computer aided design (TCAD). With recessed silicon channel, the quantum confinement effects have been considered for channel thickness

Identification of the metastatic potential represents one of the most important tasks for molecular imaging of cancer. While molecular imaging of metastases has witnessed substantial progress as an area of clinical inquiry, determining precisely what differentiates the metastatic phenotype has proven to be more elusive underscoring the need to marry emerging imaging techniques with tumor biology. In this study, we utilize both the morphological and molecular information provided by 3D optical diffraction tomography and Raman spectroscopy, respectively, to propose a label-free route for optical phenotyping of cancer cells at single-cell resolution. By using an isogenic panel of cell lines derived from MDA-MB-231 breast cancer cells that vary in their metastatic potential, we show that 3D refractive index tomograms can capture subtle morphological differences among the parental, circulating tumor cells, and lung metastatic cells. By leveraging the molecular specificity of Raman spectroscopy, we demonstrate that coarse Raman microscopy is capable of rapidly mapping a sufficient number of cells for training a random forest classifier that can accurately predict the metastatic potential of cells at a single-cell level. We also leverage multivariate curve resolution – alternating least squares decomposition of the spectral dataset to demarcate spectra from cytoplasm and nucleus, and test the feasibility of identifying metastatic phenotypes using the spectra only from the cytoplasmic and nuclear regions. Overall, our study provides a rationale for employing coarse Raman mapping to substantially reduce measurement time thereby enabling the acquisition of reasonably large training datasets that hold the key for label-free single-cell analysis and, consequently, for differentiation of indolent from aggressive phenotypes.

The paper presents a novel low-voltage/low-power class-AB flipped voltage follower cell. The proposed circuit utilizes the advantages of floating-gate and bulk-driven techniques. The floating-gate MOSFET allows low-voltage operation and improves the current sinking capability whereas bulk-driven transistor improves the current sourcing capability without increasing complexity of the circuit. The proposed circuit has approximately unity voltage gain, low output resistance, large bandwidth, high current driving capability and improved linearity. The proposed circuit has been simulated using 180 nm CMOS technology of BSIM3v3.

The paper proposes a class-AB flipped voltage follower (FVF) cell, in which the bulk-driven transistor is used as an input transistor with a replica-biased scheme to eliminate the DC level shift while a cascoding transistor is used to reduce the output resistance. The proposed FVF cell has several advantages such as low output resistance, approximately unity voltage gain, high symmetrical slew rate, high current sourcing capability, high current sinking capability and wide bandwidth. The proposed FVF cell has been simulated in Cadence Virtuoso Analog Design Environment using BSIM3v3 180 nm CMOS technology with a power supply voltage of 1.2 V.

To meet the demand for low-voltage/low-power and high speed analog-to-digital convertors, a new fully differential double-tail dynamic comparator is proposed. To reduce the power dissipation and speed up the comparison process, charge sharing technique has been used in the latch stage of the proposed dynamic comparator. In addition, differential pair and double-tail dynamic comparator topologies are combined to minimize the offset voltage. The proposed dynamic comparator has worst case delay of 0.219 ns, power dissipation of 156.3 μW and offset voltage of 0.184 mV with 1σ deviation of 7.65 mV. The proposed dynamic comparator has been simulated in 0.18 μm CMOS technology with supply voltages of ± 0.75 V using Cadence virtuoso analog design environment.

The chapter discusses emerging applications of Raman spectroscopy in the areas of biomedical imaging of cells and tissues with the ultimate goal of clinical translation for disease diagnosis. The technological developments in lasers, detectors, and fiber optics during the last few decades have enabled identification of subtle molecular differences driving pathological transformations using Raman spectroscopy. The ex vivo studies conducted to examine biofluids, mineralized tissues, and solid tumors that demonstrated the initial feasibility of harnessing the specificity of Raman data for clinical diagnosis have been presented. Next, the resultant early in vivo studies conducted with the goal of establishing Raman spectroscopy as a real-time tool for intraoperative surgical margin assessment and endoscopic diagnosis have been reviewed. In addition, emerging preclinical studies for characterizing metastatic progression of cancer and response to therapy have been discussed. Finally, the biomedical applications enabled by integration of this spectroscopic modality with microscopy and incorporation of nanomaterials for surface selective electromagnetic enhancement of Raman signal have been briefly reviewed.

The elevated concentration of heavy metal ions poses severe challenges to environmental homeostasis and human health. Although significant efforts have been made towards the development of heavy metal ion sensors with varying degrees of success, these sensors are largely tailored for, and hence limited to, the detection of a single metal ion. Here we present a novel fluorescence-based sensor featuring polyindole/cadmium sulphide (PIN/CdS) nanocomposite that uniquely detects the presence and concentration of three important heavy metal ions, namely chromium (Cr3+), iron (Fe3+) and tin (Sn2+). The PIN/CdS nanocomposite was found to be an excellent receptor for the target ions via significant fluorescent enhancement owing to the inhibition of internal charge transfer (ICT) process and an efficient chelation enhanced fluorescence (CHEF) effect. A linear relationship between fluorescence intensity and Cr3+, Fe3+ and Sn2+ concentrations was obtained. Importantly, no interference was observed from 17 other commonly tested metal ions thereby making it a highly selective, yet multiplexed, probe for detection of these three ions. Finally, the sensor was used to detect and quantify aforementioned ions in routine drinking water samples. The multiplexed sensing ability and remarkable functional reversibility coupled with its straightforward synthesis and easy-to-use characteristics make this sensor particularly attractive for environmental and biomedical applications.

Raman spectroscopy has drawn considerable attention in biomedical sensing due to the promise of label-free, multiplexed, and objective analysis along with the ability to gain molecular insights into complex biological samples. However, its true potential is yet to be realized due to the intrinsically weak Raman signal. Here, we report a simple, inexpensive and reproducible signal enhancement strategy featuring graphene as a substrate. Taking key blood constituent proteins as representative examples, we show that Raman spectra acquired from biomacromolecules can be reproducibly enhanced when these molecules are placed in contact with graphene. In particular, we demonstrate that hemoglobin and albumin display significant, but different, enhancement with the enhancement factor depending on the Raman modes, excitation wavelengths, and analyte concentrations. This technique offers a new strategy for label-free biosensing owing to the molecular fingerprinting capability, signal reliability, and simplicity of th...

In this study, a novel level shifted version of flipped voltage follower (FVF) cell, which provides efficient class-AB operation, is presented. The level shifter is used to increase the swing of the FVF cell. In the proposed circuit, a bulk-driven metal-oxide-semiconductor field effect transistor is used as a current source to improve the sourcing capability and symmetrical slew rate for the class-AB operation. The circuit has a high-input/-output swing of 1.01 V/0.80 V, wide bandwidth of 751 MHz and low-output resistance of 107 Ω. The proposed circuit has been designed and simulated in a Cadence Virtuoso Analog Design Environment using BSIM3v3 180 nm complementary metal-oxide-semiconductor technology. The post-layout simulation results have also been presented to demonstrate the performance of the proposed circuit.

Rural livelihoods in Nepal are generally based on ecosystem resources. Despite a large number of studies on the Himalayan livelihoods, representation of the Trans-Himalaya, particularly Upper-Mustang, are rare. Such a scarcity could be associated with the fact that the place was isolated from the rest of the world and mainstream Nepali societies for a long time and also used to be known as ‘forbidden kingdom.’ This paper documents livelihood situation of Upper-Mustang in reference to the data collected in 66 households, in-depth interviews taken with 22 key informants, and focus group discussions conducted in 6 locations. Household livelihood system was studied with reference to five livelihood capitals, which were transformed into Livelihood Capital Index (LCI) at first and Livelihood Sustainability Index (LSI) later. Households in the Trans-Himalaya fulfill their livelihood requirement from multiple sources such as farming and livestock ranching together with small-scale enterprises, remittance and labouring. Overall status of livelihood capital is weak that cannot satisfy households’ food and livelihood requirements. There exists inter-household variation in the status of livelihood capitals.The households with diversified livelihood options have relatively secured livelihood, although such security is relative to the households of Upper-Mustang. Considering the weak status of agro-livestock system, which is mostly associated with unfavorable geographic conditions and lack of agro-livestock service provision, the region has sound scope for tourism industries and production as well as marketing of medicinal and aromatic plants, and fruits. Therefore, there is a plenty of possibility of diversifying livelihoods, however, neither the communities are eager to do so nor the state policies are encouraging. Therefore, together with expansion and advancement of physical infrastructure, effective service delivery and provision for social welfare, government programs should be facilitative for optimum and sustainable utilization of ecosystem resources for the sustainability of household livelihood system.Dhaulagiri Journal of Sociology and Anthropology Vol.11, 2017; 24-59

Raman spectroscopy has emerged as a non-invasive and versatile diagnostic technique due to its ability to provide molecule-specific information with ultrahigh sensitivity at near-physiological conditions. Despite exhibiting substantial potential, its translation from optical bench to clinical settings has been impacted by associated limitations. This perspective discusses recent clinical and biomedical applications of Raman spectroscopy and technological advancements that provide valuable insights and encouragement for resolving some of the most challenging hurdles.

Acute lymphoblastic leukemia (ALL) is one of the most common malignancies that account for nearly one-third of all pediatric cancers. The current diagnostic assays are time-consuming, labor-intensive, and require expensive reagents. Here, we report a label-free approach featuring diffraction phase imaging and Raman microscopy that can retrieve both morphological and molecular attributes for label-free optical phenotyping of individual B cells. By investigating leukemia cell lines of early and late stages along with the healthy B cells, we show that phase images can capture subtle morphological differences among the healthy, early, and late stages of leukemic cells. By exploiting its biomolecular specificity, we demonstrate that Raman microscopy is capable of accurately identifying not only different stages of leukemia cells but also individual cell lines at each stage. Overall, our study provides a rationale for employing this hybrid modality to screen leukemia cells using the widefield QPI and using Raman microscopy for accurate differentiation of early and late-stage phenotypes. This contrast-free and rapid diagnostic tool exhibits great promise for clinical diagnosis and staging of leukemia in the near future.

Leukocyte differential test is a widely carried out clinical procedure for screening infectious diseases. Existing hematology analyzers require labor‐intensive work and a panel of expensive reagents. Herein, an artificial‐intelligence‐enabled reagent‐free imaging hematology analyzer (AIRFIHA) modality is reported that can accurately classify subpopulations of leukocytes with minimal sample preparation. AIRFIHA is realized through training a two‐step residual neural network using label‐free images of isolated leukocytes acquired from a custom‐built quantitative phase microscope. By leveraging the rich information contained in quantitative phase images, not only high accuracy is achieved in differentiating B and T lymphocytes, but also CD4 and CD8 T cells are classified, therefore outperforming the classification accuracy of most current hematology analyzers. The performance of AIRFIHA in a randomly selected test set is validated and is cross‐validated across all blood donors. Due to its easy operation, low cost, and accurate discerning capability of complex leukocyte subpopulations, AIRFIHA is clinically translatable and can also be deployed in resource‐limited settings, e.g., during pandemic situations for the rapid screening of infectious diseases.

This study investigates the implications of climate change on agricultural ecology of Lumle Village as a representative example of the Middle-Mountains of Nepal. Primary data were collected through face-to-face interviews taken in 141 households. Supplementary data of public domain were collected from 9 Focus Group Discussions, 3 Historical Timeline Calendars, 20 Key Informant Interviews and sketches of 2 Crop Calendars. The findings suggest that traditional agro-livestock-based livelihood of the farming households of Lumle is ruined because of farmland abandonment and shift of agro-livestock activities to others options. A sharp decline in contribution of agro-livestock-based activities in household livelihoods in the last decade justifies this statement. Many factors might have been interplaying in abandoning agro-livestock activities. However, as the impacts of climate change are complex because of their spiral effects in existing poverty and marginality of households, it is contributing to agro-ecology through the effects of changes in weather pattern, increased invasive species and crop–livestock pest, as well as labour migration abroad caused by reduced farm output. The damage in agricultural ecology of mountain area in general and of Lumle in particular, however, has not yet been addressed by contemporary development policies of Nepal. Considering the importance of agricultural ecology for social-ecological sustainability and meeting the Sustainable Development Goal of eliminating hunger by 2030, Nepali agricultural policies should urgently recognise the need of agro-ecological restoration policy. It is expected that the integration of migration and climate change adaptation policies with agriculture and landuse policies to restrict farmland abandonment as well as provision of incentives for agricultural restoration would benefit in this regard.

Structural analysis of electrically poled samples of polycrystalline, (1-x)Bi(Mg1/2Zr1/2)O-3-xPbTiO(3) piezoceramics across morphotropic phase boundary reveals electric field-induced cubic to tetragonal phase transition and significant domain reorientation in tetragonal and two-phase compositions. The c-axis domain elongation is observed for tetragonal compositions after poling. The morphotropic phase boundary composition, having coexisting cubic and tetragonal phases in the unpoled state, exhibits alteration in relative proportion of the two phases, in addition to domain extension and reorientation along c-axis. For the morphotropic phase boundary composition, the tetragonality (c/a) is enhanced with significantly large c-axis strain (similar to 0.92%) in tetragonal phase after poling. Origin of ferroelectric P-E loop in cubic compositions is linked with the electric field-induced phase transition.

The successful development of a noninvasive blood glucose sensor that can operate reliably over sustained periods of time has been a much sought after but elusive goal in diabetes management. Since diabetes has no well-established cure, control of elevated glucose levels is critical for avoiding severe secondary health complications in multiple organs including the retina, kidney and vasculature. While fingerstick testing continues to be the mainstay of blood glucose detection, advances in electrochemical sensing-based minimally invasive approaches have opened the door for alternate methods that would considerably improve the quality of life for people with diabetes. In the quest for better sensing approaches, optical technologies have surfaced as attractive candidates as researchers have sought to exploit the endogenous contrast of glucose, notably its absorption, scattering, and polarization properties. Vibrational spectroscopy, especially spontaneous Raman scattering, has exhibited substantial promise due to its exquisite molecular specificity and minimal interference of water in the spectral profiles acquired from the blood-tissue matrix. Yet, it has hitherto been challenging to leverage the Raman scattering signatures of glucose for prediction in all but the most basic studies and under the least demanding conditions. In this Account, we discuss the newly developed array of methodologies that address the key challenges in measuring blood glucose accurately using Raman spectroscopy and unlock new prospects for translation to sustained noninvasive measurements in people with diabetes. Owing to the weak intensity of spontaneous Raman scattering, recent research has focused on enhancement of signals from the blood constituents by designing novel excitation-collection geometries and tissue modulation methods while our attempts have led to the incorporation of nonimaging optical elements. Additionally, invoking mass transfer modeling into chemometric algorithms has not only addressed the physiological lag between the actual blood glucose and the measured interstitial fluid glucose values but also offered a powerful tool for predictive measurements of hypoglycemia. This framework has recently been extended to provide longitudinal tracking of glucose concentration without necessitating extensive a priori concentration information. These findings are advanced by the results of recent glucose tolerance studies in human subjects, which also hint at the need for designing nonlinear calibration models that can account for subject-to-subject variations in skin heterogeneity and hematocrit levels. Together, the emerging evidence underscores the promise of a blood withdrawal-free optical platform-featuring a combination of high-throughput Raman spectroscopic instrumentation and data analysis of subtle variations in spectral expression-for diabetes screening in the clinic and, ultimately, for personalized monitoring.

The unprecedented capability to control and characterize materials on the nanometer scale has led to the rapid expansion of nanostructured materials. The expansion of nanotechnology, resulting into myriads of consumer and industrial products, causes a concern among the scientific community regarding risk associated with the release of nanomaterials in the environment. Bioavailability of excess nanomaterials ultimately threatens ecosystem and human health. Over the past few years, the field of nanotoxicology dealing with adverse effects and the probable risk associated with particulate structures

CD8(+) T cells constitute an essential compartment of the adaptive immune system. During immune responses, naïve T cells become functional, as they are primed with their cognate determinants by the antigen presenting cells. Current methods of identifying activated CD8(+) T cells are laborious, time-consuming and expensive due to the extensive list of required reagents. Here, we demonstrate an optical imaging approach featuring quantitative phase imaging to distinguish activated CD8(+) T cells from naïve CD8(+) T cells in a rapid and reagent-free manner. We measured the dry mass of live cells and employed transport-based morphometry to better understand their differential morphological attributes. Our results reveal that, upon activation, the dry cell mass of T cells increases significantly in comparison to that of unstimulated cells. By employing deep learning formalism, we are able to accurately predict the population ratios of unknown mixed population based on the acquired quantitative phase images. We envision that, with further refinement, this label-free method of T cell phenotyping will lead to a rapid and cost-effective platform for assaying T cell responses to candidate antigens in the near future.

Polymer–piezoceramic composites show mutual properties of piezoceramics and polymers that can be efficiently utilized in energy harvesting applications. Here we fabricated 0–3 composite films using high-performance low-lead piezoceramic (x)Bi(Ni1/2Zr1/2)O3-(1-x)PbTiO3 (BNZ-PT) as ceramic filler and polyvinylidene fluoride (PVDF) as polymer matrix. Unlike the conventional morphotropic phase boundary piezoelectrics such as the (1-x)PbTiO3-(x)PbZrO3, the large piezoelectric response of the BNZ-PT can be obtained by poling-induced cubic-like-to-tetragonal phase transformation. This leads to high piezoelectric coefficient of the PVDF–BNZ-PT composite films as well as high-energy harvesting performance. Composite films with different volume fractions of ceramic showed surface power density of 1.3– $3.5~\mu \text{W}$ /cm2, and volume power density of 72.2– $175~\mu \text{W}$ /cm3 using simple bending and unbending movements. Energy harvester in the form of cantilever fixed at both ends showed surface power density of 56.97– $163.63~\mu \text{W}$ /cm2 and volume power density of 3165– $8165~\mu \text{W}$ /cm3 in response to impact pressure pulses. The generated power from the composite films is comparable to composite energy generators reported to date. The volume power density, however, is highest to the best of our knowledge among the reported 0–3 polymer–piezoceramic composite energy harvesters.

We have constructed a convolutional neural network for classifying white blood cells by using data from a quantitative phase microscope. Better than 90% classification accuracy is obtained in both training set and test set.

Label-free quantitative imaging is highly desirable for studying live cells by extracting pathophysiological information without perturbing cell functions. Here, we demonstrate a novel label-free multimodal optical imaging system with the capability of providing comprehensive morphological and molecular attributes of live cells. Our morpho-molecular microscopy (3M) system draws on the combined strength of quantitative phase microscopy (QPM) and Raman microscopy to probe the morphological features and molecular fingerprinting characteristics of each cell under observation. While the commonr-path geometry of our QPM system allows for highly sensitive phase measurement, the Raman microscopy is equipped with dual excitation wavelengths and utilizes the same detection and dispersion system, making it a distinctive multi-wavelength system with a small footprint. We demonstrate the applicability of the 3M system by investigating nucleated and nonnucleated cells. This integrated label-free platform has a promising potential in preclinical research, as well as in clinical diagnosis in the near future.

A new lead-free perovskite solid solution (1−x)BaTiO3–xBi(Mg1/2Zr1/2)O3 with morphotropic phase boundary (MPB) has been developed, and its structural and dielectric properties have been investigated. Rietveld structural analysis of the X-ray diffraction data suggest a composition-dependent tetragonal (P4mm) to cubic (Pm3¯m) phase transition with an intermediate, phase coexistence region, demarcating the MPB. The compositions with x ≤ 0.05 are tetragonal in the P4mm space group and the compositions with x ≥ 0.25 are cubic in the space group. Coexistence of monoclinic phase (space group Cm) with tetragonal/cubic phase (space group P4mm/Pm3¯m) is observed in the MPB region for the compositions with 0.10 ≤ x ≤ 0.22. The temperature dependence of permittivity exhibits a nonrelaxor type diffuse phase transition for all the compositions across the MPB.

There is a general perception that a large piezoelectric response in ferroelectric solid solutions requires a morphotropic/polymorphic phase boundary (MPB/PPB), i.e., a composition driven interferroelectric instability. This correlation has received theoretical support from models which emphasize field driven polarization rotation and/or interferroelectric transformations. Here, we show that the ferroelectric system ( 1 − x ) PbTi O 3 − ( x ) Bi ( Zr 1 / 2 Ni 1 / 2 ) O 3 (PT-BNZ), which shows d 33 ( ∼ 400 p C / N ) comparable to the conventional MPB/PPB systems, does not belong to this category. In the unpoled state the compositions of PT-BNZ showing large d 33 exhibit a coexistence of tetragonal and cubiclike (CL) phases on the global length scale. A careful examination of the domain strucures and global structures (both in the unpoled and poled states) revealed that the CL phase has no symptom of average rhombohedral distortion even on the local scale. The CL phase is rather a manifestation of tetragonal regions of short coherence length. Poling increases the coherence length irreversibly which manifests as poling induced CL → P 4 m m transformation on the global scale. PT-BNZ is therefore qualitatively different from the conventional MPB piezoelectrics. In the absence of the composition and temperature driven interferroelectric instability in this system, polarization rotation and interferroelectric transformation are no longer plausible mechanisms to explain the large electromechanical response. The large piezoelectricity is rather associated with the increased structural-polar heterogeneity due to domain miniaturization without the system undergoing a symmetry change. Our study proves that attainment of large piezoelectricity does not necessarily require interferroelectric instability (and hence morphotropic/polymorphic phase boundary) as a criterion.

International audience; Piezoelectric actuators transform electrical energy into mechanical energy, and because of their compactness, quick response time and accurate displacement, they are sought after in many applications. Polycrystalline piezoelectric ceramics are technologically more appealing than single crystals due to their simpler and less expensive processing, but have yet to display electrostrain values that exceed 1%. Here we report a material design strategy wherein the efficient switching of ferroelectric–ferroelastic domains by an electric field is exploited to achieve a high electrostrain value of 1.3% in a pseudo-ternary ferroelectric alloy system, BiFeO3–PbTiO3–LaFeO3. Detailed structural investigations reveal that this electrostrain is associated with a combination of several factors: a large spontaneous lattice strain of the piezoelectric phase, domain miniaturization, a low-symmetry ferroelectric phase and a very large reverse switching of the non-180° domains. This insight for the design of a new class of polycrystalline piezoceramics with high electrostrains may be useful to develop alternatives to costly single-crystal actuators.

Otitis media with effusion (OME) is an important and common condition affecting hearing in pediatric patients characterized by the presence of fluid in the middle ear space. The fluid is normally described as serous or mucoid based on differences in the fluid viscosity. The differential diagnosis of two OMEs, namely serous and mucoid is of significant clinical value because while the former is self-limiting, surgical procedure is commonly required for the latter. However, accurate identification of fluid types remains a challenging target unattainable with current clinical modalities due to unavailability of nonperturbative molecular tools. Here, we report an emerging spectroscopy approach featuring Raman scattering and multivariate analysis of spectral patterns to discern serous and mucoid fluids, obtained from pediatric patients undergoing myringotomy and tube placement, by providing information of differentially expressed molecules with high specificity. We demonstrate the feasibility of Raman spectroscopy-based approach to categorize middle ear effusion based on the characteristic spectral markers, notably of mucin, with classification accuracy of 91% and 93% for serous and mucoid, respectively. Our findings pave the way for further development of such a tool for fully noninvasive application that will lead to objective and accurate diagnosis thereby reducing unnecessary visits and surgical procedures.

Biogenic synthesis of metal nanoparticles is of considerable interest, as it affords clean, biocompatible, nontoxic, and cost-effective fabrication. Driven by their ability to withstand variable extremes of environmental conditions, several microorganisms, notably bacteria and fungi, have been investigated in the never-ending search for optimal nanomaterial production platforms. Here, we present a hitherto unexplored algal platform featuring Chlorella pyrenoidosa, which offers a high degree of consistency in morphology of synthesized silver nanoparticles. Using a suite of characterization methods, we reveal the intrinsic crystallinity of the algae-derived nanoparticles and the functional moieties associated with its surface stabilization. Significantly, we demonstrate the antibacterial and photocatalytic properties of these silver nanoparticles and discuss the potential mechanisms that drive these critical processes. The blend of photocatalytic and antibacterial properties coupled with their intrinsic biocompatibility and eco-friendliness make these nanoparticles particularly attractive for wastewater treatment.

The climate sensitive social-ecological systems of the Nepali Himalaya are increasingly exposed to the impacts of rapid climate change. As a result, the changing climate is negatively impacting upon livelihoods of the region. Effective adaptation responses could reduce the negative impacts of change, and assessments of vulnerability of local social-ecosystems are helping to initiate that process. However, insufficient research has assessed climate change-induced vulnerability of Nepali Himalayan social-ecosystems at different scales. This study measures the vulnerability of social-ecosystems at the household level and within three village clusters of the Kaligandaki Basin in the Central Himalaya, Nepal. The clusters represent different ecological zones: Meghauli in the hot and wet tropical Tarai; Lumle in the cool, wet temperate Middle-Mountains; and Upper-Mustang in the cold and dry Trans-Himalaya. Data on the exposure, sensitivity and adaptive capacity of the social-ecosystems were collected through face-to-face interviews with 360 households. Exposure, sensitivity and adaptive capacity sub-indices were calculated and integrated to develop the vulnerability indices. The social-ecosystems reveal significant levels of exposure to climate change and are sensitive to change and extreme weather events, but limited capacities to adapt across all spatial scales result in very high social-ecological vulnerability. Yet, there is variation in the levels of vulnerability across the households, primarily because of different non-climatic factors such as the livelihood assets that a household commands. Given that many Nepali households have very limited adaptive capacities, the country requires an adaptation policy to address the needs of the most vulnerable households through a ‘poor people first’ approach, before adaptation planning and investment is extended gradually to reduce the vulnerability of social-ecosystems across the country.

In the quest for less toxic and cleaner methods of nanomaterials production, recent developments in the biosynthesis of nanoparticles have underscored the important role of microorganisms. Their intrinsic ability to withstand variable extremes of temperature, pressure, and pH coupled with the minimal downstream processing requirements provide an attractive route for diverse applications. Yet, controlling the dispersity and facile tuning of the morphology of the nanoparticles of desired chemical compositions remains an ongoing challenge. In this Focus Review, we critically review the advances in nanoparticle synthesis using microbes, ranging from bacteria and fungi to viruses, and discuss new insights into the cellular mechanisms of such formation that may, in the near future, allow complete control over particle morphology and functionalization. In addition to serving as paradigms for cost-effective, biocompatible, and eco-friendly synthesis, microbes hold the promise for a unique template for synthesis of tailored nanoparticles targeted at therapeutic and diagnostic platform technologies.

Otoscopic examination using white-light illumination has remained virtually unchanged for well over a century. However, the limited contrast of white-light otoscopy constrains the ability to make accurate assessment of middle ear pathology and is subject to significant observer variability. Here, we employ a modified otoscope with multi-color imaging capabilities for superior characterization of the middle ear constituents in vivo and for enhanced diagnosis of acute otitis media and cholesteatoma. In this pilot study, five patients undergoing surgery for tympanostomy tube placement and congenital cholesteatoma excision were imaged using the custom-designed multi-color video-rate reflectance imaging system. We show that the multi-color imaging approach offers an increase in image contrast, thereby enabling clear visualization of the middle ear constituents, especially of the tympanic membrane vascularity. Differential absorption at the multiple wavelengths provides a measure of biochemical and morphological information, and the rapid acquisition and analysis of these images aids in objective evaluation of the middle ear pathology. Our pilot study shows the potential of using label-free narrow-band reflectance imaging to differentiate middle ear pathological conditions from normal middle ear. This technique can aid in obtaining objective and reproducible diagnoses as well as provide assistance in guiding excisional procedures.

A common motif in otolaryngology is the lack of certainty regarding diagnosis for middle ear conditions, resulting in many patients being overtreated under the worst-case assumption. Although pneumatic otoscopy and adjunctive tests offer additional information, white light otoscopy has been the main tool for diagnosis of external auditory canal and middle ear pathologies for over a century. In middle ear pathologies, the inability to avail high-resolution structural and/or molecular imaging is particularly glaring, leading to a complicated and erratic decision analysis. Here, we propose a novel multiwavelength fluorescence-based video-rate imaging strategy that combines readily available optical elements and software components to create a novel otoscopic device. This modified otoscope enables low-cost, detailed and objective diagnosis of common middle ear pathological conditions. Using the detection of congenital cholesteatoma as a specific example, we demonstrate the feasibility of fluorescence imaging to differentiate this proliferative lesion from uninvolved middle ear tissue based on the characteristic autofluorescence signals. Availability of real-time, wide-field chemical information should enable more complete removal of cholesteatoma, allowing for better hearing preservation and substantially reducing the well-documented risks, costs and psychological effects of repeated surgical procedures.

Solvent polarity has been known to influence the triplet state structure and reactivity. Here, we present our experimental and theoretical study on the effect of solvent on the lowest triplet excited state structure of 2-chlorothioxanthone (CTX). Time-resolved absorption (TA) spectroscopy has been employed to understand the triplet state electronic structure; whereas solvent-induced structural changes have been studied using time-resolved resonance Raman (TR3) spectroscopy. Both the DFT and TD-DFT calculations have been performed in the solution phase employing self-consistent reaction field implicit solvation model to support the experimental data. It has been observed that CO stretching frequencies of the excited triplet state are sensitive to the solvent polarity and increase with the increase in the solvent polarity. Both TA and TR3 studies reveal that specific solvent effect (H-bonding) is more pronounced in comparison to the nonspecific solvent effect.

This paper introduces a novel approach of transconductance boosting for current differencing transconductance amplifier (CDTA). Generally, the variation in the transconductance is achieved by changing the bias current and/or by increasing the aspect ratios of differential pair MOSFETs. These techniques of transconductance variations suffer from several serious drawbacks which include higher power dissipation, limited range of transconductance gain and lower input/output swing. The proposed approach of transconductance boosting overcomes these drawbacks at certain extent and also provides a high value of transconductance gain with acceptable range of bandwidth and power dissipation. It includes two different techniques to make it more effective for transconductance boosting. In the first technique, common source amplifiers have been used between gate and source terminals of the differential pair MOSFETs whereas in the second technique the concept of partial positive feedback is utilized. Using this approach, a new structure of CDTA namely cross-coupled common source current differencing transconductance amplifier I (CCCS-CDTA I) is proposed. To further improve the transconductance gain of CCCS-CDTA I, another structure CCCS-CDTA II is also proposed, in which the differential pair MOSFETs are replaced by two networks of “n” parallel MOSFETs having same aspect ratios. The proposed CCCS-CDTAs are simulated in Mentor Graphics Eldo simulator using TSMC 0.18[Formula: see text][Formula: see text]m process parameters. To confirm the performance of CCCS-CDTA II, physical layout and post-layout simulation results have been presented using Mentor Graphics Calibre tool. The advantages of proposed CCCS-CDTAs have also been discussed by realizing KHN filters and oscillators.

This paper presents a novel current mirror structure based on level shifted class-AB flipped voltage follower cell, which operates at the supply voltage of 1.2[Formula: see text]V. The level shifted class-AB flipped voltage follower cell and regulated cascode structure are used at the input and the output stages to achieve low input resistance and very high output resistance, respectively. A comparison of performance parameters of the proposed current mirror with existing structures shows that the proposed current mirror has a very less current tracking error of 0.99%, high output resistance of 18.7[Formula: see text]M[Formula: see text], wide bandwidth of 239.245[Formula: see text]MHz and low power dissipation of 104[Formula: see text][Formula: see text]W. The proposed circuit has been simulated in Cadence virtuoso analog design environment and layout of the proposed circuit has been designed in Cadence virtuoso layout XL editor using BSIM3V3 180[Formula: see text]nm CMOS technology. The post-layout simulation results have also been presented to demonstrate the effectiveness of the proposed circuit.

The advancement in battery operated portable devices, noise sensitive devices and other devices, which need high precision supply voltages has fuelled the growth of Low Drop-Out Regulators. Low Drop-Out Regulators showed advantage over its counterpart. The design of Low Drop-Out Regulators with high performance and less Die area is challenging problem now-a-days. This paper is a study of various techniques that are used to achieve better performance of low drop-out regulators.Â