Surface plasmon enhanced ultrathin Cu2ZnSnS4/crystalline-Si tandem solar cells.

Thin-film silicon solar cells have sparked a great deal of research interest because of their low material usage and cost-effective processing. Despite the potential benefits, thin-film silicon solar cells have low power-conversion efficiency, which limits their commercial usage and mass production. To solve this problem, we design an ultrathin dual junction tandem solar cell with Cu2ZnSnS4 (CZTS) and crystalline silicon (c-Si) as the main absorbing layer for the top and bottom cells, respectively, through optoelectronic simulation. To enhance light absorption in thin-film crystalline silicon, we use silver nanoparticles at the rear end of the bottom cell. We utilize amorphous Si with a c-Si heterojunction to boost the carrier collection efficiency. Computational analyses show that within 9 µm thin-film c-Si, we achieve 28.28% power conversion efficiency with a 220 nm top CZTS layer. These findings will help reduce the amount of Si (∼10 vs. ∼180 µm) in silicon-based solar cells while maintaining high power conversion efficiency.

NOTCH pathway inactivation reprograms stem-like oral cancer cells to JAK-STAT dependent state and provides the opportunity of synthetic lethality.

BACKGROUND: We have recently provided the evidence of interconvertible cellular states, driving non-genetic heterogeneity among stem-like oral cancer cells (oral-SLCCs). Here, NOTCH pathway-activity status is explored as one of the possible mechanisms behind this stochastic plasticity. METHODS: Oral-SLCCs were enriched in 3D-spheroids. Constitutively-active and inactive status of NOTCH pathway was achieved by genetic or pharmacological approaches. RNA sequencing and real-time PCR was performed for gene expression studies. in vitro cytotoxicity assessments were performed by AlamarBlue assay and in vivo effects were studied by xenograft growth in zebrafish embryo. RESULTS: We have observed stochastic plasticity in oral-SLCCs, spontaneously maintaining both NOTCH-active and inactive states. While cisplatin refraction was associated with post-treatment adaptation to the active-state of NOTCH pathway, oral-SLCCs with inactive NOTCH pathway status showed aggressive tumor growth and poor prognosis. RNAseq analysis clearly suggested the upregulation of JAK-STAT pathway in NOTCH pathway-inactive subset. The 3D-spheroids with lower NOTCH-activity status displayed significantly higher sensitivity to JAK-selective drugs, Ruxolitinib or Tofacitinib or siRNA mediated downregulation of tested partners STAT3/4. Oral-SLCCs were programmed to adapt the inactive status of NOTCH pathway by exposing to Î³-secretase inhibitors, LY411575 or RO4929097, followed by targeting with JAK-inhibitors, Ruxolitinib or Tofacitinib. This approach resulted in a very significant inhibition in viability of 3D-spheroids as well as xenograft initiation in Zebrafish embryos. CONCLUSION: Study revealed for the first time that NOTCH pathway-inactive state exhibit activation of JAK-STAT pathways, as synthetic lethal pair. Therefore, co-inhibition of these pathway may serve as novel therapeutic strategy against aggressive oral cancer.

Characterizing diversity among human oral stem-like cancer cells using flow cytometry.

We have developed the protocol of flow cytometry for characterizing diversity among oral stem-like cancer cells (SLCCs) using CD44, CD24, and aldehyde dehydrogenase (ALDH) in oral tumors. We are also reporting the protocol for tumor-derived explant cultures to develop oral cancer cell lines and enriching these diverse hybrid states of cancer cells in 3D spheroids from established cell lines. For complete details on the use and execution of this protocol, please refer to Vipparthi et al. (2022) and Vipparthi et al. (2021).

Cohort profile of the largest health & demographic surveillance system (Dibrugarh-HDSS) from North-East India.

Dibrugarh Health and Demographic Surveillance System (Dibrugarh-HDSS), was started in the year 2019 with the objective to create the health and demographic database of a population from a defined geographical area and a surveillance system for providing technical assistance for the implementation of programmes and formulating intervention strategies for reducing disease morbidities and mortalities in the population. Dibrugarh-HDSS adopted a panel design and covered 60 contiguous villages and 20 tea gardens. Line listing of all the households was conducted and a unique identification number detailing State, district, village/tea garden and serial number was provided along with geotagging. Detailed sociodemographic variables, anthropometric measurements (subjects ≥five years) and blood pressure data (subjects ≥18 yr), disease morbidity and mortality were collected. All data were collected in pre-designed and pre-tested questionnaires using a mobile application package developed for this purpose. Dibrugarh-HDSS included a total of 106,769 individuals (rural: 46,762, tea garden: 60,007) with 52,934 males (49.6%) and 53,835 females (50.4%). The number of females per thousand males were significantly higher (1042 in tea garden vs. 985 in rural populations) in the tea-garden community as compared to the village population. More than one-third (35.1%) of tea populations were illiterate compared to the rural population (17.1%). Villagers had significantly higher body mass index than the tea-garden community. The overall prevalence of hypertension (adjusted for age) was 29.4 vs. 28.2 per cent, respectively, for the village and tea-garden population. For both these communities, males (village=30.8%, tea garden=31.1%) showed a higher prevalence of hypertension (adjusted for age) than females (village=28.2%, tea garden=25.8%). The findings of the present study give an insight into the profile of the native rural and tea-garden populations that will help to identify risk factors of different health problems, review the effectiveness of different ongoing programmes, implement intervention strategies for reducing morbidity and mortality and assist the State health authorities in prioritizing their resource allocation and implementation strategies.

Integrated Photonic Platform for Rare-Earth Ions in Thin Film Lithium Niobate.

Rare-earth ion ensembles doped in single crystals are a promising materials system with widespread applications in optical signal processing, lasing, and quantum information processing. Incorporating rare-earth ions into integrated photonic devices could enable compact lasers and modulators, as well as on-chip optical quantum memories for classical and quantum optical applications. To this end, a thin film single crystalline wafer structure that is compatible with planar fabrication of integrated photonic devices would be highly desirable. However, incorporating rare-earth ions into a thin film form-factor while preserving their optical properties has proven challenging. We demonstrate an integrated photonic platform for rare-earth ions doped in a single crystalline thin film lithium niobate on insulator. The thin film is composed of lithium niobate doped with Tm3+. The ions in the thin film exhibit optical lifetimes identical to those measured in bulk crystals. We show narrow spectral holes in a thin film waveguide that require up to 2 orders of magnitude lower power to generate than previously reported bulk waveguides. Our results pave the way for scalable on-chip lasers, optical signal processing devices, and integrated optical quantum memories.

Boosting the efficiency of single junction kesterite solar cell using Ag mixed Cu2ZnSnS4 active layer.

We propose a silver (Ag) mixed Cu2ZnSnS4 (ACZTS) based solar cell architecture to improve the efficiency of single junction Cu2ZnSnS4 (CZTS) solar cells. The configuration exploits enhancement of depletion region using a CdS/ACZTS/CZTS architecture. The doping concentration of different layers is adapted such that the primary absorber layer (ACZTS) may become fully depleted and CZTS acts as back surface field layer. We analyze the prospect and performance of the proposed architecture through rigorous optoelectronic simulations. We also study the role of the Schottky barrier at the back-contact interface of a conventional CZTS cell. In this regard, we propose to use an Ohmic contact to increase the open circuit voltage by replacing the molybdenum (Mo) with indium tin oxide (ITO). We further optimize the ACZTS thickness and calculated a maximum obtainable efficiency of 17.59% at 550 nm ACZTS with 940 mV open circuit voltage, 24.65 mA cm-2 short circuit current and 75.94% fill factor including the effects of Shockley-Read-Hall, radiative and surface recombination mechanisms. The efficiency of the optimized cell is ∼6.6% higher than that of the existing best single junction kesterite cell. We also vary the minority carrier life time (τ c) and surface recombination velocity of back contact (SRVback) and report an ideal efficiency of 22.14% with τ c = 1 µs and SRVback = 1000 cm s-1. Finally, we replace the toxic CdS buffer layer with eco-friendly ZnS and observe a relative improvement of 12.91% in the efficiency. The concept proposed and analyses performed in this work advance the efficiency of single junction kesterite solar cells.

A new half-condensed Schiff base compound: highly selective and sensitive pH-responsive fluorescent sensor.

A new probe, 3-[(3-benzyloxypyridin-2-ylimino)methyl]-2-hydroxy-5-methylbenzaldehyde (1-H) behaves as a highly selective fluorescent pH sensor in a Britton-Robinson buffer at 25 °C. The pH titrations show a 250-fold increase in fluorescence intensity within the pH range of 4.2 to 8.3 with a pK(a) value of 6.63 which is valuable for studying many of the biological organelles.

A highly selective fluorescent chemosensor for zinc ion and imaging application in living cells.

A new 2,6-bis(5,6-dihydrobenzo[4,5]imidazo[1,2-c]quinazolin-6-yl)-4-methylphenol (1) serves as a highly selective and sensitive fluorescent probe for Zn(2+) in a HEPES buffer (50 mM, DMSO:water = 1:9 (v/v), pH = 7.2) at 25 °C. The increase in fluorescence in the presence of Zn(2+) is accounted for by the formation of dinuclear Zn(2+) complex [Zn(2)(C(35)H(25)N(6)O)(OH)(NO(3))(2)(H(2)O)] (2), characterized by X-ray crystallography. The fluorescence quantum yield of the chemosensor 1 is only 0.019, and it increases more than 12-fold (0.237) in the presence of 2 equiv of the zinc ion. Interestingly, the introduction of other metal ions causes the fluorescence intensity to be either unchanged or weakened. By incubation of cultured living cells (A375 and HT-29) with the chemosensor 1, intracellular Zn(2+) concentrations could be monitored through selective fluorescence chemosensing.

A new water-soluble copper(II) complex as a selective fluorescent sensor for azide ion.

{[Cu(2)(H(2)L)(OH)(H(2)O)].(ClO(4))(2)(H(2)O)} (1) serves as a selective azide ion fluorescent sensor in aqueous medium. 1 binds with N(3)(-) to give [Cu(6)(HL)(2)(mu(1,1)-N(3))(6)] (2) which imposes rigidity and decreases the non-radiative decay of the excited state to give rise to fluorescent enhancement. 1 is highly selective over other various anions in aqueous medium.