RESUMEN
Background & objectives: The tribal population in India is considered as one of the vulnerable groups with respect to their achievements in health and other developmental issues. In this context, this mapping review attempted to understand the health profile of the Tharu tribal community residing in the northern State of Uttar Pradesh, India through literature mining. Tharu tribe is one of the indigenous groups living in the Terai plain on the Indo-Nepal border. In 1967, this tribe was documented as a Scheduled Tribe by the Government of India. The present review aimed to map the health-seeking behaviour of the Tharu population and review other factors pertaining to their health such as socioeconomic, developmental, employment, education, etc. Methods: Online data search was carried out on PubMed and Google Scholar using search terms 'Tharu' AND 'India'. In addition, official reports avaibale in public domain and grey literature was also searched. Results: Twenty seven studies including reviews, articles, books/book chapters were evaluated along with 13 reports (including reports from government organizations and grey literature) were retrieved and analyzed. Of the 27 published reports, 16 were found relevant to Tharu tribe in India. A total of 29 (16 articles + 13 reports ) were included in this review. Interpretation & Conclusions: This mapping review highights the health seeking behaviour of the Tharu tribe in India that can help inform future interventions to improve the health status of the Tharu tribe as well as other aspects of their development.
Asunto(s)
Conductas Relacionadas con la Salud , Estado de Salud , Humanos , India/epidemiología , Nepal , Aceptación de la Atención de SaludRESUMEN
Aim: The purpose of this meta-analysis was to evaluate the impact of oral health on quality of life in oral cancer patients (OCPs). Methods: PubMed, Scopus and Web of Science databases were searched for publications on oral health-related quality of life (OHRQoL) in OCP and the information was extracted according to the PRISMA guidelines. A random effect model was used to obtain the pooled standard mean differences of Oral Health Impact Profile (OHIP)-14 questionnaire responses in meta-analysis. Results: total of 12 research papers were analyzed and revealed poor OHRQoL in OCPs (standard mean difference: 2.53; 95% CI: 1.55-3.50; p < 0.00001) compared with healthy individuals due to the effects of oncotherapy. Moreover, OHRQoL deteriorated with combinations of different treatment modalities. Conclusion: Oral health and oncotherapy can affect the quality of life in OCPs.
Asunto(s)
Quimioradioterapia/efectos adversos , Neoplasias de la Boca/psicología , Salud Bucal/estadística & datos numéricos , Calidad de Vida , Traumatismos por Radiación/psicología , Humanos , Mucosa Bucal/efectos de los fármacos , Mucosa Bucal/patología , Mucosa Bucal/efectos de la radiación , Mucosa Bucal/cirugía , Neoplasias de la Boca/complicaciones , Neoplasias de la Boca/patología , Neoplasias de la Boca/terapia , Traumatismos por Radiación/epidemiología , Traumatismos por Radiación/etiología , Salivación/efectos de la radiación , Estomatitis/epidemiología , Estomatitis/etiología , Estomatitis/psicología , Encuestas y Cuestionarios/estadística & datos numéricos , Resultado del Tratamiento , Xerostomía/epidemiología , Xerostomía/etiología , Xerostomía/psicologíaRESUMEN
Metal halide perovskite thin films can be crystallized via a broad range of solution-based routes. However, the quality of the final films is strongly dependent upon small changes in solution composition and processing parameters. Here, this study demonstrates that a fractional substitution of PbCl2 with PbI2 in the 3CH3 NH3 I:PbCl2 mixed-halide starting solution has a profound influence upon the ensuing thin-film crystallization. The presence of PbI2 in the precursor induces a uniform distribution of regular quadrilateral-shaped CH3 NH3 PbI3 perovskite crystals in as-cast films, which subsequently grow to form pinhole-free perovskite films with highly crystalline domains. With this new formulation of 3CH3 NH3 I:0.98PbCl2 :0.02PbI2 , this study achieves a 19.1% current-voltage measured power conversion efficiency and a 17.2% stabilized power output in regular planar heterojunction solar cells.
RESUMEN
We investigate the effect of a post heat treatment of the absorber layer in air for antimony sulfide (Sb2S3) sensitized solar cells. Phenomenologically, exposing the Sb2S3 surface of sensitised solar cells to air at elevated temperatures is known to improve device performance. Here, we have investigated the detailed origins of this improvement. To this end, samples were annealed in air for different time periods and the build-up of an antimony oxide layer was monitored by XPS. A very short heat treatment resulted in an increase in power conversion efficiency from η = 1.4% to η = 2.4%, while longer annealing decreased the device performance. This improvement was linked to a reduction in charge carrier recombination at the interface of Sb2S3 with the organic hole conductor, arising from the oxide barrier layer, as demonstrated by intensity modulated photovoltage spectroscopy (IMVS).
RESUMEN
This review gives a detailed summary and evaluation of the use of TiO2 doping to improve the performance of dye sensitized solar cells. Doping has a major effect on the band structure and trap states of TiO2, which in turn affect important properties such as the conduction band energy, charge transport, recombination and collection. The defect states of TiO2 are highly dependent on the synthesis method and thus the effect of doping may vary for different synthesis techniques, making it difficult to compare the suitability of different dopants. High-throughput methods may be employed to achieve a rough prediction on the suitability of dopants for a specific synthesis method. It was however found that nearly every employed dopant can be used to increase device performance, indicating that the improvement is not so much caused by the dopant itself, as by the defects it eliminates from TiO2. Furthermore, with the field shifting from dye sensitized solar cells to perovskite solar cells, the role doping can play to further advance this emerging field is also discussed.
RESUMEN
Chemical doping is a powerful method to improve the charge transport and to control the conductivity in organic semiconductors (OSs) for a wide range of electronic devices. We demonstrate protic ionic liquids (PILs) as effective p-dopant in both polymeric and small molecule OSs. In particular, we show that PILs promote single electron oxidation, which increases the hole concentration in the semiconducting film. The illustrated PIL-doping mechanism is compatible with materials processed by solution and is stable in air. We report the use of PIL-doping in hybrid solar cells based on triarylamine hole transporting materials, such as 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-spirobifluorene (spiro-OMeTAD). We show improved power conversion efficiency by replacing lithium salts, typical p-dopants for spiro-OMeTAD, with PILs. We use photovoltage-photocurrent decay and photoinduced absorption spectroscopy to establish that significantly improved device performance is mainly due to reduced charge transport resistance in the hole-transporting layer, as potentiated by PIL-doping.
RESUMEN
Lithium salts have been shown to dramatically increase the conductivity in a broad range of polymeric and small molecule organic semiconductors (OSs). Here we demonstrate and identify the mechanism by which Li(+) p-dopes OSs in the presence of oxygen. After we established the lithium doping mechanism, we re-evaluate the role of lithium bis(trifluoromethylsulfonyl)-imide (Li-TFSI) in 2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9'-Spirobifluorene (Spiro-OMeTAD) based solid-state dye-sensitized solar cells (ss-DSSCs). The doping mechanism consumes Li(+) during the device operation, which poses a problem, since the lithium salt is required at the dye-sensitized heterojunction to enhance charge generation. This compromise highlights that new additives are required to maximize the performance and the long-term stability of ss-DSSCs.
RESUMEN
BACKGROUND: The aim of this prospective study was to assess the effectiveness of a single ultrasound-guided steroid injection in the treatment of Morton's neuromas and whether the response to injection correlates with the size of the neuroma. METHODS: Forty-three patients with clinical features of Morton's neuroma underwent ultrasound scan assessment. Once the lesion was confirmed in the relevant web space, a single corticosteroid injection was given using 40 mg of methylprednisolone along with 1% lidocaine. All scans and injections were performed by a single musculoskeletal radiologist. Patients were divided into two groups on the basis of the size of the lesion measured on the scan. Group 1 included patients with neuromas of 5 mm or less and group 2 patients had neuromas larger than 5 mm. A visual analog scale (VAS) for pain (scale 0 to 10), the American Orthopaedic Foot and Ankle Society (AOFAS) score, and the Johnson satisfaction scale were used to assess patients before injection and then at 6 weeks, 6 months, and 12 months following the injection. Thirty-nine patients had confirmed neuromas. Group 1 (lesion ≤ 5 mm) included 17 patients (mean age, 30 years) (7 males, 10 females) and group 2 (lesion >5 mm) had 22 patients (mean age, 33 years) (8 males, 14 females). RESULTS: VAS scores, AOFAS scores, and Johnson scale improved significantly in both groups at 6 weeks (p < .0001). At 6 months postinjection, this improvement remained significant only in group 1 with all scores (p < . 001). At 12 months, there was no difference between both groups and outcome scores nearly approached preinjection scores. At the final review, two patients in group 1 and four patients in group 2 had severe recurrent symptoms and therefore underwent surgical excision of the neuroma after they rejected the offer for a repeat injection (p = 0.6). CONCLUSION: A single ultrasound-guided corticosteroid injection resulted in generally short-term pain relief for symptomatic Morton's neuromas. The effectiveness of the injection appears to be more significant and long-lasting for lesions smaller than 5 mm.
Asunto(s)
Corticoesteroides/administración & dosificación , Enfermedades del Pie/tratamiento farmacológico , Enfermedades del Pie/patología , Neuroma/tratamiento farmacológico , Neuroma/patología , Adulto , Femenino , Humanos , Masculino , Dimensión del Dolor , Satisfacción del Paciente , Estudios Prospectivos , Resultado del Tratamiento , Adulto JovenRESUMEN
Urologists and general surgeons alike are familiar with assessing acute perineal pathology. A Cowper's gland syringocele is a rare cystic dilatation of the male bulbourethral gland, typically seen in children. We report the diagnosis and emergency management of two adult cases of large, infected Cowper's gland syringoceles. A comorbid 76-year old was diagnosed with sepsis and penile swelling, but there was no discrete superficial pathology. Magnetic resonance imaging (MRI) revealed a perineal collection communicating with the membranous urethra. A suprapubic catheter was inserted, and aspiration was attempted. Meanwhile, a 55-year-old diabetic presented with severe perineal pain. MRI revealed a deep perineal collection, involving the scrotum and proximal penis. He improved with antibiotics and aspiration of the collection. This rare diagnosis may be more common in older men than previously thought. Pelvic MRI is a key diagnostic tool. A minimally invasive approach is possible in those with considerable perioperative risk.
RESUMEN
Perovskite photovoltaics advance rapidly, but questions remain regarding point defects: while experiments have detected the presence of electrically active defects no experimentally confirmed microscopic identifications have been reported. Here we identify lead monovacancy (VPb) defects in MAPbI3 (MA = CH3NH3+) using positron annihilation lifetime spectroscopy with the aid of density functional theory. Experiments on thin film and single crystal samples all exhibited dominant positron trapping to lead vacancy defects, and a minimum defect density of ~3 × 1015 cm-3 was determined. There was also evidence of trapping at the vacancy complex [Formula: see text] in a minority of samples, but no trapping to MA-ion vacancies was observed. Our experimental results support the predictions of other first-principles studies that deep level, hole trapping, [Formula: see text], point defects are one of the most stable defects in MAPbI3. This direct detection and identification of a deep level native defect in a halide perovskite, at technologically relevant concentrations, will enable further investigation of defect driven mechanisms.
RESUMEN
Organic-inorganic hybrid lead halide perovskites have shown significant progress in the last few years having achieved efficiencies over 25% at the lab scale. The sequential deposition technique has provided a robust approach in the perovskite film fabrication. However, obtaining a reproducible and quality perovskite film has always been challenging because of the highly crystalline and ordered (001) oriented underlying PbI2 film. Here, we report a simple solution approach to fabricate a PbI2 residue-free, superior grade perovskite film by using a compositional engineered PbI2-precursor solution. We demonstrate that the Pb-precursor film crystallized into a R-centered Hexagonal metric lattice with (h0l), (hk0), and (00l) orientations provides a more efficient and quicker conversion into perovskites compared to conventional (001) oriented 2H-PbI2. A porous and multi-oriented PbI2 film is prepared by rationally incorporating a volumetric fraction of Pb(Ac)2·3H2O in the typical PbI2/dimethylformamide precursor solution, which significantly improves the surface features of PbI2 as well as the structural properties. As a result, a compact, smooth, and large grain perovskite can be obtained by accomplishing a full conversion with comparatively much less reaction time. Furthermore, a comprehensive mechanism of structural modification of PbI2 and the role of its orientation in ameliorating the reaction kinetics has been demonstrated.
RESUMEN
BACKGROUND: Oral exfoliative cytology is simple, non-invasive, inexpensive tools prone to subjective bias. Objective computer-based quantitative cytomorphometry technique was developed in last few decades to overcome its limitation. However, there is no consensus about the utility of cytomorphometry as a routine screening tool for early detection of dysplastic changes. OBJECTIVES: To review the utility of cytomorphometry in OPMDs in the detection of dysplasia changes. METHOD: A scoping review was undertaken focusing on cytomorphometric analysis in exfoliative cells for detection of oral epithelial dysplasia and cytomorphometric parameter denoting dysplasia. The systematic search was carried out in the online journal databases (Scopus, Google Scholar, PubMed, Web of Science) using keywords until December 2019 for the studies evaluated the cytomorphometry in the detection of dysplastic changes in OPMDs. Three authors independently extracted data using collection forms. RESULT: The search strategy found seven analytical cross-sectional studies for scoping review after eliminating 8940 out of 8947 initial results. The scoping review showed that cytomorphometry is useful tool in detecting the dysplastic changes in OPMDs. In addition, decrease in mean cellular area, increase in mean nuclear area, and decrease in mean cell diameter, increase mean nuclear diameter, increase in mean nuclear and cytoplasmic area ratio, associated with development of dysplastic changes in OPMDs. CONCLUSION: Cytomorphometry is promising tool, yet there is currently no-good evidence to support role of cytomorphometry in detecting the dysplastic changes in OPMDs in this setting. More research is required for refinement of cytomorphometry as a screening tool.
RESUMEN
Mixed organic-inorganic halide perovskite solar cells have reached unprecedentedly high efficiency in a short term. Two major challenges in its large-scale deployment is the material instability and hazardous lead waste. Several studies have identified that lead replacement with its other alternatives does not show the similar assurance. In this manuscript, we introduce the concept of recycling of the degraded perovskite film (PbI2), gaining back the initial optoelectronic properties as the best possible solution to avoid lead waste. The simple recycling procedure allows the utilization of some of the most expensive (fluorine-doped tin oxide), primary energy-consuming (TiO2), and toxic (Pb) parts of the solar cell, reducing the payback time even further. This addresses the major issues of instability and expensive toxic lead disposal, altogether. We have demonstrated the comparative study of feasibility of recycling in degraded perovskite films deposited by three different standard fabrication routes. Films fabricated via acetate route shows efficient recycling compared to the other routes, i.e., chloride and sequential deposition routes. Moreover, recycling in sequentially deposited films needs further optimization.
RESUMEN
Despite the remarkable efficiencies of perovskite solar cells, moisture instability has still been the major constraint in the technology deployment. Although, some research groups have discussed the possible mechanisms involved in the perovskite degradation, no broader understanding has been developed so far. Here, we demonstrate that the crystal orientation of perovskite film plays a major role in its degradation. We observed that the films fabricated via different routes led to different degradation behaviors and unraveled that diversity in the degradation rate arises due to the difference in crystallographic characteristics of the films. Using optical and electrical measurements, we show that the film prepared via a single-step (lead chloride precursor based) route undergoes a much faster degradation rate as compared with films prepared using single step (acetate precursor based) and two-step (or sequential deposition) routes. Although the resulting film is methylammonium lead iodide (MAPbI3) regardless of processing via different routes, their respective crystal orientation is different. In this manuscript, we correlate crystal orientation of MAPbI3 with their degradation pattern. Our studies also suggest a possible way to make stable perovskite film.
RESUMEN
Since the first reports of efficient organic-inorganic perovskite solar cells in 2012, an explosion of research activity has emerged around the world, which has led to a rise in the power conversion efficiencies (PCEs) to over 20%. Despite the impressive efficiency, a key area of the device which remains suboptimal is the electron extraction layer and its interface with the photoactive perovskite. Here, we implement an electron collection "bilayer" composed of a thin layer of zirconia coated with titania, sitting upon the transparent conductive oxide fluorine-doped tin oxide (FTO). With this double collection layer we have reached up to 17.9% power conversion efficiency, delivering a stabilized power output (SPO) of 17.0%, measured under simulated AM 1.5 sunlight of 100 mW cm-2 irradiance. Finally, we propose a mechanism of the charge transfer processes within the fabricated architectures in order to explain the obtained performance of the devices.
RESUMEN
Sb2S3 sensitized solar cells are a promising alternative to devices employing organic dyes. The manufacture of Sb2S3 absorber layers is however slow and cumbersome. Here, we report the modified aqueous chemical bath synthesis of Sb2S3 absorber layers for sensitized solar cells. Our method is based on the hydrolysis of SbCl3 to complex antimony ions decelerating the reaction at ambient conditions, in contrast to the usual low temperature deposition protocol. This simplified deposition route allows the manufacture of sensitized mesoporous-TiO2 solar cells with power conversion efficiencies up to η = 5.1%. Photothermal deflection spectroscopy shows that the sub-bandgap trap-state density is lower in Sb2S3 films deposited with this method, compared to standard deposition protocols.
RESUMEN
Organic-inorganic halide perovskite solar cells have recently emerged as high-performance photovoltaic devices with low cost, promising for affordable large-scale energy production, with laboratory cells already exceeding 20% power conversion efficiency (PCE). To date, a relatively expensive organic hole-conducting molecule with low conductivity, namely spiro-OMeTAD (2,2',7,7'-tetrakis(N,N-di-p-methoxyphenyl-amine) 9,9'- spirobifluorene), is employed widely to achieve highly efficient perovskite solar cells. Here, we report that by replacing spiro-OMeTAD with much cheaper and highly conductive poly(3,4-ethylenedioxythiophene) (PEDOT) we can achieve PCE of up to 14.5%, with PEDOT cast from a toluene based ink. However, the stabilized power output of the PEDOT-based devices is only 6.6%, in comparison to 9.4% for the spiro-OMeTAD-based cells. We deduce that accelerated recombination is the cause for this lower stabilized power output and postulate that reduced levels of p-doping are required to match the stabilized performance of Spiro-OMeTAD. The entirely of the materials employed in the perovskite solar cell are now available at commodity scale and extremely inexpensive.
RESUMEN
To date, there have been a plethora of reports on different means to fabricate organic-inorganic metal halide perovskite thin films; however, the inorganic starting materials have been limited to halide-based anions. Here we study the role of the anions in the perovskite solution and their influence upon perovskite crystal growth, film formation and device performance. We find that by using a non-halide lead source (lead acetate) instead of lead chloride or iodide, the perovskite crystal growth is much faster, which allows us to obtain ultrasmooth and almost pinhole-free perovskite films by a simple one-step solution coating with only a few minutes annealing. This synthesis leads to improved device performance in planar heterojunction architectures and answers a critical question as to the role of the anion and excess organic component during crystallization. Our work paves the way to tune the crystal growth kinetics by simple chemistry.
Asunto(s)
Compuestos de Calcio/química , Óxidos/química , Titanio/química , Cristalización , CinéticaRESUMEN
Recently, solution-processable organic-inorganic metal halide perovskites have come to the fore as a result of their high power-conversion efficiencies (PCE) in photovoltaics, exceeding 17%. To attain reproducibility in the performance, one of the critical factors is the processing conditions of the perovskite film, which directly influences the photophysical properties and hence the device performance. Here we study the effect of annealing parameters on the crystal structure of the perovskite films and correlate these changes with its photophysical properties. We find that the crystal formation is kinetically driven by the annealing atmosphere, time and temperature. Annealing in air produces an improved crystallinity and large grain domains as compared to nitrogen. Lower photoluminescence quantum efficiency (PLQE) and shorter photoluminescence (PL) lifetimes are observed for nitrogen annealed perovskite films as compared to the air-annealed counterparts. We note that the limiting nonradiative pathways (i.e., maximizing PLQE) is important for obtaining the highest device efficiency. This indicates a critical impact of the atmosphere upon crystallization and the ultimate device performance.
RESUMEN
Moisture, in the form of ambient humidity, has a significant impact on methylammonium lead halide perovskite films. In particular, due to the hygroscopic nature of the methylammonium component, moisture plays a significant role during film formation. This issue has so far not been well understood and neither has the impact of moisture on the physical properties of resultant films. Herein, we carry out a comprehensive and well-controlled study of the effect of moisture exposure on methylammonium lead halide perovskite film formation and properties. We find that films formed in higher humidity atmospheres have a less continuous morphology but significantly improved photoluminescence, and that film formation is faster. In photovoltaic devices, we find that exposure to moisture, either in the precursor solution or in the atmosphere during formation, results in significantly improved open-circuit voltages and hence overall device performance. We then find that by post-treating dry films with moisture exposure, we can enhance photovoltaic performance and photoluminescence in a similar way. The enhanced photoluminescence and open-circuit voltage imply that the material quality is improved in films that have been exposed to moisture. We determine that this improvement stems from a reduction in trap density in the films, which we postulate to be due to the partial solvation of the methylammonium component and "self-healing" of the perovskite lattice. This work highlights the importance of controlled moisture exposure when fabricating high-performance perovskite devices and provides guidelines for the optimum environment for fabrication. Moreover, we note that often an unintentional water exposure is likely responsible for the high performance of solar cells produced in some laboratories, whereas careful synthesis and fabrication in a dry environment will lead to lower-performing devices.