Mechanism of the enhancement of electrical conductivity of nanocrystalline silicon due to hydrogen plasma treatment.

The mechanism of electrical charge transport in hydrogenated nanocrystalline silicon (nc-Si:H) and the enhancement in electrical conductivity by hydrogen plasma exposure has been studied. Nanoscale electrical conduction measurements (laterally on the surface) suggested that the dominant charge transport in nc-Si:H occurs through the crystalline grain interiors while grain boundaries are highly resistive. Room temperature low-power/short-duration (10 W, 10 s) surface hydrogen plasma treatment enhanced the local surface and bulk electrical conductivity of nc-Si:H films which was attributed to improved passivation of surface and bulk dangling bonds, increase in crystalline fraction and decrease in grain boundary (GB) fraction. However, the improvement in electrical conductivity due to high-power/long-duration (50 W, 10 min) hydrogen plasma exposure was not as pronounced as low-power/short-duration exposure. Temperature-dependent dark conductivity measurements showed dual activation-energy behavior; increase in activation energy in the high-temperature regime (400-585 K) was attributed to the temperature dependence of tunneling probability of carriers and explained using a heteroquantum dots model. A decrease in activation energy with plasma exposure was observed which was explained using the framework of a three-phase model of nc-Si:H where GB width and barrier potential played a critical role in determining the relative contribution of tunneling and thermally activated carrier transport.

A standards-based method for compositional analysis by energy dispersive X-ray spectrometry using multivariate statistical analysis: application to multicomponent alloys.

Given an unknown multicomponent alloy, and a set of standard compounds or alloys of known composition, can one improve upon popular standards-based methods for energy dispersive X-ray (EDX) spectrometry to quantify the elemental composition of the unknown specimen? A method is presented here for determining elemental composition of alloys using transmission electron microscopy-based EDX with appropriate standards. The method begins with a discrete set of related reference standards of known composition, applies multivariate statistical analysis to those spectra, and evaluates the compositions with a linear matrix algebra method to relate the spectra to elemental composition. By using associated standards, only limited assumptions about the physical origins of the EDX spectra are needed. Spectral absorption corrections can be performed by providing an estimate of the foil thickness of one or more reference standards. The technique was applied to III-V multicomponent alloy thin films: composition and foil thickness were determined for various III-V alloys. The results were then validated by comparing with X-ray diffraction and photoluminescence analysis, demonstrating accuracy of approximately 1% in atomic fraction.

Directly Linking Low-Angle Grain Boundary Misorientation to Device Functionality for GaAs Grown on Flexible Metal Substrates.

A new growth method to make highly oriented GaAs thin films on flexible metal substrates has been developed, enabling roll-to-roll manufacturing of flexible semiconductor devices. The grains are oriented in the <001> direction with <1° misorientations between them, and they have a comparable mobility to single-crystalline GaAs at high doping concentrations. At the moment, the role of low-angle grain boundaries (LAGBs) on device performance is unknown. A series of electron backscatter diffraction (EBSD) and cathodoluminesence (CL) studies reveal that increased doping concentrations decrease the grain size and increase the LAGB misorientation. Cross-sectional scanning transmission electron microscopy (STEM) reveals the complex dislocation structures within LAGBs. Most importantly, a correlative EBSD/electron beam-induced current (EBIC) experiment reveals that LAGBs are carrier recombination centers and that the magnitude of recombination is dependent on the degree of misorientation. The presented results directly link increased LAGB misorientation to degraded device performance, and therefore, strategies to reduce LAGB misorientations and densities would improve highly oriented semiconductor devices.

Effectuation to Cognize malignancy risk and accuracy of fine needle aspiration cytology in salivary gland using "Milan System for Reporting Salivary Gland Cytopathology": A 2 years retrospective study in academic institution.

BACKGROUND: To accost things in a particular disciple, egress related to Fine Needle Aspiration Cytology (FNAC) and to standardize reporting pattern, a framework "Milan System for Reporting Salivary Gland Cytopathology" (MSRSGC) has been sponsored. AIM: Aim of this study was to evaluate the potency of salivary gland FNAC reported under Milan guidelines, to calculate malignancy risk, and to compare the preoperative cytological diagnoses with the postoperative histopathological diagnoses. SETTINGS AND DESIGN: This was a retrospective study over a period of 2 years (May 2016 to April 2018), which was classified according to Milan system and correlation with histopathology. Furthermore, the risk of malignancy was calculated for all the diagnostic categories. MATERIALS AND METHODS: FNAC were analyzed on 105 patients with palpable salivary gland. Results were distributed into six categories. About 76 cases were surgically treated and resected tissues were submitted for histopathological examination. STATISTICAL ANALYSIS: The various diagnostic values of the procedure were calculated using the standard formula. RESULTS: We reviewed 105 salivary gland FNA samples and recorded interpretations according to the proposed standardized six categories. Among them, category IV (neoplastic) had more cases (57.14%). The rates of malignancy in histology were as follows: (1) nondiagnostic, 0.0%; (2) nonneoplastic, 0.0%; (3) atypia of undermined significance, 50.00%; (4a) benign, 02.44%; (4b) uncertain malignant potential, 33.33%; (5) suspicious for malignancy, 100%; and (6) malignancy, 93.33%. The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of Milan system came out to be 85.00%, 98.14%, 94.44%, 94.64%, and 94.59%, respectively. CONCLUSION: The six-tier diagnostic categories of the Milan system helps in triaging patients with salivary gland swelling and thus facilitate individualized management.

High-Performance Flexible Thin-Film Transistors Based on Single-Crystal-like Silicon Epitaxially Grown on Metal Tape by Roll-to-Roll Continuous Deposition Process.

Single-crystal-like silicon (Si) thin films on bendable and scalable substrates via direct deposition are a promising material platform for high-performance and cost-effective devices of flexible electronics. However, due to the thick and unintentionally highly doped semiconductor layer, the operation of transistors has been hampered. We report the first demonstration of high-performance flexible thin-film transistors (TFTs) using single-crystal-like Si thin films with a field-effect mobility of ∼200 cm2/V·s and saturation current, I/lW > 50 µA/µm, which are orders-of-magnitude higher than the device characteristics of conventional flexible TFTs. The Si thin films with a (001) plane grown on a metal tape by a "seed and epitaxy" technique show nearly single-crystalline properties characterized by X-ray diffraction, Raman spectroscopy, reflection high-energy electron diffraction, and transmission electron microscopy. The realization of flexible and high-performance Si TFTs can establish a new pathway for extended applications of flexible electronics such as amplification and digital circuits, more than currently dominant display switches.

Bilateral retiform variant of sertoli leydig cell tumour of ovary: An uncommon tumor with review of literature.

Sertoli-leydig cell tumors are the uncommon sex-cord stromal tumors of the ovary. We report a case of 42-year-old female with retiform variant of sertoli-leydig cell tumour. She presented with the complaint of mass in abdomen for 7 years. Ultrasound revealed bilateral ovarian mass suggestive of malignancy. Bilateral salpingo-oopherectomy with surgical staging was done. The tumor was diagnosed as stage I retiform variant of sertoli-leydig cell tumor on histopathology and immunohistochemistry.

Cytomorphological Aspects of Hashimoto's Thyroiditis: Our Experience at a Tertiary Center.

INTRODUCTION: Hashimoto's thyroiditis is the most common form of acquired hypothyroidism. Fine needle aspiration cytology is one important tool in diagnosing Hashimoto's thyroditis, along with clinical, biochemical, immunological and ultrasonographical modalities. The present study examines cytological aspects of Hashimoto's thyroiditis along with their correlation with clinical, biochemical and immunological findings, whenever available. MATERIALS AND METHODS: This is a retrospective study of 50 cases of Hashimoto's thyroiditis. Cytological findings were reviewed and correlated with clinical, biochemical and immunological findings whenever available. RESULTS: The majority of the patients were middle-aged females, with a female to male ratio of 6.14:1. Most patients presented with diffuse thyromegaly (68%) and/or hypothyroidism (56.09%). The antibody profile was available in 22% of patients. Of these, anti-thyroid peroxidase antibodies were raised in 81.81% of patients and anti-thyroglobulin antibodies were raised in 63.63% of patients. In the present study, high lymphoid to epithelial cell ratio was seen in 78% of cases, and 74% of cases showed Hurthle cell change. Follicular atypia was seen in 36% of cases. Lymphoid follicle formation was seen in seen in 54% of cases. Follicular cell infiltration by lymphocytes, eosinophils and neutrophils was seen in 72%, 48% and 26% of cases, respectively. Plasma cells were seen in 18% of cases. CONCLUSION: Thyroid function tests and immunological tests cannot diagnose all cases of Hashimoto's thyroiditis. Fine needle aspiration cytology continues to be a diagnostic tool of significance in diagnosing Hashimoto's thyroiditis. The presence of inflammatory cells, particularly lymphocytes and eosinophils, was detected in a significant proportion of cases.

Brooke-spiegler syndrome: a rare entity.

Brooke-Spiegler syndrome is a rare entity. It is an autosomal dominant syndrome in which multiple trichoepitheliomas, cylindromas, or other adnexal tumors are seen. Very few cases of Brooke-Spiegler syndrome are reported in the literature. We came across a 40 -year-old female in which multiple trichoepitheliomas and cylindromas were seen on scalp. In view of clinical history and histopathological examination it was diagnosed as Brooke-Spiegler syndrome. We report this case because of its rarity.

Twisted fimbrial cyst (paraovarian cyst): a rare cause of acute abdomen.

We present a case of a 22-year-old female who presented with acute abdomen and amenorrhea. Emergency laprotomy was done with a clinical diagnosis of ectopic pregnancy. On laprotomy, twisted fimbrial cysts were found. Thus, although fimbrial cysts are rarely twisted, they should be considered as a cause of acute abdomen in a female of reproductive age group.

Benign pairs: a significant entity in aspiration cytology smears from breast lesions.

INTRODUCTION: Fine needle aspiration cytology (FNAC) is a reliable diagnostic tool used to diagnose breast lesions preoperatively. However, FNAC is also associated with diagnostic pitfalls. Further studies are needed to improve its diagnostic efficacy. We noticed ovoid, bare nuclei arranged in closely touching diads (benign pairs) in a significant number of cytology smears. This prompted us to assess their diagnostic utility. MATERIALS AND METHODS: This was a prospective study conducted in Sarojini NaiduMedical College, Agra, India. Quantitative estimation of benign pairs per 1000 ductal cells in at least 20 high power field was attempted in cytology smears of 128 cases. RESULTS: The average number of pairs in benign and malignant lesions was calculated as 7.07 + 5.96 and 0.28 + 0.78, respectively. Statistical analysis showed a significant difference between the number of pairs in benign and malignant cases (P < 0.0005). CONCLUSIONS: Quantitative estimation of benign pairs is helpful in distinguishing benign from malignant cases.

Facile synthesis of MOF-5 confined in SBA-15 hybrid material with enhanced hydrostability.

A MOF-5 [Zn(4)O(BDC)(3); BDC = 1,4-benzenedicarboxylate]@SBA-15 hybrid material has been prepared by using SBA-15 as a matrix. This hybrid material exhibits improved hydrostability under ambient conditions and unique gas adsorption behavior compared with pristine MOF-5.