Ultrahigh Photo-Responsivity and Detectivity in 2D Bismuth Sulfide Photodetector for Vis-NIR Radiation.

Bismuth sulfide (Bi2S3) exhibits a direct energy bandgap and an exceptional optical absorption capability over a broadband radiation, thus presents a novel class of 2D photodetector material. The field effect transistor (FET) photodetector device is fabricated from 2D Bi2S3. An anomalous variation in the transport characteristics of 2D Bi2S3 is observed with the variation in temperature. The electrical resistance reduces by 99.26% at 10 K compared to the response at 300 K. Defects due to the bismuth and sulfur vacancies play a critical role in the dramatic behavior, which is confirmed using photoluminescence, time-resolved photoluminescence, Hall measurements, and energy dispersive X-ray spectroscopy. The density functional theory calculations provide a significant insight into the thermodynamic properties of intrinsic defects in Bi2S3. Moreover, the effect of gate bias on responsivity additionally confirms its invariance at low temperature. The Bi2S3 based FET photodetector achieves ultrahigh responsivity in the order of ≈106 A W-1 and detectivity of ≈1014 Jones. Moreover, the external quantum efficiency of ≈107% is measured in a wide spectrum of optical illumination (532 to 1064 nm) with a noise-equivalent power of 3.5 × 10-18 W/√Hz at a bias of 0.2 V. The extraordinary performance of Bi2S3 photodetector outstands 2D photodetectors.

Semiconductor Nanoparticle Anchored Single-Walled Carbon Nanotubes for a Bolometer.

The bolometer is developed using single-walled carbon nanotubes (SWCNT) anchored with semiconductor nanoparticles of cadmium sulfide, stannous disulfide, and zinc oxide (ZnO). The bolometric responses were recorded at varying temperatures from 10 K to room temperature. The anchored SWCNTs provided a higher temperature coefficient of resistance (TCR) than pristine SWCNTs. The largest TCR is recorded from SWCNTs/ZnO (-0.11%/K) at room temperature, which is 200% higher than pristine SWCNTs. The largest photoresponsivities of SWCNTs/ZnO under near-infrared (NIR) and wide wavelength source (200-1200 nm) illuminations are 5.06 and 37.51 mV/W, respectively. The extraordinary performance of SWCNTs/ZnO stands out at ∼17 × 104% under IR illumination. The study presents a significant advancement in the development of high-performance SWCNT bolometric materials by anchoring with semiconductor nanoparticles.

Histoplasmosis masquerading as tuberculosis: A report of three cases in immunocompetent children.

The most common cause of granulomatous lymphadenitis in countries like ours is mycobactrium tuberculosis followed by atypical mycobacterial infection, fungal infections, parasitic infection, cat scratch disease, lymphogranuloma venereum (inguinal lymphadenopathy), and leprosy Here, we present three cases of lymphadenopathy due to histoplasmosis in immunocompetent children. Two of them presented with fever, lymphadenopathy, initially diagnosed as granulomatous lymphadenitis consistent with tuberculosis on FNAC and were put on antitubercular drugs. However, their condition gradually became worse. As the patients continued to deteriorate, subsequent lymph node biopsies were done and diagnosed as histoplasmosis. Third case presented with acute loss of vision with hepatosplenomegaly and lymphadenopathy. Initially considered as acute leukemia, but eventually established as histoplasmosis. Histoplasmosis should be considered as one of the possible causes of granulomatous lymphadenitis in children.

Automated credit assessment framework using ETL process and machine learning.

In the current business scenario, real-time analysis of enterprise data through Business Intelligence (BI) is crucial for supporting operational activities and taking any strategic decision. The automated ETL (extraction, transformation, and load) process ensures data ingestion into the data warehouse in near real-time, and insights are generated through the BI process based on real-time data. In this paper, we have concentrated on automated credit risk assessment in the financial domain based on the machine learning approach. The machine learning-based classification techniques can furnish a self-regulating process to categorize data. Establishing an automated credit decision-making system helps the lending institution to manage the risks, increase operational efficiency and comply with regulators. In this paper, an empirical approach is taken for credit risk assessment using logistic regression and neural network classification method in compliance with Basel II standards. Here, Basel II standards are adopted to calculate the expected loss. The required data integration for building machine learning models is done through an automated ETL process. We have concluded this research work by evaluating this new methodology for credit risk assessment.

Retiform hemangioendothelioma: An uncommon vascular neoplasm.

Retiform hemangioendothelioma is a rare vascular neoplasm of intermediate grade, the diagnosis of which can be challenging. We report a case of 35-year-old man with swelling in the postauricular region. He had undergone FNAC which had revealed blood only. Microscopic examination showed narrow, arborizing, vascular channels resembling normal rete testis. Evidence of mitoses or cytological atypia were lacking. Immunohistochemistry showed diffuse and strong staining for CD34 along with CD31 positivity. Immunostains for D240 and GLUT1 were negative. A diagnosis of retiform hemangioendothelioma was made. Histologically, it should be distinguished from Kaposiform hemangioendothelioma, Dabska tumor, epithelioid hemangioendothelioma, and angiosarcoma.

Spontaneous dislocation of a crystalline lens to the anterior chamber with pupillary block glaucoma in Noonan Syndrome: a case report.

We report a 13-year-old child with Noonan Syndrome who developed spontaneous dislocation of the crystalline lens in anterior chamber leading to pupillary block glaucoma in the left eye and subluxation of lens in right eye. Intracapsular extraction of the dislocated lens was done in the left eye. Prompt diagnosis and management is needed in such cases to avoid glaucoma and corneal endothelial cell damage. We could not find any such case after thorough Medline search.

Retrospective observational study of penetrating keratoplasty in the management of non-responsive microbial keratitis.

Microbial keratitis tops the list of the diseases leading to corneal blindness. Corneal transplant, either partial or full thickness, is the most helpful technique for infective keratitis that remains non- responsive, even with the most suitable medical treatment. Aims of this study are to evaluate the success of therapeutic penetrating keratoplasty in non-responsive microbial keratitis in eradication of infection, restoration of anatomical integrity of the globe and prevention of complication that influence the visual prognosis in a positive way. Result of the retrospective study of 60 patients who underwent therapeutic penetrating keratoplasty, following infected keratitis showed restoration of anatomical integrity in 51 cases (85%). Success rate of penetrating keratoplasty was higher in non- perforated (92%) than in perforated group (74.28%) and in non-mycotic than in mycotic group. Penetrating keratoplasty in non-responsive infected keratitis is thus helpful.

Enhancement of storage capacity and conversion efficiency of photoelectrochemical cells: effect of dyes adsorbed on carbon nano tubes.

We report here our studies on photoelectrochemical (PEC) cells where two commonly used photosensitive dyes, thionine and Rose Bengal were used as photosensitizers for conversion of light energy to electrical energy. The performance of the cells increased radically in presence of oxidized multiwalled carbon nano tubes (OMWCNTs) as reflected by the values of conversion efficiency (∼3.69%) and open circuit voltage (∼548.9 mV). To understand the role of OMWCNTs in enhancing the performance of the cells, the spectral study of dye­OMWCNT mixed systems were performed. The absorption spectra indicated more absorption of incident photons in presence of OMWCNT, whereas the infrared spectra suggested that the basic structure of dyes remained unaltered. The spectral studies implied that the dye molecules got adsorbed on OMWCNTs side walls causing efficient absorption of the incident light quanta. Moreover, insertion of planar lipid membrane (PLM) separating the two chambers of PEC cell could effectively counteract the recombination of photodissociated charges and thereby caused better storage capacity of the PEC cells with further increase in efficiency.

Tissue adhesive in ophthalmology.

Tissue adhesive in ophthalmology is commonly used for corneal wound and restricted for superficial closure. Only synthetic adhesive available is butyl-2-cyanoacrylate. However, if it gets between the wound margins it inhibits healing by forming impervious barrier.

Clinicobacteriological study of chronic dacryocystitis in adults.

Chronic dacryocystitis is the inflammation of lacrimal sac, frequently caused by bacteria. Obstruction of nasolacrimal duct converts the lacrimal sac a reservoir of infection. It is a constant threat to cornea and orbital soft tissue. Moreover, it causes social embarrassment due to chronic watering from the eye. This study was conducted to find out the current clinicobacteriological profile of chronic dacryocystitis in adults. A total of 56 adult patients were selected from ophthalmology OPD. Detail history and clinical examinations were carried out. All patients underwent either dacryocystorhinostomy or dacryocystectomy. A part of the sac was collected for culture and sensitivity. This study revealed that chronic dacryocystitis is more common in females and left eye is more frequently involved than right eye. It is common among lower socioeconomic strata with habit of pond-bathing. Some form of nasal pathology like hypertrophied inferior turbinate, deviated nasal septum, nasal polyp and allergic rhinitis werefound in 19.6% of the patients. Complications of chronic dacryocystitis like conjunctivitis, corneal ulcer, acute on chronic dacryocystitis, lacrimal abscess and fistula were seen in 25.0% of these patients; 53.6% of the culture samples were positive for bacterial growth. Gram-positive organisms were most common isolate. Unlike other studies, Staphylococcus aureus (40.0%) was found to be most common Gram-positive organism, followed by Staphylococcus epidermidis (10.0%) and Steptococcus pneumoniae (10.0%). Among the Gram-negative organisms, Pseudomonas aeruginosa (16.6%) was the most common, followed by Klebsiella pneumoniae (6.6%) and Haemophilus influenzae (6.6%). Antibiotic sensitivity tests were done. Most of the organisms were resistant to penicillin. Chloramphenicol was effective against most of the Gram-positive organisms. Aminoglycosides, tobramycin in particular, was effective against Staphylococcus epidermidis. Fluoroquinolones, namely ciprofloxacin and ofloxacin were effective against Pseudomonas aeruginosa and Klebsiella pneumoniae.

Malignant melanoma of conjunctiva--a case report.

A 65-year-old male patient presented with a rapidly increasing mass in his left eye. It did not show any intra-ocular extension as examined by slit lamp, gonioscopy, indirect ophthalmoscopy and ultrasonography, nor there was any sign of systemic metastasis. The mass was excised completely. Buccal mucous membrane grafting was done to cover up the lower forniceal area and conjunctival autograft taken from right eye and placed over upper fornix and bulbar area. Postoperative radiotherapy was suggested. Histopathological examination of the mass revealed the diagnosis of malignant melanoma of conjunctiva.