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1.
Nano Lett ; 24(7): 2376-2383, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38329912

RESUMEN

The remarkable spin-charge interconversion ability of transition metal dichalcogenides (TMDs) makes them promising candidates for spintronic applications. Nevertheless, their potential as spintronic terahertz (THz) emitters (STEs) remains constrained mainly due to their sizable resistivity and low spin Hall conductivity (SHC), which consequently result in modest THz emission. In this work, the TMD PtTe2, a type-II Dirac semimetal is effectively utilized to develop efficient STEs. This high efficiency primarily results from the large SHC of PtTe2, stemming from its low resistivity and significant spin-to-charge conversion efficiency, attributed to surface states and the local Rashba effect in addition to the inverse spin Hall effect. Remarkably, the peak THz emission from PtTe2/Co-STE exceeds that of Pt/Co-STE by ∼15% and is nearly double that of a similarly thick Pt/Co-STE. The efficient THz emission in the PtTe2/Co heterostructure opens new possibilities for utilizing the semimetal TMDs for developing THz emitters.

2.
BMC Public Health ; 24(1): 451, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38347565

RESUMEN

BACKGROUND: Food safety is a critical factor in promoting public health and nutrition, especially in developing countries like India, which experience several foodborne disease outbreaks, often with multidrug-resistant pathogens. Therefore, implementing regular surveillance of enteric pathogens in the human-animal-environment interface is necessary to reduce the disease burden in the country. OBJECTIVE: To establish a network of laboratories for the identification of major food and waterborne pathogens prevailing in the northeast region of India through integrated surveillance of animal, food, human, and environment and investigate the antimicrobial susceptibility pattern of the pathogens of public health significance. METHODS: The Indian Council of Medical Research (ICMR) has identified FoodNet laboratories; based on their geographical location, inclination to undertake the study, preparedness, proficiency, and adherence to quality assurance procedures, through an 8-step process to systematically expand to cover the Northeastern Region (NER) with comprehensive diagnostic capacities for foodborne pathogens and diarrhea outbreak investigations. Network initiated in the NER given the unique food habits of the ethnic population. FINDINGS: This surveillance network for foodborne enteric pathogens was established in Assam, Arunachal Pradesh, Tripura, and Sikkim, and expanded to other four states, i.e., Manipur, Mizoram, Meghalaya, and Nagaland, thereby covering the entire NER by including nine medical and three veterinary centers. All these centers are strengthened with periodic training, technical support, funding, capacity building, quality assurance, monitoring, centralized digital data management, and website development. RESULTS: The ICMR-FoodNet will generate NER-specific data with close to real-time reporting of foodborne disease and outbreaks, and facilitate the updating of food safety management protocols, policy reforms, and public health outbreak response. During 2020-2023, 13,981 food samples were tested and the detection of enteric pathogens ranged from 3 to 4%. In clinical samples, the detection rate of the pathogens was high in the diarrheal stools (8.9%) when 3,107 samples were tested. Thirteen outbreaks were investigated during the study period. CONCLUSION: Foodborne diseases and outbreaks are a neglected subject. Given the frequent outbreaks leading to the deaths of children, it is crucial to generate robust data through well-established surveillance networks so that a strong food safety policy can be developed for better public health.


Asunto(s)
Enfermedades Transmitidas por los Alimentos , Salud Única , Niño , Animales , Humanos , Estados Unidos , Salud Pública , India/epidemiología , Enfermedades Transmitidas por los Alimentos/epidemiología , Enfermedades Transmitidas por los Alimentos/prevención & control , Diarrea/epidemiología , Brotes de Enfermedades/prevención & control
3.
Nano Lett ; 23(24): 11925-11931, 2023 Dec 27.
Artículo en Inglés | MEDLINE | ID: mdl-38088819

RESUMEN

As a topological Dirac semimetal with controllable spin-orbit coupling and conductivity, PtSe2, a transition-metal dichalcogenide, is a promising material for several applications, from optoelectrics to sensors. However, its potential for spintronics applications has yet to be explored. In this work, we demonstrate that the PtSe2/Ni80Fe20 heterostructure can generate large damping-like current-induced spin-orbit torques (SOT), despite the absence of spin-splitting in bulk PtSe2. The efficiency of charge-to-spin conversion is found to be -0.1 ± 0.02 nm-1 in PtSe2/Ni80Fe20, which is 3 times that of the control sample, Ni80Fe20/Pt. Our band structure calculations show that the SOT due to PtSe2 arises from an unexpectedly large spin splitting in the interfacial region of PtSe2 introduced by the proximity magnetic field of the Ni80Fe20 layer. Our results open up the possibilities of using large-area PtSe2 for energy-efficient nanoscale devices by utilizing proximity-induced SOT.

4.
Nanotechnology ; 33(30)2022 May 04.
Artículo en Inglés | MEDLINE | ID: mdl-35439737

RESUMEN

Integration of nanolayered metal chalcogenides with wide-bandgap semiconductors forming pn heterojunction leads to the way of high-performance photodetection. This work demonstrates the fabrication of a few nanometer thick Molybdenum diselenide (MoSe2)/Mg-doped Gallium Nitride (p-GaN) heterostructure for light detection purposes. The device exhibits low noise broadband spectral response from ultraviolet to near-infrared range (300-950 nm). The band-alignment and the charge transfer at the MoSe2/p-GaN interface promote self-powered photodetection with high photocurrent to dark current ratio of 2000 and 1000 at 365 nm and 640 nm, respectively. A high responsivity of 130 A W-1, detectivity of 4.8 × 1010Jones, and low noise equivalent power of 18 fW/Hz1/2at 365 nm is achieved at an applied bias of 1 V. Moreover, the transient measurements reveal a fast rise/fall time of 407/710µsec for the fabricated device. These outcomes exemplify the viability of MoSe2/p-GaN heterostructure for high-speed and low-noise broadband photodetector applications.

5.
Nanotechnology ; 32(31)2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33845466

RESUMEN

A CMOS-compatible infrared (IR; 1200-1700 nm) detector based on Ge quantum dots (QDs) decorated on a single Si-nanowire channel on a silicon-on-insulator (SOI) platform with a superior detectivity at room temperature is presented. The spectral response of a single nanowire device measured in a back-gated field-effect transistor geometry displays a very high value of peak detectivity ∼9.33 × 1011Jones at ∼1500 nm with a relatively low dark current (∼20 pA), which is attributed to the fully depleted Si nanowire channel on SOI substrates. The noise power spectrum of the devices exhibits a1/fγ,with the exponent,γshowing two different values of 0.9 and 1.8 owing to mobility fluctuations and generation-recombination of carriers, respectively. Ge QD-decorated nanowire devices exhibit a novel polarization anisotropy with a remarkably high photoconductive gain of ∼104. The superior performance of a Ge QDs/Si nanowire phototransistor in IR wavelengths is potentially attractive to integrate electro-optical devices into Si for on-chip optical communications.

6.
J Clin Monit Comput ; 35(4): 741-748, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-32435933

RESUMEN

Cerebral protection against secondary hypoxic-ischemic brain injury is a key priority area in post-resuscitation intensive care management in survivors of cardiac arrest. Nevertheless, the current understanding of the incidence, diagnosis and its' impact on neurological outcome remains undetermined. The aim of this study was to evaluate jugular bulb oximetry as a potential monitoring modality to detect the incidences of desaturation episodes during post-cardiac arrest intensive care management and to evaluate their subsequent impact on neurological outcome. We conducted a prospective, observational study in unconscious adult patients admitted to the intensive care unit who had successful resuscitation following out of hospital cardiac arrest of presumed cardiac causes. All the patients were treated as per European Resuscitation Council 2015 guidelines and they received jugular bulb catheter. Jugular bulb oximetry measurements were performed at six hourly intervals. The neurological outcomes were evaluated on 90th day after the cardiac arrest by cerebral performance categories scale. Forty patients met the eligibility criteria. Measurements of jugular venous oxygen saturation were performed for 438 times. Altogether, we found 2 incidences of jugular bulb oxygen saturation less than 50% (2/438; 0.46%), and 4 incidences when it was less than 55% (4/438; 0.91%). The study detected an association between SjVO2 and CO2 (r = 0.26), each 1 kPa increase in CO2 led to an increase in SjvO2 by 3.4% + / - 0.67 (p < 0.0001). There was no association between SjvO2 and PaO2 or SjvO2 and MAP. We observed a statistically significant higher mean SjvO2 (8.82% + / - 2.05, p < 0.0001) in unfavorable outcome group. The episodes of brain hypoxia detected by jugular bulb oxygen saturation were rare during post-resuscitation intensive care management in out of hospital cardiac arrest patients. Therefore, this modality of monitoring may not yield any additional information towards prevention of secondary hypoxic ischemic brain injury in post cardiac arrest survivors. Other factors contributing towards high jugular venous saturation needs to be considered.


Asunto(s)
Paro Cardíaco Extrahospitalario , Adulto , Circulación Cerebrovascular , Humanos , Venas Yugulares , Oximetría , Oxígeno , Estudios Prospectivos
7.
Nanotechnology ; 31(45): 455208, 2020 Nov 06.
Artículo en Inglés | MEDLINE | ID: mdl-32442984

RESUMEN

Transition metal dichalcogenides (TMDs) and their heterojunctions are drawing immense research interest for various applications including infrared detection. They are being studied with different semiconductor materials to explore their heterojunction properties. In this regard, we report a MoSe2/Si heterojunction broadband photodiode which is highly sensitive for a wide spectral range from 405 nm to 2500 nm wavelength with the maximum responsivity of ∼522 mA W-1 for 1100 nm of incident light. The hydrothermal synthesis approach leads to the imperfect growth of the MoSe2, creating defects in the lattice, which was confirmed by x-ray photo-spectroscopy. These sub-bandgap defects caused high optical absorption of the SWIR light as observed in the absorption spectra. The speed of the device ranges to 18/10 µs for 10 kHz modulated light. Furthermore, the photodetector has been fully operational even at zero bias voltage, making it a potential contender for self-powered photodetection.

8.
Nanotechnology ; 31(38): 385501, 2020 Sep 18.
Artículo en Inglés | MEDLINE | ID: mdl-32498051

RESUMEN

The present study investigates the piezoresistive properties of polycrystalline MoS2 film for strain-sensing applications. The gauge factor (GF) of the flexible MoS2 device (MoS2/PET) has been calculated to be 102 ± 5 in the stress range from ~7 MPa to ~14 MPa. In addition, to improve the sensing stress range, the flexible strain sensors are encapsulated by SU-8. The effect of encapsulation layer thickness is reflected in the GF, which is attributed to the shifting of the neutral axis. However, the calculated GF is constant in the higher stress range, 80 ± 2 and 12 ± 1 for 2 µm and 10 µm thick SU-8, respectively. Herein, we report a cost-effective and scalable approach to fabricate large-area polycrystalline MoS2-based flexible sensors for a wider stress range. The encapsulated devices remained undistorted and intact for stress values beyond 14 MPa. Further, we demonstrate the durability of the fabricated sensors with body movements, such as hand gestures, for all the three types of strain sensor.

9.
Indian J Crit Care Med ; 24(7): 565-569, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32963441

RESUMEN

COVID-19 outbreak has caused a pandemonium in modern world. As the virus has spread its tentacles across nations, territories, and continents, the civilized society has been compelled to face an unprecedented situation, never experienced before during peacetime. We are being introduced to an ever-growing new terminologies: "social distancing," "lockdown," "stay safe," "key workers," "self-quarantine," "work-from-home," and so on. Many countries across the globe have closed their borders, airlines have been grounded, movement of public transports has come to a grinding halt, and personal vehicular movements have been restricted or barred. In the past couple of months, we have witnessed mayhem in an unprecedented scale: social, economic, food security, education, business, travel, and freedom of movements are all casualties of this pandemic. Our experience about this virus and its epidemiology is limited, and mostly the treatment for symptomatic patients is supportive. However, it has been observed that COVID-19 not only attacks the respiratory system; rather it may involve other systems also from the beginning of infection or subsequent to respiratory infection. In this article, we attempt to describe the systemic involvement of COVID-19 based on the currently available experiences. This description is up to date as of now, but as more experiences are pouring from different corners of the world, almost every day, newer knowledge and information will crop up by the time this article is published. HOW TO CITE THIS ARTICLE: Munjal M, Das S, Chatterjee N, Setra AE, Govil D. Systemic Involvement of Novel Coronavirus (COVID-19): A Review of Literature. Indian J Crit Care Med 2020;24(7):565-569.

10.
Indian J Crit Care Med ; 24(9): 763-770, 2020 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-33132557

RESUMEN

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and has been declared as a pandemic. COVID-19 patients may require transport for diagnostic or therapeutic purposes intra- or interhospital or transport from an outside hospital to a healthcare facility. Transport of critically ill or infectious patients is always challenging and involves the integration of various tasks and manpower. The adverse events have been attributed to various factors such as a multidisciplinary team and lack of appropriate communication among team members, absence of equipment, or failure during transport, apart from physiological alteration inherent to the disease of the patient. The transport of COVID-19 patients carries an additional risk of not only the disease itself but also due to the risk of its transmission to the transport team. The human-to-human transmission of the virus can occur via respiratory droplets. So, the person involved in the transport of such patients shall be at risk and warrants appropriate steps for their safety. Appropriate planning by a well-trained transport team is an essence for the safe transport of the suspected or confirmed COVID-19 patients. The Transport Medicine Society guidelines present consensus guidelines for the safe transport of COVID-19 patients. DISCLAIMER: These consensus guidelines are applicable for the safe transport of suspected or confirmed COVID-19 adult patients. These recommendations should be used in conjunction with medical management guidelines and advisories related to COVID-19. These recommendations should be adapted to the local policies prevalent at the workplace and also per agreement among the hospitals for transport (agreement between referring and receiving facilities). With the emergence of new scientific evidence, these guidelines may require modification. HOW TO CITE THIS ARTICLE: Munjal M, Ahmed SM, Garg R, Das S, Chatterjee N, Mittal K, et al. The Transport Medicine Society Consensus Guidelines for the Transport of Suspected or Confirmed COVID-19 Patients. Indian J Crit Care Med 2020;24(9):763-770.

11.
Nanotechnology ; 30(49): 495205, 2019 Dec 06.
Artículo en Inglés | MEDLINE | ID: mdl-31476745

RESUMEN

Hybrid semiconductor nanostructures have attracted tremendous response due to their unique properties and applications in nano-optoelectronics and sensors. Here, we fabricated a back-gated transistor based on 300 nm channel of the Azurin-TiO2 hybrid nanostructure, whose enhanced performance is attributed to the synergetic effect of the metal oxide and azurin. Surface potential mapping under the dark and light condition using Kelvin probe force microscopy, gives the perfect correlation of band gap estimation for Azurin, TiO2 and Azurin-TiO2 nanostructures. The extracted parameters of the transistor exhibit the majority carrier mobility of 2.26 cm2 V-1 s-1, Schottky barrier height of 133.56 meV and low off current (6 × 10-10 A). The photodetector showed the high spectral response of 8.7 × 105 A W-1 and detectivity of 6.4 × 1014 Jones for 260 nm wavelength, at an applied gate bias of 5 V. The short carrier transit time (3 µs) and large recombination time (0.4 s) with multiple recirculations of photo generated carries facilitate the high gain of 2.6 × 106. A significant rejection ratio (R 260/R 530) of 56.2 at V GS = 5 V and the linear dynamic range of 45.75 dB for 260 nm wavelength is achieved. The obtained rise and fall time of the photodetector is 0.52 s, and 0.65 s, respectively. This study suggests the applicability of Azurin-TiO2 hybrid nanostructures with high performance for the biocompatible optoelectronic devices.

12.
Nanotechnology ; 29(27): 275503, 2018 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-29745370

RESUMEN

This paper presents the development of an extremely sensitive and selective acetone sensor prototype which can be used as a platform for non-invasive diabetes detection through exhaled human breath. The miniaturized sensors were produced in high yield with the use of standard microfabrication processes. The sensors were based on a heterostructure composed of MoO3 and nano-porous silicon (NPS). Features like acetone selective, enhanced sensor response and 0.5 ppm detection limit were observed upon introduction of MoO3 on the NPS. The sensors were found to be repeatable and stable for almost 1 year, as tested under humid conditions at room temperature. It was inferred that the interface resistance of MoO3 and NPS played a key role in the sensing mechanism. With the use of breath analysis and lab-on-chip, medical diagnosis procedures can be simplified and provide solutions for point-of-care testing.


Asunto(s)
Acetona/análisis , Diabetes Mellitus/diagnóstico , Molibdeno/química , Óxidos/química , Silicio/química , Humanos , Microscopía de Fuerza Atómica , Nanoporos/ultraestructura , Espectroscopía de Fotoelectrones , Porosidad , Propiedades de Superficie , Compuestos Orgánicos Volátiles/análisis , Difracción de Rayos X
13.
ACS Appl Mater Interfaces ; 16(24): 30648-30657, 2024 Jun 19.
Artículo en Inglés | MEDLINE | ID: mdl-38843092

RESUMEN

Organic and inorganic hybrid field-effect transistors (FETs), utilizing layered molybdenum diselenide (MoSe2) and an organic semiconductor poly(3-hexylthiophene) (P3HT), are presented for biosensing applications. A new hybrid device structure that combines organic (P3HT) and inorganic (MoSe2) components is showcased for accurate and selective bioanalyte detection in human bodily fluids to overcome 2D-transition metal dichalcogenides (TMDs) nonspecific interactions. This hybrid structure utilizes organic and inorganic semiconductors' high surface-to-volume ratio, carrier transport, and conductivity for biosensing. Ammonia concentrations in saliva and plasma are closely linked to physiological and pathological conditions of the human body. A highly sensitive hybrid FET biosensor detects total ammonia (NH4+ and NH3) from 0.5 µM to 1 mM concentrations, with a detection limit of 0.65 µM in human bodily fluids. The sensor's ammonia specificity in artificial saliva against interfering species is showcased. Furthermore, the fabricated hybrid FET device exhibits a stable and repeatable response to ammonia in both saliva and plasma, achieving a remarkable response level of 2300 at a 1 mM concentration of ammonia, surpassing existing literature by 10-fold. This hybrid FET biosensing platform holds significant promise for developing a precise tool for the real-time monitoring of ammonia concentrations in human biological fluids, offering potential applications in point-of-care diagnostics.


Asunto(s)
Amoníaco , Técnicas Biosensibles , Saliva , Transistores Electrónicos , Amoníaco/análisis , Humanos , Técnicas Biosensibles/instrumentación , Técnicas Biosensibles/métodos , Saliva/química , Saliva/metabolismo , Tiofenos/química , Molibdeno/química , Límite de Detección , Semiconductores
14.
Heliyon ; 10(11): e31903, 2024 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-38882280

RESUMEN

Food and waterborne outbreaks are a neglected public health problem in India. However, it is important to identify the source of infection and the causative pathogen to curb the outbreak quickly and minimize mortality and morbidity. A retrospective descriptive study was conducted with a line list of 130 diarrheal cases. Epidemiological investigation and laboratory investigation were done. Data were collected from hospital case report forms as well as interviewed affected cases. A case of acute diarrheal disease was reported among the people in the village with abdominal pain, vomiting, and diarrhea from December 31, 2022 to January 3, 2023. Out of a total of 130 recorded cases, 33 stool samples were collected and were positive for Enteroaggregative Escherichia coli, Shigella flexneri 3a, and Shigella sonnei by cultural and molecular tests. The presumptive fecal pollution indicator assay indicated high coliform counts in the water samples (most probable number [MPN]-05) and the presence of Escherichia coli. The identified pathogens showed susceptibility to gentamicin and meropenem. People who used public drinking water were found to be infected with acute diarrheal disease (ADD). Quick identification of the causative pathogens and their antimicrobial resistance pattern helped correct antibiotic prescriptions and quick recovery of the patients without any deaths. Thus, a timely implementation of food and waterborne outbreak investigation is crucial to saving lives and preventing the spread of infection.

15.
Opt Express ; 21(23): 28219-31, 2013 Nov 18.
Artículo en Inglés | MEDLINE | ID: mdl-24514333

RESUMEN

Direct band gap optical transition in compressively strained Ge film is demonstrated for the first time under current injection through a metal-insulator-semiconductor diode structure. The compressively strained Ge layer is grown on the relaxed Si0.5Ge0.5 substrate by solid source molecular beam epitaxy. The electroluminescence of direct band gap emission from strained Ge film and TO phonon assisted transition in Si and SiGe from the virtual substrate is observed under different current injections. The signature of heavy hole and light hole splitting in valence band is observed in the electroluminescence spectra from strained Ge layer. The temperature dependent electroluminescence characteristics have been studied over a temperature range of 10-300 K. AC frequency modulation for the Ge direct band electroluminescence has been studied to improve the emission efficiency over the DC bias.

16.
Saudi J Anaesth ; 17(1): 87-90, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37032691

RESUMEN

Acute pancreatitis is one of the major causes of abdominal pain and is mainly related to either gallstone or heavy alcohol intake. We have managed a patient with acute pancreatitis with a bilateral erector spinae catheter because he was not suitable for other analgesics. A 72-year-old male with a known alcoholic patient was admitted with severe acute pancreatitis. He also had the chronic obstructive pulmonary disease (COPD) and oesophageal reflux disease. He was allergic to nonsteroidal anti-inflammatory medications and opioids. Therefore, his pain was managed successfully with bilateral erector spinae block with a continuous infusion with 0.125% levobupivacaine 1 ml/hr background infusion and 30 ml every 4 hours using a CADD Solis regional analgesia pump. Although erector spinae block is relatively new and to date, the optimal dose is not determined. We inserted the catheters at the T8 level; however, further study is needed to determine the ideal insertion site and drug volumes. We have mentioned key features, techniques, and management plans and reviewed the latest literature in this case report.

17.
Lab Chip ; 23(19): 4352-4365, 2023 09 26.
Artículo en Inglés | MEDLINE | ID: mdl-37712390

RESUMEN

Compartmentalizing magnetically controlled drug molecules is critical in several bioanalytical trials and tests, such as drug screening, digital PCR, magnetic hyperthermia, and controlled magnetic drug targeting (MDT). However, several studies have focused on diluting the nonmagnetic drug using various passive devices based on traditional microfabrication and 3D printing techniques, leading to the requirement of sterilized cleanroom facilities and expensive equipment, respectively. This work develops a strategically designed and straightforward lithography-free process to fabricate a magnetic microfluidic device using a multilayered PMMA substrate for concentration-dependent compartmentalization of a magnetically controlled anticancer drug. The device contains an array of outlet chamber wells connected to five primary separation microfluidic channels for collecting different drug concentrations. The microfluidic design geometry, magnet configuration, and fluid flow rate are optimized using FEM (Finite Element Method) simulations to attain a systematic concentration gradient region within the microfluidic channel. A stair-step-like patterned magnet creates an attenuating magnetic force between 0.01-0.24 pN on magnetic nanoparticles, capable of generating the concentration gradient for the clinically acceptable flow range of Q = 0.6-1.1 µL min-1. The chamber well of the device is designed to adapt different cell cultures and simultaneously expose five different concentrations by introducing a predefined concentration from the inlet. As a result, this innovative design provides a predictable concentration control in each well through a single injection port to minimize drug loading errors. The concentration gradient generation of the drug and exposure to cell culture chambers are controlled using the magnetic and drag forces capable of running a time-varying dose screening experiment. The concentration range of the compartmentalized drug sample in the device is determined as 10-480 µg mL-1 using inductively coupled plasma mass spectrometry (ICPMS) measurement and fluorescence intensity. The cytotoxicity test of MCF7 and NIH3T3 cells using the device was consistent with the results obtained with the manual dilution method, resulting in the reusability of the device.


Asunto(s)
Técnicas Analíticas Microfluídicas , Animales , Ratones , Células 3T3 NIH , Microfluídica , Técnicas de Cultivo de Célula , Dispositivos Laboratorio en un Chip
18.
ACS Appl Mater Interfaces ; 15(22): 27285-27298, 2023 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-37216628

RESUMEN

Here, we report on the comprehensive growth, characterization, and optoelectronic application of large-area, two-dimensional germanium selenide (GeSe) layers prepared using the pulsed laser deposition (PLD) technique. Back-gated phototransistors based on few-layered 2D GeSe have been fabricated on a SiO2/Si substrate for ultrafast, low noise, and broadband light detection, showing spectral functionalities over a broad wavelength range of 0.4-1.5 µm. The broadband detection capabilities of the device have been attributed to the self-assembled GeOx/GeSe heterostructure and sub-bandgap absorption in GeSe. Besides a high photoresponsivity of 25 AW-1, the GeSe phototransistor displayed a high external quantum efficiency of the order of 6.14 × 103%, a maximum specific detectivity of 4.16 × 1010 Jones, and an ultralow noise equivalent power of 0.09 pW/Hz1/2. The detector has an ultrafast response/recovery time of 3.2/14.9 µs and can show photoresponse up to a high cut-off frequency of 150 kHz. These promising device parameters exhibited by PLD-grown GeSe layers-based detectors make it a favorable choice against present-day mainstream van der Waals semiconductors with limited scalability and optoelectronic compatibility in the visible-to-infrared spectral range.

19.
Artículo en Inglés | MEDLINE | ID: mdl-35658392

RESUMEN

Recently explored black arsenic is a layered two-dimensional low-symmetry semiconducting material that, owing to its inherent narrow bandgap (∼0.31 eV) in its bulk form, is attractive for mid-infrared optoelectronics. Several studies have been conducted on its structural, charge-transport, and thermal properties for implementation in nanoelectronics. Herein, the thickness-dependent optoelectronic performance of black arsenic devices for mid-infrared wavelengths (2.0-4.0 µm) is investigated. The device was fabricated over an hBN/SiO2/Si substrate using mechanical exfoliation of black arsenic. It is observed that the optoelectronic properties of the devices vary significantly with the thickness of the black arsenic channel of the devices. A peak photoresponsivity of 244 A/W was achieved at 3.00 µm for a 60 nm-thick black arsenic channel. However, the maximum detectivity of 6.14 × 109 Jones was found for a lower thickness (∼25 nm) of black arsenic, along with an excellent (i.e., the least) noise-equivalent power of ∼89 fW/Hz1/2. Our findings reveal that the optoelectronic properties of black arsenic are excellent and can be tuned through thickness control. The promising results suggest the considerable potential of black arsenic in future opto- and nanoelectronic devices.

20.
Cureus ; 14(12): e32515, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36654572

RESUMEN

Background Severe postoperative pain and immobility increase the length of hospital stay and immobility-related life-threatening complications after total hip replacement (THR). Pericapsular nerve group (PENG) block is a recent addition to pain management of neck of femur (NoF) fracture, the use of which has been incorporated into THR as alternative analgesia or as an adjunct with other regional analgesia techniques. The present study primarily aims to assess postoperative mobility. Secondary outcomes measured were the length of hospital stay, pain score, opioid consumption, and side effects. Methods This is a retrospective study of 50 patients who underwent primary THR. Twenty-eight patients received PENG block after spinal anesthesia (PENG Group), seven patients had general anesthesia (GA) with patient-controlled analgesia (PCA) postoperatively (PCA Group), and the remaining 15 received spinal anesthesia with fascia iliaca block (FIB Group). Mobilization was attempted in all patients (ability to stand and walk a few steps with a walker) 10 hours after the end of surgery. Data was collected for average postoperative pain score, time of mobilization, total opioid consumption (till discharge from the hospital), opioid-related side effects, and time of discharge. Results Mobilization was attempted in all patients 10 hours after the end of the surgery, irrespective of their anesthetic technique. In the PENG Group, 26 patients (n=28) could be mobilized after the first 10 hours without opioids. The total morphine requirement until discharge was significantly less in the PENG Group of patients compared to the FIB and GA+PCA patients. The average time of discharge (hours) from the hospital (22.1+/-4.9) was also significantly lower in the PENG Group compared to all other groups (31.7 +/- 3.4, p=<0.01). The average postoperative pain score was significantly low in the PENG Group within the first 48 hours. Conclusion The PENG block helps in early mobilization and enhanced recovery after THR.

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