Abstract
Monolayer transition metal dichalcogenides (TMD) have numerous potential applications in ultrathin electronics and photonics. The exposure of TMD-based devices to light generates ...photo-carriers resulting in an enhanced conductivity, which can be effectively used, e.g., in photodetectors. If the photo-enhanced conductivity persists after removal of the irradiation, the effect is known as persistent photoconductivity (PPC). Here we show that ultraviolet light (λ = 365 nm) exposure induces an extremely long-living giant PPC (GPPC) in monolayer MoS
2
(ML-MoS
2
) field-effect transistors (FET) with a time constant of ~30 days. Furthermore, this effect leads to a large enhancement of the conductivity up to a factor of 10
7
. In contrast to previous studies in which the origin of the PPC was attributed to extrinsic reasons such as trapped charges in the substrate or adsorbates, we show that the GPPC arises mainly from the intrinsic properties of ML-MoS
2
such as lattice defects that induce a large number of localized states in the forbidden gap. This finding is supported by a detailed experimental and theoretical study of the electric transport in TMD based FETs as well as by characterization of ML-MoS
2
with scanning tunneling spectroscopy, high-resolution transmission electron microscopy, and photoluminescence measurements. The obtained results provide a basis for the defect-based engineering of the electronic and optical properties of TMDs for device applications.
An audit of decompressive craniectomies Kapadia FN, Masurkar VikramA, Sankhe MS, Gursahani RD
Indian journal of critical care medicine,
01/2006, Letnik:
10, Številka:
1
Journal Article
Odprti dostop
Background: The management of acute intracranial hypertension
refractory, to the medical management, remains a challenging endeavour.
Mortality and morbidity rates remain high despite optimal medical
...management. Decompressive craniectomy has been proposed as an effective
treatment for patients who have raised intracranial pressure (ICP)
refractory, to the medical management. This study examined the outcome
of patients who underwent this procedure. Aim: To assess the outcome
of patients who underwent decompressive craniectomy. Materials and
Methods: We conducted a prospective audit of consecutive patients of
one neurosurgical unit, who underwent decompressive craniectomy at a
tertiary care centre between 01/01/2004 to 31/03/2005. A complete
neurological assessment, including Glasgow coma scale (GCS) and pupils
was done and recorded at the time of admission, deterioration, post-op
one wk and post-op three wks. End points were Glasgow outcome score
(GOS) and Karnofsky score at 30 days, at discharge and at 6 months.
Results: We studied 12 patients who were aged 30 to 69 yrs (Mean = 47
yrs). Unlike most interventions in critical care, survival is not an
acceptable single end point. Good recovery ( Karnofsky score ≥80
/ GOS≥4) was seen in five patients. Three patients were alive
with severe disability ( Karnofsky score 1-70 / GOS 2-3), at follow up.
Four patients died (Karnofsky score 0 / GOS 1). Conclusion: Eight
patients who underwent decompressive craniectomy survived. Five of
these patients had a good recovery. The other three survived with
severe disability.
Monolayer transition metal dichalcogenides (TMD) have numerous potential applications in ultrathin electronics and photonics. The exposure of TMD based devices to light generates photo-carriers ...resulting in an enhanced conductivity, which can be effectively used, e.g., in photodetectors. If the photo-enhanced conductivity persists after removal of the irradiation, the effect is known as persistent photoconductivity (PPC). Here we show that ultraviolet light (wavelength = 365 nm) exposure induces an extremely long-living giant PPC (GPPC) in monolayer MoS2 (ML-MoS2) field-effect transistors (FET) with a time constant of ~30 days. Furthermore, this effect leads to a large enhancement of the conductivity up to a factor of 107. In contrast to previous studies in which the origin of the PPC was attributed to extrinsic reasons such as trapped charges in the substrate or adsorbates, we unambiguously show that the GPPC arises mainly from the intrinsic properties of ML-MoS2 such as lattice defects that induce a large amount of localized states in the forbidden gap. This finding is supported by a detailed experimental and theoretical study of the electric transport in TMD based FETs as well as by characterization of ML-MoS2 with scanning tunneling spectroscopy, high-resolution transmission electron microscopy, and photoluminescence measurements. The obtained results provide a basis towards the defect-based engineering of the electronic and optical properties of TMDs for device applications.
Individually controlled conducting polymer tri-layer microactuators Jager, E. W. H.; Masurkar, N.; Nworah, N. F. ...
2013 Transducers & Eurosensors XXVII: The 17th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS & EUROSENSORS XXVII),
2013-June
Conference Proceeding
Odprti dostop
We are currently developing a range of microdevices based on polypyrrole (PPy) tri-layer microactuators that function in air. Here, we present recently developed microfabrication and patterning ...methods using photolithography for both thick, membrane and thin film poly(vinylidene difluoride) (PVDF) based PPy tri-layer actuators. We fabricated monolithically integrated, articulated actuator devices, i.e. comprising individually controllable actuators. We also introduce an interface for such PPy actuators based on a flexible printed circuit board, comprising the electrical contacts, into which the actuator device was inserted. Compartive evaluations showed that the microfabricated tri-layer actuators functioned as good as the normally fabricated actuators. The new interface seemed to actually improve the actuator performance.
This paper focuses on the automated extraction of textural features from segmented Sentinel-1A Synthetic Aperture Radar (SAR) imagery, which was captured on 25th August 2017. Textural properties play ...a pivotal role in discerning regions of interest in satellite imagery, essential for precise classification in diverse applications, including remote sensing, medical image analysis, biometric analysis, and document image analysis. To achieve this, the Local Adaptive Threshold (LAT) technique was employed for segmenting the foreground and background areas of the pre-processed vertical transmit-vertical receive (VV) polarized Sentinel-1A SAR data. The approach relies on second-order statistics, specifically co-occurrence measures, which evaluate the relationships between pairs of pixels within their local neighbourhood’s in the input image. Four fundamental second-order statistical measures, namely correlation, energy, homogeneity, and contrast, were computed using the Grey Level Co-occurrence Matrix (GLCM). The GLCM was generated by quantizing the foreground region of the segmented grey-scale image into different levels, including 8, 16, and 64 grey levels, considering two inter-pixel distances, d=1 and d=2, and adopting an omni-directional orientation (θ = 00, 450, 900, 1350).The results underscore the effectiveness of the GLCM-based approach in computing second-order statistical texture measures from the segmented SAR image. Notably, the findings highlight that quantizing the image to Ng=8 with d=1 and considering omni-directional statistical measures (θ = 00, 450, 900, 1350) significantly enhances performance.
Genetic diversity assessment and population structure analysis are essential for characterization of pathogens and their isolates. Markers are essential tools for exploring genetic variation among ...the isolates. False smut of rice caused by Ustilaginoidea virens, formerly Villosiclava virens, is a major emerging disease of rice in India. A high level of variability is observed at the field level, but no information is available from India on genetic diversity and population structure. This is the first report of genetic diversity and population structure of U. virens from India that included 63 isolates distributed across the vast geographical area of eastern and north‐eastern India (18.9 to 26.7°N and 82.6 to 94.2°E). Seventeen RAPDs and 14 SSRs were identified as polymorphic and a total of 140 alleles were detected across the populations. The average number of alleles per locus for each primer was 4.5. All the isolates were grouped into two major clusters, with partial geographical segregation that was supported by principal coordinate analysis. Mantel test suggested genetic distance within the isolates increased with increasing geographical distance. Analysis of molecular variation showed more genetic variation within populations and less among populations. This outcome will help in understanding genetic diversity of U. virens from eastern and north‐eastern India and in planning effective management strategies.
Genetic diversity studies of U. virens from India revealed two major groups. The molecular variation was associated fairly with geographical origin and observed more genetic disparity within population and less among populations.
Background: Fibrinolytic therapy has reduced mortality following acute
myocardial infarction (AMI) with the major effect coming from early
achievement of infarct-related artery patency. Aim: To ...evaluate the
door-to-needle time for fibrinolytic administration for AMI and to
identify factors associated with a prolonged door-to-needle time.
Materials and Methods: Our study was a prospective audit of patients
who were thrombolyzed for AMI at our hospital from July 1, 2004 to
March 15, 2005. All patients admitted with AMI, who were candidates for
fibrinolysis, were included. We recorded the door-to-needle time.
Whenever possible, we tried to find out the reason for prolonged
door-to-needle time. Results: A door-to-needle time of < 30 min
could be achieved in 19 of our 35 patients (54.28%). Mean
door-to-needle time was 45.25 min. Discussion: Although most
guidelines recommend a door-to-needle time of less than 30 min, most
hospitals fail to achieve this in most patients. A study conducted by
Zed et al. at the Vancouver General Hospital showed that a
door-to-needle time of less than 30 min was achieved in only 24.3%. The
door-to-needle time achieved at our center was shorter. In most of our
patients who were thrombolyzed late, a delay in taking or interpreting
an electrocardiogram was responsible. Transfer to the intensive care
unit for thrombolysis also resulted in considerable delay.
Conclusions: A door-to-needle time of less than 30 mins could be
achieved in 19 of our 35 patients (54.28%). A significant number of AMI
patients thrombolyzed did not meet the guideline for door-to-needle
time of less than 30 min.
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