Micro-Extinction Spectroscopy (MExS): a versatile optical characterization technique

Micro-Extinction Spectroscopy (MExS), a flexible, optical, and spatial-scanning hyperspectral technique, has been developed and is described with examples. Software and hardware capabilities are described in detail, including transmission, reflectance, and scattering measurements. Each capability is demonstrated through a case study of nanomaterial characterization, i.e., transmission of transition metal dichalcogenides revealing transition energy and efficiency, reflectance of transition metal dichalcogenides grown on nontransparent substrates identifying the presence of monolayer following electrochemical ablation, and scattering to study single plasmonic nanoparticles and obtain values for the refractive index sensitivity and sensing figure of merit of over a hundred single particles with various shapes and sizes. With the growing integration of nanotechnology in many areas, MExS can be a powerful tool to both characterize and test nanomaterials

Structural and Optical Properties of Discrete Dendritic Pt Nanoparticles on Colloidal Au Nanoprisms.

Catalytic and optical properties can be coupled by combining different metals into nanoscale architectures in which both the shape and the composition provide fine-tuning of functionality. Here, discrete, small Pt nanoparticles (diameter = 3-6 nm) were grown in linear arrays on Au nanoprisms, and the resulting structures are shown to retain strong localized surface plasmon resonances. Multidimensional electron microscopy and spectroscopy techniques (energy-dispersive X-ray spectroscopy, electron tomography, and electron energy-loss spectroscopy) were used to unravel their local composition, three-dimensional morphology, growth patterns, and optical properties. The composition and tomographic analyses disclose otherwise ambiguous details of the Pt-decorated Au nanoprisms, revealing that both pseudospherical protrusions and dendritic Pt nanoparticles grow on all faces of the nanoprisms (the faceted or occasionally twisted morphologies of which are also revealed), and shed light on the alignment of the Pt nanoparticles. The electron energy-loss spectroscopy investigations show that the Au nanoprisms support multiple localized surface plasmon resonances despite the presence of pendant Pt nanoparticles. The plasmonic fields at the surface of the nanoprisms indeed extend into the Pt nanoparticles, opening possibilities for combined optical and catalytic applications. These insights pave the way toward comprehensive nanoengineering of multifunctional bimetallic nanostructures, with potential applications in plasmon-enhanced catalysis and in situ monitoring of chemical processes via surface-enhanced spectroscopy.R. K. L. acknowledges support from a Clare College Junior Research Fellowship. S. M. C. acknowledges support from a Gates Cambridge Scholarship. This work has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483-ESTEEM2 (Integrated Infrastructure Initiative-I3), and support from the European Research Council, Reference 291522 3DIMAGE. J. E. M. acknowledges support from the Research Corporation for Science Advancement.This is the author accepted manuscript. The final version is available from the American Chemical Society via http://dx.doi.org/10.1021/acs.jpcc.6b0210

Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

In Situ Optical Tracking of Electroablation in Two-Dimensional Transition-Metal Dichalcogenides.

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) are a unique class of 2D materials possessing unique optoelectronic properties when exfoliated into mono- and few-layer sheets. Recently, electroablation (EA) has become of interest as a promising synthesis method for single-layer sheets of TMDs. Here, we introduce spectroelectrochemical micro-extinction spectroscopy (SE-MExS) as a high-throughput technique to study electrochemical thinning of TMDs as it occurs. This approach enables the parallel use of spectroscopy and imaging to nondestructively characterize 2D materials in situ. We unravel optoelectronics of the TMDs by observing changes in optical properties during EA. We find that the EA process for MoS2, WS2, MoSe2, and WSe2 occurs edge first, generating high density of edge sites. Our results show that stable monolayers of MoS2, WS2, and MoSe2 can be synthesized from bulk precursors by the EA process, while conversely, no WSe2 remains postablation

In Situ Optical Tracking of Electroablation in Two-Dimensional Transition-Metal Dichalcogenides

Two-dimensional (2D) transition-metal dichalcogenides (TMDs) are a unique class of 2D materials possessing unique optoelectronic properties when exfoliated into mono- and few-layer sheets. Recently, electroablation (EA) has become of interest as a promising synthesis method for single-layer sheets of TMDs. Here, we introduce spectroelectrochemical micro-extinction spectroscopy (SE-MExS) as a high-throughput technique to study electrochemical thinning of TMDs as it occurs. This approach enables the parallel use of spectroscopy and imaging to nondestructively characterize 2D materials in situ. We unravel optoelectronics of the TMDs by observing changes in optical properties during EA. We find that the EA process for MoS2, WS2, MoSe2, and WSe2 occurs edge first, generating high density of edge sites. Our results show that stable monolayers of MoS2, WS2, and MoSe2 can be synthesized from bulk precursors by the EA process, while conversely, no WSe2 remains postablation

Oliguric and non-oliguric acute renal failure in malaria in west zone of rajasthan, India-A comparative study

Objective: To report a comparative clinical and histopathological study on oliguric and non-oliguric acute renal failure (ARF) in malaria. Method: 311 consecutive cases of malaria out of which 74 (23.79%) had ARF as per WHO criteria were conducted. Mean age was 32.58 (range 15–60 years) and male: female was 2:1. Result: Most of the cases developed ARF within 10 d of onset. 18 cases (11 falciparum, 2 mixed, 5 vivax) presented with oliguric and 56 (41 falciparum, 6 mixed, 9 vivax) with non-oliguric renal failure. Associated major manifestations were jaundice (75.68%), cerebral malaria (41.89%), bleeding manifestations (32.43%), severe anemia (27.03%), hypotension (25.68%), multi-organ failure (18.92%), severe thrombocytopenia (12.16%), and ARDS (8.11%). Kidney biopsy (n=20) showed acute tubular necrosis (n=7), Mesangioproliferative glomerulonephritis (n=4) or both (n=9). Hemodialysis was done in 8 cases of oliguric renal failure out of which 4 survived (average no. of session 2.9). Conclusion: Most of the cases recovered within 3 weeks. Total mortality was 28.38% (n=21) and mortality was more in oliguric renal failure (72.22%) as compare to non-oliguric renal failure (14.29%)

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Additional file 1. Additional figures

Clinical Profile and Prognostic Indicators in Adults Hospitalized with Severe Malaria Caused by Different Species

Introduction Severe malaria remains a major cause of death and morbidity among adults in the Asiatic tropics. This study was planned to evaluate clinical profile and prognostic indicators of severe malaria in adults so as to improve insight into this highly prevalent disease. Materials and Methods This prospective observational study was conducted on 60 confirmed cases of malaria. Cases were divided into two groups: (a) study group: suffering from severe malaria and (b) control group: no severe manifestations. All cases were thoroughly studied for clinical features, laboratory evaluation, and outcome. Prognostic evaluation was also done by different score systems. Results In all, 40 cases suffer from severe malaria (study group), while 20 cases belong to the control group. The majority of our cases were males of age 21–40 years. The most common species of malaria in the study group was vivax (52.5%), followed by falciparum (25%) and mixed malaria species (22.5%). The clinical predictors for severe malaria were rural habitat, longer duration of fever, marked chills, tiredness, giddiness, nausea, vomiting, decreased urine output, jaundice, and altered sensorium. Extreme weakness (80%), jaundice (55%), renal failure (50%), and severe anemia (27.5%) were the most common presenting features in severe malaria. Two patients died of severe mixed malaria. The mortality rate was significantly associated with lower hemoglobin level ( P = 0.002); higher total leukocyte count ( P = 0.006), blood urea ( P < 0.001), serum creatinine ( P < 0.001), SGOT ( P = 0.001), SGPT ( P < 0.007), serum bilirubin ( P = 0.003), and parasite density ( P = 0.033); lower platelet count ( P = 0.043); and those who had more APACHE II score ( P = 0.003), SOFA score ( P = 0.04), and Multiple Organ Dysfunction Score ( P < 0.001) and lower Glasgow Coma Scale ( P < 0.001). Conclusions Manifestations of severe malaria is becoming increasingly more prevalent specifically in vivax and mixed malaria cases. Our study proposes that there are certain clinical predictors and prognostic indicators that should be kept in mind for better management of severe malaria

From Newspaper Substrate to Nanotubes—Analysis of Carbonized Soot Grown on Kaolin Sized Newsprint

Herein, we report the successful use of newspaper as a substrate for the growth of single-walled carbon nanotubes (SWCNTs) by chemical vapor deposition (CVD) with intriguing results demonstrating that (a) the large surface area of newspaper stock allows for SWCNT growth and (b) only newspaper produced with kaolin clay sizing allowed for SWCNT growth. Kaolin newsprint was impregnated with Al2O3 and Fe(NO3)3&middot;9H2O (as precursors to FexOy nanoparticles), and calcined (30 min at 400 &deg;C). The subsequent char residue was loaded into a CVD chamber and used as a substrate for SWCNT growth at 750 &deg;C, using H2, C2H2, and water vapor as the growth gas. Samples of raw carbon soot exhibiting fluorescence spectra, indicative of SWCNTs, were further evaluated by resonant Raman spectroscopy, and by transmission electron microscopy (TEM). The calcinated substrate remnants were evaluated by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Experiments utilizing paper substrates produced with kaolin filler resulted in hybridized sp2&ndash;sp3 bonded carbon species. The soot was found to consist primarily of carbon nanotubes and bi-layer graphene in the form of collapsed nanotubes, also known as graphene nanoribbons (GNR)