Unexplained Syncope: The Importance of the Electrophysiology Study

Syncope of cardiac origin may be associated with an increased risk of sudden cardiac death if not treated in a timely and appropriate manner. The diagnostic approach of syncope imposes a significant economic burden on society. The investigation and elucidation of the pathogenetic mechanism of syncope are of great clinical importance, as both prognosis and appropriate therapeutic approaches depend on these factors. The responsible mechanism of presyncope or syncope can only be revealed through the patient history, baseline clinical examination and electrocardiogram. The percentage of patients who are diagnosed with these tests alone exceeds 50%. In patients with a history of organic or acquired heart disease or/and the presence of abnormal findings on the electrocardiogram, a further diagnostic electrophysiology inclusive approach should be followed to exclude life threatening arrhythmiological mechanism. However, if the patient does not suffer from underlying heart disease and does not show abnormal electrocardiographic findings in the electrocardiogram, then the probability in the electrophysiology study to find a responsible cause is small but not absent. The role of a two-step electrophysiology study inclusive risk stratification approach for the effective management of the former is thoroughly discussed in this review.

Glaucoma following Infant Lensectomy: 2021 Update

Purpose To review information pertaining to glaucoma following infant lensectomy surgery and to provide evidence to support the responsible mechanism of this condition. Methods and Results Described risk factors and proposed mechanisms for infantile aphakic glaucoma were assessed. The clinical evidence observed in affected glaucoma patients was analyzed, and evidence of postoperative anterior chamber fibrosis was reviewed and interpreted. Conclusion The review and assessment of laboratory and clinical evidence support the proposal that infantile aphakic glaucoma is caused, in part, by postoperative anterior chamber fibroization related to lens cell dispersion and active epithelial-mesenchymal transition with resultant filtration angle tissue injury and loss of function.

Influence of Chronic Ocular Hypertension on Emmetropia: Refractive, Structural and Functional Study in Two Rat Models

Chronic ocular hypertension (OHT) influences on refraction in youth and causes glaucoma in adulthood. However, the origin of the responsible mechanism is unclear. This study analyzes the effect of mild-moderate chronic OHT on refraction and neuroretina (structure and function) in young-adult Long-Evans rats using optical coherence tomography and electroretinography over 24 weeks. Data from 260 eyes were retrospectively analyzed in two cohorts: an ocular normotension (ONT) cohort (<20 mmHg) and an OHT cohort (>20 mmHg), in which OHT was induced either by sclerosing the episcleral veins (ES group) or by injecting microspheres into the anterior chamber. A trend toward emmetropia was found in both cohorts over time, though it was more pronounced in the OHT cohort (p < 0.001), especially in the ES group (p = 0.001) and males. IOP and refraction were negatively correlated at week 24 (p = 0.010). The OHT cohort showed early thickening in outer retinal sectors (p < 0.050) and the retinal nerve fiber layer, which later thinned. Electroretinography demonstrated early supranormal amplitudes and faster latencies that later declined. Chronic OHT accelerates emmetropia in Long–Evans rat eyes towards slowly progressive myopia, with an initial increase in structure and function that reversed over time.

Enhanced Photocatalytic Activity and Magnetic Properties of CNTs/Sn-doped Co3O4 Nanocomposite

Photocatalysis is a green technology which transforms available photon energy into useful chemical energy. The reaction mechanism is based on the ability to create electron-hole pairs under appropriate light. Semiconductors have attracted great attention in photocatalysts because of their high photosensitivity. Spinel–type cobalt oxide nanorods have been prepared by a simple hydrothermal method using cobalt nitrate as precursor. Sn-doped Co3O4 was composited with carbon nanotubes for better photocatalytic activity. An extensive characterization of the prepared samples was carried out using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Vibrating sample magnetometer (VSM) and UV–Visible absorption spectroscopy. The XRD results show the formation of Co3O4 phase with FCC structure, FESEM confirms the nanorods morphology of the cobalt oxide and the VSM taken at room temperature shows an antiferromagnetic behavior. The investigation of photocatalytic activity of Co3O4 based was done by methyl orange dye. At the end, the responsible mechanism of CNT/Sn-CO was discussed.

A Brief Study of Physical Properties of Rf Magnetron Sputtered Azo Thin Films

We reported the physical properties of undoped and Aluminium doped ZnO (AZO) thin films that were synthesized by the RF magnetron sputtering method on a quartz substrate. The effect of dopant concentration on structure, morphology, optical and electrical properties of the thin films have been studied systematically by XRD, Raman spectroscopy, AFM, FE-SEM, UV-VIS spectroscopy and I-V measurement (two probe method) respectively. The crystallite growth of the thin films is along c-axis (002) orientations with hexagonal wurtzite structure. The crystallinity is enhanced in the 1%AZO thin films as compared to undoped ZnO. The transition of stress value after introducing the dopant is discussed. These changes are further correlated with the observed morphological changes. The alteration in optical transmission and optical band gap is also discussed extensively. For the AZO (1% and 2%) thin films the n-type conductivity and ohmic nature measured by using Keithley two probe set up. The responsible mechanism for improved conductivity is discussed. In the FTIR spectrum the peaks originated by the tetrahedral coordination of ZnO are observed which further confirms the wurtzite structure of the deposited thin film sample that are recorded by the XRD pattern.

Control of kinetics of plasma assisted nitriding process of Ni-base alloys by substrate roughness

The present study investigated the effect of surface roughness on plasma assisted nitriding (PAN) process kinetics of Ni-base alloys. Two model alloys, namely Ni-10Cr and Ni-14Cr-4Al (wt.%) and commercial Rene 80, were examined. To elucidate the effect of surface roughness on nitriding kinetics, three methods of surface preparation were used, (1) polishing up with 1 μm diamond suspension, (2) grinding up to 220 grit sand-paper, and (3)grit blasting. The samples from each type of material were nitrided under the same conditions and investigated after processing. It was found that increase in roughness results in decreasing nitriding kinetics. The decrease of nitriding kinetics depends on alloy chemical composition, namely more complex chemistry resulted in smaller decrease of kinetics. Moreover, grit-blasting was found to be an improper method for surface preparation for PAN. The responsible mechanism for the effect of surface roughness on PAN kinetics of Ni-base alloys was proposed.

Periodic modulation of the upper ionosphere by ULF waves as observed by SuperDARN radars and GPS/TEC technique

&lt;p&gt;We compare the simultaneous magnetometer, SuperDARN radar, and GPS observations during Pc5 wave event on March 02, 2002. A possible correspondence between those instruments may help to determine the mechanism of the ionosphere modulation by magnetospheric disturbances. Transient Pc5 pulsations (2.6 mHz) in the morning sector, stimulated by the solar wind density jumps, have been detected simultaneously by ground magnetometers and the Kodiak and King Salmon SuperDARN radars.&amp;#160; Besides that, pulsations with the same periodicity have been found in the rate of total electron content (TEC), dTEC/dt (ROT), variations in several GPS radio paths. The ratio between the spectral amplitudes of the Doppler velocities and magnetic pulsations (X component) on the ground are Vx/Bx~7-12 (m/s)/nT and Vy/Bx~27 (m/s)/nT. The ratio between the oscillation amplitudes of ROT and ionospheric Doppler meridional (Vx) and azimuthal (Vy) velocities are ROT/Vx~0.02-0.07 (dTECu/min)/(m/s) and ROT/Vy~0.004 (dTECu/min)/(m/s). The correspondence between simultaneous periodic variations of the ionospheric Doppler velocity and geomagnetic field can be reasonably well interpreted quantitively on the basis of theory of Alfven wave interaction with the thin ionospheric layer. However, order-of-magnitudes estimates of possible TEC modulation mechanisms show that a responsible mechanism which can interpret the observed ratios has not been found yet.&amp;#160;&lt;/p&gt;

LocusFocus: A web-based colocalization tool for the annotation and functional follow-up of GWAS

Genome-wide association studies (GWAS) have primarily identified trait-associated loci in the non-coding genome. Colocalization analyses of SNP-level associations from GWAS with expression quantitative trait loci (eQTL) evidence enable the generation of hypotheses about responsible mechanism, genes and tissues of origin to guide functional characterization. Here, we present a web-based colocalization browsing and testing tool named LocusFocus (https://locusfocus.research.sickkids.ca). LocusFocus formally tests colocalization using our established Simple Sum method to identify the most relevant genes and tissues for a particular GWAS locus in the presence of high linkage disequilibrium and/or allelic heterogeneity. Full documentation and source code for LocusFocus are publicly available.

Application of Soret Effect in Optimum Desalination Process

The ocean makes up 70 percent of the earth’s surface and accounts for 96 percent of the water on the planet. Unfortunately this water cannott be consumed. It is s oversaturated with salt. Desalination is the process of turning salty ocean water into drinking water. With 783 million people lacking access to clean water and more areas facing severe droughts, desalination can be the answer of this problem. But like other ajor industrial processes, desalination has environental impacts that must be understood and mitigated. The effects on the marine environment associated with the construction and long-term operation of seawater desalination plants, including withdrawing water from the ocean and discharging the highly concentrated brine. With that disadvantages a more optimum and environmentally responsible mechanism is needed to supply clean water.

Sorption Mechanism and Performance of Peat Soil Humin for Methylene Blue and p-Nitrophenol

The responsible mechanism and performance of peat soil humin for the sorption of methylene blue (MB) and p-nitrophenol (p-NP) have been investigated. Humin was obtained from peat soil of Siantan, West Kalimantan, Indonesia, after removing the content of humic and fulvic acids into a NaOH solution using the recommended procedure of International Humic Substances Society (IHSS). The obtained humin was then purified by rigorous stirring in a mixed solution of HCl 0.1 M and HF 0.3 M. Ash content in humin after the purification abruptly decreased from 36.84 to 1.26 wt.% indicating that minerals and other inorganic impurities were mostly removed. Phenolic –OH and carboxyl (–COOH) functional groups contributing to the acidity of humin were in the level of 3.44 and 2.10 mmol/g, respectively. At optimum medium pH of 6.20 for MB and 7.00 for p-NP, –COO– as the deprotonated product of –COOH was the most responsible active site in sorbing MB and p-NP through electrostatic interaction and hydrogen bonding, respectively. The homogeneity of –COO– as the active site for the sorption of MB and p-NP implied that the surface of humin sorbent was energetically uniform and thereby the sorption of both MB and p-NP followed better the Langmuir than the Freundlich isotherm model with sorption capacity of 0.19 and 0.26 mmol/g and sorption energy of 32.92 and 27.27 kJ/mol, respectively.