Aging and brain free cholesterol concentration on amyloid-β peptide accumulation in guinea pigs

Alzheimer's disease is a complex multifactorial neurodegenerative disorder wherein age is a major risk factor. The appropriateness of the Hartley guinea pig (GP), which displays high sequence homologies of its amyloid-β (Aβ40 and Aβ42) peptides, Mdr1 and APP (amyloid precursor protein) and similarity in lipid handling to humans, was appraised among 9-40 weeks old guinea pigs. Protein expression levels of P-gp (Abcb1) and Cyp46a1 (24(S)-hydroxylase) for Aβ40, and Aβ42 efflux and cholesterol metabolism, respectively, were decreased with age, whereas those for Lrp1 (low-density lipoprotein receptor related protein 1), Rage (receptor for advanced glycation endproducts) for Aβ efflux and influx, respectively, and Abca1 (the ATP binding cassette subfamily A member 1) for cholesterol efflux, were unchanged among the ages examined. There was a strong, negative correlation of the brain Aβ peptide concentrations and Abca1 protein expression levels with free cholesterol. The correlation of Aβ peptide concentrations with Cyp46a1 was, however, not significant, and concentrations of the 24(S)-hydroxycholesterol metabolite revealed a decreasing trend from 20 weeks old toward 40 weeks old guinea pigs. The composite data suggest a role for free cholesterol on brain Aβ accumulation. The decreases in P-gp and Lrp1 protein levels should further exacerbate the accumulation of Aβ peptides in guinea pig brain.

[Visualization analysis of research hotspots in pathogenesis of diabetic nephropathy in China]

The aim of this study is to analyze the research hotspots and development trends in the field of pathogenesis of diabetic nephropathy in China from 2013 to 2022. Based on China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform, China Science and Technology Journal Database, China Biology Medicine disc, Web of Science core collection and PubMed database, the related literatures in the field of pathogenesis of diabetic nephropathy in China from 2013 to 2022, were retrieved to establish the database, and the VOSviewer software was used for bibliometric analysis. A total of 1 664 Chinese and 2 149 English literatures are included in this study. The scientific research results from 2013 to 2022 have shown an overall increasing trend. The research hotspots in the field of pathogenesis of diabetic nephropathy in China are mainly concentrated in Podocytes, Oxidative stress, Inflammation, Renal fibrosis, Urine protein, etc. The frontier hotspots in this field include Biomarkers, Nrf2, Gut microbiota, NLRP3 inflammasome, Apoptosis, MicroRNA, etc. Through visual analysis, the research hotspots and frontier trends of the pathogenesis of diabetic nephropathy in China can be visually presented, and then provide new ideas and directions for the further in-depth research on the pathogenesis of diabetic nephropathy.

Estimation of broadband emissivity (8-12 um) from ASTER data by using RM-NN

Land surface window emissivity is a key parameter for estimating the longwave radiative budget. The combined radiative transfer model (RM) with neural network (NN) algorithm is utilized to directly estimate the window (8-12 um) emissivity from the brightness temperature of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with 90 m spatial resolution. Although the estimation accuracy is very high when the broadband emissivity is estimated from AST05 (ASTER Standard Data Product) by using regression method, the accuracy of AST05 is about ± 0.015 for 86 spectra which is determined by the atmosphere correction for ASTER 1B data. The MODTRAN 4 is used to simulate the process of radiance transfer, and the broadband emissivity is directly estimated from the brightness temperature of ASTER 1B data at satellite. The comparison analysis indicates that the RM-NN is more competent to estimate broadband emissivity than other method when the brightness temperatures of band 11, 12, 13, 14 are made as input nodes of dynamic neural network. The estimation average accuracy is about 0.009, and the estimation results are not sensitive to instrument noise. The RM-NN is applied to extract broadband emissivity from an image of ASTER 1B data in China, and the comparison against a classification based multiple bands with 15 m spatial resolution shows that the estimation results from RM-NN are very good.

Effects of dielectric values of human body on Specific Absorption Rate (SAR) following 800 MHz radio frequency exposure to ingestible wireless device

In order to assess the compliance of Ingested Wireless Device (IWD) within safety guidelines, the Specific Absorption Rate (SAR) and near fields of IWD in two realistic human body models whose dielectric values are increased from the original by +/-10 and +/-20% are studied using the Finite-Difference Time-Domain (FDTD) method. The radiation characteristics of the IWD in the human body models with original and changed dielectric values are compared. Simulations are carried out at 13 scenarios where the IWD is placed at center positions of abdomens in the two models at the operation frequency of 800 MHz. Results show that variation of radiation intensity near the surface of abdomen is around 1.6 dB within 20% variation of dielectric values at the frequency of 800 MHz. Electric fields in the anterior of the human body models are higher than those in the posterior for all scenarios. SAR values increase as the conductivities of human body tissues increase and usually decrease as the increase of relative permittivities of human body tissues increase. The effect of the dielectric values of human body on SAR is orientation, human body and frequency dependent. An increment up to 20% in conductivities and relative permittivities alone or simultaneously always causes a SAR variation less than 20%. As far as the compliance of safety was concerned, the IWD was safe to be used at the input power less than 9.3 mW according to IEEE safety standards.

[The importance of prophylactic fluorographic studies for the timely diagnosis of lung diseases]

Analysis of the results of fluorographic screening of the population in the city of Kiev and Zaporozhye region suggests unadvisability of carrying out mass chest X-rays examination if the tuberculosis morbidity is less than 30 per 100,000. Also, prophylactic fluorography of the population being performed once in 2-3 years fails to ensure timely diagnosis of bronchitis, bronchiectasis and lung cancer.

[The antitryptic activity of the blood in pulmonary tuberculosis patients who smoke tobacco]

The general activity of the antitryptic system of the blood was studied in 60 practically healthy persons and in 65 patients with active tuberculosis. A group of tobacco smokers (5 years, 6-10 years) was singled out. It was established that tobacco smoking and pulmonary tuberculosis was accompanied by activation of the antitryptic system which should be considered as a peculiar defensive reaction of the body to increase of the proteolytic activity of enzymes in the lungs. In persons that have been smoking from 6 to 10 years there was a reduction of the general antitryptic activity which can further the development of dystrophic changes in the pulmonary parenchyma and produce an unfavourable effect on the course of specific inflammation.