Bridge’s Overall Structural Scheme Analysis in High Seismic Risk Permafrost Regions

The mechanism of pile-soil reaction in frozen ground is not clear at present, but it is obvious that the reduction of dead weight will be beneficial to the seismic resistance of bridges. In view of the limited bridge engineering practice in high seismic risk permafrost regions, the paper addressed the structural performance of the superstructure and its effect on piles in these special regions. Four superstructures with different dead weights were compared, and bored piles were designed. Numerical simulations were implemented to investigate the refreezing time of the bored pile foundation. The concrete pile cooled rapidly in the first two days. The refreezing times of the GFRP, prestressed concrete T-girder, integrated composite girder, and MVFT girder were 15d, 37d, 39d, and 179d, respectively. The refreezing time of a pile in the same soil layer is mainly affected by the pile’s diameter, and it is significantly correlated to the square of the pile diameter. It reflects that the selection of bridge superstructures in the permafrost region is very important, which has been ignored in previous studies. The pile length and pile diameter of the lighter superstructure can be shorter and smaller to reduce the refreezing time and alleviate the thermal disturbance. Doi: 10.28991/CEJ-2022-08-07-01 Full Text: PD

Attenuation of doxorubicin-induced cardiac injury by mitochondrial glutaredoxin 2

AbstractWhile the cardiotoxicity of doxorubicin (DOX) is known to be partly mediated through the generation of reactive oxygen species (ROS), the biochemical mechanisms by which ROS damage cardiomyocytes remain to be determined. This study investigates whether S-glutathionylation of mitochondrial proteins plays a role in DOX-induced myocardial injury using a line of transgenic mice expressing the human mitochondrial glutaredoxin 2 (Glrx2), a thiotransferase catalyzing the reduction as well as formation of protein–glutathione mixed disulfides, in cardiomyocytes. The total glutaredoxin (Glrx) activity was increased by 76% and 53 fold in homogenates of whole heart and isolated heart mitochondria of Glrx2 transgenic mice, respectively, compared to those of nontransgenic mice. The expression of other antioxidant enzymes, with the exception of glutaredoxin 1, was unaltered. Overexpression of Glrx2 completely prevents DOX-induced decreases in NAD- and FAD-linked state 3 respiration and respiratory control ratio (RCR) in heart mitochondria at days 1 and 5 of treatment. The extent of DOX-induced decline in left ventricular function and release of creatine kinase into circulation at day 5 of treatment was also greatly attenuated in Glrx2 transgenic mice. Further studies revealed that heart mitochondria overexpressing Glrx2 released less cytochrome c than did controls in response to treatment with tBid or a peptide encompassing the BH3 domain of Bid. Development of tolerance to DOX toxicity in transgenic mice is also associated with an increase in protein S-glutathionylation in heart mitochondria. Taken together, these results imply that S-glutathionylation of heart mitochondrial proteins plays a role in preventing DOX-induced cardiac injury

Attenuation of Doxorubicin-Induced Cardiac Injury by Mitochondrial Glutaredoxin 2

While the cardiotoxicity of doxorubicin (DOX) is known to be partly mediated through the generation of reactive oxygen species (ROS), the biochemical mechanisms by which ROS damage cardiomyocytes remain to be determined. This study investigates whether S-glutathionylation of mitochondrial proteins plays a role in DOX-induced myocardial injury using a line of transgenic mice expressing the human mitochondrial glutaredoxin 2 (Glrx2), a thiotransferase catalyzing the reduction as well as formation of protein–glutathione mixed disulfides, in cardiomyocytes. The total glutaredoxin (Glrx) activity was increased by 76% and 53 fold in homogenates of whole heart and isolated heart mitochondria of Glrx2 transgenic mice, respectively, compared to those of nontransgenic mice. The expression of other antioxidant enzymes, with the exception of glutaredoxin 1, was unaltered. Overexpression of Glrx2 completely prevents DOX-induced decreases in NAD- and FAD-linked state 3 respiration and respiratory control ratio (RCR) in heart mitochondria at days 1 and 5 of treatment. The extent of DOX-induced decline in left ventricular function and release of creatine kinase into circulation at day 5 of treatment was also greatly attenuated in Glrx2 transgenic mice. Further studies revealed that heart mitochondria overexpressing Glrx2 released less cytochrome c than did controls in response to treatment with tBid or a peptide encompassing the BH3 domain of Bid. Development of tolerance to DOX toxicity in transgenic mice is also associated with an increase in protein S-glutathionylation in heart mitochondria. Taken together, these results imply that S-glutathionylation of heart mitochondrial proteins plays a role in preventing DOX-induced cardiac injury

Label-free microfluidic paper-based electrochemical aptasensor for ultrasensitive and simultaneous multiplexed detection of cancer biomarkers

Simultaneous detection of multiple tumor biomarkers in body fluids could facilitate early diagnosis of lung cancer, so as to provide scientific reference for clinical treatment. This paper depicted a multi-parameter paper-based electrochemical aptasensor for simultaneous detection of carcinoembryonic antigen (CEA) and neuron-specific enolase (NSE) in a clinical sample with high sensitivity and specificity. The paper-based device was fabricated through wax printing and screen-printing, which enabled functions of sample filtration and sample auto injection. Amino functional graphene (NG)-Thionin (THI)- gold nanoparticles (AuNPs) and Prussian blue (PB)- poly (3,4- ethylenedioxythiophene) (PEDOT)- AuNPs nanocomposites were synthesized respectively. They were used to modify the working electrodes not only for promoting the electron transfer rate, but also for immobilization of the CEA and NSE aptamers. A label-free electrochemical method was adopted, enabling a rapid simple point-of-care testing. Experimental results showed that the proposed multi-parameter aptasensor exhibited good linearity in ranges of 0.01-500 ng mL for CEA (R  = 0.989) and 0.05-500 ng mL for NSE (R  = 0.944), respectively. The limit of detection (LOD) was 2 pg mL for CEA and 10 pg mL for NSE. In addition, the device was evaluated using clinical serum samples and received a good correlation with large electrochemical luminescence (ECL) equipment, which would offer a new platform for early cancer diagnostics, especially in those resource-limit areas

Harmonic-seeded remote laser emissions in N2-Ar, N2-Xe and N2-Ne mixtures: a comparative study

We report on the investigation on harmonic-seeded remote laser emissions at 391 nm wavelength from strong-field ionized nitrogen molecules in three different gas mixtures, i.e., N2-Ar, N2-Xe and N2-Ne. We observed a decrease in the remote laser intensity in the N2-Xe mixture because of the decreased clamped intensity in the filament; whereas in the N2-Ne mixture, the remote laser intensity slightly increases because of the increased clamped intensity within the filament. Remarkably, although the clamped intensity in the filament remains nearly unchanged in the N2-Ar mixture because of the similar ionization potentials of N2 and Ar, a significant enhancement of the lasing emission is realized in the N2-Ar mixture. The enhancement is attributed to the stronger third harmonic seed, and longer gain medium due to the extended filament.Comment: 10 pages, 5 figure

Low sample volume origami-paper-based graphene-modified aptasensors for label-free electrochemical detection of cancer biomarker-EGFR

In this work, an electrochemical paper-based aptasensor was fabricated for label-free and ultrasensitive detection of epidermal growth factor receptor (EGFR) by employing anti-EGFR aptamers as the bio-recognition element. The device used the concept of paper-folding, or origami, to serve as a valve between sample introduction and detection, so reducing sampling volumes and improving operation convenience. Amino-functionalized graphene (NH2-GO)/thionine (THI)/gold particle (AuNP) nanocomposites were used to modify the working electrode not only to generate the electrochemical signals, but also to provide an environment conducive to aptamer immobilization. Electrochemical characterization revealed that the formation of an insulating aptamer–antigen immunocomplex would hinder electron transfer from the sample medium to the working electrode, thus resulting in a lower signal. The experimental results showed that the proposed aptasensor exhibited a linear range from 0.05 to 200 ngmL−1 (R2 = 0.989) and a detection limit of 5 pgmL−1 for EGFR. The analytical reliability of the proposed paper-based aptasensor was further investigated by analyzing serum samples, showing good agreement with the gold-standard enzyme-linked immunosorbent assa

Comparison of curative effect between OBS assisted by 3D printing and PFNA in the treatment of AO/OTA type 31-A3 femoral intertrochanteric fractures in elderly patients

ObjectiveTo compare and analyze the Ortho-Bridge System (OBS) clinical efficacy assisted by 3D printing and proximal femoral nail anti-rotation (PFNA) of AO/OTA type 31-A3 femoral intertrochanteric fractures in elderly patients.MethodsA retrospective analysis of 25 elderly patients diagnosed with AO/OTA type 31-A3 femoral intertrochanteric fracture was conducted from January 2020 to August 2022 at Yan’an Hospital, affiliated to Kunming Medical University. The patients were divided into 10 patients in the OBS group and 15 in the PFNA group according to different surgical methods. The OBS group reconstructed the bone models and designed the guide plate by computer before the operation, imported the data of the guide plate and bone models into a stereolithography apparatus (SLA) 3D printer, and printed them using photosensitive resin, thus obtaining the physical object, then simulating the operation and finally applying the guide plate to assist OBS to complete the operation; the PFNA group was treated by proximal femoral nail anti-rotation. The operation time, the intraoperative blood loss, Harris hip score (HHS), Oxford Hip Score (OHS), and complications were compared between the two groups.ResultsThe operation time and the intraoperative blood loss in the PFNA group were less than that in the OBS group, and there was a significant difference between the two groups (P < 0.05). The HHS during the 6th month using OBS was statistically higher than PFNA (P < 0.05), however, there were no significant differences in OHS during the 6th month between the OBS group and PFNA group (P > 0.05). The HHS and OHS during the 12th month in the OBS group were statistically better than in the PFNA group (P < 0.05).ConclusionThe OBS assisted by 3D printing and PFNA are effective measures for treating intertrochanteric fractures. Prior to making any decisions regarding internal fixation, it is crucial to evaluate the distinct circumstances of each patient thoroughly

Attenuation of doxorubicin-induced cardiac injury by mitochondrial glutaredoxin

While the cardiotoxicity of doxorubicin (DOX) is known to be partly mediated through the generation of reactive oxygen species (ROS), the biochemical mechanisms by which ROS damage cardiomyocytes remain to be determined. This study investigates whether S-glutathionylation of mitochondrial proteins plays a role in DOX-induced myocardial injury using a line of transgenic mice expressing the human mitochondrial glutaredoxin 2 (Glrx2), a thiotransferase catalyzing the reduction as well as formation of protein–glutathione mixed disulfides, in cardiomyocytes. The total glutaredoxin (Glrx) activity was increased by 76% and 53 fold in homogenates of whole heart and isolated heart mitochondria of Glrx2 transgenic mice, respectively, compared to those of nontransgenic mice. The expression of other antioxidant enzymes, with the exception of glutaredoxin 1, was unaltered. Overexpression of Glrx2 completely prevents DOX-induced decreases in NAD- and FAD-linked state 3 respiration and respiratory control ratio (RCR) in heart mitochondria at days 1 and 5 of treatment. The extent of DOX-induced decline in left ventricular function and release of creatine kinase into circulation at day 5 of treatment was also greatly attenuated in Glrx2 transgenic mice. Further studies revealed that heart mitochondria overexpressing Glrx2 released less cytochrome c than did controls in response to treatment with tBid or a peptide encompassing the BH3 domain of Bid. Development of tolerance to DOX toxicity in transgenic mice is also associated with an increase in protein S-glutathionylation in heart mitochondria. Taken together, these results imply that S-glutathionylation of heart mitochondrial proteins plays a role in preventing DOX-induced cardiac injury

Numerical Study of the Influence of Secondary Air Uniformity on Jet Penetration and Gas-Solid Diffusion Characteristics in a Large-Scale CFB Boiler

The uniformity of secondary air (SA) in large-scale CFB boilers has an important influence on gas-solid flow and combustion, but was seldom considered in previous studies. Numerical simulation based on the Eulerian–Eulerian and RNG k-ε turbulence models was conducted to explore the influence of SA uniformity and load variation on jet penetration, diffusion characteristics and gas-solid mixing in the first 600 MW supercritical CFB boiler. The results showed that better SA uniformity was conductive to the uniformity of SA penetration and gas-solid mixing along the furnace height, although the penetration depth and diffusion distance showed an opposite trend. In addition, the penetration depth and diffusion distance got enhanced with higher boiler load. The inner and outer SA jets could not cover the furnace width, and the uneven SA uniformity led to a huge deviation of the solid concentration within 10 m of the air distributor. Eventually, a calculation model was successfully established for predicting the penetration depth of inclined thermal SA jets during boiler operation

Photodynamic Therapy of Up-Conversion Nanomaterial Doped with Gold Nanoparticles

Two key concerns exist in contemporary cancer chemotherapy: limited therapeutic efficiency and substantial side effects in patients. In recent years, researchers have been investigating the revolutionary cancer treatment techniques of photodynamic therapy (PDT) and photothermal therapy (PTT) proposed by many scholars. A photothermal treatment of cancer was synthesized using the hydrothermal method which has high photothermal conversion efficiency and can generate reactive oxygen species (ROS) in cells. Photothermal treatment of tumors has a good short-term effect and photodynamic therapy lasts longer. However, both PTT and PDT have their inevitable shortcomings and it is difficult to completely eradicate a tumor using a single mode of treatment. PTT and PDT synergistic treatment not only inherits the advantages of low toxicity and side effects of phototherapy but also enables the two treatment methods to complement each other. It is an effective strategy to improve curative effects and reduce toxic and side effects. Furthermore, gold doped UCNPs have an exceptionally high target recognition for tumor cells. The gold doped UCNPs, in particular, are non-toxic to normal tissues, endowing the as-prepared medications with outstanding therapeutic efficacy and exceptionally low side effects. These findings may encourage the creation of fresh, effective imaging-guided approaches to meet the goal of photothermal cancer therapy