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Chemical Science May 2021Clean and sustainable electrochemical energy storage has attracted extensive attention. It remains a great challenge to achieve next-generation rechargeable battery... (Review)
Review
Clean and sustainable electrochemical energy storage has attracted extensive attention. It remains a great challenge to achieve next-generation rechargeable battery systems with high energy density, good rate capability, excellent cycling stability, efficient active material utilization, and high coulombic efficiency. Many catalysts have been explored to promote electrochemical reactions during the charge and discharge process. Among reported catalysts, single-atom catalysts (SACs) have attracted extensive attention due to their maximum atom utilization efficiency, homogenous active centres, and unique reaction mechanisms. In this perspective, we summarize the recent advances of the synthesis methods for SACs and highlight the recent progress of SACs for a new generation of rechargeable batteries, including lithium/sodium metal batteries, lithium/sodium-sulfur batteries, lithium-oxygen batteries, and zinc-air batteries. The challenges and perspectives for the future development of SACs are discussed to shed light on the future research of SACs for boosting the performances of rechargeable batteries.
PubMed: 34168819
DOI: 10.1039/d1sc00716e -
Open Access Macedonian Journal of... Dec 2015Lamivudine is a nucleoside analogue antiretroviral drug, known for its low toxicity at clinically prescribed dose. However, the toxicity or mechanism of toxicity and...
BACKGROUND
Lamivudine is a nucleoside analogue antiretroviral drug, known for its low toxicity at clinically prescribed dose. However, the toxicity or mechanism of toxicity and target tissue effects during prolonged administration of higher doses were hardly given sufficient laboratory attention.
AIM
The present work was designed to investigate the biochemical and histopathological changes in the liver of rat administered with prolonged doses of lamivudine.
MATERIAL AND METHODS
Lamivudine in multiple doses of five ranging from 4 mg/kg to 2500 mg/kg were administered, in vitro, by injection into the air-sac of 10-day old fertile embryonated eggs of Gallus domesticus. Also, female rats of the Wistar strain received oral doses, up to 500 mg/kg singly or repeatedly for 15 or 45 days, respectively. Spectrophotometric techniques were employed to monitor activities of the aminotransferases (ALT and AST), γ-glutamyltransferase (GGT) and total protein concentration in serum while activities of glutathione S-transferase (GST), GGT and superoxide dismutase (SOD) as well as concentrations of malondialdehyde (MDA) and protein were determined in liver. Histopathological studies were carried out on liver. Data were analysed using ANOVA and were considered significant when p < 0.05.
RESULTS
The LD50 for the drug calculated from the incubation experiment was 427 mg/kg. Total serum protein concentration significantly reduced while enzymes activities significantly increased at 500 mg/kg only among the repeat-dosed rats. Hepatic GGT, GST and SOD activities as well as MDA concentration were significantly elevated at 20 mg/kg. Histopathological studies showed multifocal lymphoid cell population in the liver sinusoid of the chicken and hydropic degeneration of hepatocytes were recorded among rats repeatedly exposed to the drug respectively at doses ≥ 100 mg/kg.
CONCLUSION
Lamivudine toxicity in rat liver appeared to be mediated by oxidative stress.
PubMed: 27275285
DOI: 10.3889/oamjms.2015.110 -
Neurology Jan 2023Declines in stroke admission, IV thrombolysis (IVT), and mechanical thrombectomy volumes were reported during the first wave of the COVID-19 pandemic. There is a paucity...
BACKGROUND AND OBJECTIVES
Declines in stroke admission, IV thrombolysis (IVT), and mechanical thrombectomy volumes were reported during the first wave of the COVID-19 pandemic. There is a paucity of data on the longer-term effect of the pandemic on stroke volumes over the course of a year and through the second wave of the pandemic. We sought to measure the effect of the COVID-19 pandemic on the volumes of stroke admissions, intracranial hemorrhage (ICH), IVT, and mechanical thrombectomy over a 1-year period at the onset of the pandemic (March 1, 2020, to February 28, 2021) compared with the immediately preceding year (March 1, 2019, to February 29, 2020).
METHODS
We conducted a longitudinal retrospective study across 6 continents, 56 countries, and 275 stroke centers. We collected volume data for COVID-19 admissions and 4 stroke metrics: ischemic stroke admissions, ICH admissions, IVT treatments, and mechanical thrombectomy procedures. Diagnoses were identified by their codes or classifications in stroke databases.
RESULTS
There were 148,895 stroke admissions in the 1 year immediately before compared with 138,453 admissions during the 1-year pandemic, representing a 7% decline (95% CI [95% CI 7.1-6.9]; < 0.0001). ICH volumes declined from 29,585 to 28,156 (4.8% [5.1-4.6]; < 0.0001) and IVT volume from 24,584 to 23,077 (6.1% [6.4-5.8]; < 0.0001). Larger declines were observed at high-volume compared with low-volume centers (all < 0.0001). There was no significant change in mechanical thrombectomy volumes (0.7% [0.6-0.9]; = 0.49). Stroke was diagnosed in 1.3% [1.31-1.38] of 406,792 COVID-19 hospitalizations. SARS-CoV-2 infection was present in 2.9% ([2.82-2.97], 5,656/195,539) of all stroke hospitalizations.
DISCUSSION
There was a global decline and shift to lower-volume centers of stroke admission volumes, ICH volumes, and IVT volumes during the 1st year of the COVID-19 pandemic compared with the prior year. Mechanical thrombectomy volumes were preserved. These results suggest preservation in the stroke care of higher severity of disease through the first pandemic year.
TRIAL REGISTRATION INFORMATION
This study is registered under NCT04934020.
Topics: Humans; Brain Ischemia; COVID-19; Follow-Up Studies; Intracranial Hemorrhages; Pandemics; Retrospective Studies; SARS-CoV-2; Stroke; Stroke Volume; Thrombectomy; Thrombolytic Therapy; Treatment Outcome
PubMed: 36257718
DOI: 10.1212/WNL.0000000000201426 -
Brazilian Journal of Biology = Revista... 2021Bisphenol A (BPA) is a monomer used in the production of polycarbonate, a polymer commonly found in plastics, epoxy resins and thermal papers. The presence of BPA in...
Bisphenol A (BPA) is a monomer used in the production of polycarbonate, a polymer commonly found in plastics, epoxy resins and thermal papers. The presence of BPA in food, water, air and dust has been of great concern in recent years not only due to environmental and ecological issues but also because of its supposed risk to public health related to its mutagenic and carcinogenic potential. In this study we evaluated the toxicity of bisphenol A in zebrafish embryos (Danio rerio) and determined the 50% lethal concentration (LC50) of this chemical. BPA was used at concentrations ranging from 1 μM to 100 μM in E3 medium/0.5% dimethylsulfoxide (DMSO) from previously prepared stock solutions in 100% DMSO. Controls included embryos exposed only to E3 medium or supplemented with 0.5% DMSO. Camptothecin (CPT), a known inhibitor of cell proliferation was used as positive control at a concentration of 0.001 μM in E3 medium/0.5% DMSO. Adults zebrafish were placed for breeding a day before the experimental set up, then, viable embryos were collected and selected for use. Experiments were carried out in triplicates, according to specifications from Organization for Economic Cooperation and Development (OECD). One embryo/well (25 embryos per concentration) was distributed in 96 well microplates in presence or absence of the chemicals. The plates were kept in BOD incubators with a controlled temperature of 28.5 ºC and with photoperiod of 14 h light:10 h dark. After 24h, 48h, 72h and 96h exposure, the exposed embryos were evaluated according to the following parameters: mortality, coagulation, rate of heartbeat, hatching and presence of morphological abnormalities. Photography was obtained by photomicroscopy. Apoptosis was evaluated by DNA ladder assay. DNA was extracted by phenol:chloroform method and analyzed by 2% agarose gel electrophoresis. DNA fragments were visualized after ethidium bromide staining in ultraviolet transilluminator. The LC50 determined for BPA was 70 μM after 24 hours, 72 μM after 48 hours, 47 μM after 72 hours and 31 μM after 96 hours exposure. BPA induced morphological and physiological alterations such as yolk sac and pericardial edema, hatching delay or inhibition, spine deformation, decreasing in heartbeat rate and mortality. In conclusion, this study demonstrated that BPA induced marked malformations in zebrafish embryos at concentrations above 25 μM corroborating the current concerns related to the widespread presence of BPA in the air, food and water used by humans as well as in the bodily fluids and tissues.
Topics: Animals; Benzhydryl Compounds; Embryo, Nonmammalian; Humans; Phenols; Water Pollutants, Chemical; Zebrafish
PubMed: 32490983
DOI: 10.1590/1519-6984.230562 -
Wireless Personal Communications 2022Pneumonia is a lung infection caused by bacteria, viruses and fungi. In this infection, the air sac (alveoli) of the lungs gets inflamed and breathing becomes difficult...
Pneumonia is a lung infection caused by bacteria, viruses and fungi. In this infection, the air sac (alveoli) of the lungs gets inflamed and breathing becomes difficult which causes mild to severe illness among people. They are diagnosed by performing chest X-ray, blood test, pulse oximetry. Pneumonia can also be identified using lung sounds that are recorded in the digital stethoscope. In this proposed work, a software is developed to diagnose pneumonia from the lung sound using gradient boosting algorithm. Lung sounds give enough symptoms for pneumonia identification. Lung sounds are recorded by doctors using Electronic Stethoscope. The recorded lung sounds are processed using audacity software. This software separates the required sound from unwanted noises. The healthy individual's audio files are labelled as 0 and the pneumonia patient's audio files are labelled as 1 for training the algorithm. During diagnosis study and the performance evaluation with various machine learning algorithms like support vector machine and k-nearest neighbours (KNN) algorithms, it was observed that the gradient boosting algorithm exhibits good identification property with 97 percent accuracy. This proposed method also reveals excellent diagnoses of pneumonia over other artificial intelligence and deep learning techniques. This method can also be used to predict Covid affected lungs sounds.
PubMed: 35789578
DOI: 10.1007/s11277-022-09885-7 -
International Journal of Molecular... Jul 2018The acquisition of invasive properties preceding tumor metastasis is critical for cancer progression. This phenomenon may result from mutagenic disruption of typical... (Review)
Review
The acquisition of invasive properties preceding tumor metastasis is critical for cancer progression. This phenomenon may result from mutagenic disruption of typical cell function, but recent evidence suggests that cancer cells frequently co-opt normal developmental programs to facilitate invasion as well. The signaling cascades that have been implicated present an obstacle to identifying effective therapeutic targets because of their complex nature and modulatory capacity through crosstalk with other pathways. Substantial efforts have been made to study invasive behavior during organogenesis in several organisms, but another model found in has not been thoroughly explored. The air sac primordium (ASP) appears to be a suitable candidate for investigating the genes and morphogens required for invasion due to the distinct overlap in the events that occur during its normal growth and the development of metastatic tumor cells. Among these events are the conversion of larval cells in the trachea into a population of mitotically active cells, reduced cell⁻cell contact along the leading edge of the ASP, and remodeling of the extracellular matrix (ECM) that surrounds the structure. Here, we summarize the development of ASPs and invasive behavior observed therein.
Topics: Air Sacs; Animals; Drosophila melanogaster; Gene Expression Regulation, Developmental; Humans; Neoplasm Invasiveness; Neoplasms; Organogenesis; Signal Transduction; Trachea
PubMed: 30018198
DOI: 10.3390/ijms19072074 -
Science (New York, N.Y.) Mar 2019We investigated the roles of components of neuronal synapses for development of the air sac primordium (ASP). The ASP, an epithelial tube, extends specialized signaling...
We investigated the roles of components of neuronal synapses for development of the air sac primordium (ASP). The ASP, an epithelial tube, extends specialized signaling filopodia called cytonemes that take up signals such as Dpp (Decapentaplegic, a homolog of the vertebrate bone morphogenetic protein) from the wing imaginal disc. Dpp signaling in the ASP was compromised if disc cells lacked Synaptobrevin and Synaptotagmin-1 (which function in vesicle transport at neuronal synapses), the glutamate transporter, and a voltage-gated calcium channel, or if ASP cells lacked Synaptotagmin-4 or the glutamate receptor GluRII. Transient elevations of intracellular calcium in ASP cytonemes correlate with signaling activity. Calcium transients in ASP cells depend on GluRII, are activated by l-glutamate and by stimulation of an optogenetic ion channel expressed in the wing disc, and are inhibited by EGTA and by the GluR inhibitor NASPM (1-naphthylacetyl spermine trihydrochloride). Activation of GluRII is essential but not sufficient for signaling. Cytoneme-mediated signaling is glutamatergic.
Topics: Animals; Animals, Genetically Modified; Calcium Channels; Calcium Signaling; Drosophila Proteins; Drosophila melanogaster; Glutamates; Imaginal Discs; Optical Imaging; Pseudopodia; R-SNARE Proteins; Receptors, Ionotropic Glutamate; Sarcoplasmic Reticulum Calcium-Transporting ATPases; Synapses; Synaptotagmin I; Tissue Culture Techniques
PubMed: 30819957
DOI: 10.1126/science.aat5053 -
Current Biology : CB Feb 2022The freshwater aquatic larvae of the Chaoborus midge are the world's only truly planktonic insects, regulating their buoyancy using two pairs of internal air-filled...
The freshwater aquatic larvae of the Chaoborus midge are the world's only truly planktonic insects, regulating their buoyancy using two pairs of internal air-filled sacs, one in the thorax and the other in the seventh abdominal segment. In 1911, August Krogh demonstrated the larvae's ability to control their buoyancy by exposing them to an increase in hydrostatic pressure. However, how these insects control the volume of their air-sacs has remained a mystery. Gas is not secreted into the air-sacs, as the luminal gas composition is always the same as that dissolved in the surrounding water. Instead, the air-sac wall was thought to play some role. Here we reveal that bands of resilin in the air-sac's wall are responsible for the changes in volume. These bands expand and contract in response to changes in pH generated by an endothelium that envelops the air-sac. Vacuolar type H V-ATPase (VHA) in the endothelium acidifies and shrinks the air-sac, while alkalinization and expansion are regulated by the cyclic adenosine monophosphate signal transduction pathway. Thus, Chaoborus air-sacs function as mechanochemical engines, transforming pH changes into mechanical work against hydrostatic pressure. As the resilin bands interlaminate with bands of cuticle, changes in resilin volume are constrained to a single direction along the air-sac's longitudinal axis. This makes the air-sac functionally equivalent to a cross-striated pH muscle and demonstrates a unique biological role for resilin as an active structural element.
Topics: Animals; Fresh Water; Hydrogen-Ion Concentration; Larva; Water
PubMed: 35081331
DOI: 10.1016/j.cub.2022.01.018 -
Anatomical Record (Hoboken, N.J. : 2007) Jan 2023Avian respiratory systems are comprised of rigid lungs connected to a hierarchically organized network of large, regional air sacs, and small diverticula that branch... (Review)
Review
Avian respiratory systems are comprised of rigid lungs connected to a hierarchically organized network of large, regional air sacs, and small diverticula that branch from them. Paramedullary diverticula are those that rest in contact with the spinal cord, and frequently invade the vertebral canal. Here, we review the historical study of these structures and provide the most diverse survey to date of paramedullary diverticula in Aves, consisting of observations from 29 taxa and 17 major clades. These extensions of the respiratory system are present in nearly all birds included in the study, with the exception of falconiforms, gaviiforms, podicipediforms, and piciforms. When present, they share connections most commonly with the intertransverse and supravertebral diverticula, but also sometimes with diverticula arising directly from the lungs and other small, more posterior diverticula. Additionally, we observed much greater morphological diversity of paramedullary airways than previously known. These diverticula may be present as one to four separate tubes (dorsal, lateral, or ventral to the spinal cord), or as a single large structure that partially or wholly encircles the spinal cord. Across taxa, paramedullary diverticula are largest and most frequently present in the cervical region, becoming smaller and increasingly absent moving posteriorly. Finally, we observe two osteological correlates of paramedullary diverticula (pneumatic foramina and pocked texturing inside the vertebral canal) that can be used to infer the presence of these structures in extinct taxa with similar respiratory systems.
Topics: Osteology; Tomography
PubMed: 35338748
DOI: 10.1002/ar.24923