Structural evolution during inverse vulcanization.

Inverse vulcanization exploits S8 to synthesize polysulfides. However, evolution of products and its mechanism during inverse vulcanization remains elusive. Herein, inverse vulcanization curves are obtained to describe the inverse vulcanization process in terms of three stages: induction, curing and over-cure. The typical curves exhibit a moduli increment before declining or plateauing, reflecting the process of polysulfide network formation and loosing depending on monomers. For aromatic alkenes, in the over-cure, the crosslinked polysulfide evolves significantly into a sparse network with accelerated relaxation, due to the degradation of alkenyl moieties into thiocarbonyls. The inverse vulcanization product of olefins degrades slowly with fluctuated relaxation time and modulus because of the generation of thiophene moieties, while the inverse vulcanization curve of dicyclopentadiene has a plateau following curing stage. Confirmed by calculations, the mechanisms reveal the alkenyl groups react spontaneously into thiocarbonyls or thiophenes via similar sulfur-substituted alkenyl intermediates but with different energy barriers.

Reducing scan time in 177 Lu planar scintigraphy using convolutional neural network: A Monte Carlo simulation study.

PURPOSE: The aim of this study was to reduce scan time in 177 Lu planar scintigraphy through the use of convolutional neural network (CNN) to facilitate personalized dosimetry for 177 Lu-based peptide receptor radionuclide therapy. METHODS: The CNN model used in this work was based on DenseNet, and the training and testing datasets were generated from Monte Carlo simulation. The CNN input images (IMGinput ) consisted of 177 Lu planar scintigraphy that contained 10-90% of the total photon counts, while the corresponding full-count images (IMG100% ) were used as the CNN label images. Two-sample t-test was conducted to compare the difference in pixel intensities within region of interest between IMG100% and CNN output images (IMGoutput ). RESULTS: No difference was found in IMGoutput for rods with diameters ranging from 13 to 33 mm in the Derenzo phantom with a target-to-background ratio of 20:1, while statistically significant differences were found in IMGoutput for the 10-mm diameter rods when IMGinput containing 10% to 60% of the total photon counts were denoised. Statistically significant differences were found in IMGoutput for both right and left kidneys in the NCAT phantom when IMGinput containing 10% of the total photon counts were denoised. No statistically significant differences were found in IMGoutput for any other source organs in the NCAT phantom. CONCLUSION: Our results showed that the proposed method can reduce scan time by up to 70% for objects larger than 13 mm, making it a useful tool for personalized dosimetry in 177 Lu-based peptide receptor radionuclide therapy in clinical practice.

Regulatory Effects of Clock and Bmal1 on Circadian Rhythmic TLR Expression.

Circadian locomotor output cycles kaput (Clock) and brain and muscle ARNT-like 1 (Bmal1) are two core circadian clock genes. They form a heterodimer that can bind to the E-box element in the promoters of Period circadian protein (Per) and Cryptochrome (Cry) genes, thereby inducing the rhythmic expression of circadian clock control genes. Toll-like receptors (TLRs) are type I transmembrane proteins belonging to the pattern recognition receptor (PRR) family. They can recognize a variety of pathogens and play an important role in innate immunity and adaptive immune responses. Recent studies have found that the circadian clock is closely associated with the immune system. TLRs have a certain correlation with the circadian rhythms; Bmal1 seems to be the central mediator connecting the circadian clock and the immune system. Research on Bmal1 and TLRs has made some progress, but the specific relationship between TLRs and Bmal1 remains unclear. Understanding the relationship between TLRs and Clock/Bmal1 genes is increasingly important for basic research and clinical treatment.

[Protective effect of edaravone on chlorpyrifos-induced brain injury in rats and its mechanism].

Objective: To investigate the protective effect of edaravone on chlorpyrifos-induced neuronal apoptosis and its mitochondrial mechanism. Methods: Under the principle of randomization and double-blindness, the rats were divided into control group, chlorpyrifos group, and edaravone group (n=6). The rats in edaravone group were treated with edaravone (10 mg/1.6 ml/kg, ip.) 1 h after chlorpyrifos injection. After continuous injection of chlorpyrifos and edaravone for 28 days, the learning and memory abilities of the rats were tested by open field and water maze tests. The rat brain tissue was collected after cardiac perfusion, and the neuronal damage in the hippocampus of the brain was detected by HE staining and the mitochondrial and nuclear damage were observed by transmission electron microscopy. The contents of Na+-K+-ATPase and ATP were measured to evaluate mitochondrial damage. The expression of mitochondrial fission protein DRP1 and phosphorylation at Ser 637 of DRP1 were determined by immunohistochemistry and immunoblotting. Results: Compared with the control group, the total movement distance and average speed of the rats in the chlorpyrifos group were decreased significantly within 3 minutes of the open field test (P＜0.01), and the escape latency within 1 minute of the water maze test was prolonged significantly. The number of platform crossings was reduced significantly (P＜0.01), the activity of ATPase in brain tissue was decreased significantly (P＜0.01) , the content of ATP and the phosphorylation level of Ser637 of mitochondrial DRP1 were decreased significantly (P＜0.05, P＜0.01). After edaravone treatment, the total movement distance and average speed of rats in the open field test were increased (P＜0.05), the latency in the water maze test was decreased, and the number of crossing platforms was increased (P＜0.01), brain pathological sections showed that nerve cells were arranged neatly, nucleus and mitochondrial damage was significantly improved, the activity of ATPase in brain tissue was increased (P＜0.01), the levels of ATP and mitochondrial DRP1 Ser637 phosphorylation increased (P＜0.05, P＜0.01).Conclusion: Edaravone alleviates chlorpyrifos-induced brain injury in rats by promoting the phosphorylation of DRP1 at Ser637.

Investigating the lesion detectability of Tc-99m planar scintigraphy acquired with LEHRS collimator for patients with different body sizes: A phantom study.

PURPOSE: The aim of this work was to investigate the lesion detectability of Tc-99m planar scintigraphy acquired with a low-energy high-resolution and sensitivity (LEHRS) collimator and processed by Clarity 2D for patients with different body sizes through phantom study. METHODS: A NEMA IEC body phantom set was covered by two layers of 25-mm-thick bolus to construct phantom in three different sizes. All image data were performed on a Discovery NM/CT 870 DR with an LEHRS collimator and processed by Clarity 2D with blend ratio a of 0%, 20%, 40%, 60%, 80%, and 100%. The lesion detectability in gamma scintigraphy was evaluated by calculating the contrast-to-noise ratio (CNR). Multiple linear regression methods were used to analyze the impact of body size, target size, and Clarity 2D blending weight on the lesion detectability of Tc-99m planar scintigraphy. RESULTS: It was found that changing the blend ratio could improve CNR, and this phenomenon was more significant in anterior view than in posterior view. Our results also suggested that the blend ratio should be selected according to patient body size in order to maintain consistent CNR. Hence, when a blend ratio of 60% was used for a patient before cancer treatment, a lower blend ratio should be used for the same patient experiencing treatment-related weight loss to achieve consistent lesion detectability in Tc-99m planar scintigraphy acquired with LEHRS and processed by Clarity 2D. CONCLUSION: The magnitude of photon attenuation and scattering is higher in patients with larger body size, so Tc-99m planar scintigraphy usually has lower lesion detectability in obese patients. Although photon attenuation and scattering are inevitable during image formation, their impacts on image quality can be eased by employing appropriate image protocol parameters.

Low-Cost and Rapid Method of DNA Extraction from Scaled Fish Blood and Skin Mucus.

PCR-based DNA amplification has been one of the major methods in aquaculture research for decades, although its use outside the modern laboratory environment is limited due to the relatively complex methods and high costs. To this end, we investigated a swabbing and disc protocol for the collection of DNA samples from fish which could extract DNA from fish skin mucus by a non-invasion technique costing only $0.02 (USD) and requiring less than 30 seconds. The disc method that we chose could use the cheap filter paper to extract DNA from above 104 crucian carp blood cells, which is comparable to the commercial kit. By using skin mucus swabbing and the disc method, we can obtain amplification-ready DNA from mucus to distinguish different species from our smallest fish (medaka, ~2.5 cm and crucian carp, ~7 cm) to our biggest fish (tilapia, ~15 cm). Furthermore, the viral pathogen Carassius auratus herpesvirus (CaHV) of crucian carp was detected using our method, which would make performing molecular diagnostic assays achievable in limited-resource settings including aquafarms and aqua stores outside the laboratory environment.

Carvacryl acetate, a semisynthetic monoterpenic ester obtained from essential oils, provides neuroprotection against cerebral ischemia reperfusion-induced oxidative stress injury via the Nrf2 signalling pathway.

Carvacryl acetate (CA) is a semisynthetic monoterpenic ester obtained from essential oils, and it exerts an antioxidation effect. The purpose of our study was to investigate whether CA could provide neuroprotection against oxidative stress caused by cerebral ischemia-reperfusion injury (CIRI) and elucidate the underlying mechanism. Middle cerebral artery occlusion (MCAO)-induced damage was established in Sprague Dawley (SD) rats and PC12 cells were exposed to hydrogen peroxide (H2O2) to imitate oxidative stress damage. TTC, HE and Nissl staining were used to observe the pathological morphology of lesions. The contents of ROS and MDA, and the activity of SOD were measured to reflect the level of oxidative stress. In addition, the TUNEL method was used to assess injuries in vitro, and the expression of Nrf2 was determined by immunohistochemical staining and western blot analysis. Importantly, we constructed and validated Nrf2 knockdown PC12 cells to confirm the key role of Nrf2 in the neuroprotective effect of CA against oxidative stress injuries. CA alleviated CIRI in rats with MCAO, as shown by brain tissue pathophysiology. The contents of ROS and MDA were reduced, and the SOD activity was augmented by the simultaneous promotion of Nrf2 expression. In addition, the H2O2-induced injury in Nrf2-knockdown PC12 cells was more serious than it was in control cells, and CA-mediated neuroprotection was exclusively inhibited by the knock down of Nrf2 in PC12 cells. In conclusion, it is shown here that CA has the effect of relieving cerebral ischemia reperfusion-induced oxidative stress injury via the Nrf2 signalling pathway.

Minireview: The Introduction of COVID-19 and Microvascular Disease-Introduction of COVID-19 and the Relationship between Its Receptor and Diabetic Vascular Complications.

In December of 2019, a novel coronavirus, which is SARS-CoV-2, broke out in the world and caused tremendous human and financial losses. According to a descriptive study by the relative hospital about the epidemiological and clinical features of 52 critically ill patients, the expert panel found that people with cardiovascular disease and diabetes comprise a large proportion of the patients with chronic disease. In this review, we discuss the structural biology of the SARS-CoV-2 in combination with the characteristics of its binding protein, ACE2, which is an important receptor in the cardiovascular system and may have potential relationships with various diabetic diseases. We hope we can provide useful recommendations for patients with diabetes after becoming infected by the virus or provide directions to doctors on treatment options.

Evaluation of 5-[18F]fluoro-2'-deoxycytidine as a tumor imaging agent: A comparison of [18F]FdUrd, [18F]FLT and [18F]FDG.

One of the hallmarks of cancer is increased cell proliferation. Measurements of cell proliferation by estimation of DNA synthesis with several radiolabeled nucleosides have been tested to assess tumor growth. Deoxycytidine can be phosphorylated by deoxycytidine kinase (dCK) and is incorporated into DNA. This study evaluated a radiofluorinated deoxycytidine analog, 5-[18F]fluoro-2'-deoxycytidine ([18F]FdCyd), as a proliferation probe and compared it with 5-[18F]fluoro-2'-deoxyuridine ([18F]FdUrd), 3'-deoxy-3'-[18F]fluorothymidine ([18F]FLT), and [18F]fluorodeoxyglucose ([18F]FDG) in a tumor-bearing mouse model. [18F]FdCyd was synthesized from two precursors by direct electrophilic substitution. The serum stability and partition coefficient of [18F]FdCyd were evaluated in vitro. Positron emission topography (PET) imaging of Lewis lung carcinoma (LLC)-bearing mice with [18F]FdCyd, [18F]FdUrd, [18F]FLT, and [18F]FDG were evaluated. [18F]FdCyd was stable in mouse serum and normal saline for up to 4 h. With all radiotracers except [18F]FLT, PET can clearly delineate the tumor lesion. [18F]FdCyd and [18F]FdUrd showed high accumulation in the liver and kidney. The SUV and tumor-to-muscle (T/M) ratios derived from PET imaging of the radiotracers were [18F]FDG > [18F]FdCyd > [18F]FdUrd > [18F]FLT. Selective retention in tumors with a favorable tumor/muscle ratio makes [18F]FdCyd a protential candidate for further investigation as a proliferation imaging agent.