System ASC Research Articles

Model-Based NH3 Slip Detection for SCR + ASC System Control and OBD

Model-Based NH3 Slip Detection for SCR + ASC System Control and OBD

Corrosion behavior and mechanism of NiCrAl–NiC abradable sealing coating system in NaCl solution

As an important component of aviation turbine engines, abradable sealing coatings have the function of protecting turbine blades and improving engine efficiency. However, Abradable Sealing Coating systems (ASCs) are often damaged by corrosion in their applications, which may cause safety accidents. This article uses atmospheric plasma spraying technology to prepare NiCrAl–NiC ASC system, which is divided into three layers with a porous structure on the top. In order to fully explore the corrosion behavior of NiCrAl–NiC ASC system, corrosion tests were conducted on the ASC system using immersion method. The corrosion potential of this coating system is −0.96V, and a low corrosion potential indicates that the coating is more prone to corrosion. On the other hand, its current density is 51.64 × 10−6 A cm−2, indicating a slower corrosion rate of the coating. After immersion for 600 h, the corrosive medium Penetrated into the interior of the coating, forming interlayer corrosion. The electrochemical impedance results showed that the corrosion process of the coating was divided into three stages, and the impedance fitting results were consistent with the changes in coating porosity during the immersion process. The corrosion products of the coating are oxygen-containing compounds of various metal elements, including Al2O3, Al (OH)3, NiO, Ni(OH)2, and Cr2O3. The porous, multi-layered, and multiphase characteristics of coatings result in their unique corrosion behavior.

MiR-122-5p Restrains Pancreatic Cancer Cell Growth and Causes Apoptosis by Negatively Regulating ASCT2.

System ASC amino acid transporter-2 (ASCT2) is abnormally highly expressed in tumor cells and closely associated with a poor prognosis, but the regulatory mechanism of abnormally high ASCT2 expression is scarcely investigated. MicroRNAs (miRNAs) that are abnormally expressed regulate gene expression to have either oncogenic or tumor-suppressive effects in pancreatic cancer (PC). MicroRNA-122-5p (miR-122-5p) dysregulation has been seen in various cancer entities, but the biological function of miR-122-5p in PC and its regulation mechanisms remain unknown. Western blot and quantitative RT-PCR were used to measure the expression of miR-122-5p, ASCT2, and apoptosis-related proteins. CCK-8 assays were used to elucidate the effect on cell proliferation. Flow cytometry (FCM) assays were utilized to evaluate cell apoptosis. A dual-luciferase reporter assay was utilized to determine if miR-122a-5p directly targeted ASCT2. Glutamine consumption and the α-ketoglutarate (α-KG) and adenosine triphosphate (ATP) contents were determined using respective assays. MiR-122-5p expression was low whereas ASCT2 expression was high in PC tissues and cells. Overexpressing miR-122-5p restrained pancreatic cancer cell proliferation, accelerated apoptosis, and decreased glutamine consumption, α-ketoglutarate (α-KG) production and ATP generation, whereas suppressing miR-122-5p had the opposite effect. Moreover, the reporter gene test established ASCT2 as a miR-122-5p target. Overexpression of miR-122-5p decreased ASCT2 expression, whereas miR-122-5p repression increased ASCT2 expression. In addition, miR-122-5p also regulated apoptosis-related pathways. MiR-122-5p may function as a tumor suppressor by inhibiting the proliferation, glutamine metabolism, and inducing apoptosis via altering the expression of ASCT2 in pancreatic cancer cells.

Mechanism of quinone mediators modified polyurethane foam for enhanced nitrobenzene reduction and denitrification

The nitrobenzene (NB) reduction and denitrification performance of the immobilized biofilm (I-BF) reactors based on 9,10-anthraquinone-2-sulfonyl chloride (ASC) modified polyurethane foam (PUF-ASC) carriers were investigated. Experiments demonstrated that the quinone mediators enhanced NB reduction and denitrification performance. The NB reduction rates increased by 1.46, while the NO3--N removal rates increased by 1.55 times in the PUF-0.1ASC system. The quinone mediators promote extracellular polymeric substances (EPS) secretion. Electrochemical tests indicated that quinone mediators enhanced the electron transfer of biofilm systems. NADH generation was accelerated and microbial electron transport system activity (ETSA) was promoted. The abundance of genera with electrochemical activity, NB degradation and denitrification ability (Pseudomonas sp., Diaphorobate sp., and Acinetobacter sp.) increased. Metabolic pathways relating to NO3--N and NB reduction were uploaded. In conclusion, electron acquisition by NO3--N and NB was facilitated, bacterial community structure and metabolic pathways were affected by the quinone mediators.

Recent progress of amino acid transporters as a novel antitumor target

Abstract Glutamine transporters transport different amino acids for cell growth and metabolism. In tumor cells, glutamine transporters are often highly expressed and play a crucial role in their growth. By inhibiting the amino acid transport of these transporters, the growth of cancer cells can be inhibited. In recent years, more and more attention has been paid to the study of glutamine transporter. In this article, the differences between the ASC system amino acid transporter 2 (ASCT2), L-type amino acid transporter 1 (LAT1), and the cystine–glutamate exchange (xCT) transporters research progress on the mechanism of action and corresponding small molecule inhibitors are summarized. This article introduces 62 related small molecule inhibitors of different transporters of ASCT2, LAT1, and xCT. These novel chemical structures provide ideas for the research and design of targeted inhibitors of glutamine transporters, as well as important references and clues for the design of new anti-tumor drugs.

(Digital Presentation) Vanadium Intercalated Cobalt Trimesic MOF Composite for Enhanced Solid-State Asymmetric Supercapacitor Storage

Metal organic framework (MOF) is a supramolecular coordination material composed of metal ions coordination, nodes, and organic ligands. MOFs were used as active materials for chemical capacitors to realize the high electrochemical performance, providing adequate redox sites and accelerating ion diffusion rate. Using MOF as a template to fabricate a novel platform can deliver large specific surface areas and abundant oxidation-active sites to augment electrical conductivity. The electrode material based on a MOF has a unique morphology that can significantly shorten charge transport paths to alleviate the electron transport and diffusion, thus strengthening the catalytic performance of the electrode materials. Also, the incorporation of vanadium in the intermediate leads to a broad impact on the morphology and the electrochemical energy storage of Cobalt-Trimesic matrix worked as a base for fabricating the composite. The DMF is a solvent to prepare the vanadium cobalt oxide composite derived using the MOF matrix. Trimesic acid is used as an initial organic linker precursor to initiate the formation of MOF of cobalt in DMF solvent. Then the vanadium ion is integrated into the same material matrix. In this study, the impact of organic system precursors and the integration of annealing play a pivotal role in alleviating the enhanced electrochemical storage response. After analyzing through XRD, the corresponding MOF crystal peaks are prominently affirmed. The high intensified peaks in the obtained patterns symbolize the oxide phase of cobalt vanadium and confirm the formation derived from MOF. The FTIR spectroscopy investigation depicted the proper presence of cobalt, vanadium, carbon, and nitrogen. The observed FESEM morphology illustrated the dissimilar structure and involved in the charge storage likewise. The morphology significantly impacts surface-dependent charge storage with having porosity introduced. High-temperature annealing also consists of the crystal orientation of the bi-metallic MOF matrix and creates porosity on the effective surface area.The Co-MOF-V oxide composite is thoroughly investigated individually in three-electrode arrangements for analyzing the electrochemical charge storage in 2MKOH represented in Fig.1 (c-d). Firstly, the oxide is scrutinized as working positive electrodes and measured in the potential window of -0.2 to 0.6 V w.r.t the saturated calomel reference electrode. The accomplished specific capacitance value from the cyclic voltammetry plot is 549 F/g at 2mV/s scan rate. Furthermore, the charge-discharge analysis of the composite delineated an admirable discharge time at 3mA/cm2 current density. It portrayed 349 F/g specific capacitance, leading to higher specific energy and specific power of 31.02Wh/kg and 159.53W/kg at the value of the same current density. The Nyquist plot corroborates that the electrode resistance, electrode-electrolyte interfacing resistance, and the value of diffuse layer resistance are significantly less. This study can bestow a greater pathway of ion transportation from the electrolyte to active electrode material that abetted to conversate superior storage using complete morphology. The transition metal possesses a variational oxidation state that directly contributes to this MOF composite's pseudocapacitive charge storage process. Alternatively, comparable analysis is directed over anode material that is lignocellulose derived activated porous carbon. It is depicted in Fig.1(e-f) in the potential window of -1 to 0v w.r.t the Ag/AgCl electrode in 2M KOH. The gained specific capacitance from the cyclic voltammetry analysis is 426 F/g at a 2mV/s scan rate. Besides, the charge-discharge study of the same carbon depicted admirable discharge time at 0.5A/g current density and portrayed 565 F/g specific capacitance. The specific energy and power of 78.47Wh/kg and 282W/kg at the same current density. Also, the integrated porous system with the high active surface area, which significantly comes from the MOF matrix, provides an added phase to strengthen the amount of storage like EDLC formation.Furthermore, combining both of those active materials, the asymmetric supercapacitor storage is made up [Fig.1 (g-h)]. That system works upon 0 to 1.4V windows. The attained areal capacitance is 0.54 F/cm2, and volumetric capacitance is 0.68 F/cm3 in the current density of 4mA/cm2. The Ragone plot shows its perfect positioning in the region of asymmetric storage. This ASC system delineated coulombic efficiency 79% of capacitive retention 75% after the 10,000 long cycle stability study. From the electrochemical impedance spectroscopy analysis, the obtained interfacing and electrode resistance diffuse layer resistance is found significantly lesser and upwards. Figure 1

MP39-01 SYSTEM ASC TRANSPORTER 2, A KEY ENZYME FOR GLUTAMINE PATHWAY, IS A POSSIBLE BIOMARKER FOR METASTATIC PROGRESSION AND SURVIVAL IN RENAL CELL CARCINOMA

You have accessJournal of UrologyKidney Cancer: Basic Research & Pathophysiology I (MP39)1 Sep 2021MP39-01 SYSTEM ASC TRANSPORTER 2, A KEY ENZYME FOR GLUTAMINE PATHWAY, IS A POSSIBLE BIOMARKER FOR METASTATIC PROGRESSION AND SURVIVAL IN RENAL CELL CARCINOMA Yoshinari Muto, Makoto Sumitomo, Kenji Zennami, Masashi Takenaka, Takuhisa Nukaya, Kosuke Fukaya, Manabu Ichino, Kiyoshi Takahara, Hitomi Sasaki, and Ryoichi Shiroki Yoshinari MutoYoshinari Muto More articles by this author , Makoto SumitomoMakoto Sumitomo More articles by this author , Kenji ZennamiKenji Zennami More articles by this author , Masashi TakenakaMasashi Takenaka More articles by this author , Takuhisa NukayaTakuhisa Nukaya More articles by this author , Kosuke FukayaKosuke Fukaya More articles by this author , Manabu IchinoManabu Ichino More articles by this author , Kiyoshi TakaharaKiyoshi Takahara More articles by this author , Hitomi SasakiHitomi Sasaki More articles by this author , and Ryoichi ShirokiRyoichi Shiroki More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002054.01AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The glutamine (Gln) pathway has been implicated in tumor progression in various malignancies including renal cell carcinoma (RCC). However, the detail underlying this pathway remains to be elucidated. Since both glutaminase 1 (GLS1) and system ASC transporter 2 (ASCT2) were reported to play a crucial role in this pathway, we investigated whether these enzymes could be associated with cancer development and survival in RCC. METHODS: Tumor (T) and non-tumor (N) tissues were sampled from 66 RCC patients. Metabolome analyses were performed by liquid chromatography mass spectrometry (LC/MS) and important metabolites including Gln and glutamate (Glu) were analyzed. The protein expression of GLS1 and ASCT2 was evaluated by immunohistochemistry (IHC) using formalin-fixed, paraffin-embedded sections of surgical specimen from 80 metastatic RCC (mRCC) patients who received standard treatment using tyrosine-kinase inhibitors (TKIs) with or without immune checkpoint inhibitors (ICIs). The mRCC patients who received treatment with ICIs in the first- or second-line treatment were categorized into the “ICI group”, whereas others were categorized into the “TKI-only group”. In this study, the endpoint was progression-free survival 2 (PFS2) defined as the interval between first-line treatment and the second relapse. RESULTS: LC/MS analyses showed that both Gln T/N ratio and Glu T/N ratio in mRCC patients were significantly increased compared with those in non-mRCC patients (p=0.002 and p=0.048, respectively). On the other hand, the median value of Gln T/N ratios was shown to be over 100-fold higher than that of Glu T/N ratios. IHC analyses using mRCC tumor tissues revealed that ASCT2 was expressed more strongly in tumor cells than in normal cells, while GLS1 was expressed both in normal and tumor cells at the equal level. Kaplan–Meier analysis showed that ICI group had better PFS2 than TKI-only group in patients with ASCT2 high expression levels (p=0.009), while there was no significant difference on PFS2 between two groups in patients with ASCT2 low expression levels. CONCLUSIONS: Our results suggest that ASCT2 rather than GLS1 may be a key enzyme for Gln pathway in RCC. Our results also suggest that ASCT2 is associated with metastatic progression and survival, confirming its role as a possible biomarker to determine the appropriate treatment for mRCC patients. Source of Funding: None © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e704-e704 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yoshinari Muto More articles by this author Makoto Sumitomo More articles by this author Kenji Zennami More articles by this author Masashi Takenaka More articles by this author Takuhisa Nukaya More articles by this author Kosuke Fukaya More articles by this author Manabu Ichino More articles by this author Kiyoshi Takahara More articles by this author Hitomi Sasaki More articles by this author Ryoichi Shiroki More articles by this author Expand All Advertisement Loading ...

Distribution of free amino acids and mRNA expression of their corresponding transporters in the intestinal mucosa of goats feeding on a corn grain versus corn gluten diet.

Intestinal amino acid (AA) chemosensing has been implicated in the regulation of AA absorption, nitrogen metabolism and hormone release, thereby playing an indispensable role in maintaining metabolic homeostasis in mammals. The objective of this experiment was to study the distribution of free AA and the expression of AA transporting related genes along the small and large intestines of Liuyang black goats, together with the effects of dietary corn grain replaced by dietary corn gluten feed (CGF). The CGF replacement did not alter (P > 0.05) AA profiles and the expression of AA transporting related genes in the intestinal mucosa. Intriguingly, in terms of gut regions, the concentrations of aspartic acid and glutamic acid in the mucosa of ileum were remarkably less (P < 0.001) than those in the large intestine. Moreover, the concentrations of most cationic and neutral AAs shared the same distribution pattern, with the jejunum and ileum holding the greatest and least levels (P < 0.05), respectively. It was notable that the expression of both anionic and cationic AA transporters in the small intestine was exceedingly greater (P < 0.001) than those in the large intestine. As for transporters of neutral AA, system ASC, L, and A showed an extremely distinctive expression pattern. The jejunum would be the primary site of transporting AA, while CGF substitution does not exert a disadvantageous influence on the AA chemosensing systems of the first-pass metabolism. © 2021 Society of Chemical Industry.

Synthesis, Radiolabeling, and Biological Evaluation of the trans-Stereoisomers of 1-Amino-3-(fluoro-18F)-4-fluorocyclopentane-1-carboxylic Acid as PET Imaging Agents.

The enantiomeric non-natural cyclic amino acids (3R,4R)-1-amino-3-fluoro-4-(fluoro-18F)cyclopentane-1-carboxylic acid and (3S,4S)-1-amino-3-fluoro-4-(fluoro-18F)cyclopentane-1-carboxylic acid ([ 18 F]5) have been prepared as a racemic mixture in 1.3% decay corrected radiochemical yield and in greater than 99% radiochemical purity. [ 18 F]5 is transported primarily via system L with some transport occurring via system ASC, as assessed in rat 9L gliosarcoma, human U87 ΔEGFR glioblastoma, and human DU145 androgen-independent prostate carcinoma tumor cells. In rats bearing intracranial 9L gliosarcoma, [ 18 F]5 gave tumor to contralateral brain tissue ratios of up to 2.8. Biodistribution studies in healthy rats demonstrated that bladder accumulation is delayed until 10 min postinjection.

Increasing the noise immunity of radio receiving paths with automatic sensitivity control

The relevance of the study of automatic sensitivity control systems (ASC) is determined by their demand for the creation and modernization of radio receiving paths (RRP) with increased noise immunity for radar systems, radio navigation and radio communication. The article analyzes typical attenuating ASCs, which are traditionally widely used to match the dynamic range (DR) of the RRP with the DR of a group radio signal, determined by the current state of the electromagnetic environment at the receiving system location. The fundamental possibility of increasing the noise immunity of RRPs with attenuating ASCs is shown on the basis of the current analysis of the resulting output signal in the IF main filter band. At the same time, it was found that the procedure for determining the optimal value of the attenuator transmission coefficient is characterized by low response speed. In addition, an increase in noise immunity in a RRP with such ASC leads to a significant loss of sensitivity. To overcome the disadvantages of attenuating ASCs, structures that implement the exchange of the transmission coefficient of the RRP to DR and linearity are proposed. Studies of various possible ASC structures have shown that with a proportional exchange of the transmission coefficient for the DR, an improvement in the noise immunity of the RRP is provided while maintaining a high sensitivity of the system. An original ASC system is proposed, which is invariant to the sampling step of the transmission coefficients of controlled elements with increased performance. The considered structural solutions and algorithms make it possible to optimize the technical appearance of RRPs for radar, radio navigation and radio communication with increased noise immunity and to adapt their characteristics to the conditions of nonstationary electromagnetic environment.

Synthesis, Radiolabeling, and Biological Evaluation of the cis Stereoisomers of 1-Amino-3-Fluoro-4-(fluoro-18F)Cyclopentane-1-Carboxylic Acid as PET Imaging Agents.

The non-natural cyclic amino acids (1S,3R,4S)-1-amino-3-fluoro-4-(fluoro-18F)cyclopentane-1-carboxylic acid ([18F]9) and (1S,3S,4R)-1-amino-3-fluoro-4-(fluoro-18F)cyclopentane-1-carboxylic acid ([18F]28) have been prepared in 10 and 1.7% decay corrected radiochemical yield, respectively, and in greater than 99% radiochemical purity. Cell assays in rat 9L gliosarcoma, human U87 ΔEGFR glioblastoma, and human DU145 androgen-independent prostate carcinoma tumor cells indicated that both compounds are substrates for amino acid transport primarily by system L, with some transport taking place via system ASC. In rats with 9L gliosarcoma, [18F]9 and [18F]28 provided high tumor to normal brain tissue ratios, with maximal ratios of 3.5 and 4.1, respectively. Biodistribution studies in healthy rats confirmed that both compounds are BBB permeable and that bladder accumulation is low until at least 5 min post injection.

Eugenol attenuates inflammatory response and enhances barrier function during lipopolysaccharide-induced inflammation in the porcine intestinal epithelial cells.

Eugenol (4-allyl-2-methoxyphenol) is an essential oil component, possessing antimicrobial, anti-inflammatory, and antioxidative properties; however, the effect of eugenol on porcine gut inflammation has not yet been investigated. In this study, an in vitro lipopolysaccharide (LPS)-induced inflammation model in porcine intestinal epithelial cells (IPEC-J2) has been set up. Cells were pretreated with 100 μM (16.42 mg/L) eugenol for 2 h followed by 10 μg/mL LPS stimulation for 6 h. Proinflammatory cytokine secretion; reactive oxygen species; gene expression of proinflammatory cytokines, tight junction proteins, and nutrient transporters; the expression and distribution of zonula occludens-1 (ZO-1); transepithelial electrical resistance (TEER); and cell permeability were measured to investigate the effect of eugenol on inflammatory responses and gut barrier function. The results showed that eugenol pretreatment significantly suppressed the LPS-stimulated interleukin-8 level and the mRNA abundance of tumor necrosis factor-α and restored the LPS-stimulated decrease of the mRNA abundance of tight junction proteins, such as ZO-1 and occludin, and the mRNA abundance of nutrient transporters, such as B0 1 system ASC sodium-dependent neutral amino acid exchanger 2, sodium-dependent glucose transporter 1, excitatory amino acid transporter 1, and peptide transporter 1. In addition, eugenol improved the expression and even redistribution of ZO-1 and tended to increase TEER value and maintained the barrier integrity. In conclusion, a low dose of eugenol attenuated inflammatory responses and enhanced selectively permeable barrier function during LPS-induced inflammation in the IPEC-J2 cell line.

Prognostic Value of L-Type Amino Acid Transporter 1 (LAT1) in Various Cancers: A Meta-Analysis.

The L-type amino acid transporter 1 (LAT1, SLC7A5) is overexpressed in various types of cancer and has been thought to assist cancer progression through its uptake of neutral amino acids. However, the prognostic role of LAT1 in human cancers remains uncharacterized. Therefore, we conducted this meta-analysis to determine the prognostic significance of LAT1 in various cancers. We systematically searched the PubMed, Web of Science, EMBASE, Chinese National Knowledge Infrastructure, and WanFang databases to collect relevant cohort studies investigating the prognostic value of LAT1 expression in patients with cancer. Hazard ratios (HRs) with corresponding 95% confidence intervals (CIs) were pooled to clarify the association between the LAT1 expression and the survival of patients with cancer. Odds ratios (ORs) with 95% CIs were calculated to appraise the correlation between LAT1 and the clinicopathological characteristics in patients with cancer. A total of 32 eligible articles, including 34 cohorts and 6410 patients, were enrolled in this meta-analysis. Our results demonstrated that high LAT1 expression was significantly associated with poor overall survival (HR = 1.66, 95% CI 1.41-1.96, P < 0.001), cancer-specific survival (HR = 1.64, 95% CI 1.31-2.05, P < 0.001), disease-free survival (HR = 1.55, 95% CI 1.31-1.83, P < 0.001), and progression-free survival (HR = 1.18, 95% CI 1.02-1.37, P = 0.026) in patients with cancer. In addition, we found that the elevated expression level of LAT1 was significantly related to certain phenotypes of tumor aggressiveness, such as tumor size, clinical stage, T stage, lymphatic invasion, vascular invasion, tumor differentiation, Ki-67, CD34, CD98, p53, and system ASC amino acid transporter-2. Elevated expression of LAT1 is associated with poor prognosis in human cancers and may serve as a potential prognostic marker and therapeutic target for patients with malignancies.

Side Chain Optimization Remarkably Enhances the in Vivo Stability of 18F-Labeled Glutamine for Tumor Imaging.

Similar to glycolysis, glutaminolysis acts as a vital energy source in tumor cells, providing building blocks for the metabolic needs of tumor cells. To capture glutaminolysis in tumors, 18F-(2S,4R)4-fluoroglutamine ([18F]FGln) and 18F-fluoroboronoglutamine ([18F]FBQ) have been successfully developed for positron emission tomography (PET) imaging, but these two molecules lack stability, resulting in undesired yet significant bone uptake. In this study, we found that [18F]FBQ-C2 is a stable Gln PET tracer by adding two more methylene groups to the side chain of [18F]FBQ. [18F]FBQ-C2 was synthesized with a good radiochemical yield of 35% and over 98% radiochemical purity. [18F]FBQ-C2 showed extreme stability in vitro, and no defluorination was observed after 2 h in phosphate buffered saline at 37 °C. The competitive inhibition assay results indicated that [18F]FBQ-C2 enters cells via the system ASC and N, similar to natural glutamine, and can be transported by tumor-overexpressed ASCT2. PET imaging and biodistribution results indicated that [18F]FBQ-C2 is stable in vivo with low bone uptake (0.81 ± 0.20% ID/g) and can be cleared rapidly from most tissues. Dynamic scan and pharmacokinetic studies using BGC823-xenograft-bearing mice revealed that [18F]FBQ-C2 accumulates specifically in tumors, with a longer half-life (101.18 ± 6.50 min) in tumor tissues than in other tissues (52.70 ± 12.44 min in muscle). Biodistribution exhibits a high tumor-to-normal tissue ratio (4.8 ± 1.7 for the muscle, 2.5 ± 1.0 for the stomach, 2.2 ± 0.9 for the liver, and 17.8 ± 8.4 for the brain). In conclusion, [18F]FBQ-C2 can be used to perform high-contrast Gln imaging of tumors and can serve as a PET tracer for clinical research.

The effect of the environmental parameters on the performance of asphalt solar collector

Abstract In this research, asphalt Solar Collector ASC was built outside the laboratory. Atmospheric air was used as a working fluid. The effect of the environmental conditions such as ambient temperature, wind speed, variation of solar day time, and ASC chimney height are considered. The construction of the ASC system consists of aluminum buried pipes under asphalt layers with the two ends open. In the present study for the construction of the used ASC and its thermal properties, experimental were carried to evaluate the effect of chimney height on the flow field. The results showed that the chimney height has a strong effect on the average air flow velocity through the ASC. Also, the ASC prototype performance for collecting the solar energy and transferring it to the flowing ambient air depends on the used chimney height, as well as the environmental/atmospheric conditions in terms of ambient air temperature, and wind speed.

Synthesis and evaluation of an N-[18F]fluorodeoxyglycosyl amino acid for PET imaging of tumor metabolism

IntroductionThe limitations of [18F]fluorodeoxyglucose ([18F]FDG), including producing false-positive or -negative results, low image contrast in brain tumor diagnosis and poor differentiation of tumor and inflammatory, necessitate the development of new radiopharmaceuticals. In the present study, a novel [18F]fluoroglycoconjugate tracer, [18F]FDGly-NH-Phe, for tumor metabolism imaging was prepared and evaluated. Methods[18F]FDGly-NH-Phe was prepared by condensing [18F]FDG with L-4-aminophenylalanine in an acidic condition, and purified with semi-preparative-high performance liquid chromatography (HPLC). The in vitro stability study was conducted in phosphate-buffered saline (PBS, pH 4.0–9.18) at room temperature (RT) and in fetal bovine serum (FBS) at 37 °C. The preliminary cellular uptake studies were performed using Hep-2 cell. The bio-distribution studies, PET/CT imaging and metabolism studies were performed and compared with [18F]FDG on ICR or BALB/c nude model mice. Results[18F]FDGly-NH-Phe was derived from a direct condensation of [18F]FDG with L-4-aminophenylalanine with high stability in FBS and PBS (pH of 6.5–9.18). In vitro cell experiments showed that [18F]FDGly-NH-Phe uptake in Hep-2 cells was primarily transported through amino acid transporters including Na+-dependent A system, ASC system, and system B0,+ system. The bio-distribution of [18F]FDGly-NH-Phe in normal ICR mice showed faster blood radioactivity clearance, and lower uptake in brain and heart than [18F]FDG. The performance of PET/CT imaging for [18F]FDGly-NH-Phe in the mice model manifested excellent tumor visualization, high tumor-to-background ratios, and low accumulation in inflammatory lesions. Metabolism studies for [18F]FDGly-NH-Phe indicated high in vivo stability in plasma and urine and decomposition into [18F]FDG in the tumor microenvironment. ConclusionThe results demonstrated that [18F]FDGly-NH-Phe as a novel amino acid PET tracer showed the capability to differentiate tumor from inflammation, and the potentials for future clinical applications.

Radiolabeling and Preclinical Evaluation of a New S-Alkylated Cysteine Derivative Conjugated to C-Substituted Macrocycle for Positron Emission Tomography.

A new S-alkylated cysteine-derivatized tumor targeting agent, 2,2′-(12-(2-((2-acetamido-2-carboxyethyl)thio)acetamido)-11,13-dioxo-1,4,7,10-tetraazacyclotridecane-4,7-diyl)diacetic acid was developed for positron emission tomography (PET) imaging. N-Acetyl cysteine (NAC) was conjugated to ATRIDAT as a specific targeting agent toward L-type and ASC amino acid transporter systems in the oncogenic cells. NAC was attached via S-alkylation to prevent its incorporation at undesired recognition sites affecting the signal-to-noise ratio. NAC-ATRIDAT was subjected to gallium-68 complexation with >75% radiolabeling yield. The radiocomplex was purified through the tc18 cartridge to obtain 99.89% radiochemical yield. IC-50 of the NAC-ATRIDAT conjugate was 0.8 mM in A549 cells as evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazonium bromide assay. Binding affinity experiments on A549 cells showed noteworthy binding with KD in the nanomolar range. A time course study showed a Km value of 0.19 μM and Vmax value of 0.49 pmol/μg protein/min showing reasonable tumor kinetics. Efflux studies showed that the synthesized radioligand is transported majorly by LAT followed by the ASC system. Clearance was found to be renal with 7.67 ± 1.48% ID/g uptake at 30 min which substantially declined to 0.52 ± 0.% ID/g at 4 h. A significant uptake of 10.06 ± 1.056% ID/g was observed at the tumor site in mice at 1 h. μPET images revealed a high contrast with a tumor-to-kidney ratio of 4.8 and a tumor-to-liver ratio of 35.85 at 1 h after injection. These preclinical in vitro and in vivo evaluation supports its potential on the way of becoming a successful 68Ga-radiolabeled amino acid-based PET imaging agent.

Esthetic abutment design for angulated screw channels: A technical report

Angulated screw channel system abutments (ASCs) have recently been introduced to address the problem with visible screw access that may compromise esthetics. ASCs allow the screw access to be modified up to 25 degrees relative to the implant axis. However, a widened channel, which may cause thinning of the facial ceramic, is needed at the implant screw head to allow for proper engagement of the screwdriver. This technical report introduces a custom titanium insert design, the Satoshi Sakamoto (SS) abutment. The SS abutment consists of a custom titanium metal insert and zirconia coping in which the access hole is located in an esthetic position with an ASC system. The SS abutment results in a crown with more normal crown dimensions that also provides more space for the soft tissues. This SS abutment design allows clinicians to obtain screw-retained restorations with optimal esthetics and mechanical strength.

Radiosynthesis and biological evaluation of N-(2-[18F]fluoropropionyl)-3,4-dihydroxy-l-phenylalanine as a PET tracer for oncologic imaging

IntroductionSeveral 11C and 18F labeled 3,4-dihydroxy-l-phenylalanine (l-DOPA) analogues have been used for neurologic and oncologic diseases, especially for brain tumors and neuroendocrine tumors PET imaging. However, 18F-labeled N-substituted l-DOPA analogues have not been reported so far. In the current study, radiosynthesis and biological evaluation of a new 18F-labeled l-DOPA analogue, N-(2-[18F]fluoropropionyl)-3,4-dihydroxy-l-phenylalanine ([18F]FPDOPA) for tumor PET imaging are performed. MethodsThe synthesis of [18F]FPDOPA was via a two-step reaction sequence from 4-nitrophenyl-2-[18F]fluoropropionate ([18F]NFP). The biodistribution of [18F]FPDOPA was determined in normal Kunming mice. In vitro competitive inhibition and protein incorporation experiments were performed with SPC-A-1 lung adenocarcinoma cell lines. PET/CT studies of [18F]FPDOPA were conducted in C6 rat glioma and SPC-A-1 human lung adenocarcinoma and H460 human large cell lung cancer-bearing nude mice. Results[18F]FPDOPA was prepared with a decay-corrected radiochemical yield of 28±5% and a specific activity of 50±15GBq/μmol (n=10) within 125min. In vitro cell experiments showed that [18F]FPDOPA uptake in SPC-A-1 cells was primarily transported through Na+-independent system L, with Na+-dependent system B0,+ and system ASC partly involved in it. Biodistribution data in mice showed that renal–bladder route was the main excretory system of [18F]FPDOPA. PET imaging demonstrated intense accumulation of [18F]FPDOPA in several tumor xenografts, with (8.50±0.40)%ID/g in C6 glioma, (6.30±0.12)%ID/g in SPC-A-1 lung adenocarcinoma, and (6.50±0.10)%ID/g in H460 large cell lung cancer, respectively. ConclusionA novel N-substituted 18F-labeled L-DOPA analogue [18F]FPDOPA is synthesized and evaluated in vitro and in vivo. The results support that [18F]FPDOPA seems to be a potential PET tracer for tumor imaging, especially be a better potential PET tracer than [18F]fluoro-2-deoxy-d-glucose ([18F]FDG) for brain tumor imaging.

Effect of branched-chain amino acid ratio on the proliferation, differentiation, and expression levels of key regulators involved in protein metabolism of myocytes

ObjectivesBranched-chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), are key regulators of protein synthesis in muscle. The aim of this study was to investigate the effect of different BCAA ratios (Leu:Ile:Val) on the proliferation, differentiation, and expression levels of the regulators related to protein metabolism of C2 C12 myocytes. MethodsStudies were conducted in C2C12 myocytes exposed to different BCAA ratios (Leu: Ile: Val = 0, 1:0.25:0.25, 1:1:1). ResultsThe ratio of 1:0.25:0.25 increased cell viability and promoted cell cycle progression from G0/G1 phase to S phase, which was an indicator of proliferation enhancement (P < 0.05). Moreover, this optimal ratio (1:0.25:0.25) promoted the differentiation of myocytes into myotubes by upregulating myogenin and interleukin-15 gene expression, and differently regulated the expression of L-type amino acid transporter 1 and 4 and system ASC amino acid transporters 2. Furthermore, the ratio stimulated mTOR expression at the mRNA and phosphorylated protein levels, as well as ribosomal protein S6 kinase and regulatory-associated protein of mTOR (raptor). In contrast, the optimal ratio decreased the amount of ubiquitin ligase muscle-specific RING finger 1 and muscle atrophy F-box during proliferation and differentiation (P < 0.05). No change was observed in the expression of key genes related to energy metabolism except for uncoupling protein 3 (P > 0.05). ConclusionsThe results suggested that appropriate BCAA ratios could enhance proliferation and differentiation of the C2 C12 myocytes, also mediate the key regulators related to protein metabolism including the mTORC1 pathway. A proper utilization of balanced BCAA ratio in food would be beneficial to human and animal nutrition.