System-on-a-Chip Based Nano Star Tracker and Its Real-Time Image Processing Approach

The star tracker is one of the most accurate components for satellite attitude determination. With the development of the nano star tracker, it is compatible for application on small satellites. However, the drawback in dynamic property of nano star tracker has limited its extensive applications. The principal objective of this study is to introduce a system-on-a-chip (SOC) based nano star tracker with enhanced dynamic property. A morphology based image processing approach was realized based on single FPGA to achieve real-time star extraction, even from a blurred image. Such nano star tracker has been developed and tested, and field experiment results indicated that its dynamic range was up to 4°/s with a data update rate of 30Hz. Moreover, the orientation of the satellite with developed nano star tracker on board has been analyzed based on the telemetry data. Thus, such nano star tracker could promote its applications on small or agile satellites

Retinal ganglion cell-inner plexiform layer, white matter hyperintensities, and their interaction with cognition in older adults

PurposeWe explored the interaction of optical coherence tomography (OCT) parameters and white matter hyperintensities with cognitive measures in our older adult cohort.MethodsThis observational study enrolled participants who underwent a comprehensive neuropsychological battery, structural 3-T brain magnetic resonance imaging (MRI), visual acuity examination, and OCT imaging. Cerebral small vessel disease (CSVD) markers were read on MR images; lacune, cerebral microbleeds (CMB), white matter hyperintensities (WMH), and enlarged perivascular spaces (EPVS), were defined according to the STRIVE standards. Retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GCIPL) thicknesses (μm) were measured on the OCT tool.ResultsOlder adults with cognitive impairment (CI) showed lower RNFL (p = 0.001), GCIPL (p = 0.009) thicknesses, and lower hippocampal volume (p = 0.004) when compared to non-cognitively impaired (NCI). RNFL (p = 0.006) and GCIPL thicknesses (p = 0.032) correlated with MoCA scores. GCIPL thickness (p = 0.037), total WMH (p = 0.003), PWMH (p = 0.041), and DWMH (p = 0.001) correlated with hippocampal volume in our older adults after adjusting for covariates. With hippocampal volume as the outcome, a significant interaction (p < 0.05) between GCIPL and PWMH and total WMH was observed in our older adults.ConclusionBoth GCIPL thinning and higher WMH burden (especially PWMH) are associated with hippocampal volume and older adults with both pathologies are more susceptible to subclinical cognitive decline

Complicated Tumor Lysis Syndrome after CVVH Treatment in a Renal Transplantation Patient: One Case Report and Literature Review

Tumor lysis syndrome (TLS) is a potentially lethal emergency causedby lysed tumor cells, and it frequently occurs in tumors of hematologic origin. Up until now, there has been only one known reportpublished overseas about TLS resulting from post-transplant lymphoproliferative disorder (PTLD)[1]. In 2008, a PTLD patient whohad previously undergone renal transplantation was treated in therenal transplantation center of our hospital, and TLS occurred duringtreatment for PTLD. At the time, no further literature regarding thetreatment of post-transplant renal inadequacy complicating TLS wasavailable. So, continuous veno-venous hemofiltration (CVVH) wasused to effectively control the progression of TLS. In this article, the experiences gained from our management of this complex case andour analysis, supported by relevant literature, are described

Metabolic engineering of an acid-tolerant yeast strain Pichia kudriavzevii for itaconic acid production

Itaconic acid (IA), or 2-methylenesuccinic acid, has a broad spectrum of applications in the biopolymer industry owing to the presence of one vinyl bond and two acid groups in the structure. Its polymerization can follow a similar mechanism as acrylic acid but additional functionality can be incorporated into the extra beta acid group. Currently, the bio-based production of IA in industry relies on the fermentation of the filamentous fungus Aspergillus terreus. However, the difficulties associated with the fermentation undertaken by filamentous fungi together with the pathogenic potential of A. terreus pose a serious challenge for industrial-scale production. In recent years, there has been increasing interest in developing alternative production hosts for fermentation processes that are more homogenous in the production of organic acids. Pichia kudriavzevii is a non-conventional yeast with high acid tolerance to organic acids at low pH, which is a highly desirable trait by easing downstream processing. We introduced cis-aconitic acid decarboxylase gene (cad) from A. terreus (designated At_cad) into this yeast and established the initial titer of IA at 135 ± 5 mg/L. Subsequent overexpression of a native mitochondrial tricarboxylate transporter (herein designated Pk_mttA) presumably delivered cis-aconitate efficiently to the cytosol and doubled the IA production. By introducing the newly invented CRISPR-Cas9 system into P. kudriavzevii, we successfully knocked out both copies of the gene encoding isocitrate dehydrogenase (ICD), aiming to increase the availability of cis-aconitate. The resulting P. kudriavzevii strain, devoid of ICD and overexpressing Pk_mttA and At_cad on its genome produced IA at 505 ± 17.7 mg/L in shake flasks, and 1232 ± 64 mg/L in fed-batch fermentation. Because the usage of an acid-tolerant species does not require pH adjustment during fermentation, this work demonstrates the great potential of engineering P. kudriavzevii as an industrial chassis for the production of organic acid.This article is published as Sun, Wan, Ana Vila-Santa, Na Liu, Tanya Prozorov, Dongming Xie, Nuno Torres Faria, Frederico Castelo Ferreira, Nuno Pereira Mira, and Zengyi Shao. "Metabolic engineering of an acid-tolerant yeast strain Pichia kudriavzevii for itaconic acid production." 10 Metabolic Engineering Communications (2020): e00124. DOI: 10.1016/j.mec.2020.e00124. Posted with permission.</p

Microbial synthesis of wax esters

Microbial synthesis of wax esters (WE) from low-cost renewable and sustainable feedstocks is a promising path to achieve cost-effectiveness in biomanufacturing. WE are industrially high-value molecules, which are widely used for applications in chemical, pharmaceutical, and food industries. Since the natural WE resources are limited, the WE production mostly rely on chemical synthesis from rather expensive starting materials, and therefore solution are sought from development of efficient microbial cell factories. Here we report to engineer the yeast Yarrowia lipolytica and bacterium Escherichia coli to produce WE at the highest level up to date. First, the key genes encoding fatty acyl-CoA reductases and wax ester synthase from different sources were investigated, and the expression system for two different Y. lipolytica hosts were compared and optimized for enhanced WE production and the strain stability. To improve the metabolic pathway efficiency, different carbon sources including glucose, free fatty acid, soybean oil, and waste cooking oil (WCO) were compared, and the corresponding pathway engineering strategies were optimized. It was found that using a lipid substrate such as WCO to replace glucose led to a 60-fold increase in WE production. The engineered yeast was able to produce 7.6 g/L WE with a yield of 0.31 (g/g) from WCO within 120 h and the produced WE contributed to 57% of the yeast DCW. After that, E. coli BL21(DE3), with a faster growth rate than the yeast, was engineered to significantly improve the WE production rate. Optimization of the expression system and the substrate feeding strategies led to production of 3.7–4.0 g/L WE within 40 h in a 1-L bioreactor. The predominant intracellular WE produced by both Y. lipolytica and E. coli in the presence of hydrophobic substrates as sole carbon sources were C36, C34 and C32, in an order of decreasing abundance and with a large proportion being unsaturated. This work paved the way for the biomanufacturing of WE at a large scale.This is a manuscript of an article published as Soong, Ya-Hue Valerie, Le Zhao, Na Liu, Peng Yu, Carmen Lopez, Andrew Olson, Hsi-Wu Wong, Zengyi Shao, and Dongming Xie. "Microbial synthesis of wax esters." 67 Metabolic Engineering (2021): 428-442. DOI: 10.1016/j.ymben.2021.08.002. Posted with permission.</p

Cyclic stretch induced oxidative stress by mitochondrial and NADPH oxidase in retinal pigment epithelial cells

Abstract Background Vitreomacular adhesion (VMA) has been reported to associated with age-related macular degeneration (AMD). Understanding the mechanisms underlying cyclic stretch induced in retinal pigment epithelial cells (RPE) may be important for the treatment of VMA-related AMD. Method Cyclic stretch (1HZ, 20% elongation) was applied to cultured ARPE-19 cells for 15 min, 2 h, 6 h, 12 h, 24 h by flexcell FX-5000 Tension system. Total reactive oxygen species (ROS) were detected using DCFH-DA. Mitochondrial superoxide were detected using MitoSOX Red mitochondrial superoxide indicator. NADPH oxidases (NOX) and signaling pathways, such as p38 and PKC, were detected using western blot. Apocycin (Apo) were used as NOX inhibitors. Result High levels of total ROS were detected from 15 min to 24 h, whereas mitochondrial superoxide were higher only in early time. NOX2 were significantly increased at 24 h. NOX4 were significantly increased at 2 h and reach its peak at 24 h. P-p38 was significantly increased at 12 h and 24 h. P-PKC was significantly increased at 15 min and kept a persistent high level. The upregulated expression of NOX4 by cyclic stretch can be significantly decreased under p-PKC inhibitor other than p-p38 inhibitor. Conclusion Cyclic stretch induce oxidative stress from both mitochodrial and NADPH oxidase in RPE cells, which may prompt oxidative damage in VMA-related AMD

Load Balancing in Data Center Networks: A Survey

Data center networks usually employ the scale-out model to provide high bisection bandwidth for applications. A large amount of da