Theoretical aspects of sorption refrigeration using organic compounds

Refrigeration devices for essential food storage and preservation of medicine are among the most significant techniques developed in the past few decades. In many regions of Africa, the shortage of sustainable power sources and the abundance of solar energy make solar refrigerators a promising solution for basic refrigeration needs. Among all the solar cooling techniques, the solar sorption refrigerator is considered to be a promising alternative to the dominant vapour-compression refrigerator, which encompasses both absorption and adsorption refrigerators. It has advantages of being silent, having no compressor, lasting a long life cycle, and utilising waste heat or solar energy. In this work, the development of sorption refrigerators is outlined, and as a part of it, a theoretical diffusion absorption chiller using organic compounds is designed. The alternative working fluids used is R134a as the refrigerant, tetraethylene glycol dimethyl ether (TEG.DME) as the absorbent, and helium as the auxiliary gas. The corresponding modelling is carried out as a potential cooling system based on calculations. Furthermore, as a second part of this work, a laboratory prototype of a solid adsorption system being developed by the "Institute of Chemical Process Engineering (ICVT)" in Stuttgart University, is studied and compared. The study focuses on adsorption properties of methanol on activated carbon in adsorption process. Adsorption equilibrium data has been measured, and a good agreement between the measured equilibrium data and theoretical Dubinin-Astakhov model has been obtained. This prediction model can now be used to provide accurate data-sets, and consequently help to optimise the adsorption performance of the cooling unit. [Please note: this thesis file has been deferred until December 2016

PDLIM2 restricts Th1 and Th17 differentiation and prevents autoimmune disease

Background: PDLIM2 is essential for the termination of the inflammatory transcription factors NF-κB and STAT but is dispensable for the development of immune cells and immune tissues/organs. Currently, it remains unknown whether and how PDLIM2 is involved in physiologic and pathogenic processes. Results: Here we report that naive PDLIM2 deficient CD4+ T cells were prone to differentiate into Th1 and Th17 cells. PDLIM2 deficiency, however, had no obvious effect on lineage commitment towards Th2 or Treg cells. Notably, PDLIM2 deficient mice exhibited increased susceptibility to experimental autoimmune encephalitis (EAE), a Th1 and/or Th17 cell-mediated inflammatory disease model of multiple sclerosis (MS). Mechanistic studies further indicate that PDLIM2 was required for restricting expression of Th1 and Th17 cytokines, which was in accordance with the role of PDLIM2 in the termination of NF-κB and STAT activation. Conclusion: These findings suggest that PDLIM2 is a key modulator of T-cell-mediated immune responses that may be targeted for the therapy of human autoimmune diseases

Simultaneous suppression of PKM2 and PHGDH elicits synergistic anti-cancer effect in NSCLC

Metabolic reprogramming is a hallmark of human cancer. Cancer cells exhibit enhanced glycolysis, which allows glycolytic intermediates to be diverted into several other biosynthetic pathways, such as serine synthesis. Here, we explored the anti-cancer effects of the pyruvate kinase (PK) M2 inhibitor PKM2-IN-1 alone or in combination with the phosphoglycerate dehydrogenase (PHGDH) inhibitor NCT-503 in human NSCLC A549 cells in vitro and in vivo. PKM2-IN-1 inhibited proliferation and induced cell cycle arrest and apoptosis, with increased glycolytic intermediate 3-phosphoglycerate (3-PG) level and PHGDH expression. The combination of PKM2-IN-1 and NCT-503 further suppressed cancer cell proliferation and induced G2/M phase arrest, accompanied by the reduction of ATP, activation of AMPK and inhibition of its downstream mTOR and p70S6K, upregulation of p53 and p21, as well as downregulation of cyclin B1 and cdc2. In addition, combined treatment triggered ROS-dependent apoptosis by affecting the intrinsic Bcl-2/caspase-3/PARP pathway. Moreover, the combination suppressed glucose transporter type 1 (GLUT1) expression. In vivo, co-administration of PKM2-IN-1 and NCT-503 significantly inhibited A549 tumor growth. Taken together, PKM2-IN-1 in combination with NCT-503 exhibited remarkable anti-cancer effects through induction of G2/M cell cycle arrest and apoptosis, in which the metabolic stress induced ATP reduction and ROS augmented DNA damage might be involved. These results suggest that the combination of PKM2-IN-1 and NCT-503 might be a potential strategy for the therapy of lung cancer

Long-term follow-up result of antithyroid drug treatment of Graves’ hyperthyroidism in a large cohort

Objective: This study evaluated the efficacy of antithyroid drugs (ATDs) and risk factors associated with the recurrence of Graves’ hyperthyroidism using a comprehensive retrospective cohort. Methods: We included 1829 patients newly diagnosed with Graves’ hyperthyroidism, with sufficient follow-up data. Clinical outcomes of the patients and risk factors associated with recurrence-free survival, including the changes in thyrotropin receptor antibody, were evaluated. Results: The median age of the patients was 44.5 years, and 69% were female. Among the patients, 1235 had a chance to withdraw ATD after a median of 23 (interquartile range (IQR) 17.0–35.5) months of treatment. The first remission rate was 55.6% during a median of 72.7 months of follow-up. After the first recurrence, 95% of patients underwent the second course of ATD treatment for a median of 21 .1 (IQR 14.8–31.7) months, and the remission rate was 54.1%. During a median of 67 months of follow-up, 7.7% of patients underwent surgery, and 10.5% underwent radioac tive iodine therapy. Approximately 30% were still on ATD therapy for recurrent disease or prolonged lowdose maintenance. Younger age (<45 years), male sex, and fluctua ting or smoldering of TRAb levels were independent risk factors of the first recurrenc e after ATD treatment. Conclusions: ATD treatment is an acceptable option for the initial treatment of Graves’ hyperthyroidism as well as for recurrent disease. The optimal treatment period for ATD treatment needs to be determined using the individual risk factors of recurrence

SHMT2 expression as a diagnostic and prognostic marker for thyroid cancer

Background: Catabolism of serine via serine hydroxymethyltransferase2 (SHMT2) through the mitochondrial one-carbon unit pathway is important in tumorigenesis. Therefore, SHMT2 may play a role in thyroid cancer. Methods: Thyroid tissue samples and The Cancer Genome Atlas (TCGA) database were used to evaluate SHMT2 expression in thyroid tissues and the association with clinical outcomes. Results: SHMT2 protein expression was evaluated in thyroid tissues consisting of 52 benign nodules, 129 papillary thyroid carcinomas (PTC) and matched normal samples, and 20 anaplastic thyroid carcinomas (ATC). ATCs presented the highest (95.0%) positivity of SMHT2 protein expression. PTCs showed the second highest (73.6%) positivity of SHMT2 expression, which was significantly higher than that of be nign nodules (19.2%, P = 0.016) and normal thyroid tissues (0%, P < 0.001). Analysis of TCGA data showed that SHMT2 messenger RNA (mRNA) expression was significantly higher in tumo rs than in normal tissues (P < 0.001). When we classified thyroid cancer into high and low gr oups according to SHMT2 mRNA expression levels, the thyroid differentiation score for t he high SHMT2 group was significantly lower than that of the low SH MT2 group (P < 0.001). There was also a significant correlation between SHMT2 mRNA expression and the stemness index (r = 0.41, P < 0.001). The high SHMT2 group had more advanced TNM stages and shorter progression-free survival rates than the low SHMT2 group (P < 0.01 and P = 0.007, respectively). Conclusion: SHMT2 expression is higher in thyroid cancers than normal or benign tissues and is associated with de-differentiation and poor clinical outc omes. Thus, SHMT2 might be useful as a diagnostic and prognostic marker for thyroid cancer

Dynamic Power-Saving Method for Wi-Fi Direct Based IoT Networks Considering Variable-Bit-Rate Video Traffic

With the arrival of the era of Internet of Things (IoT), Wi-Fi Direct is becoming an emerging wireless technology that allows one to communicate through a direct connection between the mobile devices anytime, anywhere. In Wi-Fi Direct-based IoT networks, all devices are categorized by group of owner (GO) and client. Since portability is emphasized in Wi-Fi Direct devices, it is essential to control the energy consumption of a device very efficiently. In order to avoid unnecessary power consumed by GO, Wi-Fi Direct standard defines two power-saving methods: Opportunistic and Notice of Absence (NoA) power-saving methods. In this paper, we suggest an algorithm to enhance the energy efficiency of Wi-Fi Direct power-saving, considering the characteristics of multimedia video traffic. Proposed algorithm utilizes the statistical distribution for the size of video frames and adjusts the lengths of awake intervals in a beacon interval dynamically. In addition, considering the inter-dependency among video frames, the proposed algorithm ensures that a video frame having high priority is transmitted with higher probability than other frames having low priority. Simulation results show that the proposed method outperforms the traditional NoA method in terms of average delay and energy efficiency