Experimental Study on Portable Air-Conditioning System with Enhanced PCM Condenser

Portable personal cooling systems with a vapor compression cycle (VCC), thermal battery, and electrical battery are an attractive option for localized cooling as compared with stationary air-conditioning systems. A phase change material (PCM) can be used for storing waste heat from the VCC condenser, thereby acting as a thermal battery. In the PCM condenser, copper tubes are submerged in the PCM tank. Due to the low thermal conductivity of pure PCM, the overall heat transfer coefficient of the PCM condenser is limited, which results in high condensing VCC pressure and, thus, low system COP. By applying heat transfer augmentation, the effective heat transfer coefficient can be increased. A thermal energy storage (TES) system that stores condenser heat in the PCM during VCC operation and is regenerated through solidification by a thermosyphon operation is proposed. A receiver is utilized to balance refrigerant charge in the VCC and compensate liquid refrigerant in the thermosyphon loop. In the cooling cycle, PCM stores thermal energy from the condenser pipes and changes from a subcooled solid state to a liquid state, which results in the change of condenser pressure and temperature and, thus, subcooling of the refrigerant. In this study, the system performance of the VCC and PCM condenser was experimentally investigated. Effects of the following three types of enhanced PCM condensers on system performance were studied and analyzed: copper sponge enhanced PCM with helically coiled copper tubes, graphite matrix enhanced PCM with straight copper tubes and small tube inner diameter refrigerant distribution header, and graphite matrix enhanced PCM with straight copper tubes and large tube inner diameter refrigerant distribution header. Results show that these TES systems with both PCM discharging and PCM regeneration cycles operate properly and effectively. The entire cooling system was able to provide four hours of continuous cooling, and the PCM was fully regenerated after six hours of thermosyphon operation. The comparison of three PCM condensers indicates that the system with the large header graphite matrix enhanced PCM condenser performed the best with a cooling COP of 4.7 when the PCM is in two-phase region. The copper sponge enhanced system had a COP of 4.2, and the graphite matrix with the small distributor header system had a COP of 3.1. Compared with copper sponge, graphite matrix has better enhancement of PCM heat transfer. Moreover, the condenser with the large distributor header can achieve more uniform refrigerant flow and PCM temperature distribution than one with the small header. This leads to the higher utilization ratio of PCM latent heat. The copper sponge enhanced PCM condenser with helical tube is the second best, but needs higher heat transfer surface area and condenser volume as well as more refrigerant charge because of more liquid refrigerant needed in the thermosyphon loop. In conclusion, the system design with graphite matrix enhanced PCM and condenser having a larger refrigerant distribution header and straight copper tubes is recommended due to its low refrigerant charge, higher system COP, and use of lower cost enhancement materials

HLA-E and Its Soluble Form as Indicators of a Sex-Specific Immune Response in Patients with Oral Squamous Cell Carcinoma

The human leukocyte antigene E (HLA-E) is associated with tumorigenesis in various cancers. Immunoncology along with sex-specific aspects in cancer therapy are now in scientific focus. Therefore, immunohistochemical HLA-E expression was retrospectively analysed in a cohort of oral squamous cell carcinomas (OSCC) after surgical therapy. Then, serum concentration of HLA-E (sHLA-E) was quantified in a prospective cohort by enzyme-linked immunosorbent assay. High HLA-E expression was associated with advanced UICC stage (Spearman’s correlation: p = 0.002) and worse survival (Cox-regression: progression-free survival: hazard ratio (HR) 3.129, confidence range (CI) 1.443–6.787, p = 0.004; overall survival: HR 2.328, CI 1.071–5.060, p = 0.033). The sHLA-E concentration was significantly higher in the control group than in tumor group (Mann–Whitney U-test (MW-U): p = 0.021). Within the tumor group, women showed significantly higher sHLA-E levels than men (MW-U: p = 0.049). A closer look at the tumor group and the control group showed that gender-specific differences exist: while no differences in sHLA-E concentration were detectable between female subjects of tumor group and control group (MW-U: p = 0.916), male subjects of tumor group had a significantly lower sHLA-E concentration compared to those of control group (MW-U: p = 0.001). In summary, our results provide evidence for sex-specific differences in immune responses in OSCC. This fact should be considered regarding future immunotherapy regimens

TREM2 Is Associated with Advanced Stages and Inferior Prognosis in Oral Squamous Cell Carcinoma

Triggering receptor expressed on myeloid cells 2 (TREM2) is suggested to hamper antitumor immune response in multiple cancers. However, the role of TREM2 in oral squamous cell carcinoma (OSCC) and its expression in tumor-associated macrophages (TAMs) are unknown. In this study, TREM2 expression was analyzed in the primary tumors and corresponding lymph-node metastases of OSCC patients via immunohistochemistry on tissue microarrays. Human peripheral blood mononuclear cells (PBMCs) and single-cell suspensions of tumor and healthy adjacent tissues were analyzed for the presence of TREM2+ macrophages and TAMs using flow cytometry. The serum levels of soluble TREM2 (sTREM2) were quantified using an enzyme-linked immunosorbent assay. High TREM2 expression was associated with advanced UICC stages (Spearman’s rank correlation (SRC), p = 0.04) and significantly reduced survival rates in primary tumors (multivariate Cox regression, progression-free survival: hazard ratio (HR) of 2.548, 95% confidence interval (CI) of 1.089–5.964, p = 0.028; overall survival: HR of 2.17, 95% CI of 1.021–4.613, p = 0.044). TREM2 expression was significantly increased in the PBMCs of OSCC patients in UICC stage IV compared with healthy controls (ANOVA, p < 0.05). The serum levels of sTREM2 were higher in advanced UICC stages, but they narrowly missed significance (SRC, p = 0.059). We demonstrated that TREM2 was multi-factorially associated with advanced stages and inferior prognosis in OSCC patients and that it could serve as a prognostic biomarker in OSCC patients. Targeting TREM2 has the potential to reshape the local and systemic immune landscape for the potential enhancement of patients’ prognosis

IDO1 is highly expressed in macrophages of patients in advanced tumour stages of oral squamous cell carcinoma

Purpose Strategies for Indolamine-2,3-dioxygenase 1 (IDO1) inhibition in cancer immunotherapy once produced encouraging results, but failed in clinical trials. Recent evidence indicates that immune cells in the tumour microenvironment, especially macrophages, contribute to immune dysregulation and therefore might play a critical role in drug resistance. Methods In this study, we investigated the signifcance of IDO1 expressing immune cells in primary tumours and corresponding lymph node metastases (LNMs) in oral squamous cell carcinoma (OSCC) by immunohistochemistry. The link between IDO1 and macrophages was investigated by fow cytometry in tumour tissue, healthy adjacent tissue and peripheral blood mononuclear cells (PBMCs). IDO1 activity (measured as Kynurenine/Tryptophan ratio) was assessed by ELISAs. Results High IDO1 expression in tumour-infltrating immune cells was signifcantly correlated with advanced stages [Spearman’s rank correlation (SRC), p=0.027] and reduced progression-free survival (multivariate Cox regression, p=0.034). IDO1 was signifcantly higher expressed in PBMCs of patients in advanced stages than in healthy controls (ANOVA, p<0.05) and IDO1+ macrophages were more abundant in intratumoural areas than peritumoural (t test, p<0.001). IDO1 expression in PBMCs was signifcantly correlated with IDO1 activity in serum (SRC, p<0.05). IDO1 activity was signifcantly higher in patients with LNMs (t test, p<0.01). Conclusion All in all, IDO1 expressing immune cells, especially macrophages, are more abundant in advanced stages of OSCC and are associated with reduced progression-free survival. Further investigations are needed to explore their role in local and systemic immune response. The IDO1 activity might be a suitable biomarker of metastasis in OSCC patients

Ulnar artery thrombosed aneurysm in a roofer

peer reviewedNous rapportons un cas clinique d’anévrisme thrombosé de l’artère ulnaire. Il s’agit d’une pathologie peu fréquente et mal connue, régulièrement associée au syndrome du marteau hypothénarien, retrouvé spécifiquement chez les travailleurs manuels et les sportifs exposés à des traumatismes manuels répétés.A case of ulnar artery aneurysm in an independent roofer is reported. It is a rare disease often associated with the Hammer Hypothenar Syndrome specifically found in manual workers and athletes exposed to repetitive palmar trauma

Functional modeling of the craniospinal system for in-vitro parameter studies on the pathogenesis of NPH

Normal Pressure Hydrocephalus (NPH) has become a common disease in the elderly coming along with typical symptoms of dementia, gait ataxia and urinary incontinence, which make the differential diagnosis with other forms of dementia difficult. Furthermore the pathogenesis of NPH is still not understood. About 10% of all demented patients might be suffering from NPH [1]. Many hypotheses suggest that modified biomechanical boundary conditions affect the craniospinal dynamics inducing the pathogenesis of NPH. We present a novel approach for an in-vitro model of the craniospinal system to investigate important hydrodynamic influences on the system such as (dynamic) compliance of the vascular system and especially the spinal subarachnoid space (SAS) as well as reabsorption and hydrostatics. The experimental set-up enables the individual adjustment of relevant parameters for sensitivity analyses regarding the impact of resulting CSF dynamics on the pathogenesis of NPH