Investigation wettability of carbon components with the polyurethane binder of resistive composites

The research paper deals with influence wettability of carbon components with the polyurethane binder of resistive composites. We have revealed that the polyurethane lacquer wets up to 25 wt. % of C-1 and GE-3 particles, which results in their uniform distribution over the entire volume of the binder and homogeneity of RCMs. Zero wetting of the same weight percentage is observed in the case of K-163 carbon black, which gives rise to caking and distortion of homogeneity of the composite coating after its formation and its further cracking after heat treatment. The wetting capacity of K-163 carbon black in the polyurethane lacquer is improved using a DISPERBYK-2155 dispersing agent in the amount of 10 wt. % with respect to the binder. The resulting experimental data indicate that C-1 particles exhibit the best wettability, hence their adhesion strength with the binder would be higher than that of GE-3 graphite element and K-163 carbon black

Beiträge zum ferroelektrischen Transistor und zu dessen Integration in nicht-flüchtige Speicher

Ferroelektrische Transistoren gelten als viel versprechende Bauelemente im Hinblick auf die Entwicklung neuer, nicht-flüchtiger mikroelektronischer Speicher. In dieser Arbeit werden Möglichkeiten zum Bau solcher Transistoren und daraus bestehender Speicher untersucht. Behandelt werden insbesondere Fragen des Transistoraufbaus, der Materialauswahl, der Herstellung und Charakterisierung, aber auch die Integration ferroelektrischer Feldeffekttransistoren, also der Aufbau von Zellenfeldern eines Speichers. Zum Abschluss werden neue Ideen rund um den ferroelektrischen Transistor vorgestellt, die im Rahmen dieser Arbeit entstanden sind

Role of excited states for the material gain and threshold current density in quantum wire intersubband laser structures

We calculated the material gain and the threshold current density for quantum wire intersubband laser structures. In quantum cascade laser devices with active regions of lower dimensionality a reduction of the non-radiative losses and consequently an increase in the material gain and a reduction of the threshold current density is predicted. In our calculations of the material gain and the threshold current density for a realistic quantum wire intersubband laser structure fabricated by the cleaved edge overgrowth (CEO) technique, however, it turns out that excited states formed in those structures even reduce the material gain compared to conventional quantum well cascade lasers. The threshold current density also turns out to be increased due to the reduced material gain on the one hand and due to a small optical confinement factor in such structures on the other hand. The main consequence for the design of such quantum wire laser structures is to avoid the formation of excited states to be able to benefit from the reduction of the dimensionality of the electron system in terms of reduced non- radiative losses

Current-induced heating in quantum well and quantum wire intersubband emitter structures

We discuss the influence of current-induced heating on the current-voltage (I-V) characteristics and the spectral behavior in quantum well and quantum wire intersubband emitter structures. A conventional quantum cascade laser structure in the AlGaAs/GaAs material system with undoped cladding layers and an undoped active region is examined. This heterostructure serves as a first growth step for quantum wire intersubband emitters fabricated by the cleaved-edge overgrowth technique. We discuss the influence of electrons supplied by a remote delta-silicon doping. Duty-cycle dependent measurements on the quantum wire structures confirm the influence of current-induced heating on the I-V characteristics as well as on the emission spectra

Assessing renal changes after remote ischemic preconditioning (RIPC) of the upper extremity using BOLD imaging at 3T

Acute kidney injury (AKI) is an important risk factor for a number of adverse outcomes including end-stage renal disease and cardiovascular morbidity and mortality. Whilst many clinical situations that can induce AKI are known-e.g. drug toxicity, contrast agent exposure or ischemia during surgery-targeted preventive or therapeutic measures are still lacking. As to renoprotective strategies, remote ischemic preconditioning (RIPC) is one of the most promising novel approaches and has been examined by a number of clinical trials. The aim of this study was to use blood oxygenation level-dependent (BOLD) MRI as a surrogate parameter to assess the effect of RIPC in healthy volunteers. In this IRB-approved, prospective study, 40 healthy volunteers were stratified with 20 undergoing an RIPC procedure (i.e. RIPC group) with a transient ischemia of the right arm, and 20 undergoing a sham procedure. Before and after the procedure, both kidneys of all participants were scanned using a 12-echo mGRE sequence for functional BOLD imaging at 3T. For each volunteer, 180 ROIs were placed in the cortex and the medulla of the kidneys. Ultimately, R2* values, which have an inverse correlation with the oxygenation level of tissue, were averaged for the RIPC and control groups. Following intervention, mean R2* values significantly decreased in the RIPC group in both the cortex (18.6 +/- 2.3 vs. 17.5 +/- 1.7 Hz; p = 0.0047) and medulla (34 +/- 5.2 vs. 32.2 +/- 4.2 Hz; p = 0.0001). However, no significant differences were observed in the control group. RIPC can be non-invasively assessed in healthy volunteers using BOLD MRI at 3T, demonstrating a higher oxygen content in kidney tissue. This study presents a first-in-man trial establishing a quantifiable readout of RIPC and its effects on kidney physiology. BOLD measurements may advance clinical trials in further evaluating RIPC for future clinical care

Successful use of TNF alpha blockade in a severe case of idiopathic non-granulomatous ulcerative jejunoileitis associated with thrombotic thrombocytopenic purpura

We describe the case of 50-year-old female patient who presented with severe gastrointestinal symptoms and progressive weight loss of unknown origin. Shortly after admission, she developed an acute flare of thrombotic thrombocytopaenic purpura (TTP) that had to be treated by plasma exchange therapy and rituximab administration. While the signs of TTP subsided, the gastrointestinal symptoms worsened with abdominal cramps, massive gastric retention, malnourishment and a stenosis due to extensive inflammation and wall thickening of the small bowel. Extensive diagnostic efforts yielded no specific cause, so the patient-based on the histopathological findings-was diagnosed with idiopathic non-granulomatous ulcerative jejunoileitis. Following a highly complicated clinical course over several months, successful remission of the inflammatory activity and recovery of the patient could be obtained by TNF-alpha blockade

Precision and reliability of liver iodine quantification from spectral detector CT: evidence from phantom and patient data

ObjectiveTo comprehensively assess precision, reproducibility, and repeatability of iodine maps from spectral detector CT (SDCT) in a phantom and in patients with repetitive examination of the abdomen.MethodsSeventy-seven patients who underwent examination two (n=52) or three (n=25) times according to clinical indications were included in this IRB-approved, retrospective study. The anthropomorphic liver phantom and all patients were scanned with a standardized protocol (SSDE in patients 15.8mGy). In patients, i.v. contrast was administered and portal venous images were acquired using bolus-tracking technique. The phantom was scanned three times at three time points; in one acquisition, image reconstruction was repeated three times. Region of interest (ROI) were placed automatically (phantom) or manually (patients) in the liver parenchyma (mimic) and the portal vein; attenuation in conventional images (CI [HU]) and iodine map concentrations (IM [mg/ml]) were recorded. The coefficient of variation (CV [%]) was used to compare between repetitive acquisitions. If present, additional ROI were placed in cysts (n=29) and hemangioma (n=29).ResultsDifferences throughout all phantom examinations were <2%. In patients, differences between two examinations were higher (CV for CI/IM: portal vein, 2.5%/3.2%; liver parenchyma, -0.5%/-3.0% for CI/IM). In 80% of patients, these differences were within a 20% limit. Differences in benign liver lesions were even higher (68% and 38%, for CI and IM, respectively).ConclusionsIodine maps from SDCT allow for reliable quantification of iodine content in phantoms; while in patients, rather large differences between repetitive examinations are likely due to differences in biological distribution. This underlines the need for careful clinical interpretation and further protocol optimization.Key Points center dot Spectral detector computed tomography allows for reliable quantification of iodine in phantoms.center dot In patients, the offset between repetitive examinations varies by 20%, likely due to differences in biological distribution. center dot Clinically, iodine maps should be interpreted with caution and should take the intra-individual variability of iodine distribution over time into account

Are gamers better laparoscopic surgeons? Impact of gaming skills on laparoscopic performance in Generation Y students

Background Both laparoscopic surgery and computer games make similar demands on eye-hand coordination and visuospatial cognitive ability. A possible connection between both areas could be used for the recruitment and training of future surgery residents. Aim The goal of this study was to investigate whether gaming skills are associated with better laparoscopic performance in medical students. Methods 135 medical students (55 males, 80 females) participated in an experimental study. Students completed three laparoscopic tasks (rope pass, paper cut, and peg transfer) and played two custom-designed video games (2D and 3D game) that had been previously validated in a group of casual and professional gamers. Results There was a small significant correlation between performance on the rope pass task and the 3D game, Kendall's tau(111) = -.151,P= .019. There was also a small significant correlation between the paper cut task and points in the 2D game, Kendall's tau(102) = -.180,P= .008. Overall laparoscopic performance was also significantly correlated with both the 3D game, Kendall's tau(112) = -.134,P= .036, and points in the 2D game, Kendall's tau(113) = -.163,P= .011. However, there was no significant correlation between the peg transfer task and both games (2D and 3D game),P= n.s.. Conclusion This study provides further evidence that gaming skills may be an advantage when learning laparoscopic surgery

Characterization of a splice-site mutation in the tumor suppressor gene FLCN associated with renal cancer

Abstract Background Renal cell carcinoma is among the most prevalent malignancies. It is generally sporadic. However, genetic studies of rare familial forms have led to the identification of mutations in causative genes such as VHL and FLCN. Mutations in the FLCN gene are the cause of Birt-Hogg-Dubé syndrome, a rare tumor syndrome which is characterized by the combination of renal cell carcinoma, pneumothorax and skin tumors. Methods Using Sanger sequencing we identify a heterozygous splice-site mutation in FLCN in lymphocyte DNA of a patient suffering from renal cell carcinoma. Furthermore, both tumor DNA and DNA from a metastasis are analyzed regarding this mutation. The pathogenic effect of the sequence alteration is confirmed by minigene assays and the biochemical consequences on the protein are examined using TALEN-mediated transgenesis in cultured cells. Results Here we describe an FLCN mutation in a 55-year-old patient who presented himself with progressive weight loss, bilateral kidney cysts and renal tumors. He and members of his family had a history of recurrent pneumothorax during the last few decades. Histology after tumor nephrectomy showed a mixed kidney cancer consisting of elements of a chromophobe renal cell carcinoma and dedifferentiated small cell carcinoma component. Subsequent FLCN sequencing identified an intronic c.1177-5_-3delCTC alteration that most likely affected the correct splicing of exon 11 of the FLCN gene. We demonstrate skipping of exon 11 to be the consequence of this mutation leading to a shift in the reading frame and the insertion of a premature stop codon. Interestingly, the truncated protein was still expressed both in cell culture and in tumor tissue, though it was strongly destabilized and its subcellular localization differed from wild-type FLCN. Both, altered protein stability and subcellular localization could be partly reversed by blocking proteasomal and lysosomal degradation. Conclusions Identification of disease-causing mutations in BHD syndrome requires the analysis of intronic sequences. However, biochemical validation of the consecutive alterations of the resulting protein is especially important in these cases. Functional characterization of the disease-causing mutations in BHD syndrome may guide further research for the development of novel diagnostic and therapeutic strategies

Additional file 3: Figure S3. of Characterization of a splice-site mutation in the tumor suppressor gene FLCN associated with renal cancer

a Western blots were loaded with whole cell lysates of cultured human cells (RPE-1) that had been transfected either with scrambled control siRNA or with two different siRNAs targeting FLCN. Staining with the anti-FLCN antibody shows one specific band at the expected molecular weight the intensity of which is strongly reduced by FLCN knockdown (left panel). Anti-Actin staining of the same membrane was used to control for equal loading (right panel). b To check whether the antibody was suitable for IHC as well we stained cell pellets of the established FLCN knockout cell line UOK257 lentivirally transduced to express emGFP (left image) showing little to no signal. UOK257cells that had been lentivirally transduced to express FLCN show a strong signal (magnification 40×). c IHC in human tissue shows that FLCN can still be detected in the chromophobe renal cell carcinoma of the BHD patient (middle panel). Normal human kidney tissue from a control (left side) was stained for comparison and shows a stronger signal. A control staining without the FLCN first antibody is shown on the right side of the panel (magnification 40×). (PDF 9710 kb