Theoretical Study of Electron Mobility in Double-Gate Field Effect Transistors with Multilayer (strained-)Si/SiGe Channel

Walczak, Jakub,Majkusiak, Bogdan The Institute of Electronics and Information Engin 2008 Journal of semiconductor technology and science Vol.8 No.3

Electron mobility has been investigated theoretically in undoped double-gate (DG) MOSFETs of different channel architectures: a relaxed-Si DG SOI, a strained-Si (sSi) DG SSOI (strained-Si-on-insulator, containing no SiGe layer), and a strained-Si DG SGOI (strained-Si-on-SiGe-on-insulator, containing a SiGe layer) at 300K. Electron mobility in the DG SSOI device exhibits high enhancement relative to the DG SOI. In the DG SGOI devices the mobility is strongly suppressed by the confinement of electrons in much narrower strained-Si layers, as well as by the alloy scattering within the SiGe layer. As a consequence, in the DG SGOI devices with thinnest strained-Si layers the electron mobility may drop below the level of the relaxed DG SOI and the mobility enhancement expected from the strained-Si devices may be lost.

Theoretical Study of Electron Mobility in Double-Gate Field Effect Transistors with Multilayer (strained-)Si/SiGe Channel

Jakub Walczak,Bogdan Majkusiak 대한전자공학회 2008 Journal of semiconductor technology and science Vol.8 No.3

Electron mobility has been investigated theoretically in undoped double-gate (DG) MOSFETs of different channel architectures: a relaxed-Si DG SOI, a strained-Si (sSi) DG SSOI (strained-Si-oninsulator, containing no SiGe layer), and a strained-Si DG SGOI (strained-Si-on-SiGe-on-insulator, containing a SiGe layer) at 300K. Electron mobility in the DG SSOI device exhibits high enhancement relative to the DG SOI. In the DG SGOI devices the mobility is strongly suppressed by the confinement of electrons in much narrower strained-Si layers, as well as by the alloy scattering within the SiGe layer. As a consequence, in the DG SGOI devices with thinnest strained-Si layers the electron mobility may drop below the level of the relaxed DG SOI and the mobility enhancement expected from the strained-Si devices may be lost.

The new generation of the hemispherical energy analyzer in the novel surface science research

Lukasz WALCZAK 한국진공학회 2016 한국진공학회 학술발표회초록집 Vol.2016 No.8

Fluorescence detection by miniaturized instrumentation based on non-cooled CCD minicamera and dedicated for lab-on-a-chip applications

Rafał Walczak 한국바이오칩학회 2011 BioChip Journal Vol.5 No.3

Due to high specificity and sensitivity, fluorometric detection is one of the main detection methods applied in analytical microsystems commonly known as lab-on-a-chip (LOC). In most cases, optical instrumentation for fluorescence induction and detection is based on configuration and components “borrowed” from large laboratory instruments based on an epifluorescence microscope. As a result, the optical instrumentation surrounding lab-on-a-chip is bulky, expensive and dedicated for operation only inside laboratories. In this paper a brief discussion on fluorescence detection in lab-on-a-chip is presented. Next, novel low-cost detection instrumentation utilising noncooled CCD image sensor and semiconductor laser light source is described. The instrumentation is dedicated for operation in portable and low-cost devices for different LOC-based life science applications. Finally, an example of application of the novel method and instrumentation co-working with lab-on-a-chip for real-time PCR detection of food pathogens is briefly described.

Serum copeptin as a predictor of risk of hyponatremia after transurethral prostatectomy

( Katarzyna Bryc-walczak ),( Władysław Bryc ),( Michał Nowicki ) 대한신장학회 2023 Kidney Research and Clinical Practice Vol.42 No.2

Background: Transurethral resection of the prostate gland (TURP) frequently leads to the development of dilutional hyponatremia. Copeptin has been established as a surrogate marker of vasopressin and is measured for clinical assessment of various sodium and water disturbances. This study aims to assess the utility of serum concentration of copeptin and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) for prediction of post-TURP alterations of serum sodium concentration. Methods: Forty-three patients with benign prostatic hyperplasia undergoing TURP were enrolled. Serum sodium and copeptin were measured before the procedure, then 12 hours after its completion. NT-proBNP was assessed at baseline. The total amount of fluids and sodium administered intravenously and used to flush the bladder during TURP was calculated in each patient. Receiver operator characteristic (ROC) curve analysis was used to determine value of copeptin and NT-proBNP for prediction of hyponatremia after TURP. Results: In forward stepwise multiple regression analysis of serum copeptin before surgery and the duration of TURP explained the significant portion of the sodium concentration variation 12 hours from the start of the surgery. ROC curve analysis showed that serum copeptin before surgery predicted development of hyponatremia 12 hours after TURP (area under the curve, 0.775; 95% confidence interval, 0.62-0.89; p < 0.001) with a cut-off point of >78.6 pg/mL with 77% sensitivity and 64.7% specificity. Serum NT-proBNP before surgery did not predict hyponatremia 12 hours after TURP. Conclusion: Serum copeptin before TURP surgery, but not NT-proBNP, may be a clinically useful marker of the risk of serum sodium decrease after TURP.

Myocardial Infarction Type 4b in Human Immunodeficiency Virus-Infected Patient

Aneta Cybula-Walczak,Filip M. Szymanski,Anna E. Platek,Grzegorz Karpinski 대한심장학회 2014 Korean Circulation Journal Vol.44 No.1

We report a case of a 52-year-old human immunodeficiency virus (HIV)-infected male patient receiving combined antiretroviral therapy(cART), who presented with acute ST-elevation myocardial infarction (STEMI). He was properly treated (e.g., prescribed anti-coagulationdrugs: aspirin, clopidogrel, enoxaparin) and discharged. After 1.5 months, another STEMI related with in-stent thrombosis took place. ThecART scheme was altered, resulting in no further cardiac events in the follow-up period, with undetectable levels of HIV ribonucleic acid. This case highlights the association between HIV infection and the specific drugs of cART, and the risk of cardiovascular disease develop -ment.

Preparation by the double extraction process with preliminary neutron irradiation of yttria or calcia stabilised cubic zirconium dioxide microspheres

Brykala, Marcin,Walczak, Rafal,Wawszczak, Danuta,Kilim, Stanislaw,Rogowski, Marcin,Strugalska-Gola, Elzbieta,Olczak, Tadeusz,Smolinski, Tomasz,Szuta, Marcin Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.1

A modern approach to nuclear energy involves reprocessing like transmutations of spent nuclear fuel products to reduce their radiotoxicity and time needed for their storage. For this purpose, they are immobilized in inert matrices made of zirconia and can be "burned" in fast neutron reactor or Accelerator Driven System. These matrices in spherical form can be obtained by sol-gel process. The paper presents a method of microspheres fabrication based on the combined Complex Sol-Gel Process and double extraction process consisting in the preparation of zirconium-ascorbate sol and simultaneous extraction of water and nitrates. The procedure allows obtaining gel microspheres with a diameter of 50 ㎛, which after heat treatment are processed into the final product. The synthesis of zirconia microspheres with Yttrium by internal gelation process is well known for over a decade now. However, the explanation and characterization of synthesis of such material by extraction of water process is rarely found. Parameters such as: pH, viscosity, shape, sphericity and crystal structure have been determined for synthesized products and semi-products. In addition, preliminary research consisting in irradiation of the obtained materials in fast and thermal neutron flux was carried out. The obtained results are presented and described in this work.

Extremely High Mortality Rate after a Successful Gastrectomy for Cancer in Older Adults

Ciesielski, Maciej,Kruszewski, Wieslaw Janusz,Szajewski, Mariusz,Walczak, Jakub,Spychalska, Natalia,Szefel, Jaroslaw,Zielinski, Jacek The Korean Gastric Cancer Association 2019 Journal of gastric cancer Vol.19 No.2

Purpose: Poor physiological reserve for withstanding major cancer surgery in older adults is an important concern in the selection of patients for oncologic gastrectomy. The present study aimed to analyze mortality patterns among patients who underwent gastrectomy for cancer according to age groups. The primary outcomes of this study were early- and middleterm results: 30-day and 3-, 6-, 12-, and 36-month mortality rates. Materials and Methods: A retrospective review of 288 patients who underwent surgical resection for gastric cancer in two centers was carried out. Patients were stratified into four groups according to age: 29-50 years (group I, n=27), 51-65 years (group II, n=117), 66-75 years (group III, n=81), and 76-92 years (group IV, n=58). Statistical calculations focused on the differences in the survival rates between groups I and II as well as between groups II and IV. Results: The middle-aged patients (group II) had significantly better 3-year survival than either the youngest (group I) or the oldest patients (group IV). The 6-month mortality rates were 16.9% in group III and 29.3% in group IV. Two-thirds of the patients from groups III and IV who died between 2 and 6 months after surgery had an uneventful postoperative course. Conclusions: Age is an important prognostic factor of middle-term survival after gastrectomy for cancer. Geriatric assessment and better patient selection for major surgery for cancer are required to improve the outcome of gastrectomy for cancer in patients aged over 75 years.

Novel biocidal N-halamine plastic based on poly(vinyl chloride): Preparation and characteristics

Marta Chylin´ ska,Halina Kaczmarek,Aleksandra Burkowska-But,Maciej Walczak 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.28 No.-

Preparation method of new biocidal plastics based on plasticized PVC has been elaborated. Thederivative of poly(4-vinylbenzyl chloride) containing N-halamine substituents has been mixed with PVCgranules and processed by dry blend extrusion and injection moulding. The properties of obtainedmaterial have been tested using SEM/EDX and thermogravimetry. The biocidal efficacy of modified PVCresin has been tested against two strains of bacteria: Escherichia coli (Gram-negative) and Staphylococcusaureus (Gram-positive). It was found that even small amount of biocidal component yields to efficient biocidal activity of thewhole plastic. Chemical composition and other properties of PVC remain almost unchanged

Extremely High Mortality Rate after a Successful Gastrectomy for Cancer in Older Adults

Maciej Ciesielski,Wiesław Janusz Kruszewski,Mariusz Szajewski,Jakub Walczak,Natalia Spychalska,Jarosław Szefel,Jacek Zieliński 대한위암학회 2019 Journal of gastric cancer Vol.19 No.2

Purpose: Poor physiological reserve for withstanding major cancer surgery in older adults is an important concern in the selection of patients for oncologic gastrectomy. The present study aimed to analyze mortality patterns among patients who underwent gastrectomy for cancer according to age groups. The primary outcomes of this study were early- and middleterm results: 30-day and 3-, 6-, 12-, and 36-month mortality rates. Materials and Methods: A retrospective review of 288 patients who underwent surgical resection for gastric cancer in two centers was carried out. Patients were stratified into four groups according to age: 29–50 years (group I, n=27), 51–65 years (group II, n=117), 66–75 years (group III, n=81), and 76–92 years (group IV, n=58). Statistical calculations focused on the differences in the survival rates between groups I and II as well as between groups II and IV. Results: The middle-aged patients (group II) had significantly better 3-year survival than either the youngest (group I) or the oldest patients (group IV). The 6-month mortality rates were 16.9% in group III and 29.3% in group IV. Two-thirds of the patients from groups III and IV who died between 2 and 6 months after surgery had an uneventful postoperative course. Conclusions: Age is an important prognostic factor of middle-term survival after gastrectomy for cancer. Geriatric assessment and better patient selection for major surgery for cancer are required to improve the outcome of gastrectomy for cancer in patients aged over 75 years.