INTRODUCTION: Renal cell carcinoma (RCC) accounts for approximately 3% of adult malignancies and more than 90% of neoplasms arising from the kidney. Uninformative percutaneous kidney biopsies vary from 10 to 23%. As a result, 7.5-33.6% of partial nephrectomies in patients with small renal masses (SRM) are performed on benign renal tumors. The aim of this study was to assess the feasibility of the apparent diffusion coefficient (ADC) of the diffusion-weighted imaging (DWI) of MRI, as RCC imaging biomarker for differentiation of SRM. METHOD: Adult patients (n = 158) with 170 SRM were enrolled into this study. The control group were healthy volunteers with normal clinical and radiologic findings (n = 15). All participants underwent MRI with DWI sequence included. RESULTS: Mean ADC values of solid RCC (1.65 ± 0.38 × 10-3 mm2/s) were lower than healthy renal parenchyma (2.47 ± 0.12 × 10-3 mm2/s, p < 0.05). There was no difference between mean ADC values of ccRCC, pRCC and chRCC (1.82 ± 0.22 × 10-3 vs 1.61 ± 0.07 × 10-3 vs 1.46 ± 0.09 × 10-3 mm2/s, respectively, p = ns). An inverse relationship between mean ADC values and Fuhrman grade of nuclear atypia of solid ccRCCs was observed: grade I-1.92 ± 0.11 × 10-3 mm2/s, grade II-1.84 ± 0.14 × 10-3 mm2/s, grade III-1.79 ± 0.10 × 10-3 mm2/s, grade IV-1.72 ± 0.06 × 10-3 mm2/s. This was significant (p < 0.05) only between tumors of I and IV grades. Significant difference (p < 0.05) between mean ADC values of solid RCCs, benign renal tumors and renal cysts was observed (1.65 ± 0.38 × 10-3 vs 2.23 ± 0.18 × 10-3 vs 3.15 ± 0.51 × 10-3 mm2/s, respectively). In addition, there was a significant difference (p < 0.05) in mean ADC values between benign cysts and cystic RCC (3.36 ± 0.35 × 10-3 vs 2.83 ± 0.21 × 10-3 mm2/s, respectively). CONCLUSION: ADC maps with b values of 0 and 800 s/mm2 can be used as an imaging biomarker, to differentiate benign SRM from malignant SRM. Using ADC value threshold of 1.75 × 10-3 mm2/s allows to differentiate solid RCC from solid benign kidney tumors with 91% sensitivity and 89% specificity; ADC value threshold of 2.96 × 10-3 mm2/s distinguishes cystic RCC from benign renal cysts with 90% sensitivity and 88% specificity. However, the possibility of differentiation between ccRCC histologic subtypes and grades, utilizing ADC values, is limited.

• Klíčová slova
• Apparent diffusion coefficient, Diffusion-weighted imaging, MRI, Renal cell carcinoma, Small renal masses,
• MeSH
• cystická onemocnění ledvin diagnóza   MeSH
• diferenciální diagnóza MeSH
• difuzní magnetická rezonance metody   MeSH
• dospělí MeSH
• karcinom z renálních buněk * diagnóza   patologie   chirurgie   MeSH
• léčba šetřící orgány metody   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory ledvin * diagnóza   patologie   chirurgie   MeSH
• nefrektomie metody   MeSH
• reprodukovatelnost výsledků MeSH
• senioři MeSH
• senzitivita a specificita MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

INTRODUCTION: Glioblastoma (GBM) is the most common malignant primary brain tumor, and methods to improve the early detection of disease progression and evaluate treatment response are highly desirable. We therefore explored changes in whole-brain apparent diffusion coefficient (ADC) values with respect to survival (progression-free [PFS], overall [OS]) in a cohort of GBM patients followed at regular intervals until disease progression. METHODS: A total of 43 subjects met inclusion criteria and were analyzed retrospectively. Histogram data were extracted from standardized whole-brain ADC maps including skewness, kurtosis, entropy, median, mode, 15th percentile (p15) and 85th percentile (p85) values, and linear regression slopes (metrics versus time) were fitted. Regression slope directionality (positive/negative) was subjected to univariate Cox regression. The final model was determined by aLASSO on metrics above threshold. RESULTS: Skewness, kurtosis, median, p15 and p85 were all below threshold for both PFS and OS and were analyzed further. Median regression slope directionality best modeled PFS (p = 0.001; HR 3.3; 95% CI 1.6-6.7), while p85 was selected for OS (p = 0.002; HR 0.29; 95% CI 0.13-0.64). CONCLUSIONS: Our data show tantalizing potential in the use of whole-brain ADC measurements in the follow up of GBM patients, specifically serial median ADC values which correlated with PFS, and serial p85 values which correlated with OS. Whole-brain ADC measurements are fast and easy to perform, and free of ROI-placement bias.

• Klíčová slova
• Apparent diffusion coefficient, Diffusion-weighted imaging, Glioblastoma, Histogram analyses, Magnetic resonance imaging,
• MeSH
• alkylační protinádorové látky terapeutické užití   MeSH
• chemoradioterapie mortalita   MeSH
• difuzní magnetická rezonance metody   MeSH
• glioblastom mortalita   patologie   terapie   MeSH
• kombinovaná terapie MeSH
• lidé MeSH
• míra přežití MeSH
• nádory mozku mortalita   patologie   terapie   MeSH
• následné studie MeSH
• počítačové zpracování obrazu metody   MeSH
• prognóza MeSH
• progrese nemoci MeSH
• retrospektivní studie MeSH
• temozolomid terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alkylační protinádorové látky MeSH
• temozolomid MeSH

This research paper is the result of observations made during tests according to various standards carried out on behalf of industry. The article presents diffusion coefficient values calculated according to the thermodynamic migration model for twenty different concrete mixes and some selected mixes of the codified approaches known as ASTM 1202, NT BUILD 443, NT BUILD 492, ASTM 1556. The method used here, according to the thermodynamic model of migration, allows determination of the value of the diffusion coefficient after short studies of the migration of chloride ions into concrete and was described in earlier works by one of the authors. Unfortunately, when using standard methods, the values of diffusion coefficients differ significantly from each other. In each concrete, diffusion tests were carried out in the conditions of long-term natural diffusion to verify the values determined by standard methods and according to the thermodynamic model of migration. The analysis conducted for this research paper reveals that the chloride permeability test method according to the standard ASTM C1202-97 has an almost 2.8-fold greater dispersion of the obtained results compared to the thermodynamic model of migration. It was observed that the standard NT BUILD 492 has a 3.8-fold dispersion of results compared to the method with the thermodynamic model of migration. The most time-consuming method is the standard method NT BUILD 443. The largest 3.5-fold dispersion of values concerning the reference value are observed in that method. Moreover, a method based on a thermodynamic migration model seems to be the best option of all analyzed methods. It is a quite quick, but laborious, method that should be tested for a larger number of concrete mixes. A great advantage of this method is that it is promising for a wide range of concrete mixtures, both plain concrete and concrete with various additives and admixtures, as well as high-performance concrete.

• Klíčová slova
• Fick’s second law, chloride ions, chloride migration, diffusion coefficient, diffusion model, standard methods,
• Publikační typ
• časopisecké články MeSH

This paper describes a method for determination of the diffusion coefficient and the solubility of radon in plastics. The method is based on the absorption and desorption of radon in plastics. Firstly, plastic specimens are exposed for controlled time to referent (222)Rn concentrations. After exposure, the activity of the specimens is followed by HPGe gamma spectrometry. Using the mathematical algorithm described in this report and the decrease of activity as a function of time, the diffusion coefficient can be determined. In addition, if the referent (222)Rn concentration during the exposure is known, the solubility of radon can be determined. The algorithm has been experimentally applied for different plastics. The results show that this approach allows the specified quantities to be determined with a rather high accuracy-depending on the quality of the counting equipment, it can be better than 10 %.

• MeSH
• algoritmy MeSH
• difuze MeSH
• lidé MeSH
• matematika MeSH
• monitorování radiace * MeSH
• plastické hmoty analýza   MeSH
• radon analýza   chemie   MeSH
• rozpustnost MeSH
• spektrometrie gama MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• plastické hmoty MeSH
• radon MeSH

Accurate prediction of early treatment response to systemic therapy (ST) with tyrosine kinase inhibitors (TKI) in patients with metastatic renal cell carcinoma (mRCC) could help avoid ineffective and expensive treatment with serious side effects. Neither RECIST v.1.1 nor Choi criteria successfully discriminate between patients with mRCC who received ST having a short or long time to progression (TTP). There is no biomarker, which is able to predict early therapeutic response to TKIs application in patients with mRCC. The goal of our study was to investigate the potential of apparent diffusion coefficient (ADC) of diffusion-weighted imaging (DWI) of MRI in prediction of early therapeutic response to ST with pazopanib in patients with mRCC. The retrospective study enrolled 32 adult patients with conventional mRCC who received pazopanib (mean duration-7.5 ± 3.45). The mean duration of follow-up was 11.85 ± 4.34 months. In all patients as baseline examination and 1 month after treatment, 1.5T MRI including DWI sequence was performed followed by ADC measurement of the main renal lesion. For assessment of the therapeutic response, RECIST 1.1 is used. Partial response (PR), stable disease (SD) and progressive disease (PD) were observed in 12 (37.50%), 10 (31.25%) and 10 (31.25%) cases with mean TTP of 10.33 ± 2.06 months (95% confidence interval, CI = 9.05-11.61), 7.40 ± 2.50 months (95% CI = 5.61-9.19) and 4.20 ± 1.99 months (95% CI = 2.78-5.62) accordingly (p < 0.05). There was no difference in change of main lesions' longest size 1 month after ST in patients with PR, SD and PD. Comparison of mean ADC values before and 1 month after systemic treatment showed significant decrease by 19.11 ± 10.64% (95% CI = 12.35-25.87) and by 7.66 ± 6.72% (95% CI = 2.86-12.47) in subgroups with PR and SD, respectively (p < 0.05). There was shorter TTP in patients with mRCC if ADC of the main renal lesion 1 month after the ST increased from the baseline less than 1.73% compared to patients with ADC levels above this threshold: 5.29 ± 3.45 versus 9.50 ± 2.04 months accordingly (p < 0.001). Overall, our findings highlighted the use of ADC as a predictive biomarker for early therapeutic response assessment. Use of ADC will be effective and useful for reliable prediction of responders and non-responders to systemic treatment with pazopanib.

• Klíčová slova
• Apparent diffusion coefficient, Diffusion-weighted imaging, Early response, Imaging biomarker, MRI, Prediction, Progress, Renal cell carcinoma, Systemic treatment, Targeted therapy, Tyrosine kinase inhibitor,
• MeSH
• difuzní magnetická rezonance metody   MeSH
• indazoly MeSH
• inhibitory angiogeneze terapeutické užití   MeSH
• Kaplanův-Meierův odhad MeSH
• karcinom z renálních buněk diagnostické zobrazování   farmakoterapie   mortalita   patologie   MeSH
• ledviny diagnostické zobrazování   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory ledvin diagnostické zobrazování   farmakoterapie   mortalita   patologie   MeSH
• pyrimidiny terapeutické užití   MeSH
• retrospektivní studie MeSH
• ROC křivka MeSH
• senioři MeSH
• sulfonamidy terapeutické užití   MeSH
• výsledek terapie MeSH
• zdraví dobrovolníci pro lékařské studie MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• Názvy látek
• indazoly MeSH
• inhibitory angiogeneze MeSH
• pazopanib MeSH Prohlížeč
• pyrimidiny MeSH
• sulfonamidy MeSH

Radon diffusion coefficient is a material parameter which is usually used in the radon mitigation measures design. There are different approaches used for radon diffusion coefficient measurement and assessment. The International comparison measurement which was jointly organised by National Radiation Protection Institute and Faculty of Civil Engineering CTU Prague in 2009 and 2010 has registered 11 laboratories from all over the world. Three sets of samples of polyethylene damp-proof membranes were sent to these laboratories for measurement. Till today, the organisers received only five sets of results. The results showed a great variability among laboratories involved.

• MeSH
• difuze MeSH
• lidé MeSH
• mezinárodní agentury MeSH
• monitorování radiace * MeSH
• radiační ochrana * MeSH
• radon analýza   MeSH
• vystavení vlivu životního prostředí prevence a kontrola   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• radon MeSH

This article focuses on an experimental study of the influence of imperfections on the value of the radon diffusion coefficient of various waterproofing materials. Microscopic holes were made by a thin tip or by a microdrill bit to imitate the real damage that can be incurred during construction. To determine the change in the radon diffusion coefficient, each waterproofing material was measured five times. The first measurement was performed on undamaged samples, while the following measurements were performed on samples with one, two, four and eight pinholes. The radon diffusion coefficient was measured under nonstationary conditions, because homemade radon sources with a slow rate of radon emanation were used. The radon diffusion coefficients identified in the study were compared according to the thickness of the material and the number and the size of the pinholes. The exact shape and size of the imperfections were documented by an electron microscope.

• MeSH
• difuze MeSH
• konstrukční materiály MeSH
• monitorování radiace * MeSH
• radioaktivní látky znečišťující vzduch * analýza   MeSH
• radon * analýza   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• radioaktivní látky znečišťující vzduch * MeSH
• radon * MeSH

BACKGROUND: Renal cell carcinoma (RCC) represents the most common malignant epithelial neoplasm of the kidney. Accurate assessment of the renal masses, defining the histologic subtype and the grade of differentiation of the tumor, is vital to ensure an adequate case management as well as for staging and prognosis. Recently, diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) tends to be increasingly appealing for the clinicians as an imaging procedure of choice for the diagnosis and staging of the RCC, which is predetermined by several advantages over CT. The goal of the survey was to assess the applicability of the apparent diffusion coefficient (ADC) of the DWI MRI for the differential diagnostics, histologic subtyping, and defining the grade of differentiation of the RCC. METHODS: The study enrolled 288 adult patients with renal lesions: 188 patients with solid RCC-126 patients with clear cell subtype (ccRCC), 32 patients with papillary RCC (pRCC), 30 patients with chromophobe RCC (chRCC); 27 patient with cystic form or RCC (Bosniak cyst, category IV); 32 patients with renal angiomyolipoma (AML); 25 patients with renal oncocytoma (OC); and 16 patients with the renal abscess (AB). In total, 245 lesions were pathologically verified. As a reference, 19 healthy volunteers were included into the study. All patients underwent MRI of the kidneys, involving DWI with subsequent evaluation of the ADC. RESULTS: There was a reliable difference (p < 0.05) in mean ADC values between the normal renal parenchyma (NRP), solid RCC of different histologic subtypes and grades, cystic RCC, and benign renal lesions. The mean ADC values obtained in the result of the study were (×10-3 mm2/s): 2.47 ± 0.12 in NRP, 1.63 ± 0.29 in all solid RCCs, 1.82 ± 0.22 in solid ccRCC (1.92 ± 0.11-Fuhrman grade I, 1.84 ± 0.14-Fuhrman grade II, 1.79 ± 0.10-Fuhrman grade III, 1.72 ± 0.06-Fuhrman grade IV), 1.61 ± 0.07 in pRCC, 1.46 ± 0.09 in chRCC, 2.68 ± 0.11 in cystic RCC, 2.13 ± 0.08 in AML, 2.26 ± 0.06 in OC, and 3.30 ± 0.07 in AB. CONCLUSION: The data received in our study demonstrate a substantial restriction of diffusion of hydrogen molecules in tissues of ccRCC in comparison with the healthy renal parenchyma preconditioned by the greater density of tumor. A statistically significant difference in mean ADC values of ccRCC with different grades of nuclear pleomorphism by Fuhrman was observed: Low-grade tumors showed higher mean ADC values compared to high-grade tumors. The modality of the MRI DWI along with ADC measurement allows to reliably differentiate between the solid RCC of main histologic subtypes and grades, cystic RCC, and the benign renal lesions.

• Klíčová slova
• Apparent diffusion coefficient, Diffusion-weighted imaging, Magnetic resonance imaging, Renal cell carcinoma,
• MeSH
• diferenciální diagnóza MeSH
• difuzní magnetická rezonance metody   MeSH
• dospělí MeSH
• karcinom z renálních buněk * diagnóza   patologie   MeSH
• ledviny * diagnostické zobrazování   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• přesnost dimenzionálního měření MeSH
• prognóza MeSH
• reprodukovatelnost výsledků MeSH
• senioři MeSH
• staging nádorů MeSH
• stupeň nádoru MeSH
• výběr pacientů MeSH
• zlepšení kvality MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

This paper describes a new device and a method to determine the radon diffusion coefficient in damp-proof membranes developed in the Czech Republic. The main advantage of the device is that it enables tests to be carried out in all the known measuring modes used throughout Europe. Two recently developed computer programs are presented for the numerical modelling of the time-dependent radon transport through damp-proof membranes. According to this method, the radon diffusion coefficient is derived from the process of fitting the numerical solution to the measured curve of radon concentration in a receiver container. Numerical simulation and measured data are also compared. Reasons for disagreements between different methods and specific configurations of the measuring device are also discussed.

• MeSH
• analýza selhání vybavení metody   MeSH
• dávka záření MeSH
• design vybavení MeSH
• difuze MeSH
• membrány umělé * MeSH
• radiační ochrana přístrojové vybavení   MeSH
• radiometrie metody   MeSH
• radon chemie   izolace a purifikace   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH
• Názvy látek
• membrány umělé * MeSH
• radon MeSH

Diffusion bonding has many advantages, but it also has its specifics. When creating heterogeneous joints, problems arise with the creation of intermetallic phases. For this reason, an interlayer is needed to prevent the creation of these unfavorable phases. It is important to ensure that the interlayer is of sufficient thickness to prevent the elements from diffusing through the entire interlayer and the intermetallic phases from being formed again. Conversely, too thick an interlayer causes an increase in the heterogeneity of the bond properties. The creation of the initial diffusion bonds in a heterogeneous diffusion joint of AISI 304 and AISI 316L steel with a 0.2 mm thick nickel interlayer was made in a Gleeble 3500. The experiments to determine the diffusion kinetics were carried out in a vacuum furnace, with subsequent evaluation by EDX (Energy Dispersive X-ray Spectroscopy) analysis. Subsequently, the diffusion coefficients of nickel into both steels were determined, and generalized equations were formulated to calculate the diffusion coefficients for temperatures in the range of 950 to 1150 °C and holding times in the range of 3600 to 18,000 s. Equations are also given to determine the width of the diffused zone between each steel and the Ni interlayer.

• Klíčová slova
• AISI 304, AISI 316L, diffusion bonding, diffusion coefficient, nickel, stainless steel,
• Publikační typ
• časopisecké články MeSH