Hasil untuk "nucl-ex"

C. J. Denman, V. Senyukov, S. Somanchi et al.

NK cells have therapeutic potential for a wide variety of human malignancies. However, because NK cells expand poorly in vitro, have limited life spans in vivo, and represent a small fraction of peripheral white blood cells, obtaining sufficient cell numbers is the major obstacle for NK-cell immunotherapy. Genetically-engineered artificial antigen-presenting cells (aAPCs) expressing membrane-bound IL-15 (mbIL15) have been used to propagate clinical-grade NK cells for human trials of adoptive immunotherapy, but ex vivo proliferation has been limited by telomere shortening. We developed K562-based aAPCs with membrane-bound IL-21 (mbIL21) and assessed their ability to support human NK-cell proliferation. In contrast to mbIL15, mbIL21-expressing aAPCs promoted log-phase NK cell expansion without evidence of senescence for up to 6 weeks of culture. By day 21, parallel expansion of NK cells from 22 donors demonstrated a mean 47,967-fold expansion (median 31,747) when co-cultured with aAPCs expressing mbIL21 compared to 825-fold expansion (median 325) with mbIL15. Despite the significant increase in proliferation, mbIL21-expanded NK cells also showed a significant increase in telomere length compared to freshly obtained NK cells, suggesting a possible mechanism for their sustained proliferation. NK cells expanded with mbIL21 were similar in phenotype and cytotoxicity to those expanded with mbIL15, with retained donor KIR repertoires and high expression of NCRs, CD16, and NKG2D, but had superior cytokine secretion. The mbIL21-expanded NK cells showed increased transcription of the activating receptor CD160, but otherwise had remarkably similar mRNA expression profiles of the 96 genes assessed. mbIL21-expanded NK cells had significant cytotoxicity against all tumor cell lines tested, retained responsiveness to inhibitory KIR ligands, and demonstrated enhanced killing via antibody-dependent cell cytotoxicity. Thus, aAPCs expressing mbIL21 promote improved proliferation of human NK cells with longer telomeres and less senescence, supporting their clinical use in propagating NK cells for adoptive immunotherapy.

Brian C Evans, Christopher E. Nelson, Shann S. Yu et al.

Esraa Al-Sarray, Ali Jabbar

This study focused on examining the performance of some composite materials made from a fixed mixture of epoxy and polymer with varying amounts of barium sulfate and lead powder added, to study their ability to shield against gamma rays. Eight samples were prepared with different weights of the two additives, while the base materials remained unchanged. Gamma ray attenuation was measured using a NaI(Tl) detector using ??7Cs and 60Co sources. The linear attenuation coefficient was observed to decrease with increasing photon energy. The sample containing 25 grams of barium sulfate and 5 grams of lead showed the best attenuation performance. These results suggest that effective and improved protection can be achieved by optimizing the proportions of the additives, particularly by reducing the lead content, to reduce health risks. The study recommends further research on the mechanical aspects and long-term stability of these materials before considering their practical use.

Kevser Deniz, Abdullah Calik

In the present study, outdoor gamma dose rates have been measured by using a NaI(Tl) scintillation detector in 20 measurement points in the Tavsanly district center of Kutahya province in Turkiye. Annual effective dose equivalents and lifetime cancer risks have been calculated from the obtained results as (106.64 ?6.20) ?Sv and (3.73 ?0.2) ?10-4, respectively. The results have been compared with those of other studies for Turkiye and the world literature

Yael Peleg, Itzhak Orion

This study explores the impact of solar flare events on radioactive materials, focusing in particular on the thorium decay chain. Previous research has indicated that gamma emitters are affected by solar flares, resulting in count-rate dips. In this study, we present, for the first time, concurrent gamma and beta count-rate measurements from a thorium radioactive source, revealing multiple dips in the count rate. Based on a consideration of the temporal relationship between beta and gamma emissions, we propose that the response to solar events originates primarily from beta emissions. To investigate this phenomenon further, we employ plastic scintillator beta detectors, enabling the examination of various radioactive sources and the study of neutrino interactions and their impact on decay rates. This experimental approach offers an opportunity to expand our knowledge of particle interactions and provides insights into the interplay between solar flares, neutrino flux, and the behavior of radioactive materials.

Erik Rajchl, Jiri Janda, Jiri Zelinka

The development, preparation, and properties of new plastic scintillators, based on polyvinyl toluene matrix EJ-290 and only one luminophore with a large Stokes shift, are addressed. The primary luminophores tested were 2-(1-naphthyl)-5-phenyloxazole, 1-phenyl-3-mesityl-2-pyrazoline, and 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene. These were subsequently compared with the commercially used luminophores 2,5-diphenyloxazole and p-terphenyl in combination with wavelength shifters (secondary luminophores) 1,4-bis(2-methylstyryl) benzene and 1,4-bis(5-phenyl-2-oxazolyl)benzene made from the same polyvinyl toluene matrix in the same dimensions. For plastic scintillators produced in this way, their detection properties, such as Compton edge and detection efficiency, were characterized.

M. Nicholson, S. Hosgood

Ex vivo normothermic perfusion (EVNP) is a novel method of preservation that restores circulation and allows an organ to regain function prior to transplantation. The aim of this study was to assess the effects of EVNP in kidneys from marginal donors. Eighteen kidneys from extended criteria donors (ECD) underwent a period of EVNP immediately before transplantation. Kidneys were perfused with a plasma free red‐cell based solution at a mean temperature of 34.6°C. The outcome of these kidneys was compared to a control group of 47 ECD kidneys that underwent static cold storage (CS). The mean donor age was 61 ± 1 years in the EVNP and 62 ± 6 years in the CS group (p = 0.520). EVNP kidneys were perfused for an average of 63 ± 16 min and all were transplanted successfully. The delayed graft function rate (DGF), defined as the requirement for dialysis within the first 7 days was 1/18 patients (5.6%) in the EVNP group versus 17/47 (36.2%) in the CS group (p = 0.014). There was no difference in graft or patient survival at 12 months (p = 0.510, 1.000). This first series of EVNP in renal transplantation demonstrates that this technique is both feasible and safe. Our preliminary data suggests that EVNP offers promise as a new technique of kidney preservation.

Zeljko Nikac, Srboljub Stankovic, Nenad Radovic

The paper presents the concept and characteristics of nuclear security, the elements of the nu- clear safety strategy, the legislative framework and the most important solutions from the Law on Radiation and Nuclear Safety and Security. At the international level, the most important entity in this field is the International Atomic Energy Agency, while at the national level, most important is the Directorate for Radiation and Nuclear Safety and Security of Serbia. An important role is played by the Vinca Institute of Nuclear Sciences as the most referential scientific institution in this field, as well as the operational bodies - Nuclear Facilities of Serbia, the Ministry of Internal Affairs, Ministry of Defence, and the Serbian Armed Forces. Engagement of these bodies is carried out in regular peacetime circumstances, emergency situations and wartime. The most important challenges, risks and threats to nuclear security of Serbia were pointed out as well as the need to harmonize norms, procedures and processes in purpose of the strengthening institutional mechanisms in the field of nuclear security.

M. Gertz, F. Fischer, G. Nguyen et al.

B. Ataç, I. Wagner, R. Horland et al.

G. Scarcelli, Sébastien Besner, R. Pineda et al.

Kaige Wang, Patrick A. Johnston, Robert C. Brown

B. Bruinsma, B. Bruinsma, Heidi Yeh et al.

To reduce widespread shortages, attempts are made to use more marginal livers for transplantation. Many of these grafts are discarded for fear of inferior survival rates or biliary complications. Recent advances in organ preservation have shown that ex vivo subnormothermic machine perfusion has the potential to improve preservation and recover marginal livers pretransplantation. To determine the feasibility in human livers, we assessed the effect of 3 h of oxygenated subnormothermic machine perfusion (21°C) on seven livers discarded for transplantation. Biochemical and microscopic assessment revealed minimal injury sustained during perfusion. Improved oxygen uptake (1.30 [1.11–1.94] to 6.74 [4.15–8.16] mL O2/min kg liver), lactate levels (4.04 [3.70–5.99] to 2.29 [1.20–3.43] mmol/L) and adenosine triphosphate content (45.0 [70.6–87.5] pmol/mg preperfusion to 167.5 [151.5–237.2] pmol/mg after perfusion) were observed. Liver function, reflected by urea, albumin and bile production, was seen during perfusion. Bile production increased and the composition of bile (bile salts/phospholipid ratio, pH and bicarbonate concentration) became more favorable. In conclusion, ex vivo subnormothermic machine perfusion effectively maintains liver function with minimal injury and sustains or improves various hepatobiliary parameters postischemia.

Michael E. Sutton, S. op den Dries, N. Karimian et al.

Although normothermic machine perfusion of donor livers may allow assessment of graft viability prior to transplantation, there are currently no data on what would be a good parameter of graft viability. To determine whether bile production is a suitable biomarker that can be used to discriminate viable from non-viable livers we have studied functional performance as well as biochemical and histological evidence of hepatobiliary injury during ex vivo normothermic machine perfusion of human donor livers. After a median duration of cold storage of 6.5 h, twelve extended criteria human donor livers that were declined for transplantation were ex vivo perfused for 6 h at 37°C with an oxygenated solution based on red blood cells and plasma, using pressure controlled pulsatile perfusion of the hepatic artery and continuous portal perfusion. During perfusion, two patterns of bile flow were identified: (1) steadily increasing bile production, resulting in a cumulative output of ≥30 g after 6 h (high bile output group), and (2) a cumulative bile production <20 g in 6 h (low bile output group). Concentrations of transaminases and potassium in the perfusion fluid were significantly higher in the low bile output group, compared to the high bile output group. Biliary concentrations of bilirubin and bicarbonate were respectively 4 times and 2 times higher in the high bile output group. Livers in the low bile output group displayed more signs of hepatic necrosis and venous congestion, compared to the high bile output group. In conclusion, bile production could be an easily assessable biomarker of hepatic viability during ex vivo machine perfusion of human donor livers. It could potentially be used to identify extended criteria livers that are suitable for transplantation. These ex vivo findings need to be confirmed in a transplant experiment or a clinical trial.

M. Mei, L. Ito, Ying Cao et al.

OBJECTIVES This ex vivo study compared the physico-chemical structural differences between primary carious teeth biannually treated with silver diamine fluoride (SDF) and carious teeth without such treatment. METHOD Twelve carious primary upper-central incisors were collected from 6-year-old children. Six teeth had arrested caries after 24-month biannual SDF applications and 6 had active caries when there was no topical fluoride treatment. The mineral density, elemental contents, surface morphology, and crystal characteristics were assessed by micro-computed tomography (micro-CT), energy-dispersive X-ray spectrometry (EDX), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). RESULTS Micro-CT examination revealed a superficial opaque band approximately 150μm on the arrested cavitated dentinal lesion. This band was limited in the active carious lesion. EDX examination detected a higher intensity of calcium and phosphate of 150μm in the surface zone than in the inner zone, but this zone was restricted in the active cavitated dentinal lesion. SEM examination indicated that the collagens were protected from being exposed in the arrested cavitated dentinal lesion, but were exposed in the active cavitated dentinal lesion. TEM examination suggested that remineralised hydroxyapatites were well aligned in the arrested cavitated dentinal lesion, while those in the active cavitated dentinal lesion indicated a random apatite arrangement. CONCLUSIONS A highly remineralised zone rich in calcium and phosphate was found on the arrested cavitated dentinal lesion of primary teeth with an SDF application. The collagens were protected from being exposed in the arrested cavitated dentinal lesion. CLINICAL SIGNIFICANCE Clinical SDF application positively influences dentine remineralisation.

Kyung Jang, Tae Woo

The humanoid is investigated for the mechanical and physical aspect in the nuclear disaster, especially for a severe accident, which includes the core melting. There are some mechanical studies of the leg and hand of the humanoid in which the human mimicking features are described. The management of the task is accomplished by the three regional preparations. The robot is made of the radiation-resistance substance. Therefore, it could work on the normal task of a human for the removal of the broken debris in a collapsed building. However, there is a limitation for the use in the reactor core building due to very high temperature of the nuclear fuel. The regional classification of the site is studied for the practical purposes. The post-accident analysis is accompanied with multidisciplinary research for the humanoid development in the nuclear industry.

Qingchuan Guo, R. Ghadiri, T. Weigel et al.

This article reports about nanocomposites, which refractive index is tuned by adding TiO2 nanoparticles. We compare in situ/ex situ preparation of nanocomposites. Preparation procedure is described, properties of nanocomposites are compared, and especially we examine the applicability of two-photon polymerization (2PP) of synthesized nanocomposites. All prepared samples exhibit suitable optical transparency at specific laser wavelengths. Three-dimensional structures were generated by means of two-photon polymerization effect induced by a femtosecond laser.

P. Netland, S. Sarkisian, M. Moster et al.

K. Naipal, N. Verkaik, N. Ameziane et al.

Purpose: Poly(ADP-ribose) polymerase (PARP) inhibitors are promising targeted treatment options for hereditary breast tumors with a homologous recombination (HR) deficiency caused by BRCA1 or BRCA2 mutations. However, the functional consequence of BRCA gene mutations is not always known and tumors can be HR deficient for other reasons than BRCA gene mutations. Therefore, we aimed to develop a functional test to determine HR activity in tumor samples to facilitate selection of patients eligible for PARP inhibitor treatment. Experimental design: We obtained 54 fresh primary breast tumor samples from patients undergoing surgery. We determined their HR capacity by studying the formation of ionizing radiation induced foci (IRIF) of the HR protein RAD51 after ex vivo irradiation of these organotypic breast tumor samples. Tumors showing impaired RAD51 IRIF formation were subjected to genetic and epigenetic analysis. Results: Five of 45 primary breast tumors with sufficient numbers of proliferating tumor cells were RAD51 IRIF formation deficient (11%, 95% CI, 5%–24%). This HR defect was significantly associated with triple-negative breast cancer (OR, 57; 95% CI, 3.9–825; P = 0.003). Two of five HR-deficient tumors were not caused by mutations in the BRCA genes, but by BRCA1 promoter hypermethylation. Conclusion: The functional RAD51 IRIF assay faithfully identifies HR-deficient tumors and has clear advantages over gene sequencing. It is a relatively easy assay that can be performed on biopsy material, making it a powerful tool to select patients with an HR-deficient cancer for PARP inhibitor treatment in the clinic. Clin Cancer Res; 20(18); 4816–26. ©2014 AACR.