Significant disparity in base and sugar damage in DNA resulting from neutron and electron irradiation

In this study, a comparison of the effects of neutron and electron irradiation of aqueous DNA solutions was investigated to characterize potential neutron signatures in DNA damage induction. Ionizing radiation generates numerous lesions in DNA, including base and sugar lesions, lesions involving base–sugar combinations (e.g. 8,5′-cyclopurine-2′-deoxynucleosides) and DNA–protein cross-links, as well as single- and double-strand breaks and clustered damage. The characteristics of damage depend on the linear energy transfer (LET) of the incident radiation. Here we investigated DNA damage using aqueous DNA solutions in 10 mmol/l phosphate buffer from 0–80 Gy by low-LET electrons (10 Gy/min) and the specific high-LET (∼0.16 Gy/h) neutrons formed by spontaneous ²⁵²Cf decay fissions. 8-hydroxy-2′-deoxyguanosine (8-OH-dG), (5′R)-8,5′-cyclo-2′-deoxyadenosine (R-cdA) and (5′S)-8,5′-cyclo-2′-deoxyadenosine (S-cdA) were quantified using liquid chromatography–isotope-dilution tandem mass spectrometry to demonstrate a linear dose dependence for induction of 8-OH-dG by both types of radiation, although neutron irradiation was ∼50% less effective at a given dose compared with electron irradiation. Electron irradiation resulted in an exponential increase in S-cdA and R-cdA with dose, whereas neutron irradiation induced substantially less damage and the amount of damage increased only gradually with dose. Addition of 30 mmol/l 2-amino-2-(hydroxymethyl)-1,3-propanediol (TRIS), a free radical scavenger, to the DNA solution before irradiation reduced lesion induction to background levels for both types of radiation. These results provide insight into the mechanisms of DNA damage by high-LET ²⁵²Cf decay neutrons and low-LET electrons, leading to enhanced understanding of the potential biological effects of these types of irradiation.     

Endobronchial masses encountered on fine‐needle aspiration biopsy: a focus on unusual entities

Fine‐needle aspiration biopsy (FNAB) is a useful technique in the evaluation of central lung tumors which is commonly encountered in clinical cytology practice. Some of these tumors may show endobronchial, polypoid growth which is readily apparent to the endoscopist. Pulmonary salivary gland‐type tumors and carcinoid tumors are overall uncommon in the lung, but these tumors tend to occur centrally and show endobronchial involvement. The prognosis of these tumors is generally better than that of small cell or non‐small cell carcinomas of the lung and more conservative surgical resection is often indicated. The identification of salient cytological features and a high index of suspicion when considering the differential diagnosis of a central lung tumor is essential to accurate diagnosis. This review focuses on cytological clues as well as ancillary techniques that may be useful to the practicing cytopathologist.     

Comparison of Numerical Simulation Techniques of Ballistic Ceramics under Projectile Impact Conditions

This article presents an analysis of the effectiveness of available numerical techniques in mapping the characteristic behavior of ballistic ceramics under projectile impact conditions. As part of the work, the ballistic tests were performed on the layered ceramic/steel composite armor and tested with the 7.62 × 39 mm, armor-piercing incendiary (API) BZ projectile. The experimental tests were then mapped using computer simulations. In numerical analyses, four different techniques were used to describe cubic ceramic tiles Al₂O₃ placed on the ARMOX 500T steel backing plate, i.e.,: the Finite Element Method without Erosion (FEM), Finite Element with erosion (FEM + Erosion), Smoothed Particles Hydrodynamics (SPH) and a hybrid method that converts finite elements to SPH particles after exceeding the defined failure criteria (FEM to SPH conversion). The effectiveness of the individual methods was compared in terms of quality (mapping of characteristic phenomena occurring during the penetration process), quantity (bulge height of the backing plate) and time needed to complete the calculations. On the basis of the results of the experiments and numerical simulations, it was noticed that the most accurate reproduction of the phenomenon of ballistic impact of AP projectiles on ceramic/steel composite armor can be obtained by using a hybrid method, incorporating the conversion of finite elements into SPH particles. This method should be used in cases where accuracy of the results is more important than the time required to complete the calculations. In other situations where the purpose of the calculation is not to determine, for example, the exact value of penetration depth but only to observe a certain trend, the FEM method with defined erosion criteria (variant 2), which is more than 10 times faster, can be successfully used.     

Detection of functional connectivity using temporal correlations in MR images

Functional connectivity among brain regions has been investigated via an analysis of correlations between regional signal fluctuations recorded in magnetic resonance (MR) images obtained in a steady state. In comparison with studies of functional connectivity that utilize task manipulations, the analysis of correlations in steady state data is less susceptible to confounds arising when functionally unrelated brain regions respond in similar ways to changes in task. A new approach to identifying interregional correlations in steady state data makes use of two independent data sets. Regions of interest (ROIs) are defined and hypotheses regarding their connectivity are generated in one data set. The connectivity hypotheses are then evaluated in the remaining (independent) data set by analyzing low frequency temporal correlations between regions. The roles of the two data sets are then reversed and the process repeated, perhaps multiple times. This method was illustrated by application to the language system. The existence of a functional connection between Broca's area and Wernicke's area was confirmed in healthy subjects at rest. An increase in this functional connection when the language system was actively engaged (when subjects were continuously listening to narrative text) was also confirmed. In a second iteration of analyses, a correlation between Broca's area and a region in left premotor cortex was found to be significant at rest and to increase during continuous listening. These findings suggest that the proposed methodology can reveal the presence and strength of functional connections in high-level cognitive systems.     

Eosinophilic gastroenteritis and graft‐versus‐host disease induced by transmission of Norovirus with fecal microbiota transplant

Fecal microbiota transplantation (FMT) was performed to decolonize gastrointestinal tract from antibiotic‐resistant bacteria before allogeneic hematopoietic cells transplantation (alloHCT). AlloHCT was complicated by norovirus gastroenteritis, acute graft‐versus‐host disease, and eosinophilic pancolitis. Norovirus was identified in samples from FMT material. Symptoms resolved after steroids course and second norovirus‐free FMT from another donor.     

Identification of a third evolutionarily conserved gene within the RAG locus and its RAG1-dependent and -independent regulation

Recombination-activating gene (RAG)1 and RAG2 encode T and B lymphocyte-specific endonucleases indispensable for rearrangements of antigen-receptor gene segments but also capable of causing deleterious chromosome rearrangements. The mechanisms regulating RAG expression and repression are not clear. Here we identify NWC, a third evolutionarily conserved gene within the RAG locus, and show that it is ubiquitously expressed, with the notable exception of RAG-nonexpressing immature and mature T and B lymphocytes because in lymphocytes it is regulated by the RAG1 promoter and transcribed as RAG1-NWC hybrid mRNA molecules. We also show that in all other cells NWC is controlled by the RAG2 intragenic promoter, which in immature and mature T and B lymphocytes is silent. The possible implications of these findings for understanding the activation and inactivation of RAG genes in lymphocytes and their repression in other cells are discussed.     

Additive Manufacturing as a Solution to Challenges Associated with Heat Pipe Production

The aim of this review is to present the recent developments in heat pipe production, which respond to the current technical problems related to the wide implementation of this technology. A novel approach in HP manufacturing is to utilise hi-tech additive manufacturing techniques where the most complicated geometries are fabricated layer-by-layer directly from a digital file. This technology might be a solution to various challenges that exist in HP production, i.e., (1) manufacturing of complex or unusual geometries HPs; (2) manufacturing complicated and efficient homogenous wick structures with desired porosity, uniform pore sizes, permeability, thickness and where the pores are evenly distributed; (3) manufacturing a gravity friendly wick structures; (4) high customisation and production time; (5) high costs; (6) difficulties in the integration of the HP into a unit chassis that enables direct thermal management of heated element and decrease its total thermal resistance; (7) high weight and material use of the part; (8) difficulties in sealing; (9) deformation of the flat shape HPs caused by the high pressure and uneven distribution of stress in the casing, among others.     

Wettability of Metal Surfaces Affected by Paint Layer Covering

The aim of the work was to quantify the surface wettability of metallic (Fe, Al, Cu, brass) surfaces covered with sprayed paints. Wettability was determined using the contact angle hysteresis approach, where dynamic contact angles (advancing Θ_A and receding Θ_R) were identified with the inclined plate method. The equilibrium, Θ_Y, contact angle hysteresis, CAH = Θ_A − Θ_R, film pressure, Π, surface free energy, γ_SV, works of adhesion, W_A, and spreading, W_S, were considered. Hydrophobic water/solid interactions were exhibited for the treated surfaces with the dispersive term contribution to γ_SV equal to (0.66–0.69). The registered 3D surface roughness profiles allowed the surface roughness and surface heterogeneity effect on wettability to be discussed. The clean metallic surfaces turned out to be of a hydrophilic nature (Θ_Y < 90°) with high γ_SV, heterogeneous, and rough with a large CAH. The surface covering demonstrated the parameters’ evolution, Θ_A↑, Θ_R↑, γ_SV↓, W_A↓, and W_S↓, corresponding to the surface hydrophobization and exhibiting base substratum-specific signatures. The dimensionless roughness fluctuation coefficient, η, was linearly correlated to CAH. The CAH methodology based on the three measurable quantities, Θ_A, Θ_R, and liquid surface tension, γ_LV, can be a useful tool in surface-mediated process studies, such as lubrication, liquid coating, and thermoflow.     

Chromosome and gene copy number variation allow major structural change between species and strains of Leishmania

Leishmania parasites cause a spectrum of clinical pathology in humans ranging from disfiguring cutaneous lesions to fatal visceral leishmaniasis. We have generated a reference genome for Leishmania mexicana and refined the reference genomes for Leishmania major, Leishmania infantum, and Leishmania braziliensis. This has allowed the identification of a remarkably low number of genes or paralog groups (2, 14, 19, and 67, respectively) unique to one species. These were found to be conserved in additional isolates of the same species. We have predicted allelic variation and find that in these isolates, L. major and L. infantum have a surprisingly low number of predicted heterozygous SNPs compared with L. braziliensis and L. mexicana. We used short read coverage to infer ploidy and gene copy numbers, identifying large copy number variations between species, with 200 tandem gene arrays in L. major and 132 in L. mexicana. Chromosome copy number also varied significantly between species, with nine supernumerary chromosomes in L. infantum, four in L. mexicana, two in L. braziliensis, and one in L. major. A significant bias against gene arrays on supernumerary chromosomes was shown to exist, indicating that duplication events occur more frequently on disomic chromosomes. Taken together, our data demonstrate that there is little variation in unique gene content across Leishmania species, but large-scale genetic heterogeneity can result through gene amplification on disomic chromosomes and variation in chromosome number. Increased gene copy number due to chromosome amplification may contribute to alterations in gene expression in response to environmental conditions in the host, providing a genetic basis for disease tropism.