On the Use of Optically Stimulated Luminescent Dosimeter for Surface Dose Measurement during Radiotherapy

This study was carried out to investigate the suitability of using the optically stimulated luminescence dosimeter (OSLD) in measuring surface dose during radiotherapy. The water equivalent depth (WED) of the OSLD was first determined by comparing the surface dose measured using the OSLD with the percentage depth dose at the buildup region measured using a Markus ionization chamber. Surface doses were measured on a solid water phantom using the OSLD and compared against the Markus ionization chamber and Gafchromic EBT3 film measurements. The effect of incident beam angles on surface dose was also studied. The OSLD was subsequently used to measure surface dose during tangential breast radiotherapy treatments in a phantom study and in the clinical measurement of 10 patients. Surface dose to the treated breast or chest wall, and on the contralateral breast were measured. The WED of the OSLD was found to be at 0.4 mm. For surface dose measurement on a solid water phantom, the Markus ionization chamber measured 15.95% for 6 MV photon beam and 12.64% for 10 MV photon beam followed by EBT3 film (23.79% and 17.14%) and OSLD (37.77% and 25.38%). Surface dose increased with the increase of the incident beam angle. For phantom and patient breast surface dose measurement, the response of the OSLD was higher than EBT3 film. The in-vivo measurements were also compared with the treatment planning system predicted dose. The OSLD measured higher dose values compared to dose at the surface (Hp(0.0)) by a factor of 2.37 for 6 MV and 2.01 for 10 MV photon beams, respectively. The measurement of absorbed dose at the skin depth of 0.4 mm by the OSLD can still be a useful tool to assess radiation effects on the skin dermis layer. This knowledge can be used to prevent and manage potential acute skin reaction and late skin toxicity from radiotherapy treatments.     

Prevalence and Trend of Major Transfusion-Transmissible Infections among Blood Donors in Western China, 2005 through 2010

BackgroundThe prevalence of transfusion-transmissible infections (TTIs) in blood donations is important for evaluating blood safety and potential risks to the population. This study investigated the prevalence of TTIs among blood donors in Western China and suggested measures for policy-makers.MethodsThe screening results of 66,311 donations between 2005 and 2010 from a central blood center in Western China were analyzed. The prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and syphilis infections were expressed in percentages for the entire study group as well as groups by demographic characteristics and donation frequency, with differences analyzed using Fisher''s exact or Chi-square test. Logistic regression was performed to identify the influencing factors of the detected results.Results1,769 (2.67%, 95% CI 2.55–2.79%) of the donated blood had serological evidence of infection with at least one pathogen and 44 (0.07%, 95% CI 0.05–0.09%) showed evidence of multiple infections. The seroprevalence of HBV, HCV, HIV, and syphilis infections was 0.87% (95% CI 0.80–0.94%), 0.86% (95% CI 0.79–0.93%), 0.31% (95% CI 0.26–0.35%), and 0.70% (95% CI 0.64–0.76%) respectively. Trend analysis for the prevalence of TTIs showed a significant increase from 2.44% to 3.71% (χ² = 100.72, p = 0.00) over this 6-year period. The positive rates for TTIs varied along demographic lines. The top three risk factors in test-positive donors were identified as age, education level and donation frequency. The older age group and lower educated group were linked to a higher prevalence of TTIs. A decreasing prevalence was associated with an increasing frequency of blood donations (χ2 = 562.78, p = 0.00).ConclusionsHepatitis B and C were found most, and often in conjunction with syphilis. These were the primary threats to blood safety. The high positivity rate and the increasing prevalence of TTIs among blood donors in Western China call for further actions.     

LisBeth: New cladistics for phylogenetics and biogeography

Within phylogenetics, two methods are known to implement cladistics: parsimony or maximum parsimony (MP) and three-item analysis (3ia). Despite the lack of suitable software, 3ia is occasionally used in systematic, and more regularly, in historical biogeography. Here, we present LisBeth, the first and only phylogenetic/biogeographic program freely available that uses the 3ia approach and offer some insights into its theoretical propositions. LisBeth does not rely on the conventional taxon/character matrix. Instead, characters are represented as rooted trees. LisBeth performs 3ia analyses based on maximum congruence of three-item statements and calculates the intersection tree (which differs from usual consensus). In biogeography, it applies the transparent method to handle widespread taxa and implements paralogy-free subtree analysis to remove redundant distributions. For the sake of interoperability, LisBeth may import/export characters from/to matrix in NEXUS format, allowing comparison with other cladistic programs. LisBeth also imports phylogenetic characters from Xper² knowledge bases.     

P2‐K0.75[Ni1/3Mn2/3]O2 Cathode Material for High Power and Long Life Potassium‐Ion Batteries

Rationally designed P2‐K_0.75[Ni_1/3Mn_2/3]O₂ is introduced as a novel cathode material for potassium‐ion batteries (KIBs). P2‐K_0.75[Ni_1/3Mn_2/3]O₂ cathode material designed through electrochemical ion‐exchange from P2‐Na_2/3[Ni_1/3Mn_2/3]O₂ exhibits satisfactory electrode performances; 110 mAh g^?1 (20 mA g^?1) retaining 86% of capacity for 300 cycles and unexpectedly high reversible capacity of about 91 mAh g^?1 (1400 mA g^?1) with excellent capacity retention of 83% over 500 cycles. According to theoretical and experimental investigations, the overall potassium storage mechanism of P2‐K_0.75[Ni_1/3Mn_2/3]O₂ is revealed to be a single‐phase reaction with small lattice change upon charge and discharge, presenting the Ni^4+/2+ redox couple reaction. Such high power capability is possible through the facile K⁺ migration in the K_0.75[Ni_1/3Mn_2/3]O₂ structure with a low activation barrier energy of ≈210 meV. These findings indicate that P2‐K_0.75[Ni_1/3Mn_2/3]O₂ is a promising candidate cathode material for high‐rate and long‐life KIBs.     

MHC class II transactivator negatively regulates RANKL-mediated osteoclast differentiation by downregulating NFATc1 and OSCAR

Nuclear factor of activated T cells (NFAT) c1 plays a key role in receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation and function via induction of osteoclast-specific target genes including osteoclast-associated receptor (OSCAR), cathepsin K, and tartrate-resistant acid phosphatase. To elucidate which downstream target genes are regulated by NFATc1 during osteoclastogenesis, we used microarray analyses to examine gene expression profiles in the context of bone marrow-derived macrophages overexpressing a constitutively active form of NFATc1. Herein, we demonstrate that MHC class II transactivator (CIITA) is up-regulated downstream of NFATc1. Overexpression of CIITA in osteoclast precursors attenuates RANKL-induced osteoclast formation through down-regulation of NFATc1 and OSCAR. Epigenetic overexpression of CIITA regulates NFATc1 and OSCAR by competing with c-Fos and NFATc1 for CBP/p300 binding sites. Furthermore, silencing of CIITA by RNA interference in osteoclast precursors enhances osteoclast formation as well as NFATc1 and OSCAR expression. Taken together, our data reveal that CIITA can act as a modulator of RANKL-induced osteoclastogenesis.     

Evidence of a large novel gene pool associated with prokaryotic genomic islands

Microbial genes that are “novel” (no detectable homologs in other species) have become of increasing interest as environmental sampling suggests that there are many more such novel genes in yet-to-be-cultured microorganisms. By analyzing known microbial genomic islands and prophages, we developed criteria for systematic identification of putative genomic islands (clusters of genes of probable horizontal origin in a prokaryotic genome) in 63 prokaryotic genomes, and then characterized the distribution of novel genes and other features. All but a few of the genomes examined contained significantly higher proportions of novel genes in their predicted genomic islands compared with the rest of their genome (Paired t test = 4.43E-14 to 1.27E-18, depending on method). Moreover, the reverse observation (i.e., higher proportions of novel genes outside of islands) never reached statistical significance in any organism examined. We show that this higher proportion of novel genes in predicted genomic islands is not due to less accurate gene prediction in genomic island regions, but likely reflects a genuine increase in novel genes in these regions for both bacteria and archaea. This represents the first comprehensive analysis of novel genes in prokaryotic genomic islands and provides clues regarding the origin of novel genes. Our collective results imply that there are different gene pools associated with recently horizontally transmitted genomic regions versus regions that are primarily vertically inherited. Moreover, there are more novel genes within the gene pool associated with genomic islands. Since genomic islands are frequently associated with a particular microbial adaptation, such as antibiotic resistance, pathogen virulence, or metal resistance, this suggests that microbes may have access to a larger “arsenal” of novel genes for adaptation than previously thought.