A Systematic Review and Meta-analysis of the Impact of Radiation-Related Lymphopenia on Outcomes in High-Grade Gliomas

Introduction  Malignant gliomas are the most common primary malignant brain tumors and are typically treated with maximal safe surgical resection followed by chemoradiation. One of the unintended effects of radiation is depletion of circulating lymphocyte pool, which has been correlated with inferior overall survival outcomes. Methods  A comprehensive and systematic searches of the PubMed, Cochrane Central, and Embase databases were done to assess the studies that have reported radiation-related lymphopenia in high-grade gliomas. Hazard ratios (HRs), odds ratios (OR), and mean differences were represented with Forest plots comparing patients with severe lymphopenia and no severe lymphopenia. Review Manager Version 5.3 (The Nordic Cochrane Centre, Copenhagen, Denmark) was used for the analysis. Results  Nineteen studies were included in the final systematic review and 12 studies were included in the meta-analysis. The odds of developing severe lymphopenia were 0.39 (95% CI:0.19, 0.81, I 2  = 94%, p  = 0.01). Patients with severe lymphopenia were at increased risk of death with a pooled HR = 2.19 (95% CI: 1.70, 2.83, I 2  = 0%, p \u3c0.00001) compared to patients with no severe lymphopenia. The mean difference in survival between patients with severe lymphopenia and no severe lymphopenia was −6.72 months (95% CI: −8.95, −4.49, I 2  = 99%, p \u3c0.00001), with a better mean survival in the no severe lymphopenia group. Conclusion  Radiation-induced severe lymphopenia was associated with poor overall survival and increased risk of death. Photon therapy, larger planning target volume, higher brain dose, higher hypothalamus dose, and female gender were associated with increased risk of severe lymphopenia

Fatigue behaviour of SiC p -reinforced aluminium composites in the very high cycle regime using ultrasonic fatigue

The fatigue behaviour of a 2009/SiC/15p-T4 DRA composite has been examined in the very high cycle fatigue (VHCF) regime where 10 7 ≤ N f ≤ 10 9 cycles. Ultrasonic fatigue was used to achieve the very high cycle counts. Careful processing yielded a composite with a very homogeneous particle distribution with minimal clustering. Fatigue crack initiation was observed almost exclusively at AlCuFe inclusions with no crack initiation observed at SiC particle clusters. Fatigue lives at a given stress level exhibited minimal scatter and subsurface crack initiation was observed in all cases. This behaviour is consistent with the presence of a low number density of critical inclusions that are responsible for crack initiation very early in fatigue life.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73177/1/j.1460-2695.2006.00998.x.pd

Transgenic tobacco plants constitutively expressing Arabidopsis NPR1 show enhanced resistance to root-knot nematode, Meloidogyne incognita

In Arabidopsis, non-expressor of pathogenesis related genes-1, NPR1 has been shown to be a positive regulator of the salicylic acid controlled systemic acquired resistance pathway and modulates the cross talk between SA and JA signaling. Transgenic plants expressing AtNPR1 constitutively exhibited resistance against pathogens as well as herbivory. In the present study, tobacco transgenic plants expressing AtNPR1 were studied further for their response to infection by the sedentary endoparasitic root knot nematode, Meloidogyne incognita. Transgenic plants showed enhanced resistance against the root-knot nematode infection. Prominent differences in the shoot and root weights of wild type and transgenic plants were observed post-inoculation with M. incognita. This was associated with a decrease in the number of root galls and egg masses in transgenic plants compared to WT. The transgenic plants also showed constitutive and induced expression of some PR protein genes, when challenged with M. incognita

Improved Tunability and Energy Storage Density Properties of Low-Loss, Lead-Free (Ba0.50Sr0.50)TiO3 and Ba(Zr0.15Ti0.85)O3 Bilayer Thin Film Stacks

Multilayer thin films of (Ba0.50Sr0.50)TiO3 (BST) and Ba(Zr0.15Ti0.85)O3 (BZT) were designed and grown using pulsed laser deposition technology. The periodic (BST/BZT)n thin films were deposited on Pt‹111›/SiO2/Si substrates. X-ray diffraction revealed the presence of a polycrystalline, perovskite structure corresponding to the bilayer thin film stacks. Scanning electron microscopy confirmed the multilayer structure without any interdiffusion across layers. It was also found that the dielectric and ferroelectric properties of the thin films were strongly influenced by the periodic heterostructures. The thin film stacks exhibited significantly higher tunability as compared with multilayer thin films grown on various single-crystal substrates such as LaAlO3, MgO and SrTiO3. Possible mechanisms explaining the other observed attributes such as improved dielectric properties and reduced leakage current are discussed. The effect of incorporating a comparatively lower-permittivity thin film in the multilayer stacks is presented. The observed properties of such multilayer structured films will aid in realizing low-loss and highly tunable applications. © 2021, The Minerals, Metals & Materials Society

Synthesis, consolidation and dielectric properties of BLT ceramics processed by M-PVA gel ignition technique

Polycrystalline samples of lanthanum modified bismuth titanate ceramics with composition Bi3.25La0.75Ti3O12 (BLT) were prepared at three different sintering temperatures (1050, 1100 and 1150 degrees C) using M-PVA gel ignition technique. The samples were characterised for structural and electrical properties. A significant amount of as burnt BLT powder was found to be crystalline in nature having a yellowish colour. Very fine BLT nanoparticles were characterised by TEM analysis. Single phase with orthorhombic crystal structure was observed for all the samples, confirmed by X-ray analysis. Dielectric properties were studied as a function of frequency and temperature. More than 95% relative density was observed for all the three sintered samples. The sample sintered at 1100 degrees C showed highest dielectric constant and relative density and lowest loss

Strength of hot pressed ZrB₂–SiC composite after exposure to high temperatures (1000–1700°C)

Residual strength (room temperature strength after exposure in air at high temperatures) of hot pressed ZrB2–SiC composites was evaluated as function of SiC contents (10–30 vol%) as well as exposure temperatures for 5 h (1000–1700 °C). Multilayer oxide scale structures were found after exposures. The composition and thickness of these multilayered oxide scale structure was dependent on exposure temperature and SiC contents in composites. After exposure to 1000 °C for 5 h, the residual strength of ZrB2–SiC composites improved by nearly 60% compared to the as-hot pressed composites with 20 and 30 vol% SiC. On the other hand, the residual strength of these composites remained unchanged after 1500 °C for 5 h. A drastic degradation in residual strength was observed in composites with 20 and 30 vol% SiC after exposure to 1700 °C for 5 h in ZrB2–SiC. An attempt was made to correlate the microstructural changes and oxide scales with residual strength with respect to variation in SiC content and temperature of expsoure

Ballistic Studies on TiB2-Ti Functionally Graded Armor Ceramics

The objective of this paper is to discuss the results of the ballistic testing of spark plasma sintered TiB2-Ti based functionally graded materials (FGMs) with an aim to assess their performance in defeating small-calibre armor piercing projectiles. We studied the efficacy of FGM design and compared its ballistic properties with those of TiB2-based composites as well as other competing ceramic armors. The ballistic properties are critically analyzed in terms of depth of penetration, ballistic efficiency, fractographs of fractured surfaces as well as quantification of the shattered ceramic fragments. It was found that all the investigated ceramic compositions exhibit ballistic efficiency (eta) of 5.1 -5.9. We also found that by increasing the thickness of FGM from 5 mm to 7.8 mm, the ballistic property of the composite degraded. Also, the strength of the ceramic compositions studied is sufficient to completely fracture the nose of the pointed projectile used. Analysis of the ceramic fragments (2 mu m-10 mm) showed that harder the ceramic, coarser were the fragments formed. On comparing the results with available armor systems, it has been concluded that TiB2 based composites can show better ballistic properties, except B4C. SEM analysis of the fragments obtained after testing with FGM showed formation of cleavage steps as well as presence of intergranular cracks, indicating that the FGM fractured by mixed mode of failure. It can be concluded that the FGM developed has lower ballistic properties compared to its monolith TiB2-20 wt.% Ti

Optimization of poling parameters of mechanically processed PLZT 8/60/40 ceramics based on dielectric and piezoelectric studies

Ultra high strain (Pb0.92La0.08)(Zr0.60Ti0.40)O3 (PLZT 8/60/40) piezoelectric ceramics were synthesized by high energy ball milling method to study the relation between poling conditions (poling electric fields, times and temperatures) and electrical properties. The ceramics were structurally investigated and with the help of ferroelectric P-E hysteresis loop, coercive field was determined. This study deals with the identification of optimum poling conditions and their effect on the piezoelectric and dielectric properties mechanically synthesized PLZT 8/60/40 ceramics. Different combinations of poling parameters were used to measure the values of dielectric constant, dielectric loss, piezoelectric charge (d33) and electromechanical coupling coefficients (kp). These values show that a ferroelectric material can be poled at ~5 kV/cm (<0.5Ec), contrary to common practice of poling far above the coercive field. The effect of aging on the electrical properties was also studied for ceramics poled at 0.6Ec and 3Ec. With the help of this study, poling electric field as well as another two important poling parameters, viz poling temperature and poling time, were optimized. Optimum poling temperature was found to be in the range of 75 °C to 125 °C with optimal poling time of 30 min. Additionally the effect of ceramic sample thickness on the said properties was also studied. The maximum d33 and kp values for PLZT ceramics was found to be ~715 pC/N and ~77%, respectively

Convenient procedures for the asymmetric reductions utilizing &#945;,&#945;-diphenyl- pyrrolidinemethanol and borane complexes generated using the I<SUB>2</SUB>/NaBH<SUB>4</SUB> system

Syntheses of oxazaborolidine in situ in benzene using &#945;,&#945;-diphenylpyrrolidinemethanol and diborane, generated from the iodine-sodium borohydride system are described. The oxazaboro- lidine (10 mole%), generated by the reaction of &#945;,&#945;-diphenylpyrrolidinemethanol and diborane in benzene followed by heating with N,N-diethylaniline, in combination with boranetetrahydrofuran complex reduces acetophenone to 1-phenylethanol in 94.7% ee. Formation of the oxazaborolidine in situ in the reaction of &#945;,&#945;-diphenylpyrrolidine-methanol and B2H6 is facilitated by N,N-diethy