The effect of vacuum polarisation on muon-proton scattering at small energies and angles

We give a compact expression for the unpolarised differential cross section for muon-proton scattering in the one photon exchange approximation. The effect of adding the vacuum polarisation amplitude to the no-spin-flip amplitude for one photon exchange is calculated at small energies and scattering angles and is found to be negligible for present experiments.Comment: 6 pages, one figur

Acute neuroinflammation induces AIS structural plasticity in a NOX2-dependent manner

Background Chronic microglia-mediated inflammation and oxidative stress are well-characterized underlying factors in neurodegenerative disease, whereby reactive inflammatory microglia enhance ROS production and impact neuronal integrity. Recently, it has been shown that during chronic inflammation, neuronal integrity is compromised through targeted disruption of the axon initial segment (AIS), the axonal domain critical for action potential initiation. AIS disruption was associated with contact by reactive inflammatory microglia which wrap around the AIS, increasing association with disease progression. While it is clear that chronic microglial inflammation and enhanced ROS production impact neuronal integrity, little is known about how acute microglial inflammation influences AIS stability. Here, we demonstrate that acute neuroinflammation induces AIS structural plasticity in a ROS-mediated and calpain-dependent manner. Methods C57BL/6J and NOX2−/− mice were given a single injection of lipopolysaccharide (LPS; 5 mg/kg) or vehicle (0.9% saline, 10 mL/kg) and analyzed at 6 h–2 weeks post-injection. Anti-inflammatory Didox (250 mg/kg) or vehicle (0.9% saline, 10 mL/kg) was administered beginning 24 h post-LPS injection and continued for 5 days; animals were analyzed 1 week post-injection. Microglial inflammation was assessed using immunohistochemistry (IHC) and RT-qPCR, and AIS integrity was quantitatively analyzed using ankyrinG immunolabeling. Data were statistically compared by one-way or two-way ANOVA where mean differences were significant as assessed using Tukey’s post hoc analysis. Results LPS-induced neuroinflammation, characterized by enhanced microglial inflammation and increased expression of ROS-producing enzymes, altered AIS protein clustering. Importantly, inflammation-induced AIS changes were reversed following resolution of microglial inflammation. Modulation of the inflammatory response using anti-inflammatory Didox, even after significant AIS disruption occurred, increased the rate of AIS recovery. qPCR and IHC analysis revealed that expression of microglial NOX2, a ROS-producing enzyme, was significantly increased correlating with AIS disruption. Furthermore, ablation of NOX2 prevented inflammation-induced AIS plasticity, suggesting that ROS drive AIS structural plasticity. Conclusions In the presence of acute microglial inflammation, the AIS undergoes an adaptive change that is capable of spontaneous recovery. Moreover, recovery can be therapeutically accelerated. Together, these findings underscore the dynamic capabilities of this domain in the presence of a pathological insult and provide evidence that the AIS is a viable therapeutic target

A new approximation scheme in quantum mechanics

An approximation method which combines the perturbation theory with the variational calculation is constructed for quantum mechanical problems. Using the anharmonic oscillator and the He atom as examples, we show that the present method provides an efficient scheme in estimating both the ground and the excited states. We also discuss the limitations of the present method.Comment: 14pages, to be published in Eur. J. Phy

Impact of early seed quality selection on maize inbreds and hybrids

Seed composition, genetic background, and environment influence seed quality. Plant breeders selecting for improved seed composition seldom select their inbreds for improved seed quality traits. The standard germination test evaluates seed viability, but it often overestimates field performance. Therefore, seed vigor tests are used to predict seed germination under stressful environments. There is little information on the possible genetic improvement of seed selected for both, improved seed composition and vigor. The objectives of this study were 1) to evaluate the seed quality attributes of a group of maize (Zea mays L.) inbreds selected for high protein content; 2) to assess whether early selection improves the seed quality and decreases the phenotypic variability of seed vigor in a group of inbreds; and 3) to calculate the breeding parameters of general (GCA) and specific combining ability (SCA). During summer 2002 and 2003, related sets of inbred lines were grown in replicated nurseries near Clinton, IL, and Ames, IA. Seed from each inbred was produced by self pollination. Some of the inbred lines grown in 2002 and all grown in 2003 were high-protein white lines that also had been selected for germination cold tolerance and high post-accelerated aging field emergence. In 2002, the mean percentage of standard germination test, saturated cold test, accelerated aging test, soak test, and fast green test for the group of selected high-protein white inbreds were significantly (P ≤ 0.05) higher than the corresponding average values of the yellow inbred checks. There was genetic variability for seed quality in these sets of high protein white inbreds even after a very intense selection process for improved seed quality traits. GCA effects for seed quality were more important than the SCA effects, indicating that the additive effect of the inbreds was more important than the dominant effect to the final seed quality of the hybrids. Selecting inbreds for high seed quality early in the breeding program is beneficial and important for improving germination and field performance

Nonlinear transport in nanoscale phase separated colossal magnetoresistive oxide thin films

We report a study of the I-V characteristics of 2.5–5.4 nm epitaxial La1xSrxMnO3 (x = 0.33 and 0.5) and La0.7Ca0.3MnO3 thin films. While La0.67Sr0.33MnO3 films exhibit linear conduction over the entire temperature and magnetic field ranges investigated, we observe a strong correlation between the linearity of the I-V relation and the metal-insulator transition in highly phase separated La0.5Sr0.5MnO3 and La0.7Ca0.3MnO3 films. Linear I-V behavior has been observed in the high temperature paramagnetic insulating phase, and an additional current term proportional to Va (a = 1.5–2.8) starts to develop below the metal-insulator transition temperature TMI, with the onset temperature of the nonlinearity increasing in magnetic field as TMI increases. The exponent a increases with decreasing temperature and increasing magnetic field and is significantly enhanced in ultrathin films with thicknesses close to that of the electrically dead layer. We attribute the origin of the nonlinearity to transport through the nanoscale coexisting metallic and insulating regions. Our results suggest that phase separation is not fully quenched even at low temperatures and high magnetic fields

Intracranial oligodendroglioma with optic nerve infiltration in a Labrador retriever

A seven-year-old neutered male Labrador retriever was presented with behavioral changes and reduced vision. Neurological examination revealed blindness of the left eye with a positive pupillary light reflex and a decreased mental status. Blood and cerebrospinal fluid analyses showed no abnormalities. MRI revealed a deviant area located in the thalamic, hypothalamic and caudate nuclear regions. Invasion of the left optic nerve was also observed. The dog was euthanized after 38 days of palliative treatment. Necropsy showed a non-encapsulated extruding white lardaceous mass, with a diameter of 2 cm, in the white matter, located in the ventral thalamic region near the chiasma opticum, which extended along the left optic nerve. Histologically, neoplastic cells had a “fried egg” appearance. Immunolabelling for glial fibrillary acidic protein demonstrated the presence of numerous reactive astrocytes. The tumor was diagnosed as a low grade (II) intracranial oligodendroglioma with infiltration of the optic nerve.</jats:p

Effects of light at night on laboratory animals and research outcomes

Light has substantial influences on the physiology and behavior of most laboratory animals. As such, lighting conditions within animal rooms are potentially significant, and often underappreciated variables within experiments. Disruption of the light/dark cycle, primarily by exposing animals to light at night (LAN), disturbs biological rhythms and has widespread physiological consequences due to mechanisms such as melatonin suppression, sympathetic stimulation, and altered circadian clock gene expression. Thus, attention to the lighting environment of laboratory animals and maintaining consistency of a light/dark cycle is imperative for study reproducibility. Light intensity as well as wavelength, photoperiod, and timing are all important variables. Although modern rodent facilities are designed to facilitate appropriate light cycling, there are simple ways to modify rooms to prevent extraneous light exposure during the dark period. Attention to lighting conditions of laboratory animals by both researchers and research care staff ensures best practices for maintaining animal welfare, as well as reproducibility of research results

Hydroxyl as a Tracer of H2 in the Envelope of MBM40

We observed 51 positions in the OH 1667 MHz main line transitions in the translucent, high latitude cloud MBM40. We detected OH emission in 8 out of 8 positions in the molecular core of the cloud and 24 out of 43 in the surrounding, lower extinction envelope and periphery of the cloud. Using a linear relationship between the integrated OH line intensity and E(B-V), we estimate the mass in the core, the envelope, and the periphery of the cloud to be 4, 8, and 5 solar masses. As much as a third of the total cloud mass may be found in the in the periphery (E(B-V) $<$ 0.12 mag) and about a half in the envelope (0.12 $\le$ E(B-V) $\le$ 0.17 mag). If these results are applicable to other translucent clouds the OH 1667 MHz line is an excellent tracer of gas in very low extinction regions and high-sensitivity mapping of the envelopes of molecular clouds may reveal the presence of significant quantities of molecular mass.Comment: 26 pages, 3 figures, and 5 table