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In this study, a stimulated-echo (STE) method was employed to robustify the cerebral vessel size estimation near air-tissue, bone-tissue interfaces, and large vessels. The proposed solution is to replace the relaxation rate change from gradient-echo (GRE) with that from STE with long diffusion time after the injection of an intravascular contrast agent, superparamagnetic iron oxide nanoparticles. The corresponding diffusion length of STE is shorter than the length over which the unwanted macroscopic field inhomogeneities but is still longer than the correlation length of the fields induced by small vessels. Therefore, the unwanted field inhomogeneities are refocused, while preserving microscopic susceptibility contrast from cerebral vessels. The mean vessel diameter (dimensionless) derived from the diffusion-time-varying STE method was compared to the mean vessel diameter obtained by a conventional spin-echo (SE) and GRE combination based on Monte-Carlo proton diffusion simulations and in vivo rat experiments at 7 ​T. The in vivo mean vessel diameter from the MRI experiments was directly compared to available reference mouse brain vasculature obtained by a knife-edge scanning microscope (KESM), which is considered to be the gold standard. Monte-Carlo simulation revealed that SE and GRE-based MR relaxation rate changes (ΔR2 and ΔR2∗, respectively) can be enhanced using single STE-based MR relaxation rate change (ΔRSTE) by regulating diffusion time, especially for small vessels. The in vivo mean vessel diameter from the STE method demonstrated a closer agreement with that from the KESM compared to the combined SE and GRE method, especially in the olfactory bulb and cortex. This study demonstrates that STE relaxation rate changes can be used as consistent measures for assessing small cerebral microvasculature, where macroscopic field inhomogeneity is severe and signal contamination from adjacent large vessels is significant.

A large portion of the Loess Plateau of China is characterized as “marginal” with serious land degradation and desertification problems. Consequently, two policies, Grain for Green and Western Development Action were established by the Chinese government in response to the demand for ecological protection and economic development in the Loess Plateau. These policies are designed to increase forest cover, expand farmlands, and enhance soil and water conservation, while creating sustainable vegetation restoration. Perennial grasses have gained attention as bioenergy feedstocks due to their high biomass yields, low inputs, and greater ecosystem services compared to annual crops. Moreover, perennial grasses limit nutrient runoff and reduce greenhouse gas emissions and soil losses while sequestering carbon. Additionally, perennial grasses can generate economic returns for local farmers through producing bioenergy feedstock or forage on marginal lands. Here, we suggest a United States model energy crop, switchgrass (Panicum virgatum L.) as a model crop to minimize land degradation and desertification and to generate biomass for energy on the Loess Plateau.

The detailed characterization of the molecular structure of a novel mesogen, DoBDPMP (4-(dodecyloxy)benzoic acid 4-[((4-(dimethylamino)phenyl)imino)methyl]phenyl ester), in solid, meso and isotropic phases, and also the determination of the orientational order of the core fragment is discussed. The dimethyamino-containing nematogen is expected to retain its mesophase even in the presence of a nonmesogenic nitro- or cyano-substituted phenyl ring containing acceptor.

Abstract Perennial grass mixtures established on Conservation Reserve Program (CRP) lands can be an important source of feedstock for bioenergy production. This study aimed to evaluate management practices for optimizing the quality of bioenergy feedstock and stand persistence of grass‐legume mixtures under diverse environments. A 5‐year field study (2008–2012) was conducted to assess the effects of two harvest timings (at anthesis vs after complete senescence) and three nitrogen (N) rates (0, 56, 112 kg N ha−1) on biomass chemical compositions (i.e., cell wall components, ash, volatiles, total carbon, and N contents) and the feedstock energy potential, examined by the theoretical ethanol yield (TEY) and the total TEY (i.e., the product of biomass yield and TEY, L ha−1), of cool‐season mixtures in Georgia and Missouri and a warm‐season mixture in Kansas. The canonical correlation analysis (CCA) was used to investigate the effect of vegetative species transitions on feedstock quality. Although environmental variations (mainly precipitation) greatly influenced the management effect on chemical compositions, the delayed harvest after senescence generally improved feedstock quality. In particular, the overall cell wall concentrations and TEY of the warm‐season mixtures increased by approximately 7%. Additional N supplies improved the total TEY of both mixtures by ~1.6–4.2 L ha−1 per 1.0 kg N ha−1 input but likely lowered the feedstock quality, particularly for the cool‐season mixture. The cell wall concentrations of cool‐season mixture reduced by approximately 3%–6%. The CCA results indicated that the increased legume compositions (under low N input) likely enhanced lignin but reduced ash concentrations. This field research demonstrated that with proper management, grass‐legume mixtures on CRP lands can provide high‐quality feedstock for bioenergy productions.

ABSTRACT: Objective: We report an unusual case of Prader-Willi Syndrome (PWS) presenting with clinical signs and symptoms suggestive of Angelman Syndrome (AS), without exclusive features of PWS.Methods: A deletion in the 15q11-13 region is associated with 2 distinctive genetic syndromes depending on the parent of origin: AS and PWS. AS is characterized by developmental delays, seizures, microcephaly, movement or balance disorders, speech disorders, and happy demeanor. PWS is characterized by hypotonia, hyperphagia, and developmental delays. An 11.5-year-old female was evaluated for developmental delay with cognitive disabilities, minimal speech, echolalia, and continuous hand motions. The patient had a pleasant but minimally interactive demeanor.Results: Chromosomal microarray analysis revealed a 5.02 Mb interstitial deletion of 15q11.2>q13.1 (base pairs 21,192,943 to 26,213,571), consistent with PWS or AS, and a 604 kb interstitial duplication of 16p11.2 (base pairs 29,530,197 to 30,134,432). Based on her presentation, AS was suspected; however, methylation analysis confirmed the diagnosis of PWS, with the presence of only the maternal copy of 15q11.2q13.1.Conclusion: Although variable phenotypic presentation of PWS has been reported, this case is particularly unusual in having only a few typical features of PWS while presenting as possible AS. We postulate that the 16p11.2 duplications, involving an autism susceptibility region, may have attenuated some features of PWS.Abbreviations: AS = Angelman Syndrome; ASD = Autism Spectrum Disorder; BMI = body mass index; CMA = chromosomal microarray; PWS = Prader-Willi Syndrome