Quantitative assessment of acute kidney injury by noninvasive arterial spin labeling perfusion MRI: a pilot study

The kidneys are essential for maintaining homeostasis, are responsible for the reabsorption of water, glucose and amino acids, and filter the blood by removing waste. Acute kidney injury (AKI) is a syndrome characterized by the rapid loss of renal excretory function and the accumulation of end metabolic products of urea and creatinine. AKI is associated with the later development of chronic kidney disease and end-stage kidney disease, and may eventually be fatal. Early diagnosis of AKI and assessments of the effects of treatment, however, are challenging. The pathophysiological mechanism of AKI is thought to be the imbalance between oxygen supply and demand in the kidneys. We have assessed the ability of arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI), without the administration of contrast media, to quantify renal blood flow (RBF) non-invasively. We found that RBF was significantly lower in AKI patients than in healthy volunteers. These results suggest that ASL perfusion MRI, a noninvasive measurement of RBF, may be useful in the early diagnosis of AKI.     

山西被子植物5个新记录种

【目的】为丰富山西省被子植物种质资源,促进中条山生物多样性和森林生态系统的研究。【方法】在大量野外植被调查工作基础上,通过标本鉴定、资料查阅和专家咨询,对中条山植物标本、典型特征照片进行整理。【结果】发现小酸模（Rumex acetosella L.）、伏毛银莲花（Anemone narcissiflora subsp. protracta (Ulbrich) Ziman & Fedoronczuk）、弯曲碎米荠（Cardamine flexuosa With.）、卢氏凤仙花（Impatiens lushiensis Y. L. Chen）、小酸浆（Physalis minima L.）等5种被子植物在山西未有分布记录。【结论】确认该5种植物隶属于5科5属,为山西省被子植物分布新记录,新记录发现不仅丰富了山西省被子植物种质资源,而且对研究山西省生物多样性和森林生态系统也具有重要意义。     

A New Self-Loading Locomotion Mechanism for Wall Climbing Robots Employing Biomimetic Adhesives

A versatile locomotion mechanism is introduced and experimentally verified. This mechanism comprises four rectangular wheels (legs) with rotational phase difference which enables the application of pressure to each contacting surface for securing it to the surface using bio-inspired or pressure-sensitive adhesives. In this mechanism, the adhesives are applied to two rigid plates attached to each wheel via hinges incorporating torsional springs. The springs force the plates back to their original position after the contact with the surface is lost in the course of locomotion. The wheels are made of low-modulus elastomers, and the pressure applied during contact is controlled by the elastic modulus, geometry and phase difference of wheels. This reliable adhesion system does not rely upon gravity for adhering to surfaces, and provides the locomotion mechanism with the ability to climb walls and transition from horizontal to vertical surfaces.     

Near‐future pH conditions severely impact calcification,metabolism and the nervous system in the pteropod Heliconoides inflatus

Shelled pteropods play key roles in the global carbon cycle and food webs of various ecosystems. Their thin external shell is sensitive to small changes in pH, and shell dissolution has already been observed in areas where aragonite saturation state is ~1. A decline in pteropod abundance has the potential to disrupt trophic networks and directly impact commercial fisheries. Therefore, it is crucial to understand how pteropods will be affected by global environmental change, particularly ocean acidification. In this study, physiological and molecular approaches were used to investigate the response of the Mediterranean pteropod, Heliconoides inflatus, to pH values projected for 2100 under a moderate emissions trajectory (RCP6.0). Pteropods were subjected to pH_T 7.9 for 3 days, and gene expression levels, calcification and respiration rates were measured relative to pH_T 8.1 controls. Gross calcification decreased markedly under low pH conditions, while genes potentially involved in calcification were up‐regulated, reflecting the inability of pteropods to maintain calcification rates. Gene expression data imply that under low pH conditions, both metabolic processes and protein synthesis may be compromised, while genes involved in acid–base regulation were up‐regulated. A large number of genes related to nervous system structure and function were also up‐regulated in the low pH treatment, including a GABA_A receptor subunit. This observation is particularly interesting because GABA_A receptor disturbances, leading to altered behavior, have been documented in several other marine animals after exposure to elevated CO₂. The up‐regulation of many genes involved in nervous system function suggests that exposure to low pH could have major effects on pteropod behavior. This study illustrates the power of combining physiological and molecular approaches. It also reveals the importance of behavioral analyses in studies aimed at understanding the impacts of low pH on marine animals.     

Structural, functional, and subunit assembly properties of hemoglobin Attleboro [alpha 138 (H21) Ser----Pro], a variant possessing a site maturation at a critical C-terminal residue

Hemoglobin Attleboro, a new alpha-chain variant with a substitution of proline for serine at position 138 (H21), was found to be a noncooperative high-affinity hemoglobin (P50 = 0.26 mmHg at pH 7 and 20 degrees C) which lacked an alkaline Bohr effect. Addition of 2,3-diphosphoglycerate (DPG) or inositol hexaphosphate (IHP) led to a decrease in oxygen affinity but to no alteration in either Bohr effect or cooperativity. Ligand binding kinetics studies revealed an overall rate of oxygen dissociation at pH 7.0 and 20 degrees C that was 2.7-fold slower than that for Hb A. At pH 8.5, the kinetic profile was identical with that at pH 7, confirming the absence of a Bohr effect for this variant hemoglobin. Measurement of the rate of oxygen dissociation with carbon monoxide replacement indicated a lack of cooperativity. Sedimentation velocity experiments yielded s20,w values of 2.8 and 4.3 for 65 microM solutions of oxyhemoglobins Attleboro and A, respectively (indicating an enhancement in the oxy dimer population of this variant). Studies of the carbon monoxide combination of this variant revealed an association rate 20-fold faster than that for Hb A; only in the presence of a 1000-fold molar excess of IHP was there a significant reduction in the overall rate. Rapid-scan and traditional stopped-flow experiments conducted in the Soret Soret region demonstrated an alteration in the structure and rate of assembly of the deoxy tetramer of Hb Attleboro relative to that of Hb A. The abnormal properties of this hemoglobin variant can be attributed to major perturbations in the C-terminal region.     

Effects of Post-silking Shading Stress on Enzymatic Activities and Phytohormone Contents During Grain Development in Spring Maize

Journal of Plant Growth Regulation - Low sunlight intensity from mid-June to mid-July in Southern China is the primary environmental factor that affects maize grain development. A field trial was...     

Front Cover: Stereotaxic endoscopy for the ocular imaging of awake,freely moving animal models (J. Biophotonics 5/2020)

A 3D printed stereotaxic head mount that enables high resolution imaging of the anterior chamber of the eye in alert and freely mobile mice is designed in this study. The system is placed non‐invasively using temporal mount bars and a snout mount, without breaking the skin or risking suffocation, while an endoscopic channel stabilizes the ocular probes. Further details can be found in the article by Bjorn Paulson, Sangwook Lee, Miyeon Jue, Kyungsung Lee, Sanghwa Lee, Guk Bae Kim, Youngjin Moon, Joo Yong Lee, Namkug Kim, and Jun Ki Kim ( e201960188 ).