Two-dimensional (2D) Ti3C2Tx MXene nanosheets with superior adsorption behavior for phosphate and nitrate ions from the aqueous environment

With the advancement of modern industries and metropolitan areas, negative environmental impacts such as eutrophication have become serious issues obstructing the usage of water sources in many countries. In this study, two-dimensional (2D) MXene materials were employed for the adsorptive removal of phosphate and nitrate ions from waters. The adsorption parameters of the sorption system including reaction time, solution pH, background ions, and reusability, were evaluated in batch experiments. Material characterization techniques, including X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, energy-dispersive X-ray analysis, Fourier transform infrared spectroscopy, thermal gravimetric analysis, Brunauer–Emmett–Teller analysis, and high-resolution transmission electron microscopy were performed. The mechanism of removing phosphate and nitrate was clearly described by various kinds of interactions such as electrostatic interactions, and the complexation was significant to elucidate the adsorption mechanism. The adsorption data for phosphate and nitrate update was determined using different isotherms and kinetic models. Reusability and field studies on the MXenes were also conducted. The above findings demonstrate that 2D MXenes could act as promising adsorbents for the elimination of toxic ions from water/wastewater.     

变转速电液推进机构

电液推进机构用于大型构件的移位装船作业,由夹紧模块夹持钢轨以提供反力支撑,通过推进液压缸完成构件的移位。电液推进机构采用变转速泵控方式,微控制器发出脉宽调制控制信号,作为变频器的输入指令信号,改变定量液压泵驱动电机的转速,以调节定量液压泵的输出流量,进而控制构件的移位速度。工程应用表明变转速电液推进机构具有效率高、响应快等特点,能够满足构件移位的作业需求。     

Ophthalmic complications after spinal surgery

STUDY DESIGN: A retrospective review of 3450 spinal surgeries was performed. OBJECTIVES: To review ophthalmic complications and their etiologies, as well as treatments and outcomes, in patients who have undergone spinal surgery. SUMMARY OF BACKGROUND DATA: Ophthalmic complications after major spinal reconstructive surgery are rare and have not been adequately addressed in the orthopedic literature. METHODS: In a series of 3450 spinal surgeries at three institutions, the authors identified seven patients (incidence = 0.20%) whose postoperative course was complicated by loss of visual acuity. These perioperative ophthalmic complications included posterior optic nerve ischemia, occipital lobe infarcts, and central retinal vein thrombosis. Operative time, estimated blood loss, and medical history of peripheral vascular, cardiovascular, or ophthalmic disease were obtained from the charts, as were follow-up data. RESULTS: Three patients recovered completely, and one had partial return of visual function. In the remaining three patients, significant visual loss persisted. CONCLUSIONS: The risk of ophthalmic complications with spinal surgery has not been fully appreciated. Because ophthalmic complications in spinal surgery may be reversed with prompt recognition and intervention, it is important for clinicians to be aware of their possible occurrence.     

Gender differences in hospitalizations for IDDM among adolescents in California, 1991. Implications for prevention

OBJECTIVE: Describe gender differences in hospitalizations for IDDM to investigate the need for gender-specific interventions to reduce diabetes-related morbidity. RESEARCH DESIGN AND METHODS: Analyses were based on hospital discharges with any mention of IDDM (n = 2,889) and the subset of these for IDDM as a principal diagnosis (n = 2,270) in California children, ages 0-18 years during 1991. Pregnancy-related hospitalizations were excluded. RESULTS: Females had more diabetes hospitalizations among discharges with any mention of diabetes, among discharges with diabetes as a principal diagnosis, and among discharges with diabetic ketoacidosis as a principal diagnosis. For diabetes as a principal diagnosis, females had 40% more hospitalizations, 44% more repeated hospitalizations, 23% more individuals hospitalized, and significantly higher rates of hospitalizations for ages 10-14 years (50 vs. 38 per 100,000) and for ages 15-18 years (68 vs. 29 per 100,000). Gender differences occurred primarily in adolescents, were independent of complicating conditions at the time of hospitalization, and were observed for diabetic ketoacidosis alone. CONCLUSIONS: Adolescent females had more diabetes hospitalizations than did males. The underlying cause may be biological or behavioral. Management protocols tailored for young women may be required to reduce hospitalizations for IDDM among females.     

Ultrastructural analysis of the progression of neurodegeneration in the septum following fimbria-fornix transection

The fimbria-fornix transection paradigm has been used as a model of retrograde neurodegeneration within the medial septal nucleus and anterograde degeneration of axon terminals within the lateral septal nucleus. Because the maintenance and survival of neurons may depend on the integrity of both efferents and afferents, the ultrastructure of neurons in the medial septal nucleus and dorsolateral septal nucleus was analysed at three, seven, 14, 30 days, and six months following unilateral transection of the fimbria-fornix in adult rats. Degeneration of axonal and somatodendritic compartments occurred in both nuclei on the side ipsilateral to fimbria-fornix transection. Degeneration of axons and terminals was present by three days and dissipated thereafter, although degenerating axodendritic and axosomatic terminals were still detected at 14-30 days postlesion. Dendrosomal alterations in both septal nuclei manifested as redistribution of organelles, dispersion and loss of rough endoplasmic reticulum, formation of membrane-bound vacuolar cisternae and membranous inclusions, loss of cytoplasmic matrix, and dispersion of chromatin throughout the nucleoplasmic matrix. These changes occurred in the absence of apparent ultrastructural damage to mitochondria and condensation of the nucleus. Dendritic pathology in both the medial and dorsolateral septal nuclei was most prominent at 14-30 days postlesion, but the neuropil recovered to control appearance by six months postlesion. In contrast, the cytoplasmic rarefaction and vacuolation of neuronal cell bodies were persistent in both the medial septal nucleus and the dorsolateral septal nucleus. We conclude that, following disconnection from the hippocampus, ultrastructural abnormalities occur within neurons in both the medial and lateral septal nuclei. The characteristics and time-course for these changes are similar in both nuclei. The neuropilar degeneration was transient, in contrast to the neuronal cell body injury which was persistent and was morphologically consistent with long-term neuronal atrophy.     

Correction of the copper transport defect of Menkes patient fibroblasts by expression of the Menkes and Wilson ATPases

Menkes' disease is a fatal, X-linked, copper deficiency disorder that results from defective copper efflux from intestinal cells and inadequate copper delivery to other tissues, leading to deficiencies of critical copper-dependent enzymes. Wilson's disease is an autosomally inherited, copper toxicosis disorder resulting from defective biliary excretion of copper, which leads to copper accumulation in the liver. The ATP7A and ATP7B genes that are defective in patients with Menkes' and Wilson's diseases, respectively, encode transmembrane, P-type ATPase proteins (ATP7A or MNK and ATP7B or WND, respectively) that function to translocate copper across cellular membranes. In this study, the cDNAs derived from a normal human ATP7A gene and the murine ATP7B homologue, Atp7b, were separately transfected into an immortalized fibroblast cell line obtained from a Menkes' disease patient. Both MNK and WND expressed from plasmid constructs were able to correct the copper accumulation and copper retention phenotype of these cells. However, the two proteins responded differently to elevated extracellular copper levels. Although MNK showed copper-induced trafficking from the trans-Golgi network to the plasma membrane, in the same cell line the intracellular location of WND did not appear to be affected by elevated copper.     

Medical genetic evaluation for the etiology of hearing loss in children

The purpose of the medical genetic evaluation is to identify the etiology of the hearing loss. To do so requires a multidisciplinary team that includes the otolaryngologist, audiologist, medical geneticist, and radiologist. A number of tests and procedures are now available to assist in the search for the cause of hearing losses. The importance of sensitivity when providing genetic counseling is emphasized. Molecular genetics offers potential for continued progress in understanding the etiologies of hearing loss. Recent advances in this area are discussed.