Countercurrent leaching of Ni, Co, Mn, and Li from spent lithium-ion batteries.

This study focuses on a countercurrent leaching process (CLP) for the dissolution of high-value metals from cathode active material of spent lithium-ion batteries (LIBs). Its main aim is to improve the effective utilization of acid during leaching and allow for the continuous operation of the entire CLP by adjusting the process parameters. The overall recovery of lithium (Li), cobalt (Co), nickel (Ni), and manganese (Mn) was 98%, 95%, 95%, and 92%, respectively; the acid utilization of the leaching process exceeded 95% under optimum conditions. The optimum conditions for first stage leaching were 70 g/L solid-liquid (S/L) ratio at 40°C for 30 minutes, and 2.0 M sulfuric acid, 100 g/L S/L ratio, 7 g/L starch, at 85°C for 120 minutes for second stage leaching. After five bouts of circulatory leaching, more than 98% Li, 95% Co, 95% Ni, and 92% Mn were leached under the same leaching conditions. Furthermore, we introduced the Avrami equation to describe metal leaching kinetics from spent LIBs, and determined that the second stage leaching process was controlled by the diffusion rate. In this way, Li, Ni, Co, and Mn can be recovered efficiently and the excess acid in the leachate can be reused in this hydrometallurgical process, potentially offering economic and environmental benefits.

High prevalence of chronic venous disease among health care workers in the United States.

BACKGROUND: Health care workers spend extended times standing and walking short distances and are at risk for development of chronic venous insufficiency (CVI). We conducted a hospital-wide venous screening program designed to measure the prevalence of and risk factors for clinical manifestations of CVI and ultrasound evidence of venous reflux or obstruction in health care workers. We also determined their risk for deep venous thrombosis (DVT). METHODS: Free venous screening and education were offered to all hospital employees; the program started in April 2016, and results are presented from the first year. Demographics, medical history, and use of compression stockings were recorded. A physical examination determined the clinical class of the Clinical, Etiology, Anatomy, and Pathophysiology (CEAP) classification for clinical disease, and an ultrasound test evaluated for reflux or obstruction in the common femoral vein, popliteal vein, and saphenofemoral junction. The Caprini score was recorded to evaluate risk of DVT. Descriptive statistics were reported, and logistic regression was used for multivariate analysis of risk factors. RESULTS: We enrolled 636 participants (1272 legs); 93.0% were women. The median age was 42 years (interquartile range, 31-52 years), mean body mass index was 29.2 ± 6.6 kg/m2, and most participants were white (49.1%) or African American (39.5%); 18% reported having hypertension, 7.1% had diabetes, and 6.1% were current smokers. The majority reported occasional leg pain (72.7%) and evening leg swelling (42.3%). Only 2.7% used daily compression stockings. Clinical evidence of CVI was present in at least one leg in 69.1% (C1, 49.0%; C2, 17.7%; C3, 1.9%; C4, 0.2%; C5, 0.2%). Venous reflux was present in at least one leg in 82.1%; obstruction was rare (0.2%). Reflux in either the superficial (saphenofemoral junction) or the deep (femoral or popliteal) venous system was present in the majority (71.0%) of patients with CVI (clinical class ≥C1). Reflux and white race were risk factors for clinical disease; clinical disease, age, female sex, and white race were risk factors for reflux. On the basis of the Caprini score, 14.1% of participants were in the highest risk category for DVT when experiencing a high-risk situation (including 2.2% with history of DVT). CONCLUSIONS: Prevalence of clinical CVI and venous reflux is high among health care workers despite a low frequency of cardiovascular comorbidities. Increased awareness about CVI and DVT and preventive strategies for venous disease must be instituted in this high-risk cohort.

Pathology and gene expression of the sciatic nerve after non-freezing cold injury / 中华物理医学与康复杂志

Objective To investigate the morphological changes in the sciatic nerve and the dorsal root ganglions (DRGs) and also gene expression in DRGs after non-freezing cold injury, and to explore the molecular mechanism of peripheral nerve cold injury and regeneration. Methods Twenty-four male Wistar rats were used. The sciatic nerve on one side was cooled to 4℃ for 2 h, and the sciatic nerve on the opposite side was exposed, but without cooling. Sciatic nerves and L4, L5 and L6 DRGs from both sides were harvested at the 1st, 2nd and 3rd week after cooling. Any pathological changes were observed using light and electron microscopy. Laser capture microdissection (LCM) was used to investigate the DRG neurons' gene expression. The array result was verified with RT-PCR for eight genes. Results Large fiber degeneration was obvious by the 7th day after cooling. Myelinated fiber regeneration had begun by the 14th day, so this time was chosen to explore the neurons' gene expression. Ninety-six genes and expressed sequence tags (ESTs) were up-regulated greater than 2 fold. Their proteins' functions were classified as adaptive response to external stimulus, apoptosis regulation, cell adhesion, immune and inflammation response,nerve regeneration, pain associated molecules, microtubule cytoskeleton, ion-channels, neurotransmitters and receptors, and neuropeptides. Conclusions A complex molecular mechanism is involved in cold injury and regeneration of the sciatic nerve, and many genes are involved. Large scale microarray analysis is a potent means to screen out related genes, thus suggesting future repair strategies.