Multi-Step Phase Transitions of Mn3 O4 During Galvanostatic Lithiation: An In Situ Transmission Electron Microscopic Investigation.

For study of electrochemical reaction mechanisms at nanoscale, in situ electrochemical transmission electron microscopy (EC-TEM) exceeds many other methods due to its high temporal and spatial resolution. However, the limited amount of active materials used in previous in situ TEM studies prevents the model EC cells to operate in the constant-current (galvanostatic) charge/discharge mode that is required for accurate control of electrochemical processes. Herein, a new in situ EC-TEM technique is developed to investigate multi-step phase transitions of Mn3 O4 electrodes under the galvanostatic charge/discharge mode and constant-voltage discharge mode. In galvanostatic mode, the lithiation of Mn3 O4 undergoes multi-step phase transitions following a reaction pathway of Mn3 O4 + Li+ → LiMn3 O4 + Li+ → MnO + Li2 O → Mn + Li2 O. It is also found that lithium ions prefer to enter Mn3 O4 along the {101} direction to form LiMn3 O4 with the help of transitional boundary phase of Lix Mn3 O4 . These results are in sharp contrast to that obtained under a constant-voltage discharge mode, where only a single-step lithiation process of Mn3 O4 + Li+ → Mn + Li2 O is observed.

Coupling Niobia Nanorods with a Multicomponent Carbon Network for High Power Lithium-Ion Batteries.

High power lithium-ion batteries require highly conductive electrodes. For an active electrode material that has limited electron conductivity, it is critical to build a carbon network that is not only highly conductive itself but also highly compatible with the electroactive material for efficient interfacial charge transfer. Herein, we design a multicomponent carbon network that is optimized for electrical coupling with the electroactive Nb2O5 nanorods for efficient electron injection. The self-support electrode is constructed by using 0D polypyrrole-derived (Ppy) carbon nanoparticles as glue to bind the Nb2O5 nanorods with 1D carbon nanotubes (CNTs) and 2D graphene nanosheets (GNSs). The 0D carbon nanoparticles also cross-link 1D CNTs with 2D GNSs, which can effectively prevent the GNSs from aggregation and form the 3D CNT/GNS network that provides continuous electronic and ionic pathways. This 3D Nb2O5@C self-support electrode exhibits a high discharge capacity of 246.3 mA h g-1 at 0.5 C and 100 mA h g-1 at 20 C and excellent Coulombic efficiency of 99.98% at 20 C. Even increasing the mass loading to 7.1 mg cm-2, the Nb2O5@C electrode can still reach a discharge capacity of 172.4 mA h g-1 at 0.5 C after 100 cycles. A high power density of 1043 W kg-1 can be achieved at an energy density of 104.3 W h kg-1 based on the electrode weight, which is among the highest values demonstrated so far for Nb2O5 electrodes. The results pave the way toward practical applications of Nb2O5 anodes in high-power lithium-ion batteries.

Freestanding Carbon Nanotube Film for Flexible Straplike Lithium/Sulfur Batteries.

Flexible lithium/sulfur (Li/S) batteries are promising to meet the emerging power demand for flexible electronic devices. The key challenge for a flexible Li/S battery is to design a cathode with excellent electrochemical performance and mechanical flexibility. In this work, a flexible strap-like Li/S battery based on a S@carbon nanotube/Pt@carbon nanotube hybrid film cathode was designed. It delivers a specific capacity of 1145 mAh g-1 at the first cycle and retains a specific capacity of 822 mAh g-1 after 100 cycles. Moreover, the flexible Li/S battery retains stabile specific capacity and Coulombic efficiency even under severe bending conditions. As a demonstration of practical applications, an LED array is shown stably powered by the flexible Li/S battery under flattened and bent states. We also use the strap-like flexible Li/S battery as a real strap for a watch, which at the same time provides a reliable power supply to the watch.

Reducing lithium deposition overpotential with silver nanocrystals anchored on graphene aerogel.

Li metal as an anode for high-energy-density batteries is actively pursued due to its high specific capacity and ultralow electrochemical potential. Unfortunately, Li dendrite growth might induce a short circuit creating safety hazards that limit the practical applications of Li metal anode batteries. Herein, a novel anode of graphene aerogel (GA) decorated with silver nanocrystals (AgNCs@GA) is reported for effective suppression of lithium dendrite growth and improvement in coulombic efficiency at various current densities. This improved performance is attributed to AgNCs. This loaded AgNCs with high Li affinity serve as Li deposition sites, which deeply reduce the overpotential of Li nucleation and electrodeposition. Therefore, it successfully realizes stable Li deposition/stripping processes with enhanced coulombic efficiency at various current densities and areal capacities. The pre-lithiated AgNCs@GA is evaluated as an anode in a Li battery and demonstrates remarkable performance in comparison with a commercial lithium foil.

Self-reinforcement and protein sustained delivery of hyaluronan hydrogel by tailoring a dually cross-linked network.

A series of self-reinforcing hyaluronan hydrogels were developed to improve mechanical properties and protein sustained delivery thanks to a dually cross-linked network. Hyaluronan gel particles (HGPs, 1-5 µm in diameter) with different cross-linking densities, i.e. HGPs-1.5, HGPs-3 and HGPs-15, were prepared in an inverse emulsion system and used as the reinforcing phase after glycidyl methacrylation, while glycidyl methacrylated hyaluronan with a substitution degree of 45.2% was synthesized as the matrix phase. These two phases were cross-linked under ultraviolet irradiation to form self-reinforcing hyaluronan hydrogels (srHAs) that showed typical cross-linked structure of HGPs connecting the matrix phase by cross-section observation. In comparison to hyaluronan bulk gels and their blends with HGPs, srHAs distinctly enhanced the mechanical properties and BSA long-term sustained delivery, especially srHA-1.5 showed the highest compressive modulus of 220±15 kPa and the slowest BSA delivery (67% release at 14 d). The 3T3 fibroblast cell culture showed that all the srHAs had no cytotoxicity.

Long-term lamivudine treatment achieves regression of advanced liver fibrosis/cirrhosis in patients with chronic hepatitis B.

BACKGROUND AND AIM: Antiviral therapy is important in advanced liver fibrosis/cirrhosis with chronic hepatitis B (AdLF-CHB) patients, but complete regression of cirrhosis remains to be the challenge. We aimed to investigate whether up to 10 years lamivudine treatment achieves liver fibrosis/cirrhosis regression in AdLF-CHB patients. METHODS: Improvement of hepatic fibrosis/cirrhosis, virological response and disease progression were evaluated in 28 AdLF-CHB patients with up to 10 years lamivudine treatment. Liver biopsy was performed in all of the 28 patients at baseline, but only 19 patients had second biopsy at year 10. RESULTS: There were 24 hepatitis B e antigen (HBeAg)-positive and 4 HBeAg-negative patients within the original 28 AdLF-CHB patients. At the end of 10 years lamivudine treatment, 20 of the 24 HBeAg-positive patients had HBeAg loss. HBeAg seroconversion was detected in 10 of these 20 HBeAg loss patients. HBsAg loss was observed in 4 of the original 28 patients. Among these four HBsAg loss patients, three had HBsAg seroconversion. All patients achieved hepatitis B virus DNA (HBV DNA) undetectable. Histopathology was evaluated between paired original and final liver biopsies among 19 patients as follows: 4/19 achieved complete liver fibrosis/cirrhosis regression; 9/19 improved in Ishak fibrosis score; whereas 6/19 showed no fibrosis improvement. About 75% patients achieved inflammatory/fibrotic improvement. No significant disease progression was observed in 24/28 patients. Furthermore, no significant difference in histopathology improvement, cirrhosis regression, disease progression between non-resistance and rescue for resistance was observed. CONCLUSION: Long-term lamivudine therapy achieves regression of fibrosis/cirrhosis and improvement of histological and disease progression in AdLF-CHB patients.

[Clinical characteristics of 638 patients infected with hepatitis C virus by post blood transfusion, in Shanghai].

OBJECTIVE: To investigate the clinical-epidemiologic characteristics of patients with hepatitis C virus (HCV) infection by post blood transfusion. METHODS: Polymerase chain reaction (PCR) and enzyme linked immunosorbent assay (ELISA) were used to detect HCV RNA and anti-HCV, respectively. Analysis was performed on patients' age distribution, cause of primary diseases, years of exposure, ingredient and amount of transfusion, incubation period, disorder on liver function and changes on abdominal ultrasound image, etc. RESULTS: HCV RNA levels were higher than 3.0 log(10) copy/ml in 90.8% infected patients with a median as 6.10 log(10) copy/ml. 19.2% of the patients showed viral load 3.0 to 4.0 log(10) copy/ml, and 66.1% of them showed 5.0 to 6.0 log(10) copy/ml. Only 14.7% of the infected persons had HCV RNA levels higher than 7.0 log(10) copy/ml. Eighty-one point five percent (44/54) of the infected persons were confirmed as HCV RNA positive by HCV RNA qualitative analysis with HCV genotype as primarily type 1. 99.8% (636/637) of the patients were detected as anti-HCV positive by serological test. The sensitivity of serological test was higher than both quantitative and qualitative HCV RNA assays (P = 0.000, P = 0.000, respectively). HCV infection post blood transfusion was more seen in common people at 40 to 60 years old. Most cases (85.7%) had their first exposure during 1990 to 1994. More than 10% of the cases had primary diseases as obstetrics, orthopedics or gastrointestinal tract hemorrhage. 79.9% of the patients received whole blood product transfusion. The mean interval between transfusion and clinical diagnosis was 8.5 ± 5.5 years. 90.1% of the infected patients had liver function damage, while most of them showed elevated alanine aminotransferase (ALT) no more than 5 upper limits of normal (ULN), whereas Serum total bilirubin (TBIL), ALT and aspartate aminotransferase (AST) ≥ 5 × ULN level were showing more clinical manifestations (P = 0.000, P = 0.001, P = 0.009, respectively). Abdominal ultrasound among 8.9% of the infected persons showed changes in cirrhosis, and most of them were older than 50 years of age. CONCLUSION: Most of the post transfusion HCV infected cases happened in adulthood, and were mainly exposed during 1990 to 1994. Infected patients usually had their liver function damaged with elevated ALT no more than 5 × ULN and with medium HCV RNA levels. HCV genotype was mainly for type 1. Patients who were of older age showed higher incidence of cirrhosis. If a patients' infection period was longer than 5 years, he/she would show higher incidence of cirrhosis.

The relationship between staging of hepatic fibrosis and the levels of serum biochemistry.

OBJECTIVE: To study the relationship between the degree of hepatic fibrosis and serum fibrosis markers. METHODS: Liver biopsies were performed in 67 patients with hepatitis. The sections were stained with hematoxylin eosin and immunohistochemical stain. Staging of hepatic fibrosis was made microscopically. The serum levels of hyaluronic acid(HA), type III procollagen(PC-III), laminin(LN), and type IV collagen (IV-C) were measured by radioimmunoassay. RESULTS: The serum levels of HA, PC-III, LN and IV-C were elevated from S1 to S4 because of the increase of hepatic fibrosis. The serum concentrations of HA, PC-III, LN and IV-C were increased with the progress of disease, with the highest concentration at the stage of cirrhosis. CONCLUSION: The stages of hepatic fibrosis are correlated with the serum levels of HA, PC-III, LN and IV-C, which as markers may play a role in detecting the degree of hepatic fibrosis.