Structure and electrochemical performances of co-substituted LiCo(x)Li(x-y)Mn(2-x)O4 cathode materials for the rechargeable lithium ion batteries

Spinel LiMn2O4 and Co, Li co-substituted LiCo(x)Li(x-y)Mn(2-x)O4 (x = 0.20; y = 0.05, 0.10 and 0.15) cathode materials were synthesized by sol-gel technique using lithium acetate, manganese acetate, cobalt acetate and tartaric acid as the starting materials. The effect of Co, Li substitution on the structure and surface morphology of LiCo(x)Li(x-y)Mn(2-x)O4 has been examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The materials for all the compositions have exhibited a phase pure cubic spinel structures from the XRD analysis. The crystallinity and average particle size of the synthesized materials were decreased by the substitution of Co, Li. The electrochemical properties of the assembled LiCo(x)Li(x-y)Mn(2-x)O4/Li/LiPF6 cells were evaluated for charge/discharge studies at different rates and electrochemical impedance measurements. This co-substituted LiMn2O4 has improved specific capacity and capacity retention over pure spinel LiMn2O4. The co-substitution of LiMn2O4 cathode material has increases cyclability; however, the discharge capacity reduces. Among all the compositions, LiCo(0.10)Li(0.10-)Mn(1.80)O4 cathode has improved the structural stability and excellent electrochemical performances of the rechargeable lithium-ion batteries.

Purse string suturing in a neonatal prolapsed uterus

Prolapsed uterus in a newborn is a rare condition. We present our purse-string suturing as a new technique to restore it to its normal position to avoid complications. Prolapse is usually associated with congenital spinal defects, and is often resistant to simple reduction.

Electrochemical behaviour of surface modified SiO2-coated LiNiO2 cathode materials for rechargeable lithium-ion batteries

Pristine and SiO2-coated on layered LiNiO2 nanoparticles were synthesized by polymeric sol gel process using metal nitrate precursors at 600 degrees C for 10 h. Effect of SiO2 coating on the structure and electrochemical properties of the LiNiO2 cathode material was investigated by using XRD, SEM, Cyclic voltammetry and Charge-discharge techniques. X-ray powder diffraction analysis of SiO2-coated LiNiO2 revealed that the coating did not affect the crystal structure and the R-3m space group of the cathode materials compared to uncoated LiNiO2. Surface morphology of LiNiO2 and silica coated LiNiO2 powder materials were characterized by using SEM studies. The galvanostatic charge/discharge studies of the pristine and silica coated LiNiO2 positive materials were found at 0.5-C rate in the potential range between 3-4.5 V, Silica coated positive electrode materials have improved charge/discharge capacities. Cyclic voltammetry studies have revealed that, short range deintercalation/intercalation process of Li+ ions and the 2 wt.% relatively narrower peaks with less peak separation. 2 wt.% of SiO2-coated LiNiO2 positive material met the structural stability, high reversible capacity and high electrochemical performances.

Growth of aluminum catalyzed AlGaAs nanowires on silicon substrate

Aluminum catalyzed AlGaAs nanowires were fabricated on Si (111) substrates using metal-organic chemical vapor deposition (MOCVD) technique at a low growth temperature of 450 degrees C. Grown structures were characterized by field emission scanning electron microscope (FE-SEM), energy-dispersive X-ray spectroscopy (EDS) and photoluminescence (PL) techniques. Nanowire clusters were observed all over the substrate. Multiprong root-grown AlGaAs nanowire clusters as well as catalyst particle terminated growth was observed. The growth is explained by Vapor-Solid-Solid (VSS) and Vapor-Solid (VS) growth mechanisms using Al-Si binary phase diagram. EDS and PL measurement confirm the formation of AlGaAs nanowires.

Should patients with autosomal dominant polycystic kidney disease be screened for cerebral aneurysms?

Autosomal dominant polycystic kidney disease is a genetic disorder affecting 1 in 1000 people worldwide and is associated with an increased risk of intracranial aneurysms. It remains unclear whether there is sufficient net benefit to screening this patient population for IA, considering recent developments in imaging and treatment and our evolving understanding of the natural history of unruptured aneurysms. There is currently no standardized screening protocol for IA in patients with ADPCKD. Our review of the literature focused on the above issues and presents our appraisal of the estimated value of screening for IA in the setting of ADPCKD.

Electrodeposition and characterization of Ni-ZrO2 nanocomposites by direct and pulse current methods

Direct Current (DC) and Pulse current (PC) methods were used to get nanocrystalline Ni-ZrO2 composites from tri-ammonium citrate bath. In the electrocomposite formation, the ZrO2 particles were transported to the surface by mechanical action and got entrapped in the nickel matrix. Incorporation of ZrO2 in the nickel matrix was found to increase with current densities when DC was employed. Beyond 2 A/dm2, their incorporation became saturated when PC was used. PC method offered better electrocomposites than DC method producing finer grains and uniform surface. Scanning electron micrographs (SEM) reveals that smaller grains and uniform distribution of Zirconia particles in the nickel matrix. The increased hardness of Ni-ZrO2 electrocomposite coatings is due to incorporation of ZrO2 particles in the nickel matrix and also changes in grain size. Incorporation of ZrO2 particles in Ni-matrix favoured the enhanced microhardness and corrosion resistance of the deposit.

Electrochemical performances of dual metal substituted nano LiCe(x-y)La(y)Ni1-xO2 cathode materials for rechargeable Li-ion batteries

Pristine and Cerium, Lanthanum substituted LiCe(x-y)La(y)Ni1-xO2 (x = 0.20; y = 0.05, 0.10 and 0.15) nanoparticles were synthesized by sol-gel technique using aqueous solutions of metal nitrates and tartaric acid as a chelating agent at 600 degrees C for 10 hours. The structure and Electrochemical properties of the synthesized materials were characterized by using XRD, SEM, EDAX, TEM, Cyclic voltammetry, Charge discharge and Electrochemical Impedance spectroscopy. X-ray powder diffraction analysis was showed an increase in lattice parameters with increasing Lanthanum and Cerium content, which occupies within the layer. The defined layer structure and the lattice parameters were linearly increased with increasing dual substituting contents in LiCe(x-y)La(y)Ni1-xO2. SEM analyses shows that, LiCe0.10La0.10Ni0.80O2 has smaller particle size and more regular morphological structure with narrow size distribution than those of LiNiO2. Cyclic voltammetry results suggests that, LiCe0.10La0.10Ni0.80O2 has lower electrode polarization and high lithium ion diffusivity in solid state body of sample, implying that the substitution is beneficial to the reversible intercalation/deintercalation of Li+ ions. The variations of Ce, La mixing and hexagonal ordering with the higher elements amounts of (increase in R-factor) have favoured the first charge/discharge capacity. The LiCe0.10La0.10Ni0.80O2 cathode materials may find promising applications in lithium ion batteries and electrochemical cells due to the excellent electrochemical performances.

Improved the electrochemical performance of LiCe(1-x)Ni(x)O2 cathode material for rechargeable lithium ion battery

Cerium substituted LiCe(1-x)Ni(x)O2 (0.00 < X < 0.20) (Ce = 0.00 < X < 0.20) nano-particles were synthesized by sol-gel method using nitrate as precursor at 800 degrees C for 12 hrs. XRD studies were revealed a well defined layer structure and a linear variation of lattice parameters with the addition of Cerium confirmed phase pure compounds in a rhombohedral structure for all materials. The surface morphological and particles agglomeration changes by the substitution of Cerium in LiNiO2 particles were examined by scanning electron microscope technique and TEM techniques. Ce3+ has prevented Jahn-Teller distortion and contained the NiO6 in LiCe(1-x)Ni(x)O2 through charge transfer from Ce-3d orbital to nearby Ni-3d orbital. The preferential occupation of Ce3+ in the Li sites was decreased the mixing of Ni2+ into the Li sites and improved the electrochemical properties of LiNiO2. The galvanostatic charge/discharge studies using assembled cells were carried out at 0.5 C rates. Cyclic voltammetric studies were carried out in the potential range between 3.5 V and 4.7 V at a scan rate of 0.1 mV s(-1). Electrochemical impedance spectroscopy revealed that, LiCe0.15Ni0.85O2 augmented charge transfer resistance upon cycling. The variations of cerium mixing and hexagonal ordering with the element (increase in R-factor) were favoured the first discharge capacity with the substituted element. LiCe0.15Ni0.85O2 nano cathode materials have superior electrochemical performances, such as, high charge-discharge capacity, high coulombic efficiency, high electrical conductivity and low irreversible capacity loss.

Robotic transperineal prostate biopsy: pilot clinical study

OBJECTIVE

To develope a robot (BioXbot) that performs mapping transperineal prostate biopsy (PB) with two perineal skin punctures under ultrasound guidance. Our pilot study's clinical endpoints were complications and its technical endpoints were the duration for each phase.

METHODS

This institution review board-approved prospective clinical trial included patients with indications for PB. Two urologists performed these PBs. In the lithotomy position and under general anesthesia, the transrectal biplane ultrasound probe acquired transverse images of the prostate gland. The urologist defined its boundaries and planned the biopsy. It guided the PB in 3 axes, passing through a single perineal skin puncture for each prostate side. After each biopsy, it automatically moved to the next position. The steps were repeated on the contralateral side.

RESULTS

Our 20 patients had a mean prostate-specific antigen of 8.4 ± 4.9 ng/mL. Two patients had 2 previous biopsies, whereas the rest had one. The mean number of biopsies taken was 28.5 ± 6.2 in a mean total procedure time of 32.5 ± 3.2 minutes. We detected 3 patients with prostate cancer with Gleason score 3 + 3. Two patients required brief bladder catheterization after their biopsy. Their prostate volumes were >50 mL and the number of biopsies taken was >30 cores. There was no mechanical failure, sepsis, bleeding per-rectal, or perineal hematoma.

CONCLUSION

This pilot study demonstrated BioXbot's safety and feasibility as a biopsy platform. It can potentially be used for image-guided PB and focal therapy.

Pathogenesis of cholangitis in obstructive jaundice-revisited

Obstructive jaundice produces a number of biochemical and physiologic alterations in the biliary tract. Acute cholangitis occurs in an infected, usually obstructed biliary system, at the level of the common bile duct. The most common cause of obstruction is stones. Bacterial reflux from the biliary tract to the systemic circulation is considered to be the primary etiologic factor in bacteremia and the development of sepsis in cholangitis. The main factors in the pathogenesis of acute cholangitis are biliary tract obstruction, elevated intraluminal pressure, and infection of bile. The bile is normally sterile. The route of infection may be ascending, hematogenous or by lymphatics. Bactibilia (presence of bacteria in the biliary tract) increases in the presence of biliary obstruction, particularly partial and in the presence of foreign bodies like stones. Obstruction produces local changes in the host defenses, both in chemotaxis and phagocytosis along with systemic changes. The absence of bile and secretary IgA from the gastrointestinal tract because of biliary obstruction produces changes in the bacterial flora, loss of mucosal integrity, decreased endotoxin inactivation and promotes bacterial overgrowth, portal bacteremia, endotoxemia and increased translocation of endotoxin (LPS) to the liver, resulting in sepsis and also serving to inhibit hepatic macrophage (Kupffer cell) function in these patients. Early intervention in relieving biliary decompression is imperative in restoring normal function of the Kupffer cells in the liver and to prevent functional alterations in the liver because of chronic obstruction and cholestasis and to decrease the postoperative morbidity and mortality.

Quantification of apixaban's therapeutic utility in prevention of venous thromboembolism: selection of phase III trial dose

A model-based approach was used to integrate data from a phase II study in order to provide a quantitative rationale for selecting the apixaban dosage regimen for a phase III trial. The exposure-response models demonstrated that an increase in daily steady-state area under the plasma concentration-vs.-time curve (AUC(ss)) of 1 microg x h/ml would increase the odds ratio for major bleeding by 0.118 and decrease the odds ratio for venous thromboembolism (VTE) by 0.0499. The therapeutic utility index (TUI) was used to integrate the efficacy and safety predictions to quantify apixaban's efficacy/safety balance as a function of AUC(ss). Of the apixaban dosage regimens tested in phase II, the 2.5 mg twice-daily (b.i.d.) dosage regimen had the highest TUI (86.2%). This was also higher than the TUI for either 30 mg b.i.d. enoxaparin (82.5%) or for warfarin (71.8%). Subjects with moderate renal impairment are expected to have a 43% increase in apixaban exposure; however, apixaban's TUI suggests that dose adjustment is not needed in these subjects with renal impairment.

MediNet: personalizing the self-care process for patients with diabetes and cardiovascular disease using mobile telephony

This paper describes MediNet, a mobile healthcare system that is being developed to personalize the self-care process for patients with both diabetes and cardiovascular disease. These two diseases were chosen based on their interrelationship. Patients with diabetes are at least twice as likely to have heart disease or a stroke as compared to persons without diabetes. Furthermore, persons with diabetes also tend to develop heart disease or have strokes at an earlier age than other people. MediNet uses a reasoning engine to make recommendations to a patient based on current and previous readings from monitoring devices connected to the patient and on information that is known about the patient. It caters for the uniqueness of each patient by personalizing its recommendations based on individual level characteristics of the patient, as well as on characteristics that groups of patients tend to share.