Lithium cycling efficiency and conductivity for high dielectric solvent/low viscosity solvent mixed systems

Lithium cycling efficiency on a lithium substrate (Li-on-Li cycling) and conductivity for various mixed solvent systems of high dielectric solvent (HDS) and low viscosity solvent (LVS) were examined for secondary lithium batteries. For the HDS, sulfolane, dimethylsulfoxide, γ-lactones, propylene carbonate (PC) and ethylene carbonate (EC) were used. For the LVS, tetrahydrofuran (THF), 2-methyl-THF, 1,2-dialkoxyethanes and 1,3-dioxolane (DOL) were used. For the solute, LiAsF₆, LiBF₄, LiCF₃CO₃ and LiClO₄ were used. Lithium cycling efficiencies newly measured on a Li substrate (E_a) for EC/LVS or PC/LVS were ca 5% or 15% higher than those previously obtained by simple cycling of Li on a Pt substrate, while the order of Li cycling efficiencies to LVS change is similar in both cases, except for EC/DOL or PC/DOL. The reasons seem to be that the Li-on-Li cycling minimizes the influence of electrochemical Li/Pt alloying and partial solvent oxidation during the cycle on Li cycling efficiency. The E_a values in HDS/LVS mixed systems incorporating LiAsF₆ or LiClO₄ tended to increase with a decrease in the reactivity to Li, of not only LVS but also HDS. EC/THF systems incorporating LiAsF₆ or LiClO₄ showed high E_a values of ca 95% even by Li-on-Li cycling, the value being higher than those (ca 92%) for LiBF₄ or LiCF₃SO₃ systems. In addition, for all the HDS/LVS mixed systems examined in this work, conductivities were higher than those for HDS or LVS single solvent systems. In regard to both conductivity and Li cycling efficiency, HDS/LVS mixed systems are considered to be effective in various lithium battery applications.     

Genomic organization and mutational analysis of KVLQT1, a gene responsible for familial long QT syndrome

BACKGROUND: Turcot's Syndrome is the association of multiple adenomatous polyps of the colon with a primary tumor of the central nervous system. We present the first reported case of Turcot's Syndrome in a patient with malignant ependymomas. Recent advances in the elucidation of the genetic basis for the hereditary forms of colon cancer have provided a clearer understanding of the etiology of Turcot's Syndrome. This new information is relevant to the neurosurgical community and provides updated guidelines in the diagnosis and management of patients with this complex disease process. RESULTS: Turcot's Syndrome is related to two distinct genetic errors. The first involves a germ-line mutation in the adenomatous polyposis coli (APC) gene, which is postulated to act as a tumor suppressor gene. The second is a germ-line defect in one of a group of genes responsible for DNA nucleotide mismatch repair. CONCLUSION: The elucidation of the gene defects responsible for the hereditary forms of colon cancer has provided a clearer understanding of the molecular basis of Turcot's Syndrome. Patients with hereditary forms of colon cancer and neurologic symptoms require immediate and thorough investigation because of their significantly increased risk of developing CNS tumors. Previously healthy patients diagnosed with a CNS tumor with a family history of adenomatous polyposis coli should undergo screening and surveillance colonoscopy as the CNS lesion may precede colonic symptoms. CNS screening guidelines for asymptomatic patients with adenomatous polyposis coli requires further risk analysis studies. All patients diagnosed with Turcot's Syndrome should be tested for the gene defect, including the CNS tumor tissue to provide further data on the genetic relationship between Turcot's Syndrome and the hereditary forms of colon cancer.     

Identification of Chimeric αβγ Diterpene Synthases Possessing both Type II Terpene Cyclase and Prenyltransferase Activities

Two unusual diterpene synthases composed of three domains (α, β, and γ) were identified from fungal Penicillium species. They are the first enzymes found to possess both type II terpene cyclase (TC) and prenyltransferase (PT) activities. These enzymes were characterized by heterologous expression in Aspergillus oryzae and in vitro experiments with wild-type, mutated, and truncated enzymes. The results revealed that the α domain in the C-terminal region of these enzymes was responsible for the PT activity, whereas the βγ domains in the N-terminal region composed the type II TC, and formed copalyl diphosphate ( 2 ). Additionally, between the α and βγ domains, there is a characteristic linker region, in which minimal secondary structure is predicted. This linker does not exist in the characterized three-domain (αβγ) terpene synthases known as monofunctional type I or type II TCs, or bifunctional type I and type II TC enzymes. Therefore, both the catalytic activities and protein architecture substantially differentiate these new enzymes from the previously characterized terpene synthases.     

Solid acidity of 2 : 1 type clay minerals activated by selective leaching

Various 2 : 1 type clay minerals were activated by H₂SO₄ treatment and their solid acidities were evaluated by NH₃-temperature programmed desorption (TPD). Clay minerals with various degrees of Al substitution in the tetrahedral sheets were used as the starting materials. These included montmorillonite (ideally no tetrahedral Al), saponite (low content of tetrahedral Al), vermiculite (intermediate content of tetrahedral Al) and phlogopite (high tetrahedral Al content). All these samples showed increased solid acidity after selective leaching, the solid acidities varying in the order phlogopite < montmorillonite < vermiculite < saponite. The NH₃-TPD spectra were deconvoluted into two peaks; the L-peak at < 200 °C corresponds to a weak acid site and the H-peak at > 250 °C corresponds to a strong acid site. The temperature of the H-peak was lowest in phlogopite (252 °C) and highest in saponite (305 °C). The generation of solid acidity in these samples is found to be related to the evolution of new tetrahedral Al sites showing a slightly different ²⁷Al MAS NMR chemical shift from the original tetrahedral Al NMR resonance.     

Dynamic equilibrium of self-assembled cyclic trimer and tetramer of 1-methyl-5-imidazolylcobalt(III)porphyrin

Dynamic equilibrium of self-assembled multi-porphyrin systems is of interest in obtaining switchable photoresponsive material, but rarely reported. 1-methyl-5-imidazolylcobalt(III)porphyrin ( 1Co ) synthesized here assembled automatically into cyclic trimer and tetramer by intermolecular imidazolyl-cobalt(III) coordination. The trimer-tetramer equilibrium was dependent on concentration and solvent, as examined by NMR spectrometry. In CDCl₃, the tetramer formation was favored at high concentrations, as the ratio of the trimer to the tetramer was 1:2 at 14.8 mM 1Co , and shifted to 1:8 at 74 mM. Further, when the sample was concentrated from a CHCl₃ solution to dryness, the ratio increased to 1:24 on dissolution. In CD₃OD, on the other hand, only the trimer was observed in the wide concentration range. Accordingly, both the trimeric and the tetrameric structures could be prepared selectively by the choice of concentration and solvent.     

Computer-Assisted Preoperative Planning for Reduction of Proximal Femoral Fracture Using 3-D-CT Data

This paper describes procedures for repositioning calculations of fractured bone fragments using 3-D-computed tomography (CT), aimed at preoperative planning for computer-guided fracture reduction of the proximal femur. Fracture boundaries of the bone fragments, as ldquofracture lines (FLs),rdquo and the mirror-transformed contralateral femur shape extracted from 3-D-CT were used for repositioning of the fragments. We first describe a method for extracting FLs based on 3-D curvature analysis and then formulate repositioning methods based on registration of bone fragments using the following three constraints: 1) contralateral (CL) femur shape; 2) FLs; and 3) both CL femur shape and fracture lines, as ldquoboth constraintsrdquo. We performed experiments using CT datasets from five simulated and four real patients with proximal femoral fracture. We evaluated the rotation error in reposition calculations and the contact ratio between repositioned fragment boundaries, which are crucial for the recovery of proper functional axes and bone adhesion of fragments, respectively. Experimental results showed that good accuracy and stability were attainable when registration using both constraints was performed after registration using the fracture-line constraint. On average, 6.0deg plusmn0.8deg in rotation error and 89% plusmn 3% in contact ratio were obtained without providing precise initial values.     

Pre-DFT combining space diversity assisted COFDM

A new pre-discrete Fourier transformation (DFT) combining diversity receiver is proposed for coded orthogonal frequency-division multiplexing systems and investigated in a frequency-selective fading channel. Although the post-DFT combining space diversity receiver is optimum in terms of maximizing the signal-to-noise ratio (SNR) after combining, it requires an increased number of DFT processors, which increases the computational complexity. Since the proposed pre-DFT combining receiver requires only one DFT processor, while achieving space diversity gain, the proposed scheme can drastically reduce the computational complexity. This paper derives the optimum diversity weights for the proposed receiver analytically, in order to maximize the SNR after combining. Computer simulation results show that the proposed scheme can reduce the computational complexity by tolerating a slight performance degradation     

Single-switch single-phase rectifier for step-down AC-DC conversion

A novel single-phase rectifier for step-down AC-DC conversion is presented. This has the advantage that a single active switch can provide the necessary control over the current. The experimental results confirm that the input current can be sinusoidally waveshaped with a near-unity power factor     

Fenestrated oculomotor nerve caused by meningioma around the cavernous sinus: a surgical pitfall in tumor removal: case report

OBJECTIVE AND IMPORTANCE: The preservation of oculomotor nerves is one of the most significant issues regarding the resection of meningiomas around the cavernous sinus. CLINICAL PRESENTATION: We report the case of a patient whose oculomotor nerve was fenestrated, caused by a large meningioma around the cavernous sinus. The nerve function remained intact until surgery. INTERVENTION: During surgery, one trunk of the fenestrated nerve behind the tumor was sacrificed. The fenestrated shape of the nerve led us to the misjudgment that the preserved other trunk located along the upper margin of the tumor was the whole nerve. CONCLUSION: Although fenestrated oculomotor nerves may be rare, their possibility should be kept in mind during surgery around the cavernous sinus.