Two-mode fission – experimental verification and characterization of two fission-modes

Experimental verification and characterization of the two-mode fission are reviewed. The presence of two independent deformation-paths in low energy fission of actinides is demonstrated by studying correlation among saddle-point configurations, scission-point configurations, and mass-yield distributions; the elongated scission configuration is related with the fission process that goes over a higher threshold energy and results in a symmetric mass-division mode, while the compact scission configuration with the process that experiences a lower threshold ends up with an asymmetric mass-division mode. Based on an extensive systematic analysis of scission properties in a wide range of actinide fission, the bimodal fission observed in the spontaneous fission of the heavy actinides is interpreted as the result of the presence of two fission paths, namely, the ordinary asymmetric fission path and a strongly shell-influenced symmetric mode.

Effect of membrane solubilization on the inhibition of rat and hamster liver microsomal type I 11β-hydroxysteroid dehydrogenase by bile acids

The aim of this study was to investigate the differences between rats and hamsters, Two of the most widely used experimental animals, with respect to the effects of microsomal membrane solubilization on the inhibition of liver 11β-hydroxysteroid dehydrogenase (11β-HSDI) enzyme by bile acids. Liver microsome fractions were prepared, and the 11β-HSDI enzymatic activity was measured using cortisone as a substrate. The substrate and various concentrations of bile acids were added to the assay mixtures. After incubation, the products were extracted and analyzed using high-performance liquid chromatography. To investigate the effect of detergent on the inhibitory effects of bile acids, we conducted inhibition tests using Triton X-100-solubilized animal liver microsomes. When solubilized microsomes were used, all bile acids inhibited 11β-HSDI from rats and hamsters to various degrees. 7α-Hydroxycholanoic acids (cholic acid and chenodeoxycholic acid) in particular had strong inhibitory activities. In hamsters, 7β-hydroxycholanoic acid (ursodeoxycholic acid) was the strongest inhibitor among the bile acids tested, although its effect was not very strong. When nonsolubilized microsomes were used, deoxycholic acid did not inhibit but rather enhanced the enzymatic activity in both animals. Microsomal content of cholesterol and phospholipids are significantly different between rats and hamsters. Species differences in bile acid inhibition of nonsolubilized microsomes might be reflected not only by structural difference of bile acids, which affect membrane solubilization and enzyme activity directly, but also species difference in microsomal membrane lipid content.

Dose-dependent differential effects of thrombin in allergic bronchial asthma

BACKGROUND

Apart from its role in the coagulation system, thrombin plays an important role in the inflammatory response through its protease-activated receptors (PARs). However, the role of thrombin in the immune response is not clear.

OBJECTIVE

To evaluate whether thrombin has a modulatory role in allergic bronchial asthma.

METHODS

Bronchial asthma was induced in mice by intraperitoneal sensitization and inhalation challenge with ovalbumin. Thrombin or its inhibitors were administered by inhalation before each allergen challenge.

RESULTS

Mice with low but sustained coagulation activation had reduced allergic inflammation, and allergic asthma was inhibited by low doses of thrombin but worsened by high doses. Allergic asthma was worsened by antithrombin, argatroban, hirudin, and anti-thrombomodulin antibody. Mice with a higher level of an inhibitor of both thrombin and activated protein C had worse disease. Heterozygous PAR-1 mice had less allergic inflammation, but PAR-1 agonist worsened it. Allergic bronchial inflammation was worsened in mice that received adoptive transfer of PAR-1 agonist-treated Th2 cells as compared with controls. Low levels of thrombin suppressed the maturation and secretion of cytokines in dendritic cells, but high levels enhanced this.

CONCLUSIONS

The effects of thrombin on allergic asthma are dose-dependent, with detrimental effects at high doses and protective effects at low doses. These data demonstrate that thrombin modulates the outcome in allergic bronchial asthma.

Non-destructive elemental analysis of large meteorite samples by prompt gamma-ray neutron activation analysis with the internal mono-standard method

Prompt gamma-ray neutron activation analysis (PGNAA) using the internal mono-standard method was tested for its applicability to analyzing large solid samples including irregularly shaped meteorite samples. For evaluating the accuracy and precision of the method, large quantities of the Geological Survey of Japan standardized rock powders (JB-1a, JG-1a, and JP-1) were analyzed and 12 elements (B, Na, Mg, Al, Cl, K, Ca, Ti, Mn, Fe, Sm, and Gd) were determined by using Si as an internal standard element. Analytical results were mostly in agreement with literature values within 10 %. The precision of the method was also shown to be within 10 % (1σ) for most of these elements. The analytical procedure was then applied to four stony meteorites (Allende, Kimble County, Leedey, Lake Labyrinth) and four iron meteorites (Canyon Diablo, Toluca (Mexico), Toluca (Xiquipilco), Squaw Creek) consisting of large chunks or single slabs. For stony meteorites, major elements (Mg, Al, Si, S, Ca, and Ni), minor elements (Na and Mn) and trace element (B, Cl, K, Ti, Co, and Sm) were determined with adequate accuracy. For iron meteorites, results for the Co and Ni mass fractions determined are all consistent with corresponding literature values. After the analysis, it was confirmed that the residual radioactivity remaining in the sample after PGNAA was very low and decreased down to the background level. This study shows that PGNAA with the internal mono-standard method is highly practical for determining the elemental composition of large, irregularly shaped solid samples including meteorites.

Upsizing the femoral component increases patellofemoral contact force in total knee replacement

In posterior stabilised total knee replacement (TKR) a larger femoral component is sometimes selected to manage the increased flexion gap caused by resection of the posterior cruciate ligament. However, concerns remain regarding the adverse effect of the increased anteroposterior dimensions of the femoral component on the patellofemoral (PF) joint. Meanwhile, the gender-specific femoral component has a narrower and thinner anterior flange and is expected to reduce the PF contact force. PF contact forces were measured at 90°, 120°, 130° and 140° of flexion using the NexGen Legacy Posterior Stabilized (LPS)-Flex Fixed Bearing Knee system using Standard, Upsized and Gender femoral components during TKR. Increasing the size of the femoral component significantly increased mean PF forces at 120°, 130° and 140° of flexion (p = 0.005, p < 0.001 and p < 0.001, respectively). No difference was found in contact force between the Gender and the Standard components. Among the patients who had overhang of the Standard component, mean contact forces with the Gender component were slightly lower than those of the Standard component, but no statistical difference was found at 90°, 120°, 130° or 140° of flexion (p = 0.689, 0.615, 0.253 and 0.248, respectively). Upsized femoral components would increase PF forces in deep knee flexion. Gender-specific implants would not reduce PF forces.

Synthesis of a chitosan derivative soluble at neutral pH and gellable by freeze-thawing, and its application in wound care

Conventional chitosan hydrogels exhibit an acidic nature and contain unfavorable additives because (i) chitosan is soluble only in acidic solutions and (ii) toxic chemicals or proteins of non-human origin that serve as antigens are necessary for preparing chitosan hydrogels. These characteristics of the chitosan hydrogels limit their possibilities as wound dressings. In this study, a chitosan-gluconic acid conjugate is developed, soluble in an aqueous solution at neutral pH and gellable by freeze-thawing (cryogelation) without using additives. The viability of L929 fibroblasts cultured in the presence of the chitosan derivative for 24 h was >96%. The degradation rate of the corresponding chitosan cryogels by lysozyme was tunable via the derivative concentration in the gels. The gels had low cellular adhesiveness. The gels promoted the accumulation of inflammatory cells such as polymorphonuclear leukocytes, which have the potential to release chemical mediators effective for wound healing, in full-thickness skin wounds in rats and accelerated the healing of the wounds. These results demonstrate that cryogels are promising for wound care.

Enlarged post-operative posterior condyle tightens extension gap in total knee arthroplasty

We investigated whether the extension gap in total knee replacement (TKR) would be changed when the femoral component was inserted. The extension gap was measured with and without the femoral component in place in 80 patients with varus osteoarthritis undergoing posterior-stabilised TKR. The effect of a post-operative increase in the size of the femoral posterior condyles was also evaluated. The results showed that placement of the femoral component significantly reduced the medial and lateral extension gaps by means of 1.0 mm and 0.9 mm, respectively (p < 0.0001). The extension gap was reduced when a larger femoral component was selected relative to the thickness of the resected posterior condyle. When the post-operative posterior lateral condyle was larger than that pre-operatively, 17 of 41 knees (41%) showed a decrease in the extension gap of > 2.0 mm. When a specially made femoral trial component with a posterior condyle enlarged by 4 mm was tested, the medial and lateral extension gaps decreased further by means of 2.1 mm and 2.8 mm, respectively.

If the thickness of the posterior condyle is expected to be larger than that pre-operatively, it should be recognised that the extension gap is likely to be altered. This should be taken into consideration when preparing the extension gap.

Total synthesis of 10-isocyano-4-cadinene and its stereoisomers and evaluations of antifouling activities

The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, and determination of its absolute stereochemistry were achieved. 10-Isocyano-4-cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, intermolecular Diels-Alder reaction and samarium diiodide induced Barbier-type cyclization were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined as (1S,6S,7R,10S) by comparison of the optical rotations between natural and synthetic samples. In addition, the authors successfully synthesized 10-epi- and di-1,6-epi-10-isocyano-4-cadinene through the same synthetic pathway. Antifouling activities against Balanus amphitrite with the cadinenes were also evaluated.

Electric and mass transport of a carbon nanotube encapsulating a copper nano-rod studied by in-situ transmission electron microscopy

Electric properties and current-induced structural changes of carbon nanotubes (CNTs) encapsulating copper nano-rods were studied by in-situ transmission electron microscopy (TEM). The diameter and the length of a copper filled CNT were 18 nm and 256 nm, respectively. The thickness of the graphite layer was about 1 nm. The bias voltage was applied between the two ends of the CNT inside the TEM, and the current as well as TEM images were recorded simultaneously. At a bias voltage of 1.4 V, the current increased to 10 microA, corresponding to a current density of 4.0 x 10(6) A/cm2, and at the same time the nano-rods inside the CNT started to move to an end of the CNT. After the movement of the nano-rods, an empty CNT was left. Resistivities of the CNT and the copper nano-rod were measured to be 3.0 x 10(-5) ohm m and 1.2 x 10(-4) ohm m, respectively.

[Large saphenous vein graft aneurysm after coronary artery bypass grafting]

A 64-year-old man underwent coronary artery bypass grafting (CABG) in 1994. Eleven years later, coronary angiography (CAG) showed a saphenous vein graft (SVG) aneurysm. In April 2008, the CAG demonstrated enlargement of the aneurysm. Enhanced computed tomography showed a large aneurysm measuring 53 x 44 mm in diameter of the SVG-right coronary artery (RCA) [#3] anastomosis. Off-pump coronary surgery to RCA and aneurysmectomy was planned through a median epigastric incision. However re-grafting was difficult because of severe adhesion and calcification of the coronary artery. We confirmed sufficient back flow from the distal coronary artery without hemodynamic and electrocardiographic changes under SVG clamp. Aneurysmectomy was then performed without coronary bypass. The patient was discharged 9 days after surgery and has been well for 8 months in outpatient clinic.

Laboratory and febrile features after joint surgery in patients with rheumatoid arthritis treated with tocilizumab

OBJECTIVES

To understand the acute phase responses to surgical intervention in patients with rheumatoid arthritis (RA) treated with the anti-interleukin (IL)6 receptor antibody, tocilizumab.

METHODS

In a retrospective 1:1 pair-matched case-control study, 22 tocilizumab-treated RA cases and 22 cases treated with conventional disease-modifying antirheumatic drugs (DMARDs) and matched for type of surgery, age and sex were evaluated for body temperature every day, and blood C-reactive protein (CRP) levels and white blood cell (WBC), neutrophil and lymphocyte counts on days -1, 1, 3 and weeks 1 and 2 after joint surgery. Safety issues were also monitored.

RESULTS

No complications of infection or delay of wound healing occurred in either patient group. Tocilizumab partially, but significantly, suppressed the increase in body temperature on postoperative days 1 and 2, compared with DMARDs (average (SD) maximum increase in temperature was 0.45 (0.1) degrees C in the tocilizumab group and 0.78 (0.1) degrees C in the DMARD group; p<0.01). Tocilizumab completely suppressed the increase in CRP after surgery, whereas all cases treated with DMARDs showed a significant increase of CRP at postoperative day 1 (5.5 (0.6) mg/dl; p<0.001). WBC, neutrophil and lymphocyte counts showed no remarkable change after surgery, and there was no significant difference in any cell counts between the patient groups.

CONCLUSIONS

Within this small number of cases, safe operations on patients were performed during tocilizumab treatment. Tocilizumab suppressed fever and increase of CRP after surgery, whereas there was no influence on the transition in number of leukocytes. This characteristic postoperative response should be considered during tocilizumab treatment.

[Proximal anastomotic pseudoaneurysm due to gelatin-resorcin-formalin (GRF) glue after replacement of ascending aorta for acute aortic dissection; report of a case]

A 78-year-old man had previously undergone replacement of ascending aorta using gelatin-resorcin-formalin (GRF) glue for acute aortic dissection. Five years later, a follow-up computed tomography (CT) showed an aortic root pseudoaneurysm. Ultrasound cardiography revealed moderate aortic regurgitation and pseudoaneurysm of aortic root. Aortic root replacement was planned based on a clinical diagnosis of an anastomotic pseudoaneurysm of the aortic root. The patient was discharged without complication 26 days after surgery. In the histopathological examination, the necrotic change of smooth muscle cells in the aortic media was revealed. Previous reports suggests that the use of GRF glue for reconstructing the dissected aorta results in higher rates of postoperative redissection or pseudoaneurysm. Therefore, careful postoperative follow-up is necessary in such cases and further improvements in the quality of glue or alternative methods will be necessary to prevent problems in the first place.