426 research outputs found
Enhancement of the annihilation of dark matter in a radiative seesaw model
The radiative seesaw model with an inert doublet has been shown to be
attractive from a viewpoint of both neutrino masses and cold dark matter.
However, if we apply this model to the explanation of the positron excess in
the cosmic ray observed by PAMELA, a huge boost factor is required although it
can be automatically explained that no anti-proton excess has been observed
there. We consider an extension of the model to enhance the thermally averaged
annihilation cross section without changing the features of the model favored
by both the neutrino oscillation and the relic abundance of dark matter. It is
shown that the data of PAMELA and Fermi-LAT can be well explained in this
extended model. Constraints from gamma ray observations are also discussed.Comment: 28 pages, 5 figures, final version for publicatio
Reconciliation of CDM abundance and in a radiative seesaw model
We reexamine relic abundance of a singlet fermion as a CDM candidate, which
contributes to the neutrino mass generation through radiative seesaw mechanism.
We search solutions for Yukawa couplings and the mass spectrum of relevant
fields to explain neutrino oscillation data. For such solutions, we show that
an abundance of a lightest singlet fermion can be consistent with WMAP data
without conflicting with both bounds of and . This reconciliation does not need any modification of the original
radiative seesaw model other than by specifying flavor structure of Yukawa
couplings and taking account of coannihilation effects.Comment: 16 pages, 2 figures, accepted version for publication
Neutrino masses and terms in a supersymmetric extra U(1) model
We propose a supersymmetric extra U(1) model, which can generate small
neutrino masses and necessary terms, simultaneously. Fields including
quarks and leptons are embedded in three s of in a different
way among generations. The model has an extra U(1) gauge symmetry at TeV
regions, which has discriminating features from other models studied
previously. Since a neutrino mass matrix induced in the model has a constrained
texture with limited parameters, it can give a prediction. If we impose
neutrino oscillation data to fix those parameters, a value of
can be determined. We also discuss several phenomenological features which are
discriminated from the ones of the MSSM.Comment: 27 pages, 2 figures, final version for publicatio
A cell factory of Bacillus subtilis engineered for the simple bioconversion of myo-inositol to scyllo-inositol, a potential therapeutic agent for Alzheimer's disease
<p>Abstract</p> <p>Background</p> <p>A stereoisomer of inositol, <it>scyllo</it>-inositol, is known as a promising therapeutic agent for Alzheimer's disease, since it prevents the accumulation of beta-amyloid deposits, a hallmark of the disease. However, this compound is relatively rare in nature, whereas another stereoisomer of inositol, <it>myo</it>-inositol, is abundantly available.</p> <p>Results</p> <p><it>Bacillus subtilis </it>possesses a unique inositol metabolism involving both stereoisomers. We manipulated the inositol metabolism in <it>B. subtilis </it>to permit the possible bioconversion from <it>myo</it>-inositol to <it>scyllo</it>-inositol. Within 48 h of cultivation, the engineered strain was able to convert almost half of 10 g/L <it>myo</it>-inositol to <it>scyllo</it>-inositol that accumulated in the culture medium.</p> <p>Conclusions</p> <p>The engineered <it>B. subtilis </it>serves as a prototype of cell factory enabling a novel and inexpensive supply of <it>scyllo</it>-inositol.</p
Enhanced in vivo osteogenesis by nanocarrier-fused bone morphogenetic protein-4
Purpose: Bone defects and nonunions are major clinical skeletal problems. Growth factors are commonly used to promote bone regeneration; however, the clinical impact is limited because the factors do not last long at a given site. The introduction of tissue engineering aimed to deter the diffusion of these factors is a promising therapeutic strategy. The purpose of the present study was to evaluate the in vivo osteogenic capability of an engineered bone morphogenetic protein-4 (BMP4) fusion protein.
Methods: BMP4 was fused with a nanosized carrier, collagen-binding domain (CBD), derived from fibronectin. The stability of the CBD-BMP4 fusion protein was examined in vitro and in vivo. Osteogenic effects of CBD-BMP4 were evaluated by computer tomography after intramedullary injection without a collagen-sponge scaffold. Recombinant BMP-4, CBD, or vehicle were used as controls. Expressions of bone-related genes and growth factors were compared among the groups. Osteogenesis induced by CBD-BMP4, BMP4, and CBD was also assessed in a bone-defect model.
Results: In vitro, CBD-BMP4 was retained in a collagen gel for at least 7 days while BMP4 alone was released within 3 hours. In vivo, CBD-BMP4 remained at the given site for at least 2 weeks, both with or without a collagen-sponge scaffold, while BMP4 disappeared from the site within 3 days after injection. CBD-BMP4 induced better bone formation than BMP4 did alone, CBD alone, and vehicle after the intramedullary injection into the mouse femur. -Bone-related genes and growth factors were expressed at higher levels in CBD-BMP4-treated mice than in all other groups, including BMP4-treated mice. Finally, CBD-BMP4 potentiated more bone formation than did controls, including BMP4 alone, when applied to cranial bone defects without a collagen scaffold.
Conclusion: Altogether, nanocarrier-CBD enhanced the retention of BMP4 in the bone, thereby promoting augmented osteogenic responses in the absence of a scaffold. These results suggest that CBD-BMP4 may be clinically useful in facilitating bone formation
A novel, visible light-induced, rapidly cross-linkable gelatin scaffold for osteochondral tissue engineering
Osteochondral injuries remain difficult to repair. We developed a novel photo-cross-linkable furfurylamine-conjugated gelatin (gelatin-FA). Gelatin-FA was rapidly cross-linked by visible light with Rose Bengal, a light sensitizer, and was kept gelled for 3 weeks submerged in saline at 37 degrees C. When bone marrow-derived stromal cells (BMSCs) were suspended in gelatin-FA with 0.05% Rose Bengal, approximately 87% of the cells were viable in the hydrogel at 24 h after photo-cross-linking, and the chondrogenic differentiation of BMSCs was maintained for up to 3 weeks. BMP4 fusion protein with a collagen binding domain (CBD) was retained in the hydrogels at higher levels than unmodified BMP4. Gelatin-FA was subsequently employed as a scaffold for BMSCs and CBD-BMP4 in a rabbit osteochondral defect model. In both cases, the defect was repaired with articular cartilage-like tissue and regenerated subchondral bone. This novel, photo-cross-linkable gelatin appears to be a promising scaffold for the treatment of osteochondral injury
Prevention of contrast-induced nephropathy by chronic pravastatin treatment in patients with cardiovascular disease and renal insufficiency
SummaryBackgroundContrast-induced nephropathy (CIN) is known to increase morbidity and mortality of cardiovascular disease. Recent studies have shown statins prevented CIN after contrast media exposure, but optimal statin type and dosage are still unknown.PurposeThe aims of the present study were to evaluate whether chronic pravastatin treatment before scheduled coronary angiography or percutaneous coronary intervention could reduce the incidence of CIN and to elucidate the factors related to CIN in patients with renal insufficiency.MethodsWe studied 431 consecutive patients with renal insufficiency. One hundred ninety-four patients were receiving pravastatin treatment as standard chronic treatment of hypercholesterolemia. Serum creatinine levels were measured at baseline (pre-procedure) and within 48h after contrast media exposure (peak post-procedure). CIN was defined as an increase in the serum creatinine values of ā„25% or ā„0.5mg/dl after contrast media exposure. Logistic regression analysis was performed to evaluate the important factors related to CIN using four variables: age, pravastatin, pre-procedure serum creatinine, and contrast volume.ResultsCIN was observed in 36 patients (8.4%). Patients without pravastatin (p<0.01), high level pre-procedure serum creatinine (p<0.01), and high contrast volume (p=0.034) had a significantly higher incidence of CIN. Logistic regression analysis revealed that pravastatin treatment (Ļ2=6.549, p=0.011, odds ratio=0.34), pre-procedure serum creatinine (Ļ2=6.294, p=0.009, odds ratio=2.78), and contrast volume (Ļ2=4.484, p=0.034, odds ratio=1.01) were independently related to the decreased risk of CIN.ConclusionsChronic pravastatin treatment before contrast media exposure was important for preventing CIN in patients with renal insufficiency. Also, reducing the dose of contrast media was important for preventing CIN in patients with high-baseline serum creatinine levels
Autoimmunity to citrullinated type II collagen in rheumatoid arthritis
The production of autoantibodies to citrullinated type II collagen and the citrullination of type II collagen were analyzed in rheumatoid arthritis. Autoantibodies to citrullinated type II collagen were detected in 78.5% of serum samples from 130 rheumatoid arthritis patients. Autoantibodies to native noncitrullinated type II collagen were detected in 14.6% of serum samples, all of which were positive for anti-citrullinated type II collagen antibodies. Serum samples were also positive for anti-citrullinated type II collagen antibodies in 1 of 31 systemic lupus erythematosus patients and 2 of 55 patients with osteoarthritis of the knee. In contrast, sera samples from 24 systemic sclerosis patients, 21 dermatomyositis/polymyositis patients, 21 ankylosing spondylitis patients, and 18 psoriatic arthritis patients were all negative for anti-citrullinated type II collagen antibodies. Anti-citrullinated type II collagen antibodies and fragments of citrullinated type II collagen were found in the synovial fluid obtained from affected knee joints of 15 rheumatoid arthritis patients. Moreover, anti-citrullinated type II collagen antibodies were isolated from the synovium of affected knee joints in 8 rheumatoid arthritis patients using antigen/antibody immunocomplex dissociation buffer but not by using standard buffers. These findings indicate that autoantibodies that react with citrullinated type II collagen are specifically produced and that immunocomplexes composed of fragments of citrullinated type II collagen and autoantibodies are deposited in the inflamed articular synovium in rheumatoid arthritis patients. Assaying for the presence of anti-citrullinated type II collagen antibodies may therefore be useful for diagnosing rheumatoid arthritis, and the deposition of these immunocomplexes in the articular synovium may be involved in pathogenesis
Dependence of alkyl-substituent length for bulk heterojunction solar cells utilizing 1,4,8,11,15,18,22,25-octaalkylphthalocyanine
Tetsuro Hori, Yasuo Miyake, Tetsuya Masuda, Takeshi Hayashi, Kaoru Fukumura, Hiroyuki Yoshida, Akihiko Fujii, Masanori Ozaki, and Yo Shimizu "Dependence of alkyl-substituent length for bulk heterojunction solar cells utilizing 1,4,8,11,15,18,22,25-octaalkylphthalocyanine," Journal of Photonics for Energy 2(1), 021004 (2 March 2012). DOI: https://doi.org/10.1117/1.JPE.2.02100
Plerocercoids of Nybelinia surmenicola vomited from a domestic cat in Fukuyama City, Japan
Two infective larval forms of Tetrarynchoidea-cestode were vomited from a domestic cat in 1995. The worms were identified with the plerocercoid of Nybelinia surmenicola by their morphological features, especially the shape and numbers of hooks on the proboscis. This is the first case of Nybelinia-plerocercoid infection in a domestic cat in Japan
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