450 research outputs found
Transport Exponents of Sturmian Hamiltonians
We consider discrete Schr\"odinger operators with Sturmian potentials and
study the transport exponents associated with them. Under suitable assumptions
on the frequency, we establish upper and lower bounds for the upper transport
exponents. As an application of these bounds, we identify the large coupling
asymptotics of the upper transport exponents for frequencies of constant type.
We also bound the large coupling asymptotics uniformly from above for
Lebesgue-typical frequency. A particular consequence of these results is that
for most frequencies of constant type, transport is faster than for Lebesgue
almost every frequency. We also show quasi-ballistic transport for all coupling
constants, generic frequencies, and suitable phases.Comment: 30 page
Expression pattern and activity of six glutelin gene promoters in transgenic rice*
The shortage of strong endosperm-specific expression promoters for driving the expression of recombinant protein genes in cereal endosperm is a major limitation in obtaining the required level and pattern of expression. Six promoters of seed storage glutelin genes (GluA-1, GluA-2, GluA-3, GluB-3, GluB-5, and GluC) were isolated from rice (Oryza sativa L.) genomic DNA by PCR. Their spatial and temporal expression patterns and expression potential in stable transgenic rice plants were examined with Ī²-glucuronidase (GUS) used as a reporter gene. All the promoters showed the expected spatial expression within the endosperm. The GluA-1, GluA-2, and GluA-3 promoters directed GUS expression mainly in the outer portion (peripheral region) of the endosperm. The GluB-5 and GluC promoters directed GUS expression in the whole endosperm, with the latter expressed almost evenly throughout the whole endosperm, a feature different from that of other rice glutelin gene promoters. The GluB-3 promoter directed GUS expression solely in aleurone and subaleurone layers. Promoter activities examined during seed maturation showed that the GluC promoter had much higher activity than the other promoters. These promoters are ideal candidates for achieving gene expression for multiple purposes in monocot endosperm but avoid promoter homology-based gene silencing. The GluC promoter did not contain the endosperm specificity-determining motifs GCN4, AACA, and the prolamin-box, which suggests the existence of additional regulatory mechanism in determining endosperm specificity
Sex Steroids and Osteoarthritis: A Mendelian Randomization Study
ObjectiveSex steroids are thought to contribute to the pathogenesis of osteoarthritis (OA). This study investigated the causal role of sex steroids in site- and sex-specific OA and risk of joint replacement surgery using the Mendelian randomization (MR) method.MethodsInstrumental variables for estradiol, dehydroepiandrosterone sulfate, testosterone (T), and dihydrotestosterone (DHT) were selected. We used the inverse variance weighting (IVW) approach as the main MR method to estimate causal effects based on the summary-level data for OA and joint replacement surgery from genome-wide association studies (GWAS).ResultsA positive causal association was observed between serum T level and risks of hip OA (odds ratio [OR]=1.558, 95% confidence interval [CI]: 1.193ā2.034; P=0.001) and hip replacement (OR=1.013, 95% CI: 1.008ā1.018; P=2.15Ć10ā8). Serum DHT level was also positively associated with the risk of hip replacement (OR=1.011, 95% CI: 1.006ā1.015; P=4.03Ć10ā7) and had potential causality with hip OA (OR=1.398, 95% CI: 1.054ā1.855; P=0.020).ConclusionsSerum T and DHT levels may play causal roles in the development of hip OA and contribute to the risk of hip replacement, although the underlying mechanisms require further investigation
The effects of extracts of atractylodes macrocephala koidz combined with transcutaneous electrical acupoint stimulation in treating the ovariectomized female rats
Background: The present study was to explore the effects of the extracts of Atractylodes macrocephala Koidz (EAMK) combinedĀ with transcutaneous electrical acupoint stimulation (TEAS) on the ovariectomized female rats.Materials and Methods: Forty female Sprague-Dawley rats were randomly divided into four groups: sham-operation, model, livialĀ and EAMK+TEAS groups (n=10 in each group). After the individual treatments for 8 weeks ended, the serum levels of estradiolĀ (E2), follicle stimulating hormone (FSH), luteinizing hormone (LH), osteocalcin and interleukin-6 (IL-6) were measured withĀ commercial enzyme-linked immunosorbent assay.Results: We found that in the sham-operation group, the serum E2 and osteocalcin levels were significantly higher, and the serumĀ levels of FSH, LH and IL-6 were markedly lower than those of other groups (P<0.05). No significant differences existed between theĀ livial and EAMK+TEAS groups on the serum E2 and osteocalcin levels (P>0.05), however, the serum FSH and IL-6 levels ofĀ EAMK+TEAS group were significantly lower than those of the livial group (P<0.05).Conclusion: EAMK combined with TEAS has promises in treating the ovariectomized female rats.Key words: Extracts of Atractylodes macrocephala Koidz (EAMK), transcutaneous electrical acupoint stimulation (TEAS),Ā osteocalcin, interleukin-6 (IL-6)
Clinical effects of sirolimus treatment in patients with increased serum creatinine levels after renal transplant
Purpose: To observe the clinical effects of sirolimus (SRL) immunosuppressive therapy in patients with progressively increasing levels of serum creatinine (Scr) after renal transplant.Methods: In total, 180 patients whose Scr levels had been rising after renal transplant were given an oral calcineurin inhibitor (CNI): either cyclosporine A (CsA) or tacrolimus (FK506). All patients were treated at Peopleās Hospital of Zhengzhou, China, between January 2011 and December 2013, and were given SRL-based conversion treatment. Scr level and glomerular filtration rate (GFR) were observed before and 1, 3, and 6 months after treatment initiation. In addition, liver function, blood glucose, blood lipid levels, rejection reaction incidence, and mortality were recorded to evaluate the effects of SRL.Results: Scr levels were 116.60 Ā± 30.60 Ī¼mol/L and 119.00 Ā± 24.60 Ī¼mol/L, and GFR was 70.00 Ā± 19.70 mL/min and 75.90 Ā± 15.60 mL/min, at 3 and 6 months after treatment, respectively. The 3- and 6- month Scr and GFR values were statistically different (p < 0.05) compared to pre-treatment levels (Scr: 144.10 Ā± 61.70 Ī¼mol/L vs and GFR: 59.10 Ā± 16.20 mL/min. Acute rejection (AR) occurred in 20 patients (13.30 %) within 6 months of treatment initiation, but rejection was reversed with conventional methylprednisolone therapy. Twenty-one patients (11.70 %) developed lung infections, but all were cured. There were no significant differences in liver function before and after treatment.Conclusion: SRL-based immunosuppressive therapy is effective in treating patients with increased Scr levels after renal transplant.Keywords: Renal transplant, Serum creatinine, Calcineurin inhibitors, Sirolimus, Acute rejection, Glomerular filtration rat
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