Browsing by Author "Yang, S"

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    Dynamical and thermodynamical coupling between the North Atlantic subtropical high and the marine boundary layer clouds in boreal summer
    (Climate Dynamics, 2017-06-10) Wei, W; Li, W; Deng, Y; Yang, S; Jiang, JH; Huang, L; Liu, WT
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    Effect of maternal obesity on Maternal-Fetal transfer of preoperative cefazolin at cesarean section
    (Journal of Pediatric Pharmacology and Therapeutics, 2017-05-01) Groff, SM; Fallatah, W; Yang, S; Murphy, J; Crutchfield, C; Marzinke, M; Kurtzberg, J; Lee, CKK; Burd, I; Azadeh, F
    OBJECTIVES American Congress of Obstetricians and Gynecologists recommends a single dose of antibiotic prophylaxis before all cesarean sections (C/S). This recommendation is based on pharmacokinetic studies that include only non-obese patients. We sought to evaluate 1) cefazolin plasma concentrations among obese and non-obese patients after administration of a 2-g cefazolin dose for prevention of surgical wound infections, and 2) whether cefazolin concentration in fetal circulation may be protective against pathogens that cause early onset neonatal sepsis. METHODS Maternal and fetal cefazolin plasma concentrations were compared between obese (body mass index [BMI] ≥ 30 kg/m2) and non-obese (BMI < 25 kg/m2) healthy, term pregnant women undergoing scheduled C/S. Liquid chromatographic–tandem mass spectrometric (LC-MS/MS) methods were used for quantification of total and free cefazolin concentrations in maternal blood (MB) and umbilical cord blood (UCB). RESULTS Eight women were screened and consented. There was no difference between groups in MB total and free cefazolin concentrations. All MB samples had total and free cefazolin concentrations greater than the minimum inhibitory concentration 90 (MIC90) for Group B Streptococcus (GBS), Staphylococcus aureus, and Escherichia coli. All UCB samples had total and free cefazolin concentrations greater than MIC90 for GBS and S aureus, even when administered as briefly as 18 minutes before delivery. A lower concentration of total cefazolin was detected in UCB of neonates of obese women compared to non-obese women (p > 0.05).CONCLUSIONS Administration of 2 g of cefazolin to women undergoing scheduled C/S might be an adequate prophylactic dose for surgical wound infection in both non-obese and obese patients; and cefazolin concentration in fetal circulation may be protective against GBS and S aureus.
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    Mass Footprints of the North Pacific Atmospheric Blocking Highs
    (JOURNAL OF CLIMATE, 2015-06) Park, TW; Deng, Y; Li, W; Yang, S; Cai, M
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    New insights into Hoogsteen base pairs in DNA duplexes from a structure-based survey.
    (Nucleic Acids Res, 2015-04-20) Zhou, H; Hintze, BJ; Kimsey, IJ; Sathyamoorthy, B; Yang, S; Richardson, JS; Al-Hashimi, HM
    Hoogsteen (HG) base pairs (bps) provide an alternative pairing geometry to Watson-Crick (WC) bps and can play unique functional roles in duplex DNA. Here, we use structural features unique to HG bps (syn purine base, HG hydrogen bonds and constricted C1'-C1' distance across the bp) to search for HG bps in X-ray structures of DNA duplexes in the Protein Data Bank. The survey identifies 106 A•T and 34 G•C HG bps in DNA duplexes, many of which are undocumented in the literature. It also uncovers HG-like bps with syn purines lacking HG hydrogen bonds or constricted C1'-C1' distances that are analogous to conformations that have been proposed to populate the WC-to-HG transition pathway. The survey reveals HG preferences similar to those observed for transient HG bps in solution by nuclear magnetic resonance, including stronger preferences for A•T versus G•C bps, TA versus GG steps, and also suggests enrichment at terminal ends with a preference for 5'-purine. HG bps induce small local perturbations in neighboring bps and, surprisingly, a small but significant degree of DNA bending (∼14°) directed toward the major groove. The survey provides insights into the preferences and structural consequences of HG bps in duplex DNA.
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    Preoperative Cervical Hyperlordosis and C2–T3 Angle are Correlated to Increased Risk of Post-Op Sagittal Spinal Pelvic Malalignment in Adult Spinal Deformity Patients at 2-Year Follow-Up
    (Global Spine Journal, 2015-05-01) Passias, P; Yang, S; Soroceanu, A; Scheer, J; Schwab, F; Shaffrey, C; Kim, HJ; Protopsaltis, T; Mundis, G; Gupta, M; Klineberg, E; Lafage, V; Smith, J; Ames, C
    Introduction Cervical deformity (CD) is prevalent among patients with adult spinal deformity (ASD). The effect of baseline cervical alignment and achieving optimal TL alignment in ASD surgery is unclear. This study assesses the relationship between preoperative cervical spinal parameters and global alignment following thoracolumbar ASD surgery at 2-year follow-up. Patients and Methods Using a multicenter prospective database of surgical patients with ASD, we included patients with 2-year follow-up and cervical X-rays. SRS-Schwab sagittal modifiers (PT, GA, and PI–LL) were assessed at 2-year postoperative as either normal (0) or abnormal (“ + ” or “ + +”). Patients were classified in the aligned group (AG) or maligned group (MG) if all the three sagittal modifiers were normal or abnormal, respectively. Patients were assessed for CD based on the following criteria: C2–C7 SVA > 4 cm, C2–C7 SVA < 4 cm, cervical kyphosis (CL > 0), cervical lordosis (CL < 0), any deformity (C2C7 SVA > 4 cm or CL > 0), and both CD (C2C7 SVA > 4 cm and CL > 0). Univariate testing was performed using t test or chi-square test, looking at the following pre-op parameters: CD, C2–C7 SVA, C2–T3 SVA, CL, T1S, T1S–CL, C2–T3 angle, LL, TK, PT, C7–S1 SVA, and PI–LL. Results A total of 184 patients met initial inclusion criteria with 70 in the AG and 34 in MG. Pre-op, patients in the MG had a higher cervical lordosis (11.7 vs. 4.9, p = 0.03), higher C2–T3 angle (13.59 vs. 4.9 p = 0.01), and higher PT ( p < 0.0001), higher SVA ( p < 0.0001), and higher PI–LL ( p < 0.0001) compared with the AG. Interestingly, the prevalence of CD at baseline was similar for both the groups: MG and AG. There was no statistically significant difference in the amount of improvement over 2 years on the ODI or the SF-36 PCS. Conclusion Patients with 2-year sagittal TL malalignment also have preoperative sagittal TL malalignment and concomitant cervical hyperlordosis as a compensatory mechanism to maintain horizontal gaze. Cervical radiographs suggestive of cervical hyperlordosis should be followed up with complete standing radiographs to asses for sagittal TL malalignment.
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    Understanding the Social Learning Effect in Contagious Switching Behavior
    (Management Science, 2019-10) Hu, MM; Yang, S; Xu, DY