Conjugate Acid-Base Interaction Driven Phase Transition at a 2D Air-Water Interface.

A lattice model is described to explain a recent striking Sum Frequency Generation (SFG) observation of a cooperative surface adsorption effect for an organic acid system at an air-water interface. The reported anomalous pH-dependent enhancement in p-methylbenzoic acid (pmBA) arises from an interaction between the acid (HA) and its conjugate base anion (A-), which competes with strong Coulombic repulsion between the conjugate bases (A--A -). Using a statistical mechanical approach, this lattice gas model reveals an analogy to well-studied magnetic systems in which the attraction between the two different molecular species leads to a phase transition to a two-dimensional checkerboard phase consisting of a network of anion-acid complexes formed at the low-dielectric air-water interface. Cooperative acid-anion interactions that control partitioning at solution and aerosol interfaces are of interest to fields ranging from oceanic and atmospheric chemistry, pharmacology, and chemical engineering.

Anomalous pH-Dependent Enhancement of p-Methyl Benzoic Acid Sum-Frequency Intensities: Cooperative Surface Adsorption Effects.

Vibrational sum-frequency generation (SFG) spectroscopy is used to determine the surface pKa of p-methyl benzoic acid (pMBA) at the air-water interface by monitoring the carbonyl and carboxylate stretching modes over the pH range of 2 to 12. The SFG intensities of pMBA and its conjugate base, p-methyl benzoate (pMBA-), exhibit an anomalously large enhancement over a narrow pH range (∼0.5) centered at pH 6.3 near the SFG-determined surface pKa, 5.9 ± 0.1. The increase in the surface pKa relative to the bulk value of 4.34 is consistent with the trend previously observed for long chain carboxylic acids in which the surface pKa is higher than the bulk solution pKa. SFG polarization studies help distinguish the orientation and number density contributions to this observed anomalous surface phenomenon. The large SFG intensity increase is attributed to an increase in the pMBA and pMBA- surface concentrations in this narrow pH range due to a cooperative adsorption effect between pMBA and pMBA-. This cooperativity is manifested only on the 2D air-water interface, where the interactions between the acid and base are not as dielectrically screened as in the aqueous bulk phase. Surface effects are critical to understanding and controlling the reactivity, solubility, and behavior of organic acids at interfaces and can have an impact on biomedical applications.

A 4-item PRECISE-DAPT score for dual antiplatelet therapy duration decision-making

The originally-proposed PRECISE-DAPT score is a 5-item risk score supporting decision-making for dual antiplatelet therapy1 duration after PCI. It is unknown if a simplified version of the score based on 4 factors (age, hemoglobin, creatinine clearance, prior bleeding), and lacking white-blood cell count, retains potential to guide DAPT duration. The 4-item PRECISE-DAPT was used to categorize 10,081 patients who were randomized to short (3-6 months) or long (12-24 months) DAPT regimen according to high (HBR defined by PRECISE-DAPT ≥25 points) or non-high bleeding risk (PRECISE-DAPT<25) status. Long treatment duration was associated with higher bleeding rates in HBR (ARD +2.22% [95% CI +0.53 to +3.90]) but not in non-HBR patients (ARD +0.25% [-0.14 to +0.64]; pint = 0.026), and associated with lower ischemic risks in non-HBR (ARD -1.44% [95% CI -2.56 to -0.31]), but not in HBR patients (ARD +1.16% [-1.91 to +4.22]; pint = 0.11). Only non-HBR patients experienced lower net clinical adverse events (NACE) with longer DAPT (pint = 0.043). A 4-item simplified version of the PRECISE-DAPT score retains the potential to categorize patients who benefit from prolonged DAPT without concomitant bleeding liability from those who do not. (AU)

Elective colectomy after acute diverticulitis: an international comparison.

AIM: Routine elective colectomy after acute diverticulitis is not recommended, yet significant numbers are still being performed. Amidst global concern over the rising costs of surgery and the value of healthcare, acute diverticulitis is a disease that is amenable to optimization of strategies for operative intervention. We aim to compare rates of elective colectomy after acute diverticulitis in the USA, England and Australia. METHOD: Index unplanned admissions for acute diverticulitis were found from an international administrative dataset between 2008 and 2012 for hospitals in the USA, England and Australia. Recurrent unplanned admissions for acute diverticulitis and any subsequent elective admissions for colectomy were found between 2008 and 2014 to allow a minimum 2-year follow-up period. The primary outcome measured was elective colectomy rate. Secondary outcomes included rates of emergency operative intervention and recurrence. Multivariable analysis was performed to control for patient and disease factors. RESULTS: There were 7842 index unplanned admissions for acute diverticulitis over 4 years in selected hospitals from the USA, England and Australia. The elective colectomy rates were 13%, 5.4% and 3.4% for the USA, England and Australia, respectively. The propensity for elective colectomy was higher in the USA (OR 4.2, P < 0.001) and England (OR 1.8, P < 0.001) than in Australia. The recurrence rate in all patients with acute diverticulitis was 10% across the countries. CONCLUSION: There is a higher propensity for elective colectomy after acute diverticulitis in the USA than in England and Australia. This highlights the possibilities for a less aggressive surgical approach to reduce resource utilization, but prospective analysis of information on quality of life is required to support this.

Remote Preconditioning on Rat Hepatic Ischemia-Reperfusion Injury Downregulated Bax and Cleaved Caspase-3 Expression.

OBJECTIVE: Hepatic ischemia-reperfusion injury (IRI) is considered a major cause of hepatic damage in liver surgery. The aim of this study was to investigate the effect of the remote ischemic perconditioning method on hepatic IRI in a rat model. METHODS: Seventeen rats underwent hepatic IRI for 30 minutes followed by reperfusion, and were divided into 3 groups: group I, only hepatic IRI (n = 5); group II, hepatic IRI with remote perconditioning (n = 7); and group III, hepatic IRI with remote postconditioning (n = 5). RESULTS: For Bax/ß-actin, mean values of the 3 groups (±standard deviation) were 1.29 ± 0.26 (group I), 0.89 ± 0.15 (group II), and 1.02 ± 0.23 (group III). The level of Bax/ß-actin in group II was significantly lower than in group I (P < .01). The cleaved Caspase-3/ß-actin ratio for groups I, II, and III was 0.93 ± 0.22, 0.46 ± 0.16, and 0.63 ± 0.22, respectively. The level of cleaved Caspase-3/ß-actin in groups II and III were significantly lower than in group I (P < .01 and P < .05, respectively). The Bcl-2/ß-actin ratio for groups I, II, and III was 1.01 ± 0.09, 1.19 ± 0.39, and 1.20 ± 0.12, respectively. However, there were no significant difference between groups II and III and group I. CONCLUSIONS: The remote perconditioning on rat hepatic IRI downregulated the Bax and cleaved Caspase-3 expression.

Renal denervation for treatment of uncontrolled hypertension in an Asian population: results from the Global SYMPLICITY Registry in South Korea (GSR Korea).

Reports detailing the response of hypertensive patients to renal denervation (RDN) in Asian patients are limited. We evaluated 6- and 12-month outcomes after RDN in an Asian population and compared outcomes to a primarily Caucasian population. The Global SYMPLICITY Registry (GSR) is a prospective, all-comer, worldwide registry that evaluates the safety and effectiveness of RDN and includes the Korean registry substudy (GSR Korea) and a Caucasian subset (GSR Caucasian). Given differences in baseline characteristics among GSR Korea (n=93) as compared with GSR Caucasian (n=169) patients, including lower baseline office systolic blood pressure (SBP), lower body mass index and differences in medications, propensity score adjustment was performed when comparing the change in SBP between subsets. The 6- and 12-month change in SBP in GSR Korea was -19.4±17.2 and -27.2±18.1 mm Hg, respectively (P<0.001 for both vs baseline). GSR Caucasian had a SBP change similar to GSR Korea at 6 months (-20.9±21.4 mm Hg, unadjusted P=0.547, adjusted P=0.998), whereas at 12 months the change was significantly less pronounced (-20.1±23.9 mm Hg, unadjusted P=0.004, adjusted P=0.002). There were no protocol-defined procedure-related adverse events and no chronic adverse events associated with the device in an Asian population. RDN provided a significant reduction in 6- and 12-month office SBP among Asian patients, with a favorable safety profile. The 12-month SBP reduction was larger than that observed in Caucasian patients.

Use of antimicrobial agents in aquaculture.

The aquaculture industry has grown dramatically, and plays an important role in the world's food supply chain. Antimicrobial resistance in bacteria associated with food animals receives much attention, and drug use in aquaculture is also an important issue. There are many differences between aquatic and terrestrial management systems, such as the methods used for administration of drugs. Unique problems are related to the application of drugs in aquatic environments. Residual drugs in fish products can affect people who consume them, and antimicrobials released into aquatic environments can select for resistant bacteria. Moreover, these antimicrobial-resistant bacteria, or their resistance genes, can be transferred to humans. To decrease the risks associated with the use of antimicrobials, various regulations have been developed. In addition, it is necessary to prevent bacterial diseases in aquatic animals by vaccination, to improve culture systems, and to monitor the amount of antimicrobial drugs used and the prevalence of antimicrobial-resistant bacteria.

Mid-infrared photothermal heterodyne spectroscopy in a liquid crystal using a quantum cascade laser.

We report a technique to measure the mid-infrared photothermal response induced by a tunable quantum cascade laser in the neat liquid crystal 4-octyl-4'-cyanobiphenyl (8CB), without any intercalated dye. Heterodyne detection using a Ti:sapphire laser of the response in the solid, smectic, nematic and isotropic liquid crystal phases allows direct detection of a weak mid-infrared normal mode absorption using an inexpensive photodetector. At high pump power in the nematic phase, we observe an interesting peak splitting in the photothermal response. Tunable lasers that can access still stronger modes will facilitate photothermal heterodyne mid-infrared vibrational spectroscopy.

Multi walled carbon nanotube nanocomposites with biodegradable poly(butylene succinate) and their physical characteristics.

In order to examine the influence of multi walled carbon nanotube (MWNT) on physical properties of its biodegradable polymer nanocomposite, biodegradable poly(buthylene succinate) (PBS), which was synthesized from diols and dicarboxylic acids, and MWNT nanocomposites were prepared via a melt-mixing method using a co-rotating intermeshing twin screw extruder. Microstructure of the PBS/MWNT nanocomposites and MWNT were investigated via both scanning electron microscopy and transmission electron microscopy. Their rheological properties were also characterized via rotation and oscillation tests using a rotational rheometer with parallel-plate geometry. It was found that shear viscosity, storage modulus and loss modulus of the nanocomposites examined by a rotational rheometer increased with the MWNT content. Especially their sharp increase for MWNT content of ca. 2.0 wt% was observed, indicating its percolation threshold from the rheological viewpoint which was higher than its electrical percolation threshold (1.0 wt%).

Homologous expression and quantitative analysis of T3SS-dependent secretion of TAP-tagged XoAvrBs2 in Xanthomonas oryzae pv. oryzae induced by rice leaf extract.

Xanthomonas oryzae pv. oryzae (Xoo) produces a putative effector, XoAvrBs2. We expressed XoAvrBs2 homologously in Xoo with a TAP-tag at the C-terminus to enable quantitative analysis of protein expression and secretion. Addition of rice leaf extracts from both Xoo-sensitive and Xoo-resistant rice cultivars to the Xoo cells induced expression of the XoAvrBs2 gene at the transcriptional and translational levels, and also stimulated a remarkable amount of XoAvrBs2 secretion into the medium. In a T3SS-defective Xoo mutant strain, secretion of the TAPtagged XoAvrBs2 was blocked. Thus, we elucidated the transcriptional and translational expressions of the XoAvrBs2 gene in Xoo was induced in vitro by the interaction with rice and the induced secretion of XoAvrBs2 was T3SSdependent. It is the first report to measure the homologous expression and secretion of XoAvrBs2 in vitro by rice leaf extract. Our system for the quantitative analysis of effector protein expression and secretion could be generally used for the study of host-pathogen interactions.

Faecal diversion in the management of perianal Crohn's disease.

AIM: Severe perianal Crohn's disease remains an uncommon but important indication for faecal diversion (FD). The advent of biological therapy such as infliximab for Crohn's disease is considered to have improved the outcome for these patients. The aim of this study was to assess the outcome of patients undergoing FD for perianal Crohn's disease and the impact of biological therapy (infliximab). METHOD: Retrospective chart review was undertaken of patients who underwent FD for management of perianal Crohn's disease at two tertiary centres between 1990 and 2007. Patient demographics, disease extent and use of biological therapy were recorded. Subsequent surgery was assessed. The impact of infliximab on rates of proctocolectomy and restoration of intestinal continuity was assessed. RESULTS: Twenty-one patients (one male, 20 female), median age 34 years (range 21-67 years), underwent FD for perianal Crohn's disease. At a median follow-up time of 22 months (range 4-121 months), four patients had undergone stoma closure, 11 had had proctocolectomy and six had a stoma in situ. The effects of the procedure on severity of perianal disease were no effect in four (19%), temporary improvement in six (29%), initial improvement with later plateau in seven (33%) and healing in four patients (19%). Eleven patients (52%) received infliximab. In this group, four underwent proctocolectomy and two had intestinal continuity restored. This was not significantly different from the noninfliximab group. CONCLUSION: Patients undergoing FD for perianal Crohn's disease have <20% likelihood of restoration of intestinal continuity. This is not improved with biological therapy.

10-Gb/s transmission over 20-km single fiber link using 1-GHz RSOA by discrete multitone with multiple access.

We demonstrate a novel 10.5-Gbit/s transmission scheme over 20-km single fiber link by using a remotely fed 1-GHz reflective semiconductor optical amplifier (RSOA). Discrete multitone (DMT) modulation with adaptive bit-/power-loading is applied to overcome the bandwidth limitation of the RSOA. Transmission performance of the proposed scheme is analyzed in terms of various system parameters, such as the nonlinearity of the RSOA, optical signal-to-noise ratio of the optical seed carrier, the overhead size impact on dispersion, the number of DMT subcarriers, and the reflection noise from the single fiber link. We also report flexible-bandwidth-allocated multiple access operation based on the proposed scheme. The throughput for all cases is approximately 10 Gbit/s with BER < 10(-3).

Optical coherence tomography evaluation of zotarolimus-eluting stents at 9-month follow-up: comparison with sirolimus-eluting stents.

OBJECTIVE: To evaluate the vascular response at 9 months after zotarolimus-eluting stent (ZES; Endeavor) implantation using optical coherence tomography (OCT). These findings were compared with those after implantation of a sirolimus-eluting stent (SES; Cypher Select). DESIGN: Cross-sectional observational study with prospective OCT registry. SETTING: Nine months after ZES or SES implantation. PATIENTS AND METHODS: A total of 68 patients (32 ZES and 36 SES) underwent OCT at 9 months after stent implantation. The neointima hyperplasia (NIH) thickness inside each strut and percentage of NIH area at every 1 mm cross section were measured. MAIN OUTCOME MEASUREMENT: The degree of neointimal coverage and the prevalence of malapposition at 9 months after ZES and SES implantation using OCT. RESULTS: The mean (SD) NIH thickness (251.2 (110.0) mum vs 85.5 (53.3) mum, p<0.001) and percentage of NIH area (27.9 (9.1)% vs 11.2 (7.1)%, p<0.001) were significantly greater in ZES than in SES. The prevalence of uncovered strut as well as malapposed strut was significantly lower in ZES than in SES (0.3% vs 12.3%, p<0.001 and 0.08% vs 2.6%, p<0.001). Thrombus was not observed in ZES (0.0% in ZES vs 27.8% in SES, p = 0.001). CONCLUSIONS: Neointimal coverage in ZES was almost complete and malapposition was very rare at 9-months' follow-up.

Nitrous oxide vibrational energy relaxation is a probe of interfacial water in lipid bilayers.

Ultrafast infrared spectroscopy of N 2O is shown to be a sensitive probe of hydrophobic and aqueous sites in lipid bilayers. Distinct rates of VER of the nu 3 antisymmetric stretching mode of N 2O can be distinguished for N 2O solvated in the acyl tail, interfacial water, and bulk water regions of hydrated dioleoylphosphatidylcholine (DOPC) bilayers. The lifetime of the interfacial N 2O population is hydration-dependent. This effect is attributed to changes in the density of intermolecular states resonant with the nu 3 band ( approximately 2230 cm (-1)) resulting from oriented interfacial water molecules near the lipid phosphate. Thus, the N 2O VER rate becomes a novel and experimentally convenient tool for reporting on the structure and dynamics of interfacial water in lipids and, potentially, in other biological systems.

Structure determination of new analogues of vardenafil and sildenafil in dietary supplements.

New analogues of vardenafil and sildenafil illegally added to dietary supplements were detected by high-performance liquid chromatography (HPLC) analysis with a photodiode array detector (PDA). These compounds were isolated and their structures elucidated by mass spectrometry (MS), infrared (IR) spectroscopy, one- and two-dimensional nuclear magnetic resonance (NMR). One of the new analogues given the trivial name pseudovardenafil (compound 1) was structurally elucidated and shown to be 1-[[3-(1,4-dihydro-5-methyl-4-oxo-7-propylimidazo[5,1-f][1,2,4]triazin-2-yl)-4-ethoxyphenyl]sulfonyl]-piperidine. It was a vardenafil analogue isolated from a dietary supplement capsule. Compared with vardenafil, the piperidine ring was substituted for the ethylpiperazine group. The second new analogue, trivially named hydroxyhongdenafil (compound 2), was separated from bulk powder used as a raw material for a dietary supplement. The piperazine and phenyl groups were connected through an acetyl group instead of a sulfonyl group, and hydroxyethylpiperazine was substituted for the methylpiperazine of sildenafil. It was structurally elucidated as 5-[2-ethoxy-5-[[4-(2-hydroxyethyl)-1-piperazinyl]acetyl]phenyl]-1,4-dihydro-1-methyl-3-propyl-7H-pyrazolo[4,3-d]pyrimidin-7-one.

Myocardial enhancement pattern in patients with acute myocardial infarction on two-phase contrast-enhanced ECG-gated multidetector-row computed tomography.

AIM: To evaluate the myocardial enhancement pattern of the left ventricle on two-phase contrast-enhanced electrocardiogram (ECG)-gated multidetector computed tomography (MDCT) images in patients with acute myocardial infarction (AMI). METHODS: Two-phase contrast-enhanced ECG-gated MDCT examinations were performed in 16 patients with AMI. The presence, location and pattern of myocardial enhancement were evaluated. MDCT findings were compared with the catheter angiographic results. RESULTS: Subendocardial (n = 9) or transmural (n = 6) area of early perfusion defects of the myocardium was detected in 15 of 16 patients (94%) on early-phase CT images. Variable delayed myocardial enhancement patterns on late-phase CT images were observed in 12 patients (75%): (1) subendocardial residual perfusion defect and subepicardial late enhancement (n = 6); (2) transmural late enhancement (n = 1); (3) isolated subendocardial late enhancement (n=1); and (4) isolated subendocardial residual perfusion defect (n = 2). On catheter angiography, 14 of 15 corresponding coronary arteries showed significant stenosis. CONCLUSION: Variable abnormal myocardial enhancement pattern was seen on two-phase, contrast-enhanced ECG-gated MDCT in patients with AMI. Assessment of myocardial attenuation on CT angiography gives additional information of the location and extent of infarction.

The limits of competing interest disclosures.

OBJECTIVE: To assess the effectiveness of conflict of interest disclosure policies by comparing a competing interests disclosure statement that met the requirements established by the journal in a 2003 article on health effects of secondhand smoke based on the American Cancer Society CPS-I dataset with internal tobacco industry documents describing financial ties between the tobacco industry and authors of the study. DESIGN: Descriptive analysis of internal tobacco industry documents retrieved from the Legacy Tobacco Documents Library, University of California, San Francisco. RESULTS: Meeting the requirements for financial disclosure established by the journal did not provide the reader with a full picture of the tobacco industry's involvement with the study authors. The tobacco industry documents reveal that the authors had long standing financial and other working relationships with the tobacco industry. CONCLUSION: These findings are another example of how simply requiring authors to disclose financial ties with the tobacco industry may not be adequate to give readers (and reviewers) a full picture of the author's relationship with the tobacco industry. The documents also reveal that the industry funds research to enhance its credibility and endeavours to work with respected scientists to advance its goals. These findings question the adequacy of current journal policies regarding competing interest disclosures and the acceptability of tobacco industry funding for academic research.