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To develop a respiratory-resolved motion-compensation method for free-breathing, high-resolution coronary magnetic resonance angiography (CMRA) using a 3D cones trajectory. To achieve respiratory-resolved 0.98 mm resolution images in a clinically relevant scan time, we undersample the imaging data with a variable-density 3D cones trajectory. For retrospective motion compensation, translational estimates from 3D image-based navigators (3D iNAVs) are used to bin the imaging data into four phases from end-expiration to end-inspiration. To ensure pseudo-random undersampling within each respiratory phase, we devise a phyllotaxis readout ordering scheme mindful of eddy current artifacts in steady state free precession imaging. Following binning, residual 3D translational motion within each phase is computed using the 3D iNAVs and corrected for in the imaging data. The noise-like aliasing characteristic of the combined phyllotaxis and cones sampling pattern is leveraged in a compressed sensing reconstruction with spatial and temporal regularization to reduce aliasing in each of the respiratory phases. In initial studies of six subjects, respiratory motion compensation using the proposed method yields improved image quality compared to non-respiratory-resolved approaches with no motion correction and with 3D translational correction. Qualitative assessment by two cardiologists and quantitative evaluation with the image edge profile acutance metric indicate the superior sharpness of coronary segments reconstructed with the proposed method (P < 0.01). We have demonstrated a new method for free-breathing, high-resolution CMRA based on a variable-density 3D cones trajectory with modified phyllotaxis ordering and respiratory-resolved motion compensation with 3D iNAVs. [ABSTRACT FROM AUTHOR]

Background: Prescription opioids are a major cause of the opioid epidemic. Despite the invasive nature of cardiac implantable electronic device (CIED) procedures, data on opioid prescription patterns after CIED procedures are lacking.Objective: The purpose of this study was to assess opioid prescribing patterns and the rates of new opioid refills (refills in previously opioid naïve patients) among patients undergoing CIED procedures.Methods: We performed a retrospective analysis of all patients undergoing CIED procedures from January 1, 2010, to March 30, 2018, at the Mayo Clinic (Minnesota, Arizona, and Florida). Procedures were categorized into new implant, generator change, device upgrade, lead revision or replacement, and subcutaneous implantable cardiac defibrillator (S-ICD) procedures. The rates of postoperative opioid prescription and new opioid refills were analyzed. Wilcoxon rank sum and χ2 tests assessed variations.Results: A total of 16,517 patients (mean age 70 ± 15; 36% female) underwent CIED procedures. Opioids were prescribed to 20.2% of the patients, among whom 80% were opioid naïve. Among opioid naïve patients who received opioids, 9.4% (95% confidence interval [CI] 8.3%-10.5%) had subsequent opioid refills. The percentage of patients who received more than 200 oral morphine equivalents of prescription was 38.8% (95% CI 37.2%-40.5%). Temporal trends revealed increasing rates of any opioid prescription, peaking in 2015 at 25.9%, with subsequent downtrend to 14.6% in 2018 (P <.001).Conclusion: Postoperative opioid prescription rate after CIED procedures was 20.2%, with most patients being opioid naïve. Among opioid naïve patients who received opioids, 9.4% had subsequent opioid refills. This finding suggests that perioperative pain management in CIED procedures warrants meticulous attention. [ABSTRACT FROM AUTHOR]

Highlights • A two-layer evaporator wick is fabricated by sintering and laser ablation. • The internal structure of the two-layer wick is investigated using micro-CT scanning. • Single-layer wicks are tested to study the effect of particle sizes on performance. • A two-layer wick is shown to dissipate up to 485 W/cm2 over 1 cm2 at 0.052 K/W. • The two-layer wick design offers a unique combination of high total heat dissipation at low thermal resistance. Abstract A two-layer sintered porous evaporator wick for use in vapor chambers is shown to offer very high performance in passive high-heat-flux dissipation over large areas at a low thermal resistance. The two-layer wick has an upper cap layer dedicated to capillary liquid feeding of a thin base layer below that supports boiling. An array of vertical posts bridges these two layers for liquid feeding, while vents in the cap layer provide an unimpeded pathway for vapor removal from the base wick. The two-layer wick is fabricated using a combination of sintering and laser machining processes. The thermal resistance of the wicks during boiling is characterized in a saturated environment that replicates the capillary-fed working conditions of a vapor chamber evaporator. Thermal characterization tests are first performed using conventional single-layer evaporator wicks to analyze the effect of sintered particle size on capillary-fed boiling of water. Of the particle size ranges tested, wicks sintered from 180 to 212 μm-diameter particles provided the best combination of high dryout heat flux and a low boiling resistance. A two-layer evaporator wick comprising particles of this optimal size and a 15 × 15 array of liquid feeding posts yielded a maximum heat flux dissipation of 485 W/cm2 over a 1 cm2 heat input area while also maintaining a low thermal resistance of only ∼0.052 K/W. The thermal performance of the two-layer wick is compared against various hybrid and biporous evaporator wicks previously investigated in the literature. While previous wick designs are typically restricted to small areas and low power levels or high surface superheats when dissipating such heat fluxes, the unique area-scalability of the two-layer wick design allows it to achieve an unprecedented combination of high total power and low-thermal-resistance heat dissipation over larger areas than were previously possible. [ABSTRACT FROM AUTHOR]

Highlights • Two-layer evaporator wick designs for vapor chambers are fabricated and tested. • A novel test facility is developed to characterize capillary-fed boiling in wicks while avoiding flooding. • Two-layer wicks offer significant enhancement in dryout heat flux compared to a conventional single-layer wick. • High-speed visualizations are used to observe the boiling regimes as a function of heat flux. • Top-down liquid feeding in two-layer wicks avoids partial dryout and maintains low-thermal- resistance operation. Abstract Vapor chambers with transformative evaporator wick designs capable of passively dissipating high heat fluxes over large areas, while maintaining low thermal resistances, can meet the thermal management needs of next-generation power semiconductor devices. Our prior work proposed a two-layer evaporator wick structure to enhance the performance of vapor chambers operating at high heat fluxes. The current study experimentally characterizes the capillary-fed boiling heat transfer behavior in such a two-layer evaporator wick, compared to a homogeneous (single-layer) wick, over a 1 cm2 evaporator area. The two-layer design comprises a thin base wick layer that is fed with liquid from a thick cap wick layer above using an array of vertical posts. The two-layer wick is fabricated using a sequence of sintering and laser-machining steps to form the base wick layer (200 µm), array of liquid-feeding posts, and cap wick layer (800 µm) using 90–106 µm copper particles. A test facility is constructed to replicate the conditions that exist at the evaporator of a vapor chamber; the novel facility design uses a physical restriction to prevent flooding of the wicks during testing. Two-layer wicks having 5 × 5 and 10 × 10 arrays of liquid feeding posts are characterized, along with a 200 µm-thick single-layer evaporator wick. The 10 × 10 array provides a >400% enhancement in the dryout heat flux compared to the single-layer wick. High-speed visualizations are used to identify the characteristic regimes of boiling operations for the wicks. The single-layer wick exhibits a partial dryout mode of operation, where a dry spot formed in the center of the heated evaporator area causes an increase in the thermal resistance with heat flux. In contrast, the distributed feeding provided by the two-layer wicks mitigates the development of this partial dryout regime and maintains a constant low resistance (∼0.1 K/W) during capillary-fed boiling until a complete dryout event occurs. This study demonstrates the significant enhancement in dryout heat flux offered by the liquid-feeding approach realized in the two-layer evaporator wicks characterized here. [ABSTRACT FROM AUTHOR]

Abstract The influence of the suspender on the evaporation of droplets under quiescent atmospheric conditions was studied experimentally using pendant droplets of ethanol (volatile) and water (non-volatile). Conducting and non-conducting suspenders of different materials and configurations (a steel needle, glass needle, steel rod, and glass rod) were evaluated. For both liquids, it is observed that the rate of evaporation is higher with steel suspenders. More importantly, for ethanol droplets, there is a difference in the evaporation rates between the needle and rod configurations of the same material. Thus, it is shown for the ethanol droplet that the configuration (needle versus solid rod) also plays a role in the evaporation process, apart from the material. The water droplet does not show this dependence. Visualization of internal flow and heat transfer calculations explain this observation. The results will be useful in choosing an appropriate suspender while using the pendant droplet method for studying complex interactions in an evaporating droplet. [ABSTRACT FROM AUTHOR]

Current monitoring practices fail to diagnose patients with post-transplant hyperglycaemia and tend to delay initiation of treatment, which potentially results in adverse graft and morbidity outcomes. This real-world study set out to assess the impact on insulin resistance indices of a new clinical pathway for diagnosis and treatment of hyperglycaemia following renal transplantation. A hundred and forty-seven adult renal transplant recipients, without pre-existing diabetes, from a single centre were included. Patients transplanted between January 2008 to September 2015 formed the historical cohort. Patients transplanted between October 2015 and February 2018 were subject to a new clinical pathway - if they had fasting blood sugar levels more than 7 mmol/L or random blood glucose levels more than 11.1 mmol/L, they had early introduction of oral therapy, using the DPP-4 inhibitor linagliptin. In the historical cohort, 19.8% were diagnosed with PTDM, compared to 46.3% in the protocol cohort. Amongst patients with PTDM, there was a significant difference in HOMA-IR (p = 0.02) between the historical cohort (median HOMA-IR 3.33) and the protocol cohort (median HOMA-IR 2.21). There was a significant difference at each time point (0,1,2-h measurements) of blood glucose levels form oral glucose tolerance testing between patients with and without PTDM in the historical cohort (p < 0.001), but no difference between patients in the protocol cohort. Detection of PTDM was higher with the new clinical pathway. Early treatment of hyperglycaemia resulted in better insulin resistance scores. Larger prospective controlled studies focussing on early detection and management of PTDM with linagliptin are warranted. [ABSTRACT FROM AUTHOR]

Background and Aims: The cecal intubation rate (CIR) is a widely accepted key performance indicator (KPI) in colonoscopy but lacks a universal calculation method. We aimed to assess whether differences in CIR calculation methods could have an impact on perceived trainee outcomes. Methods: A systematic review of CIR calculation methods was conducted on major societal guidelines (United Kingdom, European Society of Gastrointestinal Endoscopy [ESGE] and American Society for Gastrointestinal Endoscopy [ASGE]) and trainee-inclusive studies. Trainees awarded colonoscopy certification between June 2011 and 2016 were identified from the United Kingdom e-portfolio and selected as a validation cohort. For each trainee, both the crude and unassisted CIR were calculated for 50 post-certification procedures using definitions from the 3 international guidelines. The resulting CIRs, and the proportions of endoscopists failing to meet the minimum standard of CIR >90%, were then compared across these definitions. Results: Across the 3 guidelines and 37 eligible studies identified, differences in CIR calculation methodology were demonstrated. These related to adjustment criteria (18 studies) and whether unassisted CIR was stipulated (18 studies). In the validation cohort of 733 trainees (36,650 procedures), the median crude CIR ranged from 96% (ESGE) to 98% (ASGE) (P < .001) and whether unassisted CIR was specified (ESGE, 94%; ASGE, 96%; P < .001). The proportion of trainees failing to achieve CIR >90% varied significantly across the different definitions, from 4.9% for the crude ASGE definition to 18.6% for the unassisted ESGE definition (P < .001). Conclusions: CIR calculation methods vary among guidelines and research studies; this has an impact on trainee performance measures. With CIR used as an example, this study highlights the need for standardized definitions and calculations of KPIs in endoscopy. [ABSTRACT FROM AUTHOR]

Highlights • Empirical wavelet transform (EWT) is applied to excised normal, fibroadenoma and malignant breast tissues. • EWT derived spectral magnitude and energy of monocomponents are utilized for quantitative differentiation of breast tissues with high efficiency. • EWT derived parameters exhibits high correlation with standard histopathology which can be used for non-invasive cancer diagnosis. Abstract Empirical wavelet transform (EWT) based Photoacoustic spectral response technique is proposed for quantitative assessment of human breast masses (e.g. normal, benign and malignant) based on tissue mechano-biological property. EWT derived parameters such as spectral magnitude and total energy of mono frequency components were utilised for quantitative analysis. Spectral magnitude of second frequency component clearly proves proliferation of epithelial cells in malignant tissues compared to normal. In addition, fibroadenoma illustrates identical energy values of both mono-components which indicates identical proliferation of epithelial and stromal cells. Subsequently, EWT features are proposed that can differentiate the breast masses with 97.5% efficiency, a significant improvement in non-invasive breast cancer diagnosis which also highly correlates with standard histopathology. [ABSTRACT FROM AUTHOR]

Background: Stroke can be a devastating complication in patients with cardiovascular implantable electronic device (CIED) infection. Paradoxical septic embolism can occur in the presence of device leads and patent foramen ovale (PFO) via embolic dislodgment during transvenous lead removal (TLR).Objective: The purpose of this study was to examine stroke and its associated factors in patients undergoing TLR for CIED infection.Methods: We performed a retrospective analysis of all patients undergoing TLR for CIED infection from January 1, 2000, to July 30, 2017, from all 3 tertiary referral centers at the Mayo Clinic (Rochester, Phoenix, and Jacksonville). The primary outcome was stroke and was further categorized into preprocedural and postprocedural stroke. Associated risk factors were analyzed.Results: A total of 774 patients (mean age 67.6 ± 14.9 years) underwent TLR for CIED infection. The stroke rate in this cohort was 1.9% (95% confidence interval [CI] 1.1%-3.2%). The preprocedural and postprocedural stroke rate was 0.9% (95% CI 0.4%-1.9%) and 1.0% (95% CI 0.4%-2.0%), respectively. PFOs were identified in 46.7% of patients with stroke and in 12.9% of patients without stroke, and were independently associated with stroke (P = .0002). This was especially in patients with right-sided vegetations with right-to-left shunting (odds ratio 6.4; 95% CI 1.3-31.0; P = .022).Conclusion: In patients with CIED infection undergoing TLR, the presence of PFO, especially with right-sided vegetation with right-to-left shunting, was associated with an increased risk of stroke. This finding suggests that PFO screening before TLR warrants meticulous attention. [ABSTRACT FROM AUTHOR]

Background Cardiac resynchronization therapy (CRT) is considered as a standard adjunct therapy in symptomatic patients with congestive heart failure (CHF) who have a prolonged QRS. There is an increasing number of patients who do not receive de novo CRT devices but are upgraded from right ventricular (RV) pacing to biventricular stimulation. We wanted to evaluate the benefit of CRT in patients with chronic RV pacing in comparison to previously non-paced heart failure patients. Methods One hundred and sixty-five patients who had their device newly implanted (group I) and 116 who were upgraded from previously implanted RV pacing systems (group II) at Mayo Clinic Hospital were retrospectively analyzed. Clinical and echocardiographic response to CRT was evaluated. Mean follow-up time was 290 ± 250 days. Results Baseline characteristics did not differ between the two groups of patients. Clinical response rate was identical in Groups I and II (65 vs. 65%, respectively; P = 0.98) and echocardiographic response rate was similar in both groups of patients (64 vs. 62%; P = 0.80). Post-implant QRS increased in group I and was reduced in group II (5 (27.4) vs. − 20.0 (33.9) ms; P < 0.001). NYHA class improvement (− 0.7 (0.6) vs. − 0.7 (0.6), P = 0.81), LV ejection fraction increase (9.2 (12.9) vs. 8.2 (9.9)%; P = 0.55) and LV end-systolic volume reduction (− 34.5 (50.7) vs. − 25.7 (47.4)%; P = 0.28) were comparable in both groups. Conclusions Chronically RV-paced patients who receive CRT have similar short-term benefits when compared with patients with new CRT implantations. [ABSTRACT FROM AUTHOR]

Standardized registration and evaluation of adverse events (AEs) are essential to assess the safety of endoscopic procedures. We propose a novel classification system, named adverse events in GI endoscopy (AGREE), adapted from a widely accepted surgical tool. The Clavien-Dindo classification for surgical AEs was adapted for endoscopy. To validate the novel classification, we assessed if the severity of AEs, as perceived by 10 endoscopists, 10 endoscopy nurses, and 10 patients, corresponded with the severity grading used in the AGREE classification in 10 pairwise comparisons. We additionally assessed the correlation between the AGREE classification and the American Society for Gastrointestinal Endoscopy (ASGE) classification. The acceptability of the AGREE classification was evaluated through an international questionnaire. The perception of endoscopists, endoscopy nurses, and patients corresponded with the severity grading of the AGREE classification in 80% of cases (238/299). The AGREE classification significantly correlated with the ASGE classification (ρ =.760). Fifty-seven of 84 experts (68%) completed a questionnaire regarding the acceptability of the AGREE classification. The experts consulted considered the AGREE classification as simple (86%), reproducible (98%), logical (98%), and useful (96%). Most case presentations (84%) were correctly graded according to the AGREE classification. The AGREE classification provides a standardized and reproducible approach to the assessment of AEs in diagnostic and therapeutic GI endoscopy. Broad implementation of the AGREE classification may facilitate the evaluation of AEs across different endoscopists, disciplines, endoscopy services, and regions. This standardization of AE reporting will support improved quality assurance in GI endoscopy. [Display omitted] [ABSTRACT FROM AUTHOR]

Background: Ablation of ventricular tachycardia and premature ventricular contraction arising at the aortic root has been described. The use of radiofrequency ablation energy has been associated with life-threatening collateral damage. The use of cryoablation as a safer alternative energy source at the aortic root has not been previously described. Objective: To demonstrate that cautious cryoablation near the ostia of the left main coronary artery is technically feasible and is a safe, effective alternative energy source for ablation at the aortic root. Methods: Six patients (mean age 36 years; 4 women) with refractory frequent premature ventricular contractions or ventricular tachycardia underwent electrophysiological study and ablation. Two patients had associated nonischemic cardiomyopathy. Patients’ ventricular arrhythmias were localized by using 3D mapping, with arrhythmia foci being mapped to the left aortic cusp near the left main coronary artery. The proximity to the ostium of the left main coronary artery was confirmed by using intracardiac ultrasound and coronary angiogram. Focal ablation, up to 240 seconds with freeze-thaw-freeze cycles, was performed by using an 8-mm cryoablation catheter via a retrograde aortic approach. Results: Termination of ventricular arrhythmia during ablation was observed in all 6 patients. All patients were followed for greater than 6-month postablation. One patient had acute ST-segment elevation during ablation below the left main ostium that resolved within 30 seconds of termination of ablation. There were no postprocedure complications and no significant arrhythmia recurrences. Conclusions: Aortic root ventricular arrhythmia ablation carries an increased risk for collateral damages. This case series demonstrates that cautious cryoablation near the ostia of the left main coronary artery can be performed and is a safe, effective alternative energy source for ablation at the aortic root. [Copyright &y& Elsevier]

Background: Sudden death may occur after radiofrequency catheter ablation of the atrioventricular node (AVN) and permanent pacemaker implantation. It is unclear whether a faster initial heart rate with gradual rate reduction decreases the risk of sudden death. Objective: To evaluate the effects of initial pacing at a faster rate after AVN ablation, with a gradual rate decrease over 3 months, on the rate of sudden death in patients with atrial fibrillation. Methods: We compared the rate of likely or possible procedure-related sudden death in 2 groups of patients who had AVN ablation and pacemaker implantation. The study cohort was treated between January 2005 and December 2009, and pacemakers were programmed to a lower rate of 90 beats/min after the procedure, with a monthly decrement of 10 beats/min until 60 beats/min was reached. The control group was treated between July 1990 and December 1998 when pacemakers were programmed to a lower rate of 60 beats/min immediately after ablation. Results: The study cohort included 520 patients (mean age 73.6±10.3 years), and the control cohort comprised 334 patients (mean age 68.1±1.1 years). Sudden death deemed likely or possibly related to ablation and pacemaker implantation occurred in 1 patient in the study cohort (0.2%) and in 7 patients (2.1%) in the control group (P = .007). Conclusions: Sudden death was significantly decreased in the study cohort compared to controls. The faster lower pacing rate immediately after AVN ablation with a gradual decrease is a plausible mechanism for the improved clinical outcome. [ABSTRACT FROM AUTHOR]

Abstract: Biodiesel production has received considerable attention in the recent past as a biodegradable and nonpolluting fuel. The production of biodiesel by transesterification process employing alkali catalyst has been industrially accepted for its high conversion and reaction rates. Recently, enzymatic transesterification has attracted much attention for biodiesel production as it produces high purity product and enables easy separation from the byproduct, glycerol. But the cost of enzyme remains a barrier for its industrial implementation. In order to increase the cost effectiveness of the process, the enzyme (both intracellular and extracellular) is reused by immobilizing in a suitable biomass support particle and that has resulted in considerable increase in efficiency. But the activity of immobilized enzyme is inhibited by methanol and glycerol which are present in the reacting mixture. The use of tert-butanol as solvent, continuous removal of glycerol, stepwise addition of methanol are found to reduce the inhibitory effects thereby increasing the cost effectiveness of the process. The present review analyzes these methods reported in literature and also suggests a suitable method for commercialization of the enzymatic process. [Copyright &y& Elsevier]

Background: Among patients with acute coronary syndrome, elevated cardiac troponin and creatine phosphokinase MB fraction levels have both prognostic and diagnostic values. However, in hospitalized patients, cardiac biomarkers are measured in a variety of clinical situations including but not limited to acute coronary syndrome. Moreover, these patients may have elevated troponin levels with no increase in creatine phosphokinase MB fraction levels. Objective: To evaluate the cardiovascular outcome of acutely ill, hospitalized patients with minimal troponin I increase with normal creatine phosphokinase MB fraction. Methods: We identified 64 patients retrospectively from our database with minimal troponin I increase and normal creatine phosphokinase MB fraction hospitalized between November 1998 and April 2000. Discharged patients were questioned about re-hospitalization for myocardial infarction, unstable coronary syndrome, congestive heart failure and percutaneous coronary intervention by means of a structured questionnaire. For those patients who died during hospitalization, data were collected from hospital records. For patients who died at home or at a different institution, a surviving relative completed the questionnaire. Primary outcomes were death, myocardial infarction and the need for revascularization or re-hospitalization. Results: Composite endpoint of death, myocardial infarction, percutaneous coronary intervention or coronary artery bypass grafting and re-hospitalization for cardiac cause occurred in 35.95% of patients within 1 year. Conclusions: There is a significant composite event rate of death, myocardial infarction or re-hospitalization for cardiac causes in acutely ill, hospitalized patients with normal creatine phosphokinase MB fraction and minimally elevated troponin I, regardless of the cause for hospitalization. [Copyright &y& Elsevier]

• Developed a two-phase thermo-fluidic transport model for boiling in thin porous evaporators. • Heat transfer is modeled by conduction and volumetric pore-scale evaporation. • Fluid flow is modeled using capillary pressure and relative permeability relationships. • The model is calibrated to experimental data on dryout heat flux and thermal resistance. • Model predicts dryout limit with a mean absolute percentage error of 29%. Two-phase passive heat transport devices such as vapor chambers, loop heat pipes, and capillary pumped loops utilize porous evaporators for phase change and to drive fluid transport. Nucleate boiling can occur within such capillary-fed porous evaporators, especially under high-heat-flux operation, as has been visually observed in various experimental studies in the literature. However, prior modeling efforts have typically only considered single-phase flow of liquid through a completely saturated porous medium for characterizing the dryout limit and thermal performance. The present work offers a new semi-empirical model for prediction of thermal resistance and dryout during boiling in capillary-fed evaporators. Thermal conduction across the solid and volumetric evaporation within the pores are solved to obtain the temperature distribution in the porous structure. Capillary-driven lateral liquid flow from the outer periphery of the evaporator to its center, with vapor flow across the thickness, is considered to obtain the local liquid and vapor pressures. The capillary pressure and the relative permeabilities (fraction of single-phase permeabilities) for two-phase flow in the porous medium are modeled as a function of the local liquid saturation. The heat flux at which the liquid saturation at the center of the evaporator becomes zero is defined as the dryout limit of the evaporator. Experiments are conducted on sintered copper particle evaporators of different particle sizes and heater areas to collect data for model calibration. To demonstrate the wider applicability of the model for other types of porous evaporators, the model is further calibrated against a variety of dryout limit and thermal resistance data collected from the literature. The model is shown to predict the experimentally observed trends in the dryout limit with mean particle/pore size, heater size, and evaporator thicknesses. [ABSTRACT FROM AUTHOR]

• Various two-layer evaporator wick designs are fabricated and experimentally evaluated. • The effects of vapor venting and liquid feeding areas on performance is studied. • Increasing the vapor venting area shows a significant improvement of the dryout limit. • Visualizations reveal that smaller venting areas cause vapor to block liquid supply. • Judicious design of the wick promotes high heat flux dissipation >500 W/cm2 over 1 cm2 heated area. Vapor chambers developed for high-heat-flux operation require advanced evaporator wick designs that can sustain capillary flow when boiling occurs over the heater region. A two-layer evaporator wick integrates a thin base wick layer that is supplied with liquid from a thick cap layer through an array of vertical feeding posts distributed over the heated area. This design allows boiling to occur within the thin base layer, while separating the incoming liquid feeding and outgoing vapor venting pathways. In our prior work, boiling in two-layer wicks was experimentally demonstrated to provide high-heat-flux dissipation over larger heater areas and at low thermal resistance. The current study experimentally explores the effect of two-layer wick design parameters, specifically the dimensions that alter the area available for liquid feeding and vapor venting, on the thermal performance and dryout limit of the wick, using water as the working fluid. Four different two-layer wick designs are fabricated over a 1 cm2 evaporator area by sintering 180–212 μm copper particles. Increasing the vapor-venting area from 7% to 16% of the total evaporator area yielded a significant increase in the dryout limit, from 315 W/cm2 to 405 W/cm2. Increasing the liquid-feeding area using wider posts increased the dryout limit further. Finally, a parametrically optimized design with fewer but larger posts and vents resulted in better performance compared to a design with denser features. With this two-layer wick design, we demonstrate an extremely high dryout limit of 512 W/cm2 over the large 1 cm2 heated area at a thermal resistance of 0.08 K/W. [ABSTRACT FROM AUTHOR]

Paramagnetic resonance enhancement (PRE) is an NMR technique that allows studying three-dimensional structures of RNA-protein complexes in solution. RNA strands are typically spin labeled using nitroxide reagents, which provide minimal perturbation to the native structure. The current work describes an alternative approach, which is based on a Co 2+ -based probe that can be covalently attached to RNA in the vicinity of the protein's binding site using ‘click’ chemistry. Similar to nitroxide spin labels, the transition metal based probe is capable of attenuating NMR signal intensities from protein residues localized < 40 Å away. The extent of attenuation is related to the probe's distance, thus allowing for construction of the protein's contact surface map. This new paradigm has been applied to study binding of HIV-1 nucleocapsid protein 7, NCp7, to a model RNA pentanucleotide. [ABSTRACT FROM AUTHOR]

Abstract: Objective: In patients referred for catheter ablation for the treatment of atrial fibrillation, multislice computed tomography angiography of the thorax is routinely performed to assess pulmonary vein anatomy. We sought to investigate the incidence of unexpected cardiac and extracardiac findings in this select patient population and to establish how these findings influence subsequent patient care. Methods: Ninety-five patients (mean age 62±10 years, 35% female) referred to our institution for ablation therapy for atrial fibrillation between July 2003 and October 2007 underwent multislice computed tomography angiography of the thorax. Radiologists interpreted all images. Need for additional testing, consultation and eventual diagnosis were assessed by electronic record review. Results: A total of 83 (5 cardiac, 78 extracardiac) unexpected findings were observed in 50/95 (53%) of patients. The findings prompted 23 additional tests (5 cardiac, 18 noncardiac) in 15/95 (16%) of patients and 8 subsequent referrals in 7/95 (7%) patients. In 6 patients the findings significantly altered future patient care and resulted in postponement of ablation therapy in 4 patients. In 2 patients, extracardiac findings (pulmonary emboli and adenocarcinoma of the lung) were of potentially life-saving consequence. Conclusions: In patients undergoing multislice computed tomography angiography of the thorax in anticipation of planned catheter ablation therapy for the treatment of atrial fibrillation, unexpected findings are common and of potentially significant value. In comparison, there is a higher prevalence of unexpected extracardiac, rather than cardiac findings. Further investigation of these findings may lead to postponement of ablation therapy, but may also be of potentially lifesaving consequence. [Copyright &y& Elsevier]

Peptide deformylase catalyzes the deformylation reaction of the amino terminal fMet residue of newly synthesized proteins in bacteria, and most likely in Plasmodium falciparum, and has therefore been identified as a potential antibacterial and antimalarial drug target. The structure of P. falciparum peptide deformylase, determined at 2.8 A˚ resolution with ten subunits per asymmetric unit, is similar to the bacterial enzyme with the residues involved in catalysis, the position of the bound metal ion, and a catalytically important water structurally conserved between the two enzymes. However, critical differences in the substrate binding region explain the poor affinity of E. coli deformylase inhibitors and substrates toward the Plasmodium enzyme. The Plasmodium structure serves as a guide for designing novel antimalarials. [Copyright &y& Elsevier]

• Machined post array with sintered wick extends maximum power. • Machined post array shows improvement over sintered post array. • Vapor vent features improve thermal resistance at low power. • Combining geometric features shows significant performance improvement. To enhance the dryout heat flux of vapor chambers over a 1 cm × 1 cm area, this study describes the testing of four different vapor chamber design architectures (each having an overall size of 50 mm × 50 mm × 5.5 mm). The designs leverage a combination of internal liquid feeding posts and evaporator vapor venting features to improve the capillary-fed boiling performance. The study provides systematic insight into increasing the dryout limit of a vapor chamber and lowering the thermal resistance by assessing the effect of each geometric feature independently. A jet impingement air cooling test facility is used to measure the total thermal resistance of the package in a representative application, while a liquid cooling test facility is used to measure the thermal resistance of the vapor chamber itself. The results show that a vapor chamber with a combination of machined posts coated with sintered wick and vapor vent features has superior performance over vapor chambers with independent features. It dissipated the highest heat flux of 589 W/cm2 and provided the lowest total package thermal resistance of 0.28 K/W for a 1 cm2 heat input area. The performance improvements are attributed to an improved liquid supply utilizing the porous-wick-coated machined posts and a reduction vapor egress pressure utilizing the vent features above the heater area. [ABSTRACT FROM AUTHOR]

Food mislabelling is a growing world-wide problem that can be addressed through the authentication of ingredients via techniques like mass spectrometry or DNA sequencing. However, unfortunately traditional DNA sequencing methods are slow, expensive, and require well-equipped laboratories. We here test whether these problems can be overcome through the use of Nanopore sequencing. We sequenced 92 single and 13 mixed-species samples purchased in Singapore. We successfully obtained DNA barcodes for 94% and 100% of the single- and mixed-species samples respectively by applying a bioinformatics pipeline that was optimised for this purpose. We find comparatively low levels of clear-cut mislabelling for single-species samples (7.6%), while the rates are higher for mixed-species samples (38.5%). The low rates for single-species samples are somewhat deceptive, however, because of the use of vague species names. With regard to the clearly mislabelled single-species products, higher-value products (e.g., prawn roe, wild-caught Atlantic salmon, halibut) are replaced with lower-value ingredients (e.g., fish roe, Pacific salmon, arrowtooth flounder) while more serious problems are observed for mixed-species samples. Cuttlefish and prawn balls repeatedly contained pig DNA and all but one of the mixed samples labelled as containing crustaceans ('crab', 'prawn', 'lobster') lacked a significant number of crustacean signals. We conclude that there is a need for more regular testing of seafood samples and suggest that due to speed and low-cost, MinION would be a good instrument for this purpose. We also emphasize the need for developing clearer labelling guidelines. • We develop DNA sequencing with MinION as a seafood authentication tool. • Most of the >100 seafood samples from Singapore were correctly labelled. • Exception 1 (single species products): lower value products replace higher value products. • Exception 2 (mixed-species product): some contain ingredients not indicated (pig). • Exception 3: (mixed-species product): some lack ingredients implied by product name. [ABSTRACT FROM AUTHOR]

A new class of methionine aminopeptidase (MetAP) inhibitors, which contain an internal hydroxamate (N-acyl-N-alkylhydroxylamine) core as the metal-chelating group, has been designed, synthesized, and tested. The compounds exhibited reversible, competitive inhibition against Escherichia coli MetAP as well as human MetAP-1 and MetAP-2. The most potent inhibitor had a Ki value of 2.5 μM and >20-fold selectivity toward E. coli MAP. [Copyright &y& Elsevier]