Longitudinal reduction in fluoroscopy with continued use of 3-dimensional electroanatomic mapping systems in catheter ablation of supraventricular tachycardia - then and now.

BACKGROUND: Catheter ablation is a first-line treatment for symptomatic, recurrent supraventricular tachycardia (SVT). This study aims to demonstrate if 3D-electroanatomic mapping (EAM) during SVT ablation reduces fluoroscopy time (FT) and determine if further reductions in FT are observed longitudinally. METHODS: All cases of SVT ablation between May 2011-May 2022 at a single tertiary centre were prospectively recruited. FT between the cohorts with and without EAM were compared. Within the EAM subset, the trend of FT across the years was analysed. RESULTS: There were 1758 cases included, 563 without EAM, 1195 with EAM. EAM was associated with a longer procedure time (mean + 8.8 min, p = 0.001), but with mean reductions in FT and dose area product (DAP) by 19.6 min and 18 621 mGy*cm2 respectively (p < 0.001). There was comparable efficacy without any increase in complication rates. Over time (2011-2022), further reduction in FT of 0.9 min year on year was observed (p = 0.001). Between 2011 and 2017, there was a significant reduction in FT of 1.1 min year on year (p = 0.019), which was not observed from 2017 onwards (p = 0.061). The greatest reduction in FT was after the first year of adoption. CONCLUSION: EAM in SVT ablation reduces fluoroscopy use. FT was initially observed to reduce further over time before plateauing, likely due to increased operator experience. While there is increased interest in zero fluoroscopy SVT ablation, complementary use of fluoroscopy may still be necessary in complex cases.

Single-photon avalanche diode fabricated in standard 55†nm bipolar-CMOS-DMOS technology with sub-20†V breakdown voltage.

This paper presents a single-photon avalanche diode (SPAD) in 55 nm bipolar-CMOS-DMOS (BCD) technology. In order to realize a SPAD having sub-20 V breakdown voltage for mobile applications while preventing high tunneling noise, a high-voltage N-well available in BCD is utilized to implement the avalanche multiplication region. The resulting SPAD has a breakdown voltage of 18.4 V while achieving an excellent dark count rate of 4.4 cps/µm2 at the excess bias voltage of 7 V in spite of the advanced technology node. At the same time, the device achieves a high peak photon detection probability (PDP) of 70.1% at 450 nm thanks to the high and uniform E-field. Its PDP values at 850 and 940 nm, wavelengths of interest for 3D ranging applications reach 7.2 and 3.1%, respectively, with the use of deep N-well. The timing jitter of the SPAD, full width at half maximum (FWHM), is 91 ps at 850 nm. It is expected that the presented SPAD enables cost-effective time-of-flight and LiDAR sensors with the advanced standard technology for many mobile applications.

Non-invasive mid-term electrocardiogram patch monitoring is effective in detecting atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is a cause of serious morbidity such as stroke. Early detection and treatment of AF is important. Current guidelines recommend screening via opportunistic pulse taking or 12­lead electrocardiogram. Mid-term ECG patch monitors increases the sensitivity of AF detection. METHODS: The Singapore Atrial Fibrillation Study is a prospective multi-centre study aiming to study the incidence of AF in patients with no prior AF and a CHA2DS2-VASc score of at least 1, with the use of a mid-term continuous ECG monitoring device (Spyder ECG). Consecutive patients from both inpatient and outpatient settings were recruited from 3 major hospitals from May 2016 to December 2019. RESULTS: Three hundred and fifty-five patients were monitored. 6 patients (1.7%) were diagnosed with AF. There were no significant differences in total duration of monitoring between the AF and non-AF group (6.39 ± 3.19 vs 5.42 ± 2.46 days, p = 0.340). Patients with newly detected AF were more likely to have palpitations (50.0% vs 11.8%, p = 0.027). Half of the patients (n = 3, 50.0%) were diagnosed on the first day of monitoring and the rest were diagnosed after 24 h. On univariate analysis, only hyperlipidemia was associated with reduced odds of being diagnosed with AF (OR HR 0.08 CI 0.01-0.74, p = 0.025). In a group of 128 patients who underwent coronary artery bypass grafting and had post-operative ECG monitoring, 9 patients (7.0%) were diagnosed with post-operative AF. CONCLUSIONS: The use of non-invasive mid-term patch-based ECG monitoring is an effective modality for AF screening.

Outcomes of supraventricular tachycardia ablation: Results from the Singapore ablation and cardiac devices registry.

BACKGROUND: The Singapore Cardiac Databank was designed to monitor the performance and outcomes of catheter ablation. We investigated the outcomes of paroxysmal supraventricular tachycardia (PSVT)-ablation in a prospective, nationwide, cohort study. METHODS: Atrioventricular nodal re-entrant tachycardia (AVNRT), atrioventricular re-entry tachycardia (AVRT), or atrial tachycardia (AT)-ablations in Singapore from 2010 to 2018 were studied. Outcomes include acute success, periprocedural-complications, postoperative pacing requirement, arrhythmic recurrence and 1-year all-cause mortality. RESULTS: Among 2260 patients (mean age 45 ± 18 years, 50% female, 57% AVNRT, 37% AVRT, 6% AT), overall acute success rates of PSVT-ablation was 98.4% and increased in order of AT, AVRT, and AVNRT (p < .001). Periprocedural cardiac tamponade occurred in two AVRT patients. A total of 15 pacemakers (6 within first 30-days, 9 after 30-days) were implanted (seven AV block, eight sinus node dysfunction [SND]), with the highest incidence of pacemaker implantation after AT-ablation (5% vs. 0.6% AVNRT vs. 0.1% AVRT, p < .001). Repeat ablations (0.9% AVNRT, 7% AVRT, 4% AT, p < .001) were performed in 78 (3.5%) patients and 13 (0.6%) patients died within a year of ablation. Among outcomes considered adjusting for age, sex, PSVT-type and procedure-time, AT was independently associated with 6-fold increased odds of total (adjusted odds ratio [AOR] 6.32, 95% confidence interval [CI] 1.95-20.53) and late (AOR 6.38, 95% CI 1.39-29.29) pacemaker implantation, while AVRT was associated with higher arrhythmic recurrence with repeat ablations (AOR 4.72, 95% CI 2.36-9.44) compared to AVNRT. CONCLUSIONS: Contemporary PSVT ablation is safe with high acute success rates. Long-term outcomes differed by nature of the PSVT.

Initial experience of left bundle branch pacing using the Abbott Agilis HisPro Catheter with stylet-driven leads.

AIMS: Conduction system pacing has gained steady interest over recent years. While the majority of tools and delivery techniques were developed for His bundle pacing (HBP), the feasibility and reproducibility of using these similar tools for left bundle branch pacing (LBBP) has yet to be determined. We describe our technique for performing LBBP using the Abbott Agilis HisPro™ Steerable Catheter. METHODS AND RESULTS: A series of 22 patients with a mean age of 71.7 years (16 males, 72.7%), underwent LBBP procedure with this catheter between May and October 2021. Nineteen patients (86%) had successful LBBP lead implantation. There were no major complications or mortality. CONCLUSION: The Agilis HisPro™ catheter along with the stylet driven Tendril STS Model 2088TC lead is a safe and feasible delivery system for LBBP.

Parameterization of metabolite and macromolecule contributions in interrelated MR spectra of human brain using multidimensional modeling.

Macromolecular signals are crucial constituents of short echo-time 1 H MR spectra with potential clinical implications in themselves as well as essential ramifications for the quantification of the usually targeted metabolites. Their parameterization, needed for general fitting models, is difficult because of their unknown composition. Here, a macromolecular signal parameterization together with metabolite signal quantification including relaxation properties is investigated by multidimensional modeling of interrelated 2DJ inversion-recovery (2DJ-IR) datasets. Simultaneous and iterative procedures for defining the macromolecular background (MMBG) as mono-exponentially or generally decaying signals over TE are evaluated. Varying prior knowledge and restrictions in the metabolite evaluation are tested to examine their impact on results and fitting stability for two sets of three-dimensional spectra acquired with metabolite-cycled PRESS from cerebral gray and white matter locations. One dataset was used for model optimization, and also examining the influence of prior knowledge on estimated parameters. The most promising model was applied to a second dataset. It turned out that the mono-exponential decay model appears to be inadequate to represent TE-dependent signal features of the MMBG. TE-adapted MMBG spectra were therefore determined. For a reliable overall quantification of implicated metabolite concentrations and relaxation times, a general fitting model had to be constrained in terms of the number of fitting variables and the allowed parameter space. With such a model in place, fitting precision for metabolite contents and relaxation times was excellent, while fitting accuracy is difficult to judge and bias was likely influenced by the type of fitting constraints enforced. In summary, the parameterization of metabolite and macromolecule contributions in interrelated MR spectra has been examined by using multidimensional modeling on complex 2DJ-IR datasets. A tightly restricted model allows fitting of individual subject data with high fitting precision documented in small Cramér-Rao lower bounds, good repeatability values and a relatively small spread of estimated concentration and relaxation values for a healthy subject cohort.

A Population-wide study of electrocardiographic (ECG) norms and the effect of demographic and anthropometric factors on selected ECG characteristics in young, Southeast Asian males-results from the Singapore Armed Forces ECG (SAFE) study.

BACKGROUND: Routine use of pre-participation electrocardiograms (ECGs) has been used by the Singapore Armed Forces, targeting early detection of significant cardiac diseases. We aim to describe the impact of demographic and anthropometric factors on ECG variables and establish a set of electrocardiographic reference ranges specific to a young male multiethnic Southeast Asian cohort. METHODS AND RESULTS: Between November 1, 2009, and December 31, 2014, 144,346 young male conscripts underwent pre-participation screening that included a 12-lead ECG, demographic and anthropometric measurements. The Chinese population had the longest PR interval (146.7 ± 19.7 vs. 145.21 ± 19.2 in Malays vs. 141.2 ± 18.8 ms in Indians), QRS duration (94.5 ± 9.8 vs. 92.6 ± 9.7 in Malays vs. 92.5 ± 9.4 ms in Indians) and QTcB interval (408.3 ± 21.3 vs. 403.5 ± 21.6 in Malays vs. 401.2 ± 21.4 ms in Indians) (all p < 0.001). Body mass index (BMI) >25 kg/m2 and body fat >25% were independently associated with lower prevalence of increased QRS voltage on ECG. Systolic blood pressure of >140 mmHg or diastolic blood pressure of >90 mmHg independently increased the prevalence of increased QRS voltage on ECG. CONCLUSIONS: Electrocardiographic parameters vary across different ethnicities and in comparison with international norms. In our population, diagnosis of increased QRS voltage by ECG is less prevalent with obesity and increased body fat. Further analysis of gold standard measurements for the diagnosis of LVH in our population is ongoing, to improve the accuracy of the ECG screening process.

Allometric Relationships for Cardiac Size and Longitudinal Function in Healthy Chinese Adults　- Normal Ranges and Clinical Correlates.

BACKGROUND: Cardiac size measurements require indexing to body size. Allometric indexing has been investigated in Caucasian populations but a range of different values for the so-called allometric power exponent (b) have been proposed, with uncertainty as to whether allometry offers clinical utility above body surface area (BSA)-based indexing. We derived optimal values for b in normal echocardiograms and validated them externally in cardiac patients. METHODS AND RESULTS: Values for b were derived in healthy adult Chinese males (n=1,541), with optimal b for left ventricular mass (LVM) of 1.66 (95% confidence interval 1.41-1.92). LV hypertrophy (LVH) defined as indexed LVM >75 g/m1.66 was associated with adverse outcomes in an external validation cohort (n=738) of patients with acute coronary syndrome (odds ratio for reinfarction: 2.4 (1.1-5.4)). In contrast, LVH defined by BSA-based indexing or allometry using exponent 2.7 exhibited no significant association with outcomes (P=NS for both). Cardiac longitudinal function also varied with body size: septal and RV free wall s', TAPSE and lateral e' all scaled allometrically (b=0.3-0.9). CONCLUSIONS: An optimal b of 1.66 for LVM in healthy Chinese was found to validate well, with superior clinical utility both to that of BSA-based indexing and to b=2.7. The effect of allometric indexing of cardiac function requires further study.

A novel three base-pair deletion in domain two of the cardiac sodium channel causes Brugada syndrome.

INTRODUCTION: Mutations within SCN5A are found in a significant proportion (15-30%) of Brugada syndrome (BrS) cases and impair sodium transport across excitable cardiac cells that mediate ventricular contractions. Genetic testing offers a means to clinically assess and manage affected individuals and their family members. METHODS AND RESULTS: The proband at age 44 years old exhibited a syncopal event during exercise, and presented later with a spontaneous type-I BrS pattern on 12­lead resting electrocardiogram (ECG). Mutational analysis performed across all SCN5A exons revealed a unique three base-pair deletion p.M741_T742delinsI (c.2223_2225delGAC), in a heterozygous state in the proband and 2 siblings. This mutation was not seen in a cohort of 105 ethnicity-matched controls or in public genome databases. Patch clamp electrophysiology study conducted in TSA201 cells showed an abolishment of sodium current (INa). The proband, and several relatives, also harboured a known SCN5A variant, p.R1193Q (c.3578G>A). CONCLUSION: Our study has demonstrated the deleterious effect of a novel SCN5A mutation p.M741_T742delinsI (c.2223_2225delGAC). The findings highlight the complex effects of gender and age in phenotype manifestation. It also offers insights into improving the long-term management of BrS, and the utility of cascade genetic screening for risk stratification.

Incidence, indications, risk factors, and survival of patients undergoing cardiac implantable electronic device implantation after open heart surgery.

AIMS: The incidence, indications, and risk factors for cardiac implantable electronic device (CIED) implantation after cardiac surgery in an era with an aging population are not well described. There are limited data about the survival of these patients compared with a non-device group. We aimed to evaluate the incidence, indications, and risk factors for postoperative CIED implantation. We also assessed survival of these patients compared with a non-device group. METHODS: We included all patients without prior CIED implantation who underwent cardiac surgery at our institution from 1996 to 2008. Characteristics associated with CIED implantation were identified by multivariable logistic regression. A propensity model was constructed to compare survival. RESULTS: A total of 39 546 patients were included in the study of which 1608 patients (4.1%) underwent postoperative CIED implantation. Conduction disease accounted for most devices, but 371 patients underwent CIED implantation for secondary prevention of ventricular arrhythmias. Risk factors associated with implantation included older age, valvular disease, atrial fibrillation, and prior surgery. The propensity-adjusted risk of early death (within 1 year) was significantly less in the device group (hazard ratio [HR] 0.38; 95% confidence interval [CI] 0.22-0.65; P = 0.0004). However, the propensity-adjusted risk of late death was significantly greater in the device group (HR 1.3; 95% CI 1.2-1.5; P = <0.0001). CONCLUSION: Despite an aging population, the incidence of CIED implantation after cardiac surgery remains low and varies by the type of operation. Follow-up suggests increased early survival but decreased late survival in patients who undergo CIED implantation compared with a non-device group.

A Brugada syndrome proband with compound heterozygote SCN5A mutations identified from a Chinese family in Singapore.

AIMS: Brugada syndrome (BrS) is a rare heritable ventricular arrhythmia. Genetic defects in SCN5A, a gene that encodes the α-subunit of the sodium ion channel Nav1.5, are present in 15-30% of BrS cases. SCN5A remains by far, the highest yielding gene for BrS. We studied a young male who presented with syncope at age 11. This proband was screened for possible disease causing SCN5A mutations. The inheritance pattern was also examined amongst his first-degree family members. METHODS AND RESULTS: The proband had a baseline electrocardiogram that showed Type 2 BrS changes, which escalated to a characteristic Type I BrS pattern during a treadmill test before polymorphic ventricular tachycardia onset at a cycle length of 250 ms. Mutational analysis across all 29 exons in SCN5A of the proband and first-degree relatives of the family revealed that the proband inherited a compound heterozygote mutation in SCN5A, specifically p.A226V and p.R1629X from each parent. To further elucidate the functional changes arising through these mutations, patch-clamp electrophysiology was performed in TSA201 cells expressing the mutated SCN5A channels. The p.A226V mutation significantly reduced peak sodium current (INa) to 24% of wild type (WT) whereas the p.R1629X mutation abolished the current. To mimic the functional state in our proband, functional expression of the compound variants A226V + R1629X resulted in overall peak INa of only 13% of WT (P < 0.01). CONCLUSION: Our study is the first to report a SCN5A compound heterozygote in a Singaporean Chinese family. Only the proband carrying both mutations displayed the BrS phenotype, thus providing insights into the expression and penetrance of BrS in an Asian setting.

First clinical experience of the safety and feasibility of total subcutaneous implantable defibrillator in an Asian population.

AIMS: The safety and feasibility of a subcutaneous implantable cardioverter-defibrillator (S-ICD) has been demonstrated in the treatment of life-threatening ventricular tachyarrhythmias (VT). Nonetheless, its safety and feasibility in an Asian population with smaller body-build is unclear. METHODS AND RESULTS: Twenty-one Asian patients who underwent S-ICD from 1 April 2014 to 2 February 2015 in five institutions in Hong Kong and Singapore were retrospectively reviewed. Twenty-one patients with a mean age of 50.0 ± 14.1 years (range 29-77 years, 82.6% male) were included. Among them, 17 (81.0%) were Chinese, 3 (14.3%) were Malay, and 1 (4.8%) was Indian. Their mean body mass index was 23.0 ± 4.0 kg/m(2). An S-ICD was implanted for primary and secondary prevention in 13 (61.9%) and 8 (38.1%) patients, respectively. The indications included Brugada syndrome (n = 6, 28.6%), ischaemic cardiomyopathy (CMP, n = 6, 28.6%), dilated CMP (n = 4, 19.0%), hypertrophic CMP (n = 2, 9.5%), and idiopathic ventricular fibrillation (n = 2, 9.5%). Three patients (14.3%) had prior infected transvenous ICD. There were no acute complications but eight wound complications (persistent wound bleeding requiring intervention = 2; delayed wound healing: upper sternal wound = 3; generator site = 1; local wound infection = 2) were observed in six (28.2%) patients. After a mean follow-up of 107.2 ± 81.3 days (range of 14-254 days), one patient underwent three successful appropriate shocks for treatment of VTs. No inappropriate therapy was documented. CONCLUSION: Our initial experience shows that S-ICD is a feasible treatment for VT among an Asian population with smaller body-build. There was nonetheless a relatively high rate of wound complications.

Diffusion-weighted MR imaging of upper abdominal organs: field strength and intervendor variability of apparent diffusion coefficients.

PURPOSE: To determine the variability of apparent diffusion coefficient (ADC) values in various anatomic regions in the upper abdomen measured with magnetic resonance (MR) systems from different vendors and with different field strengths. MATERIALS AND METHODS: Ten healthy men (mean age, 36.6 years ± 7.7 [standard deviation]) gave written informed consent to participate in this prospective ethics committee-approved study. Diffusion-weighted (DW) MR imaging was performed in each subject with 1.5- and 3.0-T MR systems from each of three vendors at two institutions. Two readers independently measured ADC values in seven upper abdominal regions (left and right liver lobe, gallbladder, pancreas, spleen, and renal cortex and medulla). ADC values were tested for interobserver differences, as well as for differences related to field strength and vendor, with repeated-measures analysis of variance; coefficients of variation (CVs) and variance components were calculated. RESULTS: Interreader agreement was excellent (intraclass coefficient, 0.876). ADC values were (77.5-88.8) ×10(-5) mm(2)/sec in the spleen and (250.6-278.5) ×10(-5) mm(2)/sec in the gallbladder. There were no significant differences between ADC values measured at 1.5 T and those measured at 3.0 T in any anatomic region (P >.10 for all). In two of seven regions at 1.5 T (left and right liver lobes, P < .023) and in four of seven regions at 3.0 T (left liver lobe, pancreas, and renal cortex and medulla, P < .008), intervendor differences were significant. CVs ranged from 7.0% to 27.1% depending on the anatomic location. CONCLUSION: Despite significant intervendor differences in ADC values of various anatomic regions of the upper abdomen, ADC values of the gallbladder, pancreas, spleen, and kidney may be comparable between MR systems from different vendors and between different field strengths.

Machine learning methods for the modelling and optimisation of biogas production from anaerobic digestion: a review.

Biogas plant operators often face huge challenges in the monitoring, controlling and optimisation of the anaerobic digestion (AD) process, as it is very sensitive to surrounding changes, which often leads to process failure and adversely affects biogas production. Conventional implemented methods and mechanistic models are impractical and find it difficult to model the nonlinear and intricate interactions of the AD process. Thus, the development of machine learning (ML) algorithms has attracted considerable interest in the areas of process optimization, real-time monitoring, perturbation detection and parameter prediction. This paper provides a comprehensive and up-to-date overview of different machine learning algorithms, including artificial neural network (ANN), fuzzy logic (FL), adaptive network-based fuzzy inference system (ANFIS), support vector machine (SVM), genetic algorithm (GA) and particle swarm optimization (PSO) in terms of working mechanism, structure, advantages and disadvantages, as well as their prediction performances in modelling the biogas production. A few recent case studies of their applications and limitations are also critically reviewed and compared, providing useful information and recommendation in the selection and application of different ML algorithms. This review shows that the prediction efficiency of different ML algorithms is greatly impacted by variations in the reactor configurations, operating conditions, influent characteristics, selection of input parameters and network architectures. It is recommended to incorporate mixed liquor volatile suspended solids (MLVSS) concentration of the anaerobic digester (ranging from 16,500 to 46,700 mg/L) as one of the input parameters to improve the prediction efficiency of ML modelling. This review also shows that the combination of different ML algorithms (i.e. hybrid GA-ANN model) could yield better accuracy with higher R2 (0.9986) than conventional algorithms and could improve the optimization model of AD. Besides, future works could be focused on the incorporation of an integrated digital twin system coupled with ML techniques into the existing Supervisory Control and Data Acquisition (SCADA) system of any biogas plant to detect any operational abnormalities and prevent digester upsets.

Targeting levels or oligomerization of nucleophosmin 1 induces differentiation and loss of survival of human AML cells with mutant NPM1.

Nucleophosmin 1 (NPM1) is an oligomeric, nucleolar phosphoprotein that functions as a molecular chaperone for both proteins and nucleic acids. NPM1 is mutated in approximately one-third of patients with AML. The mutant NPM1c+ contains a 4-base insert that results in extra C-terminal residues encoding a nuclear export signal, which causes NPM1c+ to be localized in the cytoplasm. Here, we determined the effects of targeting NPM1 in cultured and primary AML cells. Treatment with siRNA to NPM1 induced p53 and p21, decreased the percentage of cells in S-phase of the cell cycle, as well as induced differentiation of the AML OCI-AML3 cells that express both NPMc+ and unmutated NPM1. Notably, knockdown of NPM1 by shRNA abolished lethal AML phenotype induced by OCI-AML3 cells in NOD/SCID mice. Knockdown of NPM1 also sensitized OCI-AML3 to all-trans retinoic acid (ATRA) and cytarabine. Inhibition of NPM1 oligomerization by NSC348884 induced apoptosis and sensitized OCI-AML3 and primary AML cells expressing NPM1c+ to ATRA. This effect was significantly less in AML cells coexpressing FLT3-ITD, or in AML or normal CD34+ progenitor cells expressing wild-type NPM1. Thus, attenuating levels or oligomerization of NPM1 selectively induces apoptosis and sensitizes NPM1c+ expressing AML cells to treatment with ATRA and cytarabine.

Clinical markers of organ dysfunction associated with increased 1-year mortality post-implantable cardioverter defibrillator implantation.

AIMS: Guidelines from the ESC and ACC/AHA recommend implantable cardioverter defibrillators (ICDs) be implanted in clinically indicated patients with a reasonable expectation of >1 year survival. Our study aimed to assess if selected clinical markers of organ dysfunction were associated with increased 1-year mortality despite ICD therapy. METHODS AND RESULTS: We retrospectively studied 283 patients with de novo ICDs implanted for primary or secondary prevention in ischaemic heart disease and dilated cardiomyopathy. We investigated the association of the following clinical markers of organ dysfunction with 1 year mortality: liver dysfunction (aspartate transaminase/alanine transaminase ≥ 3× upper limit of normal or prothrombin time/international normalized ratio ≥ 1.5 in the absence of anticoagulation), respiratory dysfunction (recent mechanical ventilation within 3 months prior to ICD implant), renal dysfunction (creatinine ≥150 µmol/L or glomerular filtration rate ≤ 30 mL/min/1.73 m(2)), anaemia (Hb ≤ 100 g/L), and prior cerebral vascular injury. With no organ dysfunction, 1 year mortality was 1.9%. In the presence of a single organ dysfunction, mortality was increased to 14.3%. With two or more markers of organ dysfunction mortality was 38.1% at 1 year (log-rank test P < 0.001). CONCLUSIONS: Clinical markers of liver dysfunction, recent mechanical ventilation, and renal impairment were independently associated with increased 1 year mortality. Presence of more than one clinical marker of organ dysfunction was associated with significantly increased risk of mortality in our study.

Selective Anomeric Acetylation of Unprotected Sugars with Acetic Anhydride in Water.

Unprotected sugars are selectively acetylated simply by stirring in aqueous solution in the presence of acetic anhydride and a weak base such as sodium carbonate. The reaction is selective for acetylation of the anomeric hydroxyl group of mannose, 2-acetamido, and 2-deoxy sugars and can be performed on a large scale. Competitive intramolecular migration of the 1-O-acetate to the 2-hydroxyl group when these two substituents are cis causes over-reaction and the formation of product mixtures.

A sub-wavelength Si LED integrated in a CMOS platform.

A nanoscale on-chip light source with high intensity is desired for various applications in integrated photonics systems. However, it is challenging to realize such an emitter using materials and fabrication processes compatible with the standard integrated circuit technology. In this letter, we report an electrically driven Si light-emitting diode with sub-wavelength emission area fabricated in an open-foundry microelectronics complementary metal-oxide-semiconductor platform. The light-emitting diode emission spectrum is centered around 1100 nm and the emission area is smaller than 0.14 µm2 (~[Formula: see text] nm). This light-emitting diode has high spatial intensity of >50 mW/cm2 which is comparable with state-of-the-art Si-based emitters with much larger emission areas. Due to sub-wavelength confinement, the emission exhibits a high degree of spatial coherence, which is demonstrated by incorporating the light-emitting diode into a compact lensless in-line holographic microscope. This centimeter-scale, all-silicon microscope utilizes a single emitter to simultaneously illuminate ~9.5 million pixels of a complementary metal-oxide-semiconductor imager.