Dynamic predictive accuracy of electrocardiographic biomarkers of sudden cardiac death within a survival framework: the Atherosclerosis Risk in Communities (ARIC) study.

BACKGROUND: The risk of sudden cardiac death (SCD) is known to be dynamic. However, the accuracy of a dynamic SCD prediction is unknown. We aimed to measure the dynamic predictive accuracy of ECG biomarkers of SCD and competing non-sudden cardiac death (non-SCD). METHODS: Atherosclerosis Risk In Community study participants with analyzable ECGs in sinus rhythm were included (n = 15,716; 55% female, 73% white, age 54.2 ± 5.8 y). ECGs of 5 follow-up visits were analyzed. Global electrical heterogeneity and traditional ECG metrics (heart rate, QRS, QTc) were measured. Adjudicated SCD was the primary outcome; non-SCD was the competing outcome. Time-dependent area under the receiver operating characteristic curve (ROC(t) AUC) analysis was performed to assess the prediction accuracy of a continuous biomarker in a period of 3,6,9 months, and 1,2,3,5,10, and 15 years using a survival analysis framework. Reclassification improvement as compared to clinical risk factors (age, sex, race, diabetes, hypertension, coronary heart disease, stroke) was measured. RESULTS: Over a median 24.4 y follow-up, there were 577 SCDs (incidence 1.76 (95%CI 1.63-1.91)/1000 person-years), and 829 non-SCDs [2.55 (95%CI 2.37-2.71)]. No ECG biomarkers predicted SCD within 3 months after ECG recording. Within 6 months, spatial ventricular gradient (SVG) elevation predicted SCD (AUC 0.706; 95%CI 0.526-0.886), but not a non-SCD (AUC 0.527; 95%CI 0.303-0.75). SVG elevation more accurately predicted SCD if the ECG was recorded 6 months before SCD (AUC 0.706; 95%CI 0.526-0.886) than 2 years before SCD (AUC 0.608; 95%CI 0.515-0.701). Within the first 3 months after ECG recording, only SVG azimuth improved reclassification of the risk beyond clinical risk factors: 18% of SCD events were reclassified from low or intermediate risk to a high-risk category. QRS-T angle was the strongest long-term predictor of SCD (AUC 0.710; 95%CI 0.668-0.753 for ECG recorded within 10 years before SCD). CONCLUSION: Short-term and long-term predictive accuracy of ECG biomarkers of SCD differed, reflecting differences in transient vs. persistent SCD substrates. The dynamic predictive accuracy of ECG biomarkers should be considered for competing SCD risk scores. The distinction between markers predicting short-term and long-term events may represent the difference between markers heralding SCD (triggers or transient substrates) versus markers identifying persistent substrate.

Vectorcardiogram in athletes: The Sun Valley Ski Study.

BACKGROUND: Global electrical heterogeneity (GEH) is associated with sudden cardiac death (SCD) in adults of 45 years and above. However, GEH has not been previously measured in young athletes. The goal of this study was to establish a reference for vectorcardiograpic (VCG) metrics in male and female athletes. METHODS: Skiers (n = 140; mean age 19.2 ± 3.5 years; 66% male, 94% white; 53% professional athletes) were enrolled in a prospective cohort. Resting 12-lead ECGs were interpreted per the International ECG criteria. Associations of age, sex, and athletic performance with GEH were studied. RESULTS: In age and training level-adjusted analyses, male sex was associated with a larger T vector [T peak magnitude +186 (95% CI 106-266) µV] and a wider spatial QRS-T angle [+28.2 (17.3-39.2)°] as compared to women. Spatial QRS-T angle in the ECG left ventricular hypertrophy (LVH) voltage group (n = 21; 15%) and normal ECG group did not differ (67.7 ± 25.0 vs. 66.8 ± 28.2; p = 0.914), suggesting that ECG LVH voltage in athletes reflects physiological remodeling. In contrast, skiers with right ventricular hypertrophy (RVH) voltage (n = 26, 18.6%) had wider QRS-T angle (92.7 ± 29.6 vs. 66.8 ± 28.2°; p = 0.001), larger SAI QRST (194.9 ± 30.2 vs. 157.8 ± 42.6 mV × ms; p < 0.0001), but similar peak SVG vector magnitude (1976 ± 548 vs. 1939 ± 395 µV; p = 0.775) as compared to the normal ECG group. Better athletic performance was associated with the narrower QRS-T angle. Each 10% worsening in an athlete's Federation Internationale de' Ski downhill ranking percentile was associated with an increase in spatial QRS-T angle by 2.1 (95% CI 0.3-3.9) degrees (p = 0.013). CONCLUSION: Vectorcardiograpic adds nuances to ECG phenomena in athletes.

Formal Total Synthesis of (+)-C9-Deoxyomuralide from l-Leucine Using a Double Sacrificial Chirality Transfer Approach.

Formal stereocontrolled syntheses of (±)- and (+)-C9-deoxyomuralide is reported, constituting one of the shortest routes to the full carbon skeleton reported to date.

Automated detection of geological landforms on Mars using Convolutional Neural Networks.

The large volume of high-resolution images acquired by the Mars Reconnaissance Orbiter has opened a new frontier for developing automated approaches to detecting landforms on the surface of Mars. However, most landform classifiers focus on crater detection, which represents only one of many geological landforms of scientific interest. In this work, we use Convolutional Neural Networks (ConvNets) to detect both volcanic rootless cones and transverse aeolian ridges. Our system, named MarsNet, consists of five networks, each of which is trained to detect landforms of different sizes. We compare our detection algorithm with a widely used method for image recognition, Support Vector Machines (SVMs) using Histogram of Oriented Gradients (HOG) features. We show that ConvNets can detect a wide range of landforms and has better accuracy and recall in testing data than traditional classifiers based on SVMs.

Multispecialty screening, brief intervention, and referral to treatment (SBIRT) training in an academic medical center: Resident training experience across specialties.

BACKGROUND: The Substance Abuse and Mental Health Services Administration (SAMHSA) has recently begun to fund programs that train medical residents on how to utilize an evidence-based validated system known as screening, brief intervention, and referral to treatment (SBIRT) for providing early detection and brief treatment of unhealthy substance use. This paper investigates training outcomes of multispecialty SBIRT training at one such program at Albany Medical Center (AMC), one of the initial SAMHSA grantees. METHODS: Training outcomes were measured across 3 domains of learning: trainee satisfaction, acquired knowledge, and perceived usefulness. The authors explored differences in learning experience by postgraduate year and by specialty. RESULTS: Overall, residents were highly satisfied with the training, and learning outcomes met objectives. Residents' ratings of usefulness did not vary by program year. However, the results indicate that relative to residents in other programs, residents in psychiatry and pediatrics found the training components significantly more useful, whereas emergency medicine residents found training components to have less utility. Residents who found the training relevant to their daily work were more satisfied and more receptive to SBIRT training overall, which may help explain difference scores by program. CONCLUSIONS: Residents were highly satisfied with SBIRT skills training, although ratings of usefulness varied by residency program. Specialization by program and on-site modeling by senior faculty may enhance trainee satisfaction and perceived usefulness.

Residents' experience of screening, brief intervention, and referral to treatment (SBIRT) as a clinical tool following practical application: A mixed-methods study.

BACKGROUND: Screening, brief intervention, and referral to treatment (SBIRT), an evidence-based validated system for providing early detection and brief treatment of substance use disorders, has been widely used in the training of medical residents across specialties at a number of sites. This article investigates the effectiveness of SBIRT training during short-term follow-up at Albany Medical Center, one of the initial Substance Abuse and Mental Health Services Administration (SAMHSA) grantees. METHODS: Training outcomes were measured by training satisfaction following opportunities to apply SBIRT skills in clinical work, the rate at which these techniques were applied in clinical work, and the degree to which residents felt that the SBIRT training provided skills that were applicable to their practice. We examined differences in learning experience by postgraduate year and by program, and conducted a qualitative analysis in a convergent parallel mixed-methods design to elucidate barriers encountered by residents upon using SBIRT techniques in clinical practice. RESULTS: Residents remained highly satisfied with the training at 4-month follow-up, with 80.1% reporting that they had used SBIRT skills in their clinical work. Use of SBIRT techniques was high at 6-month follow-up as well, with 85.9% of residents reporting that they regularly screened their patients for substance use, 74.4% reporting that they had applied brief intervention techniques, and 78.2% indicating that SBIRT training had made them overall more effective in helping patients with substance use issues. Differences in application rates and satisfaction were found by specialty. Qualitative analyses indicated that residents encountered patient readiness and specific contextual factors, such as time constraints, externally imposed values, and clinical norms, as barriers to implementation. CONCLUSIONS: Despite encountering obstacles such as time constraints and patient readiness, residents utilized many of the skills they had learned during SBIRT training in clinical practice and reported finding these skills useful in their management of patients with substance use issues.

Fluvial geomorphology on Earth-like planetary surfaces: A review.

Morphological evidence for ancient channelized flows (fluvial and fluvial-like landforms) exists on the surfaces of all of the inner planets and on some of the satellites of the Solar System. In some cases, the relevant fluid flows are related to a planetary evolution that involves the global cycling of a volatile component (water for Earth and Mars; methane for Saturn's moon Titan). In other cases, as on Mercury, Venus, Earth's moon, and Jupiter's moon Io, the flows were of highly fluid lava. The discovery, in 1972, of what are now known to be fluvial channels and valleys on Mars sparked a major controversy over the role of water in shaping the surface of that planet. The recognition of the fluvial character of these features has opened unresolved fundamental questions about the geological history of water on Mars, including the presence of an ancient ocean and the operation of a hydrological cycle during the earliest phases of planetary history. Other fundamental questions posed by fluvial and fluvial-like features on planetary bodies include the possible erosive action of large-scale outpourings of very fluid lavas, such as those that may have produced the remarkable canali forms on Venus; the ability of exotic fluids, such as methane, to create fluvial-like landforms, as observed on Saturn's moon, Titan; and the nature of sedimentation and erosion under different conditions of planetary surface gravity. Planetary fluvial geomorphology also illustrates fundamental epistemological and methodological issues, including the role of analogy in geomorphological/geological inquiry.

Differential impact of body mass index on absolute and percent breast density: implications regarding their use as breast cancer risk biomarkers.

Percent breast density (PBD), a commonly used biomarker of breast cancer risk (BCR), is confounded by the influence of non-dense breast tissue on its measurement and factors, such as BMI, which have an impact on non-dense tissue. Consequently, BMI, a potent BCR factor, is, paradoxically, negatively correlated with PBD. We propose that absolute breast density (ABD) is a more accurate biomarker of BCR. We used a volumetric method to compare the correlation between PBD and ABD with baseline demographics and dietary and physical activity variables in a group of 169 postmenopausal women enrolled in a clinical trial prior to any intervention. As expected, a strong negative correlation between PBD and BMI was observed (Rho = -0.5, p < 5e(-12)). In contrast, we observed a strong, previously not well established, positive correlation of BMI with ABD (Rho = 0.41, p < 2.5e(-8)), which supports the use of ABD as a more accurate indicator of BCR. Correction of PBD by BMI did not frequently provide the same information as ABD. In addition, because of the strong influence of BMI on ABD, many correlations between dietary variables and ABD did not emerge, until adjustment was made for BMI. ABD corrected by BMI should be the gold standard BD measurement. These findings identify the optimal measurement of BD when testing the influence of an intervention on BD as a biomarker of BCR.

Cross-functionalities of Bacillus deacetylases involved in bacillithiol biosynthesis and bacillithiol-S-conjugate detoxification pathways.

BshB, a key enzyme in bacillithiol biosynthesis, hydrolyses the acetyl group from N-acetylglucosamine malate to generate glucosamine malate. In Bacillus anthracis, BA1557 has been identified as the N-acetylglucosamine malate deacetylase (BshB); however, a high content of bacillithiol (~70%) was still observed in the B. anthracis ∆BA1557 strain. Genomic analysis led to the proposal that another deacetylase could exhibit cross-functionality in bacillithiol biosynthesis. In the present study, BA1557, its paralogue BA3888 and orthologous Bacillus cereus enzymes BC1534 and BC3461 have been characterized for their deacetylase activity towards N-acetylglucosamine malate, thus providing biochemical evidence for this proposal. In addition, the involvement of deacetylase enzymes is also expected in bacillithiol-detoxifying pathways through formation of S-mercapturic adducts. The kinetic analysis of bacillithiol-S-bimane conjugate favours the involvement of BA3888 as the B. anthracis bacillithiol-S-conjugate amidase (Bca). The high degree of specificity of this group of enzymes for its physiological substrate, along with their similar pH-activity profile and Zn²âº-dependent catalytic acid-base reaction provides further evidence for their cross-functionalities.

Comparing Approaches for Repair of Superior Semicircular Canal Dehiscence.

OBJECTIVE: Compare outcomes for subjects who underwent middle cranial fossa (MCF) or transmastoid (TM) repair of superior semicircular canal dehiscence (SSCD). STUDY DESIGN: Retrospective cohort study. SETTING: Quaternary-care, academic neurotology practice. METHODS: Subjects who underwent MCF or TM repair of SSCD between December 1999 and April 2023 were identified. Main outcome measures included demographic data, length of surgery and hospital stay, clinical presentation, and audiometric testing. RESULTS: Ninety-three subjects (97 ears) who underwent surgery for SSCD met inclusion criteria: 58.8% (57) via MCF, 39.2% (38) via TM, and 2.0% (2) via TM + MCF. Median operative time was shorter for the TM (35) compared to the MCF (29) approach (118 vs 151 minutes, P < .001). Additionally, median hospital stays were shorter for TM (36) compared to the MCF (56) approach (15.3 vs 67.7 hours, P < .001). Overall, 92% (49/53) of MCF and 92% (33/36) of TM surgeries resulted in an improvement or resolution of one or more symptoms (P = .84). There was no significant preoperative to postoperative change in the median air conduction pure-tone average (PTA), air-bone gap, or word recognition score in both the MCF and TM groups (P > .05). Improvements of >10 dB in the pre- to postoperative absolute change in bone conduction PTA were noted in 3 subjects in the MCF group and 4 subjects in the TM group (P = .49). CONCLUSION: The TM approach for SSCD demonstrates shorter operative times and length of hospital stay. The TM and MCF approaches have comparable audiometric and clinical outcomes.

Analysis of mutants disrupted in bacillithiol metabolism in Staphylococcus aureus.

Bacillithiol (BSH), an α-anomeric glycoside of l-cysteinyl-d-glucosaminyl-l-malate, is a major low molecular weight thiol found in low GC Gram-positive bacteria, such as Staphylococcus aureus. Like other low molecular weight thiols, BSH is likely involved in protection against a number of stresses. We examined S. aureus transposon mutants disrupted in each of the three genes associated with BSH biosynthesis. These mutants are sensitive to alkylating stress, oxidative stress, and metal stress indicating that BSH and BSH-dependent enzymes are involved in protection of S. aureus. We further demonstrate that BshB, a deacetylase involved in the second step of BSH biosynthesis, also acts as a BSH conjugate amidase and identify S. aureus USA 300 LAC 2626 as a BSH-S-transferase, which is able to conjugate chlorodinitrobenzene, cerulenin, and rifamycin to BSH.

Thin film CdSe/CuSe photovoltaic on a flexible single walled carbon nanotube substrate.

Liquid phase deposition (LPD), using CdSO(4) and N,N-dimethyl selenourea, has been used to grow CdSe absorber layer onto single walled carbon nanotube (SWNT) derived back contact substrates. The nanotubes are imbedded in, and penetrate into, the CdSe absorber layer for the goal of enhancing excition dissociation and carrier transport. The Cd : Se film stoichiometry varied between 1 : 1.7 to 1 : 1.3 depending on the deposition conditions. The CdSe/SWNT layers show appropriate photoresponse. LPD was also used to grow a CuSe window layer onto which silver contacts were deposited. The resulting PV device shows a characteristic IV curve. Despite both the open circuit voltage (V(OC) = 1.28 mV) and short circuit current (I(SC) = 4.85 µA) being low, the resulting device is suggestive of the possibility of fabricating a flexible thin film (inorganic) solar cell by solution processes.

Land management restrictions and options for change in perpetual conservation easements.

Conservation organizations rely on conservation easements for diverse purposes, including protection of species and natural communities, working forests, and open space. This research investigated how perpetual conservation easements incorporated property rights, responsibilities, and options for change over time in land management. We compared 34 conservation easements held by one federal, three state, and four nonprofit organizations in Wisconsin. They incorporated six mechanisms for ongoing land management decision-making: management plans (74 %), modifications to permitted landowner uses with discretionary consent (65 %), amendment clauses (53 %), easement holder rights to conduct land management (50 %), reference to laws or policies as compliance terms (47 %), and conditional use permits (12 %). Easements with purposes to protect species and natural communities had more ecological monitoring rights, organizational control over land management, and mechanisms for change than easements with general open space purposes. Forestry purposes were associated with mechanisms for change but not necessarily with ecological monitoring rights or organizational control over land management. The Natural Resources Conservation Service-Wetland Reserve Program had a particularly consistent approach with high control over land use and some discretion to modify uses through permits. Conservation staff perceived a need to respond to changing social and ecological conditions but were divided on whether climate change was likely to negatively impact their conservation easements. Many conservation easements involved significant constraints on easement holders' options for altering land management to achieve conservation purposes over time. This study suggests the need for greater attention to easement drafting, monitoring, and ongoing decision processes to ensure the public benefits of land conservation in changing landscapes.

Approach to Cochlear Implantation in Patients With Ventriculoperitoneal Shunts.

OBJECTIVE: To evaluate the safety and outcomes of cochlear implantation (CI) in patients with ventriculoperitoneal (VP) shunts to inform clinical practice. STUDY DESIGN: Historical cohort study. SETTING: Tertiary referral centers. METHODS: A multi-institutional historical cohort of patients with VP shunts and CI was identified and analyzed. RESULTS: A total of 46 patients (median age 8 years [interquratile range, IQR: 2-46]) with VP shunts and CI were identified. Of these, 41 (89%) patients had a VP shunt prior to CI. Based on institutional preference and individual patient factors, CI was performed contralateral to a pre-existing VP shunt in 24 of these 41 cases (59%) and ipsilateral in 17 (41%). Furthermore, pre-CI relocation of the VP shunt was performed in 3 cases (7%), and 2 patients (5%) underwent planned revision of their VP shunt concurrent with CI. In total, 2 of 27 pediatric patients (7%) required unanticipated revision shunt surgery, both contralateral to CI device placement, given VP shunt malfunction. One of 19 adult patients (5%) required shunt revision during CI due to shunt damage noted intraoperatively. Among 43 patients with available follow-up, 38 (88%) are regular CI users, with a median consonant-nucleus vowel-consonant word: score of 58% (IQR: 28-72). CONCLUSION: CI can be performed at low risk, either contralateral or ipsilateral, to a VP shunt, and does not mandate shunt revision in most cases. Additional considerations regarding CI receiver-stimulator placement are necessary with programmable shunts to mitigate device interaction. Preoperative planning, including coordination of care with neurosurgery, is important to achieving optimal outcomes.

Microbial Response to Increased Temperatures Within a Lava-Induced Hydrothermal System in Iceland: An Analogue for the Habitability of Volcanic Terrains on Mars.

Fossil hydrothermal systems on Mars are important exploration targets because they may have once been habitable and could still preserve evidence of microbial life. We investigated microbial communities within an active lava-induced hydrothermal system associated with the 2014-2015 eruption of Holuhraun in Iceland as a Mars analogue. In 2016, the microbial composition in the lava-heated water differed substantially from that of the glacial river and spring water sources that fed into the system. Several taxonomic and metabolic groups were confined to the water emerging from the lava and some showed the highest sequence similarities to subsurface ecosystems, including to the predicted thermophilic and deeply branching Candidatus Acetothermum autotrophicum. Measurements show that the communities were affected by temperature and other environmental factors. In particular, comparing glacial river water incubated in situ (5.7°C, control) with glacial water incubated within a lava-heated stream (17.5°C, warm) showed that microbial abundance, richness, and diversity increased in the warm treatment compared with the control, with the predicted major metabolism shifting from lithotrophy toward organotrophy and possibly phototrophy. In addition, thermophilic bacteria isolated from the lava-heated water and a nearby acidic hydrothermal system included the known endospore-formers Geobacillus stearothermophilus and Paenibacillus cisolokensis as well as a potentially novel taxon within the order Hyphomicrobiales. Similar lava-water interactions on Mars could therefore have generated habitable environments for microbial communities.

Analytical and Clinical Analysis of Two Automated Anti-SARS-CoV-2 Immunoassays in Pre-Pandemic and Pandemic Patient Populations.

BACKGROUND: In the absence of a safe, effective vaccine, the worldwide spread of COVID-19 (SARS-CoV-2) infection will continue. Laboratory tests with ideal precision, sensitivity, and specificity should be used in public health and clinical settings to gauge the extent of virus exposure. Toward this end, we evaluated the analytical and clinical performance of the Abbott SARS-CoV-2 IgG and the Roche Anti-SARS-CoV-2 immunoassays. METHODS: Quality control, pooled COVID-19, and non-COVID-19 patient specimens were used for the imprecision study. Two hundred and forty-six specimens from 70 patients with COVID-19 diagnosis were tested to study the sensitivity. Seventy-three non-COVID-19 control specimens were measured to study the specificity. All specimens were analyzed by both assays. RESULTS: Total analytic variability (CV) of the negative and positive controls were 5.5% and 3.6% for the Abbott assay and 4.5% and 1.9% for the Roche assay. Both assays demonstrated 100% qualitative reproducibility of negative and positive controls. The clinical specificities of the Abbott and the Roche assays were 100% (95% CI: 94%-100%) and 97% (95% CI: 90%-100%), respectively. The clinical sensitivities of the Abbott assay were 49% (95% CI: 41%-56%), 86% (95% CI: 74%-93%), and 100% (95% CI: 76%-100%) for samples collected at 0-6 days, 7-13 days, and ≥14 days after the first RT-PCR, while the sensitivities of the Roche assay were 55% (95% CI: 47%-62%), 86% (95% CI: 74%-93%), and 100% (95% CI: 76%-100%). CONCLUSIONS: This study demonstrates similar analytical and clinical performance of the Abbott and the Roche SARS-CoV-2 antibody assays, but the Roche assay may be slightly more sensitive for patients tested within 0-6 days after first positive RT-PCR of SARS-CoV-2.COVID-19 is a respiratory infectious disease caused by SARS-CoV-2. Laboratory tests with ideal precision, sensitivity, and specificity should be used in public health and clinical settings. We analyzed analytical and clinical performance of the Roche and Abbott SARS-CoV-2 antibody assays in pre-pandemic and pandemic patient populations. Additionally, we analyzed the sensitivity of both assays in patients at different stages of the disease. The 2 assays showed similar analytical and clinical performance, but the Roche assay may be slightly more sensitive for patients tested within 0-6 days after first positive RT-PCR of SARS-CoV-2. Our findings help other clinical labs select appropriate assays for SARS-CoV-2 antibody testing.

Renal Protective Effect of Everolimus in Liver Transplantation: A Prospective Randomized Open-Label Trial.

Renal dysfunction is associated with poor long-term outcomes after liver transplantation. We examined the renal sparing effect of everolimus (EVR) compared to standard calcineurin inhibitor (CNI) immunosuppression with direct measurements of renal function over 24 months. METHODS: This was a prospective, randomized, open-label trial comparing EVR and mycophenolic acid (MPA) with CNI and MPA immunosuppression. An Investigational New Drug Application (IND # 113882) was obtained with the Food and Drug Administration as EVR is only approved for use with low-dose tacrolimus. Serum creatinine, 24-hour urine creatinine clearance, iothalamate clearance, Cockcroft-Gault creatinine clearance (CrCl), and Modification of Diet in Renal Disease estimated glomerular filtration rate were prospectively measured at 4 study visits. Nonparametric statistical tests were used for analyses, including the Mann-Whitney U test for continuous outcomes and Pearson's chi-square test for binary outcomes. Effect size was measured using Cohen's d. Patients also completed quality of life surveys using the FACT-Hep instrument at each study visit. Comparison between the 2 groups was performed using the Student t test. RESULTS: Each arm had 12 subjects; 4 patients dropped out in the EVR arm and 1 in the CNI arm by 24 months. Serum creatinine (P = 0.015), Modification of Diet in Renal Disease estimated glomerular filtration rate (P = 0.013), and 24-hour urine CrCL (P = 0.032) were significantly better at 24 months with EVR. Iothalamate clearance showed significant improvement at 12 months (P = 0.049) and a trend toward better renal function (P = 0.099) at 24 months. There was no statistical significance with Cockcroft-Gault CrCl. Adverse events were not significantly different between the 2 arms. The EVR group also showed significantly better physical, functional, and overall self-reported quality of life (P = 0.01) at 24 months. CONCLUSIONS: EVR with MPA resulted in significant long-term improvement in renal function and quality of life at 24 months after liver transplantation compared with standard CNI with MPA immunosuppression.

Adaptive Cardiac Resynchronization Therapy Effect on Electrical Dyssynchrony (aCRT-ELSYNC): A randomized controlled trial.

BACKGROUND: Adaptive cardiac resynchronization therapy (aCRT) is known to have clinical benefits over conventional CRT, but the mechanisms are unclear. OBJECTIVE: Compare effects of aCRT and conventional CRT on electrical dyssynchrony. METHODS: A prospective, double-blind, 1:1 parallel-group assignment randomized controlled trial in patients receiving CRT for routine clinical indications. Participants underwent cardiac computed tomography and 128-electrode body surface mapping. The primary outcome was change in electrical dyssynchrony measured on the epicardial surface using noninvasive electrocardiographic imaging before and 6 months post-CRT. Ventricular electrical uncoupling (VEU) was calculated as the difference between the mean left ventricular (LV) and right ventricular (RV) activation times. An electrical dyssynchrony index (EDI) was computed as the standard deviation of local epicardial activation times. RESULTS: We randomized 27 participants (aged 64 ± 12 years; 34% female; 53% ischemic cardiomyopathy; LV ejection fraction 28% ± 8%; QRS duration 155 ± 21 ms; typical left bundle branch block [LBBB] in 13%) to conventional CRT (n = 15) vs aCRT (n = 12). In atypical LBBB (n = 11; 41%) with S waves in V5-V6, conduction block occurred in the anterior RV, as opposed to the interventricular groove in strict LBBB. As compared to baseline, VEU reduced post-CRT in the aCRT (median reduction 18.9 [interquartile range 4.3-29.2 ms; P = .034]), but not in the conventional CRT (21.4 [-30.0 to 49.9 ms; P = .525]) group. There were no differences in the degree of change in VEU and EDI indices between treatment groups. CONCLUSION: The effect of aCRT and conventional CRT on electrical dyssynchrony is largely similar, but only aCRT harmoniously reduced interventricular dyssynchrony by reducing RV uncoupling.

Dimensional standard for micro X-ray computed tomography.

The decrease in the cost of high end computing and the availability of high quality X-ray sources in the laboratory environment has led to an increased use of three-dimensional (3D) X-ray micro computed tomography (µCT). In the medical community, the primary concern for CT is calibrating for X-ray absorption and ascertaining the difference between healthy tissue and cancerous tissue or examining fractures. Absorption calibration is also important in the materials community, however confirming dimensional accuracy of voids, defects, machined parts, cracks, or the distribution of dispersed particles is typically more important. One key aspect of µCT that is often overlooked in the literature is the number of radiographs required for dimensional accuracy of the 3D reconstruction and minimization of image noise. In µCT, a number of radiographs are collected in theta increments as the sample is rotated at least 180°. They are typically collected in 1° increments (or 181 radiographs), 0.25° increments (721 radiographs), or some other multiple. The question that arises, especially in a laboratory based instrument, where the required exposure times are longer to get high-quality signal-to-noise compared to synchrotron sources, is what is the optimal number of images required to reach the volumetric statistics of the sample, and minimize the noise while not overly scanning the sample at a cost in time? A dimensional standard based upon NIST certified glass microspheres dispersed in a low density poly(styrene) matrix to answer this question is proposed. Experiments are shown that describe the microsphere size statistics as a function of number of radiographs calculated using a commercial software package, AvizoFire. These results are important in understanding the distribution of voids in a foam and confirming the accuracy of the 3D measurements obtained.