Protein Folding Stability and Kinetics in Alginate Hydrogels

Proteins are commonly encapsulated in alginate gels for drug delivery and tissue-engineering applications. However, there is limited knowledge of how encapsulation impacts intrinsic protein properties such as folding stability or unfolding kinetics. Here, we use fast relaxation imaging (FReI) to image protein unfolding in situ in alginate hydrogels after applying a temperature jump. Based on changes in the Förster resonance energy transfer (FRET) response of FRET-labeled phosphoglycerate kinase (PGK), we report the quantitative impact of multiple alginate hydrogel concentrations on protein stability and folding dynamics. The gels stabilize PGK by increasing its melting temperature up to 18.4 °C, and the stabilization follows a nonmonotonic dependence on the alginate density. In situ kinetic measurements also reveal that PGK deviates more from two-state folding behavior in denser gels and that the gel decreases the unfolding rate and accelerates the folding rate of PGK, compared to buffer. Phi-value analysis suggests that the folding transition state of an encapsulated protein is structurally similar to that of folded protein. This work reveals both beneficial and negative impacts of gel encapsulation on protein folding, as well as potential mechanisms contributing to altered stability.

Erratum: Momentum-Resolved Observation of Thermal and Quantum Depletion in a Bose Gas [Phys. Rev. Lett. 117, 235303 (2016)]

This corrects the article DOI: 10.1103/PhysRevLett.117.235303.

Correction to: Improvements in Cognitive Processing Speed, Disability, and Patient‑Reported Outcomes in Patients with Early Relapsing‑Remitting Multiple Sclerosis Treated with Natalizumab: Results of a 4‑year, Real‑World, Open‑Label Study

BACKGROUND

STRIVE was a prospective, 4-year, multicenter, observational, open-label, single-arm study of natalizumab treatment in anti-JC virus antibody-negative patients with early relapsing-remitting multiple sclerosis (RRMS).

OBJECTIVE

Study objectives examined the effects of natalizumab on cognitive processing speed, confirmed disability improvement (CDI), and patient-reported outcomes (PROs).

METHODS

Clinical and PRO secondary endpoints were assessed annually over 4 years in STRIVE. The Symbol Digit Modalities Test (SDMT) was used as a measure of cognitive processing speed. PROs were assessed using the Multiple Sclerosis Impact Score (MSIS-29) and the Work Productivity and Activity Impairment Questionnaire (WPAI).

RESULTS

At all four annual assessments, the proportion of patients in the intent-to-treat (ITT) population (N = 222) who exhibited clinically meaningful improvement in their SDMT score from baseline (i.e., change ≥ 4 points) ranged from 41.9 to 54.0%. The cumulative probability of CDI at 4 years in patients in the ITT population with a baseline Expanded Disability Status Scale score ≥ 2 (N = 133) was 43.9%. Statistically significant reductions in the mean change from screening in the MSIS-29 physical and psychological scores, indicating improved quality of life, were observed over all 4 years (P ≤ 0.0012 for all). A statistically significant decrease from screening in the impact of MS on regular activities, signifying an improvement in this WPAI measure, was also observed over all 4 years of the study.

CONCLUSION

These results further extend our knowledge of the effectiveness, specifically regarding improvements in cognitive processing speed, disability and PROs, of long-term natalizumab treatment in early RRMS patients.

CLINICALTRIALS

GOV: NCT01485003 (5 December 2011).

[Reproducibility evaluation of air-charged catheter for rest urethral pressure profilometry]

We retrospectively included 53 (9 males, 44 females) patients who underwent rest urethral pressure profilometry (RUPP) due to lower urinary tract symptoms (LUTS) in Beijing Chaoyang Hospital from May 2021 to March 2022. The age of patients was (55±16) (25-76) years old. The clinical diagnoses of the included patients with lower urinary tract symptoms were classified as: benign prostatic hyperplasia in 9 cases, interstitial cystitis in 1 case, stress urinary incontinence in 11 cases and non-obstructive dysuria in 32 cases. The full set of urodynamic examination was composed of bladder pressure measurement during the filling period, pressure flow study (PFS) and RUPP. All the urodynamic examination was performed by air-charged catheter (ACC) and corresponding equipment. All patients underwent RUPP measurements twice. The vesical pressure (Pves) values were (35.30±6.15), (35.81±5.91) cmH₂O (1 cmH₂O=0.098 kPa); the Pura@max were (141.91±36.53), (145.02±38.85) cmH₂O; functional urethral length were (41.70±16.34), (42.55±16.40) mm; the maximum urethral closure pressure for the two RUPP measurements were (106.57±36.44), (109.41±39.27) cmH₂O. There was no statistical difference between the two RUPP measurements (P>0.05). The reproducibility of the RUPP measurements obtained by ACC is good and deserves further study.

Identification and expression pattern analysis of PtCarA and PtCarB genes in Populus trichocarpa under different nitrogen treatments

Carbamoyl phosphate synthetase (CPS) catalyses the synthesis of ammonia carbamoyl phosphate (CP), which plays a key role in the biosynthesis of arginine and pyrimidine nucleotides. There are two subunits of the CPS enzyme in Populus trichocarpa, CarA (small subunit) and CarB (large subunit). Only when they coexist can CPS catalyse synthesis of CP. However, it is not clear how CPS responds to nitrogen (N) to affect arginine and pyrimidine nucleotide biosynthesis. In this study, bioinformatics methods were used to analyse the expression patterns of genes encoding CarA and CarB, and qRT-PCR and RNA-seq were used to investigate their molecular responses under different N concentrations. Phylogenetic analysis revealed that the phylogenetic trees of CarA and CarB had similar topologies. qRT-PCR showed that the PtCarA and PtCarB genes were regulated by N, while their N-regulated patterns differed in different tissues. The expression patterns of PtCarA and PtCarB show a significant positive correlation according to qRT-PCR and RNA-seq. The analysis of promoter cis-acting elements showed that the promoter regions of PtCarA1, PtCarA2 and PtCarB contained some identical cis-acting elements. According to analysis of the phylogenetic tree, expression patterns and promoter elements, we speculate that there might be coevolution among PtCarA1, PtCarA2 and PtCarB. This study provides valuable information for further understanding the function of CPS in poplar, especially for N response, and provides new ideas for studying the evolution of gene families related to heteromultimers.

Protein Stabilization by Alginate Binding and Suppression of Thermal Aggregation

Polymers designed to stabilize proteins exploit direct interactions or crowding, but mechanisms underlying increased stability or reduced aggregation are rarely established. Alginate is widely used to encapsulate proteins for drug delivery and tissue regeneration despite limited knowledge of its impact on protein stability. Here, we present evidence that alginate can both increase protein folding stability and suppress the aggregation of unfolded protein through direct interactions without crowding. We used a fluorescence-based conformational reporter of two proteins, the metabolic protein phosphoglycerate kinase (PGK) and the hPin1 WW domain to monitor protein stability and aggregation as a function of temperature and the weight percent of alginate in solution. Alginate stabilizes PGK by up to 14.5 °C, but stabilization is highly protein-dependent, and the much smaller WW domain is stabilized by only 3.5 °C against thermal denaturation. Stabilization is greatest at low alginate weight percent and decreases at higher alginate concentrations. This trend cannot be explained by crowding, and ionic screening suggests that alginate stabilizes proteins through direct interactions with a significant electrostatic component. Alginate also strongly suppresses aggregation at high temperature by irreversibly associating with unfolded proteins and preventing refolding. Both the beneficial and negative impacts of alginate on protein stability and aggregation have important implications for practical applications.

Risk of stroke with antivenom usage after venomous snakebite in Taiwan: a population-based cohort study

BACKGROUND AND PURPOSE

Stroke is a rare complication of snakebites, but may lead to serious sequelae. We aimed to explore the relationship between venomous snakebite and the risk for acute stroke, in a nationwide population-based cohort study.

METHODS

This retrospective cohort study used claims data between 1 January 2000 and 31 December 2012, from the Taiwan National Health Insurance Research Database. The study included data of patients aged 18 years or older with venomous snakebite (n = 535), matched for propensity score with controls without venomous snakebite (n = 2140). The follow-up period was the duration from the initial diagnosis of venomous snakebite and administration of antivenom to the date of an acute stroke, or until 31 December 2013. The competing risk model was used to estimate the hazard ratio (HR) and 95% confidence intervals (CIs) of stroke, ischemic stroke and hemorrhagic stroke, after adjusting for demographic and other possible stroke risk factors.

RESULTS

The adjusted HR for the venomous snakebite group compared with the control group was 2.68 for hemorrhagic stroke (95% CI = 1.35-5.33). Stratified analysis showed that the older age group (>65 years old) had a higher risk of hemorrhagic stroke. A 2.72-fold significant increase in the risk for hemorrhagic stroke was observed following venomous snakebite with antivenom usage (95% CI = 1.41-5.26).

CONCLUSION

Venomous snakebite is associated with an increased risk of hemorrhagic stroke after the use of antivenom. Further study of the underlying mechanism is warranted.

Ophiostomatoid fungi including a new species associated with Asian larch bark beetle Ips subelongatus, in Heilongjiang (Northeast China)

Ips subelongatus (Coleoptera, Scolytinae) is an important bark beetle species that infests Larix spp. in Asia. Individuals of this beetle are vectors of ophiostomatoid fungi, on their exoskeletons, that are transmitted to infested trees. In this study, the symbiotic assemblage of ophiostomatoid fungi associated with I. subelongatus in Northeast China was studied. Fungal isolates were identified based on their morphological characters and sequences of ITS, beta-tubulin, elongation factor 1-alpha and calmodulin gene regions. In total, 48 isolates were collected and identified, residing in six taxa. These included a novel species, described here as Ophiostoma gmelinii sp. nov.

Melanodevriesia, a new genus of endolichenic oleaginous black yeast recovered from the Inner Mongolia Region of China

Black yeasts are a phylogenetically diverse group of ascomycetous fungi that may exist in both unicellular and mycelial morphs. This group of fungi contains numerous commercially significant species as well as others whose precise roles are unknown, such as endolichenic species. There is currently a paucity of data about endolichenic black yeast species. To bridge this gap, we surveyed China’s Inner Mongolia Autonomous Region in July 2019. Several fungal species associated with diverse lichens were isolated during this survey. Among these were two isolates of a previously unknown species of oleaginous black yeast from Mycosphaerellales. Analyses of morphological and molecular data revealed that these two isolates were closely related to Xenodevriesia strelitziicola (Xenodevriesiaceae), although with significant differences. As a result, we established the genus Melanodevriesiagen. nov. to describe this previously unknown species, Melanodevriesia melanelixiaesp. nov. In addition, we used Transmission Electron Microscopy to visualise the intracellular oil bodies metabolised by this fungus in its unicellular state. The black yeast species identified in this study may have a wide range of commercial applications. More research is needed to determine the chemical composition of the microbial oil synthesized by this fungus and whether it has commercial value.

Citation: Chang R, Cao W, Wang Y, Li S, Li X, Bose T, Si HL (2022). Melanodevriesia, a new genus of endolichenic oleaginous black yeast recovered from the Inner Mongolia Region of China. Fungal Systematics and Evolution9: 1–9. doi: 10.3114/fuse.2022.09.01

Whole Endosome Recording of Vesicular Neurotransmitter Transporter Currents

The analysis of organellar membrane transporters presents many technical problems. In general, their activity depends on a H⁺ electrochemical driving force (Δμ_H+). However, transport itself influences the expression of Δμ_H+ in standard radiotracer flux assays, making it difficult to disentangle the role of the chemical component ΔpH and the membrane potential Δψ. Whole endosome recording in voltage clamp circumvents many of these problems, controlling ionic conditions as well as membrane potential inside and outside the organelle . This approach has been used primarily to study the properties of endolysosomal channels, which generate substantial currents (Saito et al., J Biol Chem 282(37):27327-27333, 2007; Cang et al., Nat Chem Biol 10(6):463-469, 2014; Cang et al., Cell 152(4):778-790, 2013; Chen et al., Nat Protoc 12(8):1639-1658, 2017; Samie et al., Dev Cell 26(5):511-524, 2013; Wang et al., Cell 151(2):372-383, 2012). Electrogenic transport produces much smaller currents, but we have recently reported the detection of transport currents and an uncoupled Cl^- conductance associated with the vesicular glutamate transporters (VGLUTs) that fill synaptic vesicles with glutamate (Chang et al., eLife 7:e34896, 2018). In this protocol, we will focus on the measurement of transport currents on enlarged endosomes of heterologous mammalian cells.

Stabilization and Kinetics of an Adsorbed Protein Depends on the Poly(N-isopropylacrylamide) Grafting Density

The solubility transition at the lower critical solution temperature (LCST, 32 °C) of poly(N-isopropylacrylamide) (PNIPAM) is widely used as a thermal switch to rapidly and reversibly capture and release proteins and cells. It is generally assumed that proteins adsorbed to PNIPAM above the LCST are unaffected by polymer interactions. Here we show that the folding stability of the enzyme phosphoglycerate kinase (PGK) is increased by interactions with end-grafted PNIPAM films above the LCST. We systematically compare two protein mutants with different stabilities. The stabilization mirrors the degree of protein adsorption under grafting conditions studied previously. Maximum stabilization occurs when proteins adsorb to low density, collapsed polymer "mushrooms". In the denser polymer "brush" regime, protein stabilization decreases back to a value indistinguishable from the bulk solution, consistent with low protein adsorption on dense, collapsed brushes. The temperature-dependent kinetics measured by Fast Relaxation Imaging reveals that PNIPAM does not affect the overall folding/unfolding mechanism. Based on the different stabilizations of two mutants and the relaxation kinetics, we hypothesize that the polymer acts mainly by increasing the conformational entropy of the folded protein by interacting with the protein surface and less by crowding the unfolded state of PGK.

Mobilizing COVID-19 Testing: Impact and Challenges

Introduction/Objective

In response to the rapidly evolving COVID-19 pandemic, Sanford Health developed a mobile diagnostic testing program capable of reaching geographically dispersed sites and communities. These mobile laboratories provided on-site testing and sensitive detection of SARS-CoV-2 by leveraging Cepheid’s GeneXpert platform, enabling rapid reporting of results directly to the patient and physician. Aggregation of these results allowed monitoring population infection rates and public health reporting.

Methods/Case Report

Within 3 weeks of conception, the first mobile unit was designed, engineered and deployed. Key requirements for successful implementation included mobile lab licensure, CLIA certification, COLA enrollment, Quality and Risk assessments, inventory management, lab maintenance and ongoing monitoring. Testing was performed using the Xpert Xpress SARS-CoV-2 test and the population tested were primarily asymptomatic individuals.

Results (if a Case Study enter NA)

Between May 3rd, 2020 and June 23rd, 2021, a total of 31,148 Xpert Xpress SARS-CoV-2 tests were run across 3 mobile laboratories, with an average of 600 tests performed per week. The percent positivity ranged from 0% to 5.8%, reaching highest positivity in week beginning May 10th, 2020. The average turnaround time from sample collection to result verification was 2.0 hours, and the average time from sample receipt to result verification was under 1 hour.

Conclusion

Sanford Health’s mobile testing program brings SARS-CoV-2 PCR testing to the community and dramatically reduces the time from sample collection to result reporting compared with traditional testing labs, enabling rapid intervention following a positive result. The flexibility of the GeneXpert platform, including the instrument’s robustness, the independently functioning analyzers, and the wide range of tests available, makes it particularly well suited to mobile laboratories. This program demonstrates the impact of on-site testing and highlights the challenges that were overcome for successful implementation, providing a blueprint to support the development of other mobile laboratories in the US.

Synergistic Effect between Modified Graphene Oxide and Ammonium Polyphosphate on Combustion Performance, Thermal Stability and Mechanical Properties of Polylactic Acid

To improve the thermal stability, ZF-GO (graphene oxide (GO) modified by zinc ferrite (ZF)) is prepared. In view of the anti-dripping function of ZF-GO and flame retardant effect of ammonium polyphosphate (APP), the influence of ZF-GO, APP, mixture of ZF-GO and APP on combustion performance, thermal stability and mechanical properties of polylactic acid (PLA) is investigated. Results show that the modification of GO by ZF significantly improves the residue of ZFGO by 34.7%. The char-forming capability and unique network structure of ZF-GO prevent the melt dripping of PLA. Although APP can increase the limiting oxygen index of PLA, there is still melt dripping. The combination of ZF-GO and APP improves the residual yield of 94PLA/3ZF-GO/3APP by 4.3 times relative to pure PLA, and the UL-94 level reaches V-0. The two additives show synergistic char-forming effect, and there is both physical carbonization and chemical carbonization. The incorporated fillers can decrease the total heat release (THR) of PLA composites. Specifically, the THR and peak value of heat release rate of 94PLA/3ZF-GO/3APP decrease by 21.2% and 53.9%, respectively. For the PLA/ZF-GO/APP system, plenty of residues and the anti-dripping network structure are key factors to get good flame retardancy. Addition of ZFGO and APP reduces the tensile strength, but the tensile elongation of the modified PLA composites is improved. 94PLA/ 3ZF-GO/3APP shows good integrated performance.

Management and cleanup of legacy radium-contaminated sites in the United States

The hazards associated with radium-containing materials were largely unknown when they were first introduced into household and other products over a century ago. Radium was also originally thought to have beneficial health properties, leading to confusion amongst the public about the safety of radium in household products and food items. When the adverse health effects associated with radium were discovered and became well known, radium products became unpopular and were prohibited in some countries. In the United States, after the hazards associated with radium became known, radium was first regulated by individual states in the late 1920s and early 1930s. Later, the US Nuclear Regulatory Commission (NRC) was given a role in the regulation of discrete sources of radium with the passage of the Energy Policy Act of 2005. After passage of the Act, the NRC began to systematically identify sites around the country where radium was used and reached out to site owners to determine whether existing radium contamination could pose a risk to public health and safety and the environment. The NRC devised a graded approach in response to its new regulatory responsibilities to address potential public health and safety issues at legacy radium sites. By September 2019, the NRC had dispositioned all the sites that were identified as having potential contamination from historical radium within its regulatory purview in non-Agreement States. The staff worked with site owners and federal, state and local officials, as needed, to properly disposition the sites to ensure that each site either meets the applicable criteria for unrestricted use or has controls in place to limit access during remediation so that no site poses an unacceptable risk to public health and safety and the environment.

Natalizumab in Early Relapsing-Remitting Multiple Sclerosis: A 4-Year, Open-Label Study

Introduction

STRIVE was a 4-year, multicenter, observational, open-label, single-arm study of natalizumab treatment in anti-JC virus antibody-negative (JCV-negative) relapsing-remitting multiple sclerosis (RRMS) patients with disease duration ≤ 3 years. The objective of STRIVE was to examine no evidence of disease activity (NEDA) status and predictors of NEDA in natalizumab-treated patients with early RRMS.

Methods

Proportions of patients with NEDA were evaluated along with baseline predictors of NEDA, annualized relapse rate, 24-week confirmed disability worsening (CDW), magnetic resonance imaging assessments (T2 and gadolinium-enhancing lesions), and serious adverse events.

Results

In years 1 and 2, 56.1% (95% confidence interval [CI] 48.7–63.4%) and 73.6% (95% CI 66.2–80.2%) of patients (intent-to-treat population [N = 222]), respectively, achieved NEDA. In years 3 and 4, 84.6% (95% CI 78.0–89.9%) and 91.9% (95% CI 86.4–95.8%) of patients, respectively, achieved Clinical NEDA (no relapses or 24-week CDW). Baseline predictors of NEDA in year 4 were Expanded Disability Status Scale score ≤ 2.0 (odds ratio [OR] = 3.85 [95% CI 1.54–9.63]; p = 0.004) and T2 lesion volume > 4 cc (OR = 0.39 [95% CI 0.15–0.98]; p = 0.046), with the latter also predicting Clinical NEDA in year 4 (OR = 0.21 [95% CI 0.05–0.92]; p = 0.038). The cumulative probability of CDW at year 4 was 19.3%. Serious adverse events were reported in 11.3% of patients.

Conclusion

These results support the long-term safety and effectiveness of natalizumab. Baseline predictors of NEDA help to inform benefit-risk assessments of natalizumab treatment in JCV-negative patients with early RRMS.

Trial Registration

ClinicalTrials.gov identifier NCT01485003.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01722-w.

Figs S1-S4

Fig. S1. Phylogram obtained from ML analyses of the partial BT and EF gene sequences of the O. clavatum species complex. Sequences obtained in this study are printed in bold type. Maximum-likelihood bootstrap support values (1 000 replicates) above 70 % are indicated at the nodes. Bayesian inference posterior probabilities (above 0.9) are indicated by bold lines at the relevant branches. T = ex-type cultures. Fig. S2. Phylogram obtained from ML analyses of the ITS region and the partial BT gene of the O. ips species complex. Sequences obtained in this study are printed in bold type. Maximum-likelihood bootstrap support values (1 000 replicates) above 70 % are indicated at the nodes. The Bayesian inference posterior probabilities (above 0.9) are indicated by bold lines at the relevant branches. T = ex-type cultures. Fig. S3. Phylogram obtained from ML analyses of the ITS region, and the partial BT and CAL gene sequences of the Sporothrix gossypina species complex. Sequences obtained in this study are printed in bold type. Maximum-likelihood bootstrap support values (1 000 replicates) above 70 % are indicated at the nodes. Bayesian inference posterior probabilities (above 0.9) are indicated by bold lines at the relevant branches. T = ex-type cultures. Fig. S4. Phylogram obtained from ML analyses of the ITS region, and the partial BT and EF gene sequences of Endoconidiophra. Sequences obtained in this study are printed in bold type. Maximum-likelihood bootstrap support values (1 000 replicates) above 70 % are indicated at the nodes. Bayesian inference posterior probabilities (above 0.9) are indicated by bold lines at the relevant branches. T = ex-type cultures.

Challenges in Evaluating Interactive Visual Machine Learning Systems

In interactive visual machine learning (IVML), humans and machine learning algorithms collaborate to achieve tasks mediated by interactive visual interfaces. This human-in-the-loop approach to machine learning brings forth not only numerous intelligibility, trust, and usability issues, but also many open questions with respect to the evaluation of the IVML system, both as separate components, and as a holistic entity that includes both human and machine intelligence. This article describes the challenges and research gaps identified in an IEEE VIS workshop on the evaluation of IVML systems.

Ion transport and regulation in a synaptic vesicle glutamate transporter

Synaptic vesicles accumulate neurotransmitters, enabling the quantal release by exocytosis that underlies synaptic transmission. Specific neurotransmitter transporters are responsible for this activity and therefore are essential for brain function. The vesicular glutamate transporters (VGLUTs) concentrate the principal excitatory neurotransmitter glutamate into synaptic vesicles, driven by membrane potential. However, the mechanism by which they do so remains poorly understood owing to a lack of structural information. We report the cryo-electron microscopy structure of rat VGLUT2 at 3.8-angstrom resolution and propose structure-based mechanisms for substrate recognition and allosteric activation by low pH and chloride. A potential permeation pathway for chloride intersects with the glutamate binding site. These results demonstrate how the activity of VGLUTs can be coordinated with large shifts in proton and chloride concentrations during the synaptic vesicle cycle to ensure normal synaptic transmission.

Carbon nanocarriers deliver siRNA to intact plant cells for efficient gene knockdown

Posttranscriptional gene silencing (PTGS) is a powerful tool to understand and control plant metabolic pathways, which is central to plant biotechnology. PTGS is commonly accomplished through delivery of small interfering RNA (siRNA) into cells. Standard plant siRNA delivery methods (Agrobacterium and viruses) involve coding siRNA into DNA vectors and are only tractable for certain plant species. Here, we develop a nanotube-based platform for direct delivery of siRNA and show high silencing efficiency in intact plant cells. We demonstrate that nanotubes successfully deliver siRNA and silence endogenous genes, owing to effective intracellular delivery and nanotube-induced protection of siRNA from nuclease degradation. This study establishes that nanotubes could enable a myriad of plant biotechnology applications that rely on RNA delivery to intact cells.

Broadband chiral hybrid plasmon modes on nanofingernail substrates

There is significant interest in the utility of asymmetric nanoaperture arrays as substrates for the surface-enhanced detection, fluorescence, and imaging of individual molecules. This work introduces obliquely-cut, out-of-plane, coaxial layered structures on an aperture edge. We refer to these structures as nanofingernails, which emphasizes their curved, oblique, and out-of-plane features. Broadband coupling into chiral hybrid plasmon modes and helicity-dependent near-field scattering without circular dichroism are demonstrated. The unusually-broadband, multipolar modes of nanofingernail micropore structures exhibit phase retardation effects that may be useful for achieving spatial overlap at different frequencies. The nanofingernail geometry shows new potential for simultaneous polarization-enhanced hyperspectral imaging on apertured, plasmonic surfaces.

Lexical analysis of emotional responses to "real-world" experiences in individuals with schizophrenia

Abnormalities in emotion perception, expression, and experience are considered a core component of schizophrenia. Previous laboratory studies have demonstrated that while individuals with schizophrenia report levels of positive emotions comparable to healthy individuals in response to positive stimuli, they also report co-occurring negative emotions in response to such stimuli. However, it is unknown whether this response pattern extends to "real world" naturalistic environments. To examine this question, we employed an experience sampling method (ESM) approach using mobile electronic devices to collect information up to 10 times/day over a two-day period from 53 individuals with schizophrenia and 19 non-clinical controls. As part of each experience sample, participants completed brief open-ended responses and answered questions about their emotional responses to three recent events (neutral, positive, and negative). Additionally, participants completed diagnostic and clinical measures. Lexical analyses were used to analyze ESM-based word production and characterize emotion word use. Compared to non-clinical controls, individuals with schizophrenia reported similar levels of positive emotion, but significantly higher negative emotion, which was associated with increased negative symptoms. The schizophrenia group used more anxiety words in response to negative and neutral events, and more anger words in response to positive events. Increased use of anger words was linked with elevations in positive symptoms as well as symptoms of depression, while use of sadness words was linked with anhedonia. Our findings support the co-activation of negative emotion hypothesis documented in laboratory settings and provide evidence of its ecological validity. Implications for functioning and future directions are discussed.

High aspect ratio nanomaterials enable delivery of functional genetic material without DNA integration in mature plants

Genetic engineering of plants is at the core of sustainability efforts, natural product synthesis and crop engineering. The plant cell wall is a barrier that limits the ease and throughput of exogenous biomolecule delivery to plants. Current delivery methods either suffer from host-range limitations, low transformation efficiencies, tissue damage or unavoidable DNA integration into the host genome. Here, we demonstrate efficient diffusion-based biomolecule delivery into intact plants of several species with pristine and chemically functionalized high aspect ratio nanomaterials. Efficient DNA delivery and strong protein expression without transgene integration is accomplished in Nicotiana benthamiana (Nb), Eruca sativa (arugula), Triticum aestivum (wheat) and Gossypium hirsutum (cotton) leaves and arugula protoplasts. We find that nanomaterials not only facilitate biomolecule transport into plant cells but also protect polynucleotides from nuclease degradation. Our work provides a tool for species-independent and passive delivery of genetic material, without transgene integration, into plant cells for diverse biotechnology applications.

SAT-222 Hormone Responses Associated with Letrozole Ovulation Induction in Anovulatory Women with PCOS

Abstract: The aromatase inhibitor (AI) letrozole has been shown to be the most effective oral medication for ovulation induction in anovulatory women with PCOS. It has been established that AIs block the conversion of androgens to estrogen, leading to reduction of serum estrogen levels. However, the mechanism by which letrozole induces ovulation is unknown. It has been suggested that the mechanism of AIs in ovulation induction may involve increased FSH secretion in response to reduced estrogen levels. To examine the mechanism by which AIs induce ovulation, we performed a pilot interventional study. Ten anovulatory women with PCOS, aged 24-34 years were enrolled. Each subject underwent baseline serum hormone assessment and transvaginal ultrasound. Women were excluded if they had hypogonadotropic hypogonadism, or ultrasound evidence of a dominant follicle or corpus luteum. Each subject underwent ovulation induction with letrozole 2.5 mg/day for 5 days. Repeat transvaginal ultrasound was done three days after completing letrozole. Ovulation was defined by (1) presence of >=1 ovarian follicle >=16 mm on follow up ultrasound and (2) positive home ovulation predictor test. Serum hormone levels were assessed in all subjects at baseline and at two, four, and seven days after letrozole initiation. Mean serum hormone levels were compared using paired Student’s t test with statistical significance set at p<0.05. Three of 10 subjects ovulated after completing letrozole. In all subjects, the baseline levels (mean ± SD) of serum FSH, LH, estradiol, and androstenedione were 5.4 ± 2.2 mIU/mL, 12.1 mIU/mL, 86.2 ± 32.1pg/mL, and 3.2 ± 1.5 ng/mL, respectively. A significant reduction in serum estradiol was noted on day two compared to baseline (-35.2 pg/mL). There was a significant increase in mean serum FSH (+1.8 mIU/mL) and LH (+4.7 mIU/mL) on day two after starting letrozole. Significant increases in serum androstenedione were observed on day two (+0.8 ng/mL) and day four (+1.5 ng/mL) relative to baseline values. The study was not sufficiently powered to detect differences in serum hormone levels between women that did and did not ovulate in response to letrozole administration. These data suggest that the mechanism of ovulation induction by AI may involve a transient increase in serum gonadotropins resulting from interrupted estrogen negative feedback. Sources of Research Support: NIH Grants T32 HD007203, K12 HD001259, and P50 HD012303.Key Words: Polycystic Ovary Syndrome; Infertility; Anovulation

Enhancing Flame Retardancy, Thermal Stability, Physical and Mechanical Properties of Polyethylene Foam with Polyphosphate Modified Expandable Graphite and Ammonium Polyphosphate

The method of preparing polyolefin foam with good flame retardancy, thermal stability, and physical and mechanical properties was investigated. Foaming condition of linear low density polyethylene (LLDPE) was investigated with triphenyl phosphate (TPP) as plasticizer, NaHCO3 as foaming agent. The influence of modified expandable graphite (EGP) and ammonium polyphosphate (II) on foam density, compression strength, combustion characteristics and thermal stability was explored. Results verified that EGP presented better dilatability and flame retardancy than the normal expandable graphite. Addition of EGp improved the limiting oxygen index (LOI) of 15NaHCO3/100 LLDPETPP/30EGp foam from 18.8% to 24.6%. Furthermore, the combination of EGp and ammonium polyphosphate (II) (APP) at the mass ratio of 2:1 improved the LOI of 15NaHCO3/100 LLDPETPP/20EGp/10APP sample to 27.9%, and the vertical burning UL-94 level reached V-0, indicating that this material was flame retardant. Although these additives made 15NaHCO3/100 LLDPETPP/20EGp/10APP composite exhibit a high density of 142.5 kg m−3, which was increased by 12.3 wt% relative to the 15NaHCO3/100 LLDPETPP foam, it could improve the compressive strength to 0.4747 MPa, which was about 2.7 times that of the matrix. The thermal stability of the material was also enhanced.

[Effect of interleukin-7 on the anti-tumor function of CD8(+) T cells in patients with non-small cell lung cancer]

Objective: To investigate the effect of interleukin (IL)-7 on anti-tumor activity of CD8(+) T cells in non-small cell lung cancer (NSCLC) patients. Methods: Twenty-seven NSCLC patients and ten healthy controls were included from Zhengzhou Central Hospital between January 2017 and July 2017. Plasma, peripheral blood mononuclear cells (PBMCs), and bronchial alveolar lavage fluid (BALF) (both tumor site and non-tumor site) were collect from NSCLC patients, while plasma and PBMCs were also collected from healthy controls. IL-7 level and IL-7 receptor α (CD127) mRNA relative expression was measured. Purified CD8(+) T cells and primary NSCLC cells were stimulated with recombinant IL-7. Cellular proliferation, cytokines secretion, and protein expression in IL-7 signaling pathway were investigated. Direct/indirect contact coculture system of CD8(+) T cells and primary NSCLC cells was also used to assess the cytolytic and noncytolytic activity after IL-7 stimulation. Results: Plasma IL-7 level was significantly reduced in NSCLC patients compared with normal controls[1 731 (1 364, 2 536) vs 2 686 (1 692, 4 786) ng/L, P=0.023). IL-7 level in BALF isolated from tumor site was also remarkably down-regulated compared with non-tumor site in NSCLC patients[1 045 (562, 1 550) vs 1 599 (1 166, 2 107) ng/L, P=0.006 9). There was no statistical difference of CD127 mRNA between the two groups. Recombinant IL-7 stimulation did not affect cellular proliferation and cytokines production in primary NSCLC cells, however, remarkably increased cellular proliferation, interferon (IFN)-γ/tumor necrosis factor (TNF)-α secretion, and signal transducers and activators of transcription 5 (STAT5) phosphorylation and suppressor of cytokine signaling 3 (SOCS3) expression of CD8(+) T cells from NSCLC patients. IL-7 stimulation also significantly enhanced the cytolytic and noncytolytic function of CD8(+) T cells on primary NSCLC cells. Conclusion: IL-7 enhances anti-tumor activity of CD8(+) T cells in NSCLC patients.

Delayed enhancement of the peritumoural cortex in clear cell renal cell carcinoma: correlation with Fuhrman grade

AIM

To assess the delayed enhancement of the peritumoural cortex (DEC) sign in clear cell renal cell carcinoma (ccRCC), and investigate a possible correlation among DEC and Fuhrman grade.

MATERIALS AND METHODS

This retrospective study included 506 patients with 511 histopathologically proven ccRCCs evaluated by computed tomography (CT) angiography. DEC was detected and compared in groups divided by Fuhrman grades (low grade: 1 and 2, high grade: 3 and 4) using univariate and multivariate analyses.

RESULTS

DEC was detected in 89 of 511 (17.4%) ccRCCs (grade 1: 5.7%, 2/35; grade 2: 16.2%, 70/433; grade 3: 31.4%, 11/35; grade 4: 75%, 6/8; p<0.001). The incidence was higher in high-grade ccRCCs (39.5%, 17/43) than in low-grade ccRCCs (15.4%, 72/468; p<0.001). In multivariate analysis, tumour size >5.4 cm (p<0.001, odds ratio [OR]=3.57, 95% confidence interval [CI]: 1.76-7.23) and detection of DEC (p=0.021, OR=2.33, 95% CI: 1.13-4.80) were independent predictors of high-grade ccRCC. For all ccRCCs, the area under the receiver operating characteristic (ROC) curve (AUC) of DEC in predicting high-grade ccRCC was 0.62 (95% CI: 0.53-0.72) with 39.5% sensitivity and 84.6% specificity, while for ccRCCs of >5.4 cm diameter, the AUC was 0.66 (95% CI: 0.52-0.80) with 68.4% sensitivity and 62.7% specificity.

CONCLUSIONS

The DEC sign may predict aggressive biological behaviour of ccRCC, irrespective of tumour size.

The dual role of chloride in synaptic vesicle glutamate transport

The transport of glutamate into synaptic vesicles exhibits an unusual form of regulation by Cl- as well as an associated Cl- conductance. To distinguish direct effects of Cl- on the transporter from indirect effects via the driving force Δψ, we used whole endosome recording and report the first currents due to glutamate flux by the vesicular glutamate transporters (VGLUTs). Chloride allosterically activates the VGLUTs from both sides of the membrane, and we find that neutralization of an arginine in transmembrane domain four suffices for the lumenal activation. The dose dependence suggests that Cl- permeates through a channel and glutamate through a transporter. Competition between the anions nonetheless indicates that they use a similar permeation pathway. By controlling both ionic gradients and Δψ, endosome recording isolates different steps in the process of synaptic vesicle filling, suggesting distinct roles for Cl- in both allosteric activation and permeation.

Influence of Titanium Dioxide Modified Expandable Graphite and Ammonium Polyphosphate on Combustion Behavior and Physicomechanical Properties of Rigid Polyurethane Foam

In this research, the individual influence and synergistic behavior between titanium dioxide modified expendable graphite and ammonium polyphosphate on combustion behavior and physicomechanical properties of rigid polyurethane foam (RPUF) were investigated. Combustion behavior was evaluated by limiting oxygen index, and vertical-combustion tests. Thermal stability was studied via thermogravimetric/differential thermal gravimetric (TG/DTG) analysis. Results showed that the modified expendable graphite presented better thermal stability and flame retardancy for RPUF than the normal expandable graphite. Furthermore, the combination of the modified expendable graphite and ammonium polyphosphate with the mass ratio of 1 : 1 caused the RPUF to exhibit better flame retardancy, compression strength and high temperature thermal stability. Especially, the compression strength of this polymer composite sharply increased by 52.4 % over RPUF.

Tumor-induced osteomalacia in association with PTEN-negative Cowden syndrome

Tumor-induced osteomalacia (TIO) is a rare paraneoplastic condition in which phosphaturic mesenchymal tumors (PMTs) secrete high levels of fibroblast growth factor 23 (FGF23) into the circulation. This results in renal phosphate wasting, hypophosphatemia, muscle weakness, bone pain, and pathological fractures. Recent studies suggest that fibronectin-fibroblast growth factor receptor 1 (FN1-FGFR1) translocations may be a driver of tumorigenesis. We present a patient with TIO who also exhibited clinical findings suggestive of Cowden syndrome (CS), a rare autosomal dominant disorder characterized by numerous benign hamartomas, as well as an increased risk for multiple malignancies, such as thyroid cancer. While CS is a clinical diagnosis, most, but not all, harbor a mutation in the tumor suppressor gene PTEN. Genetic testing revealed a somatic FN1-FGFR1 translocation in the FGF23-producing tumor causing TIO; however, a germline PTEN mutation was not identified. To our knowledge, this is the first reported case of concurrent TIO and CS.

The Effects of Policy-Driven Air Quality Improvements on Children's Respiratory Health

INTRODUCTION

Ambient air pollution causes substantial morbidity and mortality in the United States and worldwide. To reduce this burden of adverse health effects, a broad array of strategies to reduce ambient air pollution has been developed and applied over past decades to achieve substantial reductions in ambient air pollution levels. This has been especially true in California, where the improvement of air quality has been a major focus for more than 50 years. Direct links between regulatory policies, changes in ambient pollutant concentrations, and improvements in public health have not been extensively documented. Data from the Children's Health Study (CHS), a multiyear study of children's respiratory health development, offered a unique opportunity to evaluate the effects of long-term reductions in air pollution on children's health.

METHODS

We assessed whether changes in ambient air quality and emissions were reflected in three important indices of children's respiratory health: lung-function growth, lung-function level, and bronchitic symptoms. To make the best use of available data, these analyses were performed across the longest chronological period and largest CHS population available for the respective lung-function or bronchitic symptoms data sets. During field study operations over the course of the CHS, children's health status was documented annually by testing lung-function performance and the completion of standardized questionnaires covering a broad range of respiratory symptoms. Air quality data for the periods of interest were obtained from community monitoring stations, which operated in collaboration with regional air monitoring networks over the 20-year study time frame. Over the 20-year sampling period, common protocols were applied to collect data across the three cohorts of children. Each cohort's data set was assessed to investigate the relationship between temporal changes in lung-function development, prevalence of bronchitic symptoms, and ambient air pollution concentrations during a similar, vulnerable adolescent growth period (age 11 to 15 years). Analyses were performed separately for particulate matter ≤10 µm in aerodynamic diameter (PM₁₀), particulate matter ≤2.5 µm in aerodynamic diameter (PM₂.₅), ozone (O₃), and nitrogen dioxide (NO₂). Emissions data and regulatory policies were collected from the staff of state and regional regulatory agencies, modeling estimates, and archived reports.

RESULTS

Emissions in the regions of California studied during the 20-year period decreased by 54% for oxides of nitrogen (NOₓ), 65% for reactive organic gases (ROG), 21% for PM₂.₅, and 15% for PM₁₀. These reductions occurred despite a concurrent 22% increase in population and a 38% increase in motor vehicle miles driven during that time frame. Air quality improved over the same time frame, with reductions in NO₂ and PM₂.₅ in virtually all of the CHS communities. Annual average NO₂ decreased by about 53% (from ~41 to 19 ppb) in the highest NO₂-reporting community (Upland) and by about 28% (from ~10 to 7 ppb) in one of the lowest NO₂-reporting communities (Santa Maria). Reductions in annual average PM₂.₅ concentrations ranged from 54% (~33 to 15 µg/m³) in the community with the highest concentration (Mira Loma) to 13% (~9 to 8 µg/m³) in a community with one of the lowest concentrations (Santa Maria). Improvements in PM₁₀ and O₃ (measured during eight daytime hours, 10 AM to 6 PM) were most evident in the CHS communities that initially had the highest levels of PM and O₃. Trends in annual average NO₂, PM₂.₅, and PM₁₀ ambient air concentrations in the communities with higher-pollution levels were generally consistent with observed trends in NOₓ, ROG, PM₂.₅, and PM₁₀ emissions.

Significant improvements in lung-function growth in progressive cohorts were observed as air quality improved over the study period. Improvements in four-year growth of both forced expiratory volume in the first second of exhalation (FEV1) and forced vital capacity (FVC) were associated with declining levels of NO₂ (P < 0.0001), PM₂.₅ (P < 0.01), and PM₁₀ (P < 0.001). These associations persisted after adjustment for important potential confounders. Further, significant improvements in lung-function growth were observed in both boys and girls and among asthmatic and non-asthmatic children. Within-community decreases in O₃ exposure were not significantly associated with lung-function growth. The proportion of children with clinically low FEV1 (defined as <80% predicted) at age 15 declined significantly, from 7.9% to 3.6% across the study periods, respectively, as the air quality improved (P < 0.005). We found little evidence to suggest that improvements in lung-function development were attributable to temporal confounding.

Reductions in outdoor levels of NO₂, O₃, PM₁₀, and PM₂.₅ across the cohort years of participation were associated with significant reductions in the prevalence of bronchitic symptoms regardless of asthma status, but observed improvements were larger in children with asthma. Among asthmatic children, the reductions in prevalence of bronchitic symptoms at age 10 were 21% (P < 0.01) for NO₂, 34% (P < 0.01) for O₃, 39% (P < 0.01) for PM₁₀, and 32% (P < 0.01) for PM₂.₅ for reductions of 4.9 ppb, 3.6 ppb, 5.8 µg/m³, and 6.8 µg/m³, respectively. Similar reductions in prevalence of bronchitic symptoms were observed at age 15 among these same asthmatic children. As in the lung-function analyses, we found little evidence that temporal confounding accounted for the observed associations of symptoms reduction with air quality improvement.

The large number and breadth of regulatory activities, as well as the prolonged phase-in periods of several policy approaches to reduce emissions, precluded the close temporal linkage of specific policies with specific changes in health status. However, the combination of policies addressing motor vehicle emissions - from on-board diagnostics to emission controls, from low-sulfur fuels to vehicle smog-check recertification, and from re-formulated gasoline to the various strategies contained within the San Pedro Bay Ports Clean Air Plan (especially the Clean Truck Program) - all contributed to an impressive and substantial reduction in emissions. These reductions collectively improved local and regional air quality, and improvements in local and regional air quality were associated with improvements in respiratory health.

CONCLUSIONS

This study provides evidence that multiyear improvements in air quality and emissions, primarily driven through a broad array of science-based regulatory policy initiatives, have resulted in improved public health outcomes. Our study demonstrates that improvements in air quality, brought about by science-based regulatory actions, are associated with improved respiratory health in children. These respiratory health metrics include reductions in respiratory symptoms and improvements in lung-function development in a population widely accepted to be at risk and highly vulnerable to the effects of air pollution. Our research findings underscore the importance of sustained air regulatory efforts as an effective means of achieving improved respiratory health in communities and regions affected by airborne pollution.

Momentum-Resolved Observation of Thermal and Quantum Depletion in a Bose Gas

We report on the single-atom-resolved measurement of the distribution of momenta ℏk in a weakly interacting Bose gas after a 330 ms time of flight. We investigate it for various temperatures and clearly separate two contributions to the depletion of the condensate by their k dependence. The first one is the thermal depletion. The second contribution falls off as k^{-4}, and its magnitude increases with the in-trap condensate density as predicted by the Bogoliubov theory at zero temperature. These observations suggest associating it with the quantum depletion. How this contribution can survive the expansion of the released interacting condensate is an intriguing open question.

[Association between genetic polymorphisms of HIF-2α gene and high altitude pulmonary hypertension in Han population]

Objective: To test the hypothesis that the single nucleotide polymorphisms (SNPs) in HIF-2α gene were associated with the susceptibility of high altitude pulmonary hypertension (HAPH) in Han population in China. Methods: Those Han population who emigrated to plateau (average altitude 3 300 m) and have been lived here for more than 20 years were included as the research subjects, the method of cluster random sampling was used to enroll 49 HAPH patients as the case group (HAPH group) and 39 free of HAPH people as the control group. The Sanger chain termination method was used to detect the SNPs of rs1562453, rs1867785, rs4953361, rs7598371 and rs11125068 in HIF-2α gene. Results: The genotype and frequencies of rs1562453 were CC (49.0%), CT (46.9%) and TT (4.1%) in the HAPH group, and the locus's genotype and frequencies were CC (76.9%), CT (17.9%) and TT (5.1%) in the control group. The alleles and frequencies of rs1562453 were C (72.4%) and T (27.6%) in the HAPH group, and the locus's alleles and frequencies were C (85.9%) and T (14.1%) in the control group. Their genotypes and alleles frequencies were of significant difference between the two groups (genotypes P=0.017; allele P=0.031). Meanwhile, The genotype and frequencies of rs1867785 were AA (46.9%), AG (46.9%) and GG (6.1%) in the HAPH group, and the locus's genotype and frequencies were AA (74.4%), AG (25.6%) and GG (0.0%) in the control group. The alleles and frequencies of rs1867785 were A (70.4%) and G (29.6%) in the HAPH group, and the locus's alleles and frequencies were A (87.2%) and G (12.8%) in the control group. Their genotypes and alleles frequencies were of significant difference between the two groups (genotypes P=0.020; allele P=0.008). Genotypes frequencies of the rs1562453 and rs1867785 were analyzed by Logistic Regression which showed that the genotypes frequencies of rs1562453 were also of significant difference between two groups (Wald=9.561, P=0.008), CT vs CC (β=1.720, OR=5.580, P=0.011). Conclusion: The SNPs of rs1562453 in HIF-2α gene may be associated with the development of HAPH among Chinese Han population, and individuals with the genotype CT may be more vulnerable to HAPH than those who carry genotype CC, and allele T may be a risk factor for HAPH.

Two methods for setting child-focused tuberculosis care targets

OBJECTIVE

To allocate resources for household contact investigations, tuberculosis (TB) programs need estimates of the numbers of child contacts requiring care.

DESIGN

We developed two methods to estimate annual numbers of child contacts aged 0-14 years requiring evaluation and treatment. Method 1 combines local data using simple formulas. Using publicly available data, Method 2 uses a linear regression model based on Demographic and Health Survey and World Bank data to estimate the number of children per household, then combines these results with case notifications and risk estimates of disease and infection.

RESULTS

Applying Method 1 to data from Malawi indicated that every year ~21 000 child contacts require evaluation and ~1900 should be diagnosed with TB. Applying Method 2 to all countries suggested that, globally, 2.41 million (95% uncertainty interval [UI] 2.36-2.46) children aged <5 years, and 5.07 million (95%UI 4.81-5.34) children aged 5-14 years live in households of adult patients with known TB. Of these, 239 014 (95%UI 118 649-478581) and 419 816 (95%UI 140600-1 268805), respectively, will have TB. An additional 848 453 (95%UI 705838-1 017551) and 2660 885 (95%UI 2080517-3 413 189), respectively, will be infected.

CONCLUSION

It is feasible to use available data to set programmatic evaluation and treatment targets to improve care for child contacts of patients with TB.

Control of photo-induced voltages in plasmonic crystals via spin-orbit interactions

There is wide interest in understanding and leveraging the nonlinear plasmon-induced potentials of nanostructured materials. We investigate the electrical response produced by spin-polarized light across a large-area bottom-up assembled 2D plasmonic crystal. Numerical approximations of the Lorentz forces provide quantitative agreement with our experimentally-measured DC voltages. We show that the underlying mechanism of the spin-polarized voltages is a gradient force that arises from asymmetric, time-averaged hotspots, whose locations shift with the chirality of light. Finally, we formalize the role of spin-orbit interactions in the shifted intensity patterns and significantly advance our understanding of the physical phenomena, often related to the spin Hall effect of light.

Protons Regulate Vesicular Glutamate Transporters through an Allosteric Mechanism

The quantal nature of synaptic transmission requires a mechanism to transport neurotransmitter into synaptic vesicles without promoting non-vesicular efflux across the plasma membrane. Indeed, the vesicular transport of most classical transmitters involves a mechanism of H(+) exchange, which restricts flux to acidic membranes such as synaptic vesicles. However, vesicular transport of the principal excitatory transmitter glutamate depends primarily on membrane potential, which would drive non-vesicular efflux, and the role of protons is unclear. Adapting electrophysiology to record currents associated with the vesicular glutamate transporters (VGLUTs), we characterize a chloride conductance that is gated by lumenal protons and chloride and supports glutamate uptake. Rather than coupling stoichiometrically to glutamate flux, lumenal protons and chloride allosterically activate vesicular glutamate transport. Gating by protons serves to inhibit what would otherwise be substantial non-vesicular glutamate efflux at the plasma membrane, thereby restricting VGLUT activity to synaptic vesicles.

Characterization of a detector chain using a FPGA-based time-to-digital converter to reconstruct the three-dimensional coordinates of single particles at high flux

We report on the development of a novel FPGA-based time-to-digital converter and its implementation in a detection chain that records the coordinates of single particles along three dimensions. The detector is composed of micro-channel plates mounted on top of a cross delay line and connected to fast electronics. We demonstrate continuous recording of the timing signals from the cross delay line at rates up to 4.1 × 10(6) s(-1) and three-dimensional reconstruction of the coordinates up to 3.2 × 10(6) particles per second. From the imaging of a calibrated structure we measure the in-plane resolution of the detector to be 140(20) μm at a flux of 3 × 10(5) particles per second. In addition, we analyze a method to estimate the resolution without placing any structure under vacuum, a significant practical improvement. While we use UV photons here, the results of this work apply to the detection of other kinds of particles.

The effects of remodeling with heart failure on mode of initiation of ventricular fibrillation and its spatiotemporal organization

PURPOSE

The effect of the heart failure substrate on the initiation of ventricular fibrillation (VF) and its resulting mechanism is not known. The objective of this study was to determine the effects of substrate on VF initiation and its spatiotemporal organization in the heart failure model.

METHODS

Optical action potentials were recorded from LV wedge preparations either from structurally normal hearts (control, n = 11) or from congestive heart failure (CHF; n = 7), at the epicardial surface, endocardial surface which included a papillary muscle, and a transmural cross section. Action potential duration (APD(80)) was determined, and VF was initiated. A fast Fourier transform was calculated, and the dominant frequency (DF) was determined.

RESULTS

The CHF group showed increased VF vulnerability (69 vs 26 %, p < 0.03), and every mapped surface showed an APD(80) gradient which included islands of higher APDs on the transmural surface (M cells) which was not observed in controls. VF in the CHF group was characterized by stable, discrete, high-DF areas that correlated to either foci or spiral waves located on the transmural surface at the site of the papillary muscle. Overall, the top 10 % of DFs correlated to an APD of 101 ms while the bottom 10 % of DFs correlated to an APD of 126 ms (p < 0.01).

CONCLUSIONS

In the CHF model, APD gradients correlated with an increased vulnerability to VF, and the highest stable DFs were located on the transmural surface which was not seen in controls. This indicates that the CHF substrate creates unique APD and DF characteristics.

Association of improved air quality with lung development in children

BACKGROUND

Air-pollution levels have been trending downward progressively over the past several decades in southern California, as a result of the implementation of air quality-control policies. We assessed whether long-term reductions in pollution were associated with improvements in respiratory health among children.

METHODS

As part of the Children's Health Study, we measured lung function annually in 2120 children from three separate cohorts corresponding to three separate calendar periods: 1994-1998, 1997-2001, and 2007-2011. Mean ages of the children within each cohort were 11 years at the beginning of the period and 15 years at the end. Linear-regression models were used to examine the relationship between declining pollution levels over time and lung-function development from 11 to 15 years of age, measured as the increases in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) during that period (referred to as 4-year growth in FEV1 and FVC).

RESULTS

Over the 13 years spanned by the three cohorts, improvements in 4-year growth of both FEV1 and FVC were associated with declining levels of nitrogen dioxide (P<0.001 for FEV1 and FVC) and of particulate matter with an aerodynamic diameter of less than 2.5 μm (P= 0.008 for FEV1 and P<0.001 for FVC) and less than 10 μm (P<0.001 for FEV1 and FVC). These associations persisted after adjustment for several potential confounders. Significant improvements in lung-function development were observed in both boys and girls and in children with asthma and children without asthma. The proportions of children with clinically low FEV1 (defined as <80% of the predicted value) at 15 years of age declined significantly, from 7.9% to 6.3% to 3.6% across the three periods, as the air quality improved (P = 0.001).

CONCLUSIONS

We found that long-term improvements in air quality were associated with statistically and clinically significant positive effects on lung-function growth in children. (Funded by the Health Effects Institute and others.).