Decreased carbon accumulation feedback driven by climate-induced drying of two southern boreal bogs over recent centuries.

Northern boreal peatlands are important ecosystems in modulating global biogeochemical cycles, yet their biological communities and related carbon dynamics are highly sensitive to changes in climate. Despite this, the strength and recent direction of these feedbacks are still unclear. The response of boreal peatlands to climate warming has received relatively little attention compared with other northern peatland types, despite forming a large northern hemisphere-wide ecosystem. Here, we studied the response of two ombrotrophic boreal peatlands to climate variability over the last c. 200 years for which local meteorological data are available. We used remains from plants and testate amoebae to study historical changes in peatland biological communities. These data were supplemented by peat property (bulk density, carbon and nitrogen content), 14 C, 210 Pb and 137 Cs analyses and were used to infer changes in peatland hydrology and carbon dynamics. In total, six peat cores, three per study site, were studied that represent different microhabitats: low hummock (LH), high lawn and low lawn. The data show a consistent drying trend over recent centuries, represented mainly as a change from wet habitat Sphagnum spp. to dry habitat S. fuscum. Summer temperature and precipitation appeared to be important drivers shaping peatland community and surface moisture conditions. Data from the driest microhabitat studied, LH, revealed a clear and strong negative linear correlation (R2  = .5031; p < .001) between carbon accumulation rate and peat surface moisture conditions: under dry conditions, less carbon was accumulated. This suggests that at the dry end of the moisture gradient, availability of water regulates carbon accumulation. It can be further linked to the decreased abundance of mixotrophic testate amoebae under drier conditions (R2  = .4207; p < .001). Our study implies that if effective precipitation decreases in the future, the carbon uptake capacity of boreal bogs may be threatened.

Ecosystem state shifts during long-term development of an Amazonian peatland.

The most carbon (C)-dense ecosystems of Amazonia are areas characterized by the presence of peatlands. However, Amazonian peatland ecosystems are poorly understood and are threatened by human activities. Here, we present an investigation into long-term ecohydrological controls on C accumulation in an Amazonian peat dome. This site is the oldest peatland yet discovered in Amazonia (peat initiation ca. 8.9 ka BP), and developed in three stages: (i) peat initiated in an abandoned river channel with open water and aquatic plants; (ii) inundated forest swamp; and (iii) raised peat dome (since ca. 3.9 ka BP). Local burning occurred at least three times in the past 4,500 years. Two phases of particularly rapid C accumulation (ca. 6.6-6.1 and ca. 4.9-3.9 ka BP), potentially resulting from increased net primary productivity, were seemingly driven by drier conditions associated with widespread drought events. The association of drought phases with major ecosystem state shifts (open water wetland-forest swamp-peat dome) suggests a potential climatic control on the developmental trajectory of this tropical peatland. A third drought phase centred on ca. 1.8-1.1 ka BP led to markedly reduced C accumulation and potentially a hiatus during the peat dome stage. Our results suggest that future droughts may lead to phases of rapid C accumulation in some inundated tropical peat swamps, although this can lead ultimately to a shift to ombrotrophy and a subsequent return to slower C accumulation. Conversely, in ombrotrophic peat domes, droughts may lead to reduced C accumulation or even net loss of peat. Increased surface wetness at our site in recent decades may reflect a shift towards a wetter climate in western Amazonia. Amazonian peatlands represent important carbon stores and habitats, and are important archives of past climatic and ecological information. They should form key foci for conservation efforts.

Ultrafast Through-Space Electronic Energy Transfer in Molecular Dyads Built around Dynamic Spacer Units.

A pair of complementary molecular dyads have been synthesized around a 1,2-diaminocyclohexyl spacer that itself undergoes ring inversion. Despite these conformational exchange processes, the donor and acceptor occupy quite restricted spatial regions, and they are not interchangeable. The donor and acceptor pair comprise disparate boron dipyrromethene dyes selected to display favorable electronic energy transfer (EET). Steady-state emission spectroscopy confirms that through-space EET from donor to acceptor is almost quantitative, aided by the relatively short separations. Ultrafast time-resolved fluorescence spectroscopy has allowed determination of the rates of EET for both dyads. Surprisingly, in view of the close proximity of donor and acceptor (center-to-center separations less than 20 Å), the EET dynamics are well-accounted for in terms of the computed molecular conformations and conventional Förster theory. One dyad appears as a single family of conformations, but EET for the second dyad corresponds to dual-exponential kinetics. In this latter case, an intramolecular hydrogen bond helps stabilize an open geometry, wherein EET is relatively slow.

Moss stable isotopes (carbon-13, oxygen-18) and testate amoebae reflect environmental inputs and microclimate along a latitudinal gradient on the Antarctic Peninsula.

The stable isotope compositions of moss tissue water (δ(2)H and δ(18)O) and cellulose (δ(13)C and δ(18)O), and testate amoebae populations were sampled from 61 contemporary surface samples along a 600-km latitudinal gradient of the Antarctic Peninsula (AP) to provide a spatial record of environmental change. The isotopic composition of moss tissue water represented an annually integrated precipitation signal with the expected isotopic depletion with increasing latitude. There was a weak, but significant, relationship between cellulose δ(18)O and latitude, with predicted source water inputs isotopically enriched compared to measured precipitation. Cellulose δ(13)C values were dependent on moss species and water content, and may reflect site exposure to strong winds. Testate amoebae assemblages were characterised by low concentrations and taxonomic diversity, with Corythion dubium and Microcorycia radiata types the most cosmopolitan taxa. The similarity between the intra- and inter-site ranges measured in all proxies suggests that microclimate and micro-topographical conditions around the moss surface were important determinants of proxy values. Isotope and testate amoebae analyses have proven value as palaeoclimatic, temporal proxies of climate change, whereas this study demonstrates that variations in isotopic and amoeboid proxies between microsites can be beyond the bounds of the current spatial variability in AP climate.

Controlling charge separation and recombination by chemical design in donor-acceptor dyads.

Conjugated donor-acceptor block co-oligomers that self-organize into D-A mesomorphic arrays have raised increasing interest due to their potential applications in organic solar cells. We report here a combined experimental and computational study of charge transfer (CT) state formation and recombination in isolated donor-spacer-acceptor oligomers based on bisthiophene-fluorene (D) and perylene diimide (A), which have recently shown to self-organize to give a mesomorphic lamellar structure at room temperature. Using femtosecond transient absorption spectroscopy and Time-Dependent Density Functional Theory in combination with the Marcus-Jortner formalism, the observed increase of the CT lifetimes is rationalized in terms of a reduced electronic coupling between D and A brought about by the chemical design of the donor moiety. A marked dependence of the CT lifetime on solvent polarity is observed, underscoring the importance of electrostatic effects and those of the environment at large. The present investigation therefore calls for a more comprehensive design approach including the effects of molecular packing.

Boosting Gas-Phase TiO2 Photocatalysis with Weak Electric Field Strengths of Volt/Centimeter.

Among semiconductor nanomaterials, titanium dioxide is at the forefront of heterogeneous photocatalysis, but its catalytic activity greatly suffers from the loss of photoexcited charge carriers through deleterious recombination processes. Here, we investigate the impact of an external electric field (EEF) applied to conventional P25 TiO2 nanopowder with or without Au nanoparticles (NPs) to circumvent this issue. The study of two redox reactions in the gas phase, water splitting and toluene degradation, reveals an enhancement of the photocatalytic activity with rather modest electric fields of a few volt/centimeters only. Such an improvement arises from the electric-field-induced quenching of the green emission in anatase, allowing the photoexcited charge carriers to be transferred to the adsorbed reactants instead of pointless radiative recombinations. Applying an EEF across a trap-rich metal oxide material, such as TiO2, which, when impregnated with Au NPs, leads, respectively, to 12- and 6-fold enhancements in the production of hydrogen and the oxidation of toluene for an electric field of 8 V/cm, without any electrolysis, is a simple and elegant strategy to meet higher photocatalytic efficiencies.

Mortality-related risk factors of inpatients with diabetes and COVID-19: A multicenter retrospective study in Belgium.

BACKGROUND AND AIMS: We describe mortality-related risk factors of inpatients with diabetes and coronavirus disease 2019 (COVID-19) in Belgium. METHODS: We conducted a multicenter retrospective study from March to May, 2020, in 8 Belgian centers. Data on admission of patients with diabetes and COVID-19 were collected. Survivors were compared to non-survivors to identify prognostic risk factors for in-hospital death using multivariate analysis in both the total population and in the subgroup of patients admitted in the intensive care unit (ICU). RESULTS: The study included 375 patients. The mortality rate was 26.4% (99/375) in the total population and 40% (27/67) in the ICU. Multivariate analysis identified older age (HR 1.05 [CI 1.03-1.07], P<0.0001) and male gender (HR 2.01 [1.31-3.07], P=0.0013) as main independent risk factors for in-hospital death in the total population. Metformin (HR 0.51 [0.34-0.78], P=0.0018) and renin-angiotensin-aldosterone system blockers (HR 0.56 [0.36-0.86], P=0.0088) use before admission were independent protective factors. In the ICU, chronic kidney disease (CKD) was identified as an independent risk factor for death (HR 4.96 [2.14-11.5], P<0.001). CONCLUSION: In-hospital mortality due to the first wave of COVID-19 pandemic in Belgium was high in patients with diabetes. We found that advanced age and male gender were independent risk factors for in-hospital death. We also showed that metformin use before admission was associated with a significant reduction of COVID-19-related in-hospital mortality. Finally, we showed that CKD is a COVID-19-related mortality risk factor in patients with diabetes admitted in the ICU.

Intravenous infusion of phage-displayed antibody library in human cancer patients: enrichment and cancer-specificity of tumor-homing phage-antibodies.

Phage display is a powerful method for target discovery and selection of ligands for cancer treatment and diagnosis. Our goal was to select tumor-binding antibodies in cancer patients. Eligibility criteria included absence of preexisting anti-phage-antibodies and a Stage IV cancer status. All patients were intravenously administered 1 × 10(11) TUs/kg of an scFv library 1 to 4 h before surgical resection of their tumors. No significant adverse events related to the phage library infusion were observed. Phage were successfully recovered from all tumors. Individual clones from each patient were assessed for binding to the tumor from which clones were recovered. Multiple tumor-binding phage-antibodies were identified. Soluble scFv antibodies were produced from the phage clones showing higher tumor binding. The tumor-homing phage-antibodies and derived soluble scFvs were found to bind varying numbers (0-5) of 8 tested normal human tissues (breast, cervix, colon, kidney, liver, spleen, skin, and uterus). The clones that showed high tumor-specificity were found to bind corresponding tumors from other patients also. Clone enrichment was observed based on tumor binding and DNA sequence data. Clone sequences of multiple variable regions showed significant matches to certain cancer-related antibodies. One of the clones (07-2,355) that was found to share a 12-amino-acid-long motif with a reported IL-17A antibody was further studied for competitive binding for possible antigen target identification. We conclude that these outcomes support the safety and utility of phage display library panning in cancer patients for ligand selection and target discovery for cancer treatment and diagnosis.

Unmet Healthcare Needs among College Students during the COVID-19 Pandemic: Implications for System-Wide and Structural Changes for Service Delivery.

BACKGROUND: During the COVID-19 pandemic, college students faced health disparities in addition to a negative burden on academic performance; however, little is reported in the literature regarding healthcare utilization. METHODS: A cross-sectional survey was conducted among consenting college student participants aged 18 or older from a Hispanic-serving institution. Descriptive and bivariate statistics were used to analyze demographic characteristics and the types of healthcare services needed by such characteristics. Logistic regression was used to adjust for noted sex differences in associations between reporting limited healthcare services and types of healthcare services. RESULTS: The study population of 223 participants was mostly Hispanic/Latino (65%) and female (73%). Of the population, 11% reported they could not obtain needed healthcare services, with time being reported as the most common reason. Significant associations were found between seeking general healthcare services/routine screening, seeking mental health services, and seeking sexual health services with reporting limited healthcare services, with sex-adjusted odds ratios and 95% confidence intervals of 1.90 (95% CI: 1.08, 3.36), 3.21 (95% CI: 1.44, 4.15), and 2.58 (95% CI: 1.05, 6.35), respectively. CONCLUSIONS: Availability and inability to obtain health services may exacerbate college student health disparities. Targeted interventions are needed in the population to mitigate the potential burdens of unmet healthcare needs, particularly among minority college students.

Spontaneous Volumetric Tumor Regression During Wait-and-Scan Management of 952 Sporadic Vestibular Schwannomas.

OBJECTIVE: Spontaneous tumor shrinkage during wait-and-scan management of sporadic vestibular schwannoma is generally considered an uncommon phenomenon. However, most data informing this understanding stem from single-slice linear tumor measurements taken in the axial imaging plane. The objective of the current work was to characterize the regression capacity of sporadic vestibular schwannomas using volumetric tumor measurements. STUDY DESIGN: Retrospective cohort study using slice-by-slice, three-dimensional volumetric tumor measurements. SETTING: Three tertiary referral centers. PATIENTS: Patients with sporadic vestibular schwannoma. INTERVENTIONS: Wait-and-scan. MAIN OUTCOME MEASURES: Regression-free survival rates with regression defined as a decrease of at least 20% of the tumor volume. RESULTS: Among 952 patients undergoing a total of 3,505 magnetic resonance imaging studies during observation, 123 experienced volumetric tumor regression after diagnosis at a median of 1.2 years (interquartile range, 0.6-2.9 yr). Volumetric regression-free survival rates (95% confidence interval; number still at risk) at 1, 3, and 5 years after diagnosis were 94% (92-95%; 662), 86% (83-89%; 275), and 78% (73-82%; 132), respectively. Among 405 patients who demonstrated an initial period of tumor growth but continued wait-and-scan management, 48 experienced volumetric regression at a median of 1.2 years (interquartile range, 0.8-2.6 yr) after initial growth. Volumetric regression-free survival rates at 1, 3, and 5 years after initial growth were 94% (92-97%; 260), 84% (79-89%; 99), and 75% (67-83%; 43), respectively. Ultimately, only 82 of the 952 patients studied showed exclusively volumetric tumor regression (i.e., without any periods of tumor growth) by the time of last follow-up. CONCLUSION: Spontaneous volumetric tumor shrinkage during wait-and-scan management occurs more frequently than suggested by previous studies using linear tumor measurements and can even occur after previous episodes of documented tumor growth. These data further highlight the dynamic nature of vestibular schwannoma growth. To this end, the application of natural history data to patient management requires a nuanced approach that parallels the complex tumor behavior of vestibular schwannoma.

Recent climate change has driven divergent hydrological shifts in high-latitude peatlands.

High-latitude peatlands are changing rapidly in response to climate change, including permafrost thaw. Here, we reconstruct hydrological conditions since the seventeenth century using testate amoeba data from 103 high-latitude peat archives. We show that 54% of the peatlands have been drying and 32% have been wetting over this period, illustrating the complex ecohydrological dynamics of high latitude peatlands and their highly uncertain responses to a warming climate.

Is intermittent antiretroviral therapy a satisfactory strategy for the management of patients living with HIV?

Many innovations, such as long-acting agents, new delivery modalities (injectable and nanoparticles), and novel paradigms (immunotherapy or dual therapy), have been introduced to facilitate the administration of antiretroviral treatment (ART) to patients infected with HIV and improve their adherence and quality of life without altering the drugs' effectiveness. Studies have investigated the use of intermittent treatment, especially weekends-off ART in HIV-suppressed patients. In this review, we analyzed data concerning intermittent ART to help determine if this strategy is reasonable for the management of patients living with HIV. The results of early studies, in 2007-2015, were encouraging, but the studies were flawed because of the small number of patients included, the absence of a control arm, and random designs with variable patterns of ART administration. From 2016, studies have included more patients, and some are prospective, randomized controlled studies. While non-nucleoside reverse transcriptase inhibitors have been most studied, treatment with integrase inhibitors also has been reported, with the findings that viral resistance did not appear when treatment failed with dolutegravir but not with raltegravir. The most recent study, QUATUOR, found that a 4-day on, 3-day off pattern was non-inferior to the continuous pattern (7 days on). Better-quality studies with long-term follow-up (96 weeks or more) are needed to determine the validity of intermittent treatment and the optimal regimens and monitoring to be used in the management of viro-logically suppressed patients living with HIV.

A case of antisynthetase syndrome with chilblains-like lesions and microangiopathy.

We present the case of a 50-year-old woman with febrile myalgia, chilblains-like lesions, and cough. Antinuclear antibodies and anti-PL-12 antisynthetase autoantibodies were found in complementary examinations. Interstitial lung disease was found on chest computed tomography. Nailfold capillaroscopy showed microangiopathic lesions. Antisynthetase syndrome is a recently described entity in inflammatory myopathies, with specific clinical criteria. Interstitial lung disease is very common, especially in anti-PL-12 associated antisynthetase syndrome. Raynaud's phenomenon is another well-defined criterion. However, microangiopathic damage is probably underestimated and the role of nailfold capillaroscopy in the diagnosis has not been established yet.

The testate amoebae of New Zealand: A checklist, identification key and assessment of biogeographic patterns.

New Zealand (NZ) is a well-known hotspot of biodiversity and endemism for macroscopic organisms, but its microbial diversity is comparatively poorly documented. We assembled all records on NZ testate amoebae published since the early 20th century and present a comprehensive taxonomic checklist for NZ. Testate amoebae are reported from six major habitat types across both the North and South Islands of NZ, but the sampling effort is ecologically and geographically biased in favour of wetlands and the South Island. As a result, 93% of all 128 morphotypes recorded in NZ occur in wetlands, 28% are restricted to the South Island, and diversity is greater at higher latitudes. Around 50% of morphotypes have a broad latitudinal distribution across the NZ mainland, whereas 15% have narrow latitudinal ranges. Future research should aim to broaden the geographical and ecological ranges. We predict that our list of NZ testate amoebae will expand substantially with future work, and that the latitudinal diversity gradient will be inverted. We also introduce an interactive, fully illustrated, online Lucid key for the rapid identification of NZ testate amoebae. As many morphospecies are cosmopolitan, this key provides a useful tool for testate amoebae identification in other parts of the world.

COVID-19 Outbreak in a Hemodialysis Center: A Retrospective Monocentric Case Series.

BACKGROUND: The rapid worldwide spread of COVID-19 has posed a serious threat to patients treated with kidney replacement therapy (KRT). Moreover, the impact of the disease on hemodialysis centers, the patients, and the health care workers is still not completely understood. OBJECTIVE: We present the analysis of a COVID-19 outbreak in a hemodialysis center in Belgium and report the incidence, clinical course, and outcome of the disease. DESIGN: A retrospective cross-sectional cohort study. SETTING: A hemodialysis center during the COVID-19 outbreak. PATIENTS: A total of 62 patients on maintenance hemodialysis at a tertiary care center in Belgium attended by 26 health care workers. MEASUREMENTS: Baseline patients' characteristics were retrieved. The incidence, clinical course, and outcome were reported. The differences between COVID-19 survivors and nonsurvivors were assessed along with the differences between COVID-19-hospitalized and nonhospitalized patients. The incidence of the disease and outcome of health care workers were also reported. METHODS: Proportions for categorical variables were compared using the Fisher exact test and χ2. The Mann-Whitney rank sum test was used to compare continuous variables. Univariate analysis and a binomial logistic regression were used to explore variables as predictors of death. RESULTS: Between March 6 and April 14, 2020, 40 of 62 (65%) patients tested positive for severe acute respiratory syndrome beta coronavirus 2 (SARS-CoV-2) along with 18 of 26 (69%) health care professionals. Twenty-five (63%) of the infected patients were hospitalized with a median time for hospitalization-to-discharge of 8 (interquartile range [IQR] = 4-12) days. Eleven (28%) COVID-19-related deaths were recorded with a median time for onset of symptoms-to-death of 9 (IQR = 5-14) days. Lymphocytopenia was prevalent among the cohort and was found in 9 of 11 (82%) reported deaths (P = .4). There was no influence of the use of angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers on COVID-19-related deaths (P = .3). Advanced age, cardiovascular disease (CVD), and obstructive sleep apnea syndrome were all found to be significantly related to death. Of the 18 infected health care professionals, 13 (72%) were symptomatic and 2 (11%) were hospitalized. There was no reported death among the health care workers. LIMITATIONS: Limited follow-up time compared with the course of the disease along with a small sample size. CONCLUSIONS: Patients treated with KRT show a high mortality rate secondary to COVID-19. CVD and age are shown to impact survival. Proactive measures must be taken to prevent the spread of the virus in such facilities. TRIAL REGISTRATION: Not applicable as this is a retrospective study.

Quantifying the effect of testate amoeba decomposition on peat-based water-table reconstructions.

Testate amoebae are a widely-used tool for palaeohydrological reconstruction from peatlands. However, it has been observed that weak idiosomic siliceous tests (WISTs) are common in uppermost peats, but very rarely found as subfossils deeper in the peat profile. This taphonomic problem has been noted widely and it has been established that WISTs disaggregate and/or dissolve in the low pH condition of ombrotrophic peatlands. Here we investigate the effect of this taphonomic problem on water-table reconstructions from thirty European peatlands through the comparison of reconstructions based on all taxa and those with WISTs removed. In almost all cases the decomposition of WISTs does not introduce discernible bias to peatland water-table reconstructions. However, some discrepancy is apparent when large abundances of Corythion-Trinema type are present (9-12 cm deviation with 50-60% abundance of this particular taxon). We recommend that WISTs should be removed before carrying out water-table reconstructions, and that the minimum count of testate amoebae per sample should exclude WISTs to ensure the development of robust reconstructions.

Efficient Singlet Oxygen Photogeneration by Zinc Porphyrin Dimers upon One- and Two-Photon Excitation.

The development of photodynamic therapy (PDT) at depth requires photosensitizers which have both sufficient quantum yield for singlet oxygen generation and strong two-photon absorption. Here, we show that this can be achieved by conjugated linkage of zinc porphyrins to make dimers. We determined the quantum yield of generation of 1O2 , ϕΔ, by measuring emission at 1270 nm using a near-infrared streak camera and found it to increase from 15% for a single porphyrin unit to 27-47% for the dimers with a conjugated linker. Then, we recorded the spectra of two-photon absorption cross section, σ2, by a focus-tunable Z-scan method, which allows for nondestructive investigation of light-sensitive materials. We observed a strong enhancement of the two-photon absorption coefficient in the dimers, especially those with an alkyne linker. These results lead to an excellent figure of merit for two-photon production of singlet oxygen (expressed by the product σ2 × Ï•Δ) in the porphyrin dimers, of around 3700 GM, which is very promising for applications involving treatment of deep tumors by PDT.

Speech perception benefits of sequential bilateral cochlear implantation in children and adults: a retrospective analysis.

OBJECTIVE: To examine speech perception outcomes and determine the impact of length of deafness and time between implants on performance in the sequentially bilateral implanted population. STUDY DESIGN: Retrospective review. SETTING: Tertiary academic referral center. PATIENTS: Forty-three children (age, <18 yr) and 22 adults underwent sequential bilateral implantation with at least 6 months between surgeries. The mean age at the time of the second implant in children was 7.83 years, and mean time between implants was 5.16 years. Five children received the first side implant (C1) below 12 months of age; 16, at 12 to 23 months; 9, between the ages of 24 and 35 months; and 11, at 36 to 59 months; 2 were implanted above the age of 5 years. In adults, mean age at second implant was 46.6 years, and mean time between implants was 5.6 years. INTERVENTION: Sequential implantation with 6 months or more between implantations. MAIN OUTCOME MEASURES: Speech perception tests were performed preoperatively before the second implantation and at 3 months postoperatively. RESULTS: Results revealed significant improvement in the second implanted ear and in the bilateral condition, despite time between implantations or length of deafness; however, age of first-side implantation was a contributing factor to second ear outcome in the pediatric population. CONCLUSION: Sequential bilateral implantation leads to significantly better speech understanding. On average, patients improved, despite length of deafness, time between implants, or age at implantation.