Hadal trenches are dynamic hotspots for early diagenesis in the deep sea

AbstractThe deepest part of the global ocean, hadal trenches, are considered to act as depocenters for organic material. Relatively high microbial activity has been demonstrated in the deepest sections of some hadal trenches, but the deposition dynamics are thought to be spatially and temporally variable. Here, we explore sediment characteristics and in-situ benthic oxygen uptake along two trenches with contrasting surface primary productivity: the Kermadec and Atacama trenches. We find that benthic oxygen consumption varies by a factor of about 10 between hadal sites but is in all cases intensified relative to adjacent abyssal plains. The benthic oxygen uptake of the two trench regions reflects the difference in surface production, whereas variations within each trench are modulated by local deposition dynamics. Respiratory activity correlates with the sedimentary inventories of organic carbon and phytodetrital material. We argue that hadal trenches represent deep sea hotspots for early diagenesis and are more diverse and dynamic environments than previously recognized.

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Development of a deep-sea mercury sensor using in situ anodic stripping voltammetry

GEOCHEMICAL JOURNAL ◽

10.2343/geochemj.2.0368 ◽

2015 ◽

Vol 49 (6) ◽

pp. 613-620 ◽

Cited By ~ 4

Author(s):

Masahiro Yamamoto ◽

Hitoshi Kodamatani ◽

Yuriko Kono ◽

Akinori Takeuchi ◽

Ken Takai ◽

...

Keyword(s):

Deep Sea ◽

Anodic Stripping Voltammetry ◽

Stripping Voltammetry ◽

Anodic Stripping ◽

Mercury Sensor

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Faculty Opinions recommendation of Effects of nitric oxide synthase inhibition by L-NAME on oxygen uptake kinetics in isolated canine muscle in situ.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1087541.540599 ◽

2007 ◽

Author(s):

Michael Reid

Keyword(s):

Nitric Oxide ◽

Nitric Oxide Synthase ◽

Oxygen Uptake ◽

Oxygen Uptake Kinetics ◽

Uptake Kinetics ◽

Oxide Synthase

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Comparison of Mammography and Ultrasonography for Tumor Size of DCIS of Breast Cancer

Current Medical Imaging Formerly Current Medical Imaging Reviews ◽

10.2174/1573405614666180131163321 ◽

2019 ◽

Vol 15 (2) ◽

pp. 209-213

Author(s):

Yu Wang ◽

Jiantao Wang ◽

Haiping Wang ◽

Xinyu Yang ◽

Liming Chang ◽

...

Keyword(s):

Breast Cancer ◽

Correlation Coefficient ◽

Tumor Size ◽

Ductal Carcinoma ◽

Pearson Correlation ◽

Dense Breast ◽

Pathological Examination ◽

Negative Group ◽

The Difference

Objective: Accurate assessment of breast tumor size preoperatively is important for the initial decision-making in surgical approach. Therefore, we aimed to compare efficacy of mammography and ultrasonography in ductal carcinoma in situ (DCIS) of breast cancer. Methods: Preoperative mammography and ultrasonography were performed on 104 women with DCIS of breast cancer. We compared the accuracy of each of the imaging modalities with pathological size by Pearson correlation. For each modality, it was considered concordant if the difference between imaging assessment and pathological measurement is less than 0.5cm. Results: At pathological examination tumor size ranged from 0.4cm to 7.2cm in largest diameter. For mammographically determined size versus pathological size, correlation coefficient of r was 0.786 and for ultrasonography it was 0.651. Grouped by breast composition, in almost entirely fatty and scattered areas of fibroglandular dense breast, correlation coefficient of r was 0.790 for mammography and 0.678 for ultrasonography; in heterogeneously dense and extremely dense breast, correlation coefficient of r was 0.770 for mammography and 0.548 for ultrasonography. In microcalcification positive group, coeffient of r was 0.772 for mammography and 0.570 for ultrasonography. In microcalcification negative group, coeffient of r was 0.806 for mammography and 0.783 for ultrasonography. Conclusion: Mammography was more accurate than ultrasonography in measuring the largest cancer diameter in DCIS of breast cancer. The correlation coefficient improved in the group of almost entirely fatty/ scattered areas of fibroglandular dense breast or in microcalcification negative group.

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Air-Sea Interactions over Eddies in the Brazil-Malvinas Confluence

Remote Sensing ◽

10.3390/rs13071335 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1335

Author(s):

Ronald Souza ◽

Luciano Pezzi ◽

Sebastiaan Swart ◽

Fabrício Oliveira ◽

Marcelo Santini

Keyword(s):

Latent Heat ◽

Large Scale ◽

Surface Wind ◽

Heat Fluxes ◽

Lower Atmosphere ◽

Meteorological Variables ◽

Global Ocean ◽

Study Region ◽

Cold Core

The Brazil–Malvinas Confluence (BMC) is one of the most dynamical regions of the global ocean. Its variability is dominated by the mesoscale, mainly expressed by the presence of meanders and eddies, which are understood to be local regulators of air-sea interaction processes. The objective of this work is to study the local modulation of air-sea interaction variables by the presence of either a warm (ED1) and a cold core (ED2) eddy, present in the BMC, during September to November 2013. The translation and lifespans of both eddies were determined using satellite-derived sea level anomaly (SLA) data. Time series of satellite-derived surface wind data, as well as these and other meteorological variables, retrieved from ERA5 reanalysis at the eddies’ successive positions in time, allowed us to investigate the temporal modulation of the lower atmosphere by the eddies’ presence along their translation and lifespan. The reanalysis data indicate a mean increase of 78% in sensible and 55% in latent heat fluxes along the warm eddy trajectory in comparison to the surrounding ocean of the study region. Over the cold core eddy, on the other hand, we noticed a mean reduction of 49% and 25% in sensible and latent heat fluxes, respectively, compared to the adjacent ocean. Additionally, a field campaign observed both eddies and the lower atmosphere from ship-borne observations before, during and after crossing both eddies in the study region during October 2013. The presence of the eddies was imprinted on several surface meteorological variables depending on the sea surface temperature (SST) in the eddy cores. In situ oceanographic and meteorological data, together with high frequency micrometeorological data, were also used here to demonstrate that the local, rather than the large scale forcing of the eddies on the atmosphere above, is, as expected, the principal driver of air-sea interaction when transient atmospheric systems are stable (not actively varying) in the study region. We also make use of the in situ data to show the differences (biases) between bulk heat flux estimates (used on atmospheric reanalysis products) and eddy covariance measurements (taken as “sea truth”) of both sensible and latent heat fluxes. The findings demonstrate the importance of short-term changes (minutes to hours) in both the atmosphere and the ocean in contributing to these biases. We conclude by emphasizing the importance of the mesoscale oceanographic structures in the BMC on impacting local air-sea heat fluxes and the marine atmospheric boundary layer stability, especially under large scale, high-pressure atmospheric conditions.

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Comparison of In-Situ and Retrospective Self-Reports on Assessing Hearing Aid Outcomes

Journal of the American Academy of Audiology ◽

10.1055/s-0040-1719133 ◽

2020 ◽

Author(s):

Yu-Hsiang Wu ◽

Elizabeth Stangl ◽

Octav Chipara ◽

Anna Gudjonsdottir ◽

Jacob Oleson ◽

...

Keyword(s):

Hearing Aids ◽

Hearing Aid ◽

Outcome Data ◽

Self Report ◽

Data Collection And Analysis ◽

Self Reports ◽

Outcome Difference ◽

The Difference ◽

Ecological Momentary

Abstract Background Ecological momentary assessment (EMA) is a methodology involving repeated surveys to collect in-situ self-reports that describe respondents' current or recent experiences. Audiology literature comparing in-situ and retrospective self-reports is scarce. Purpose To compare the sensitivity of in-situ and retrospective self-reports in detecting the outcome difference between hearing aid technologies, and to determine the association between in-situ and retrospective self-reports. Research Design An observational study. Study Sample Thirty-nine older adults with hearing loss. Data Collection and Analysis The study was part of a larger clinical trial that compared the outcomes of a prototype hearing aid (denoted as HA1) and a commercially available device (HA2). In each trial condition, participants wore hearing aids for 4 weeks. Outcomes were measured using EMA and retrospective questionnaires. To ensure that the outcome data could be directly compared, the Glasgow Hearing Aid Benefit Profile was administered as an in-situ self-report (denoted as EMA-GHABP) and as a retrospective questionnaire (retro-GHABP). Linear mixed models were used to determine if the EMA- and retro-GHABP could detect the outcome difference between HA1 and HA2. Correlation analyses were used to examine the association between EMA- and retro-GHABP. Results For the EMA-GHABP, HA2 had significantly higher (better) scores than HA1 in the GHABP subscales of benefit, residual disability, and satisfaction (p = 0.029–0.0015). In contrast, the difference in the retro-GHABP score between HA1 and HA2 was significant only in the satisfaction subscale (p = 0.0004). The correlations between the EMA- and retro-GHABP were significant in all subscales (p = 0.0004 to <0.0001). The strength of the association ranged from weak to moderate (r = 0.28–0.58). Finally, the exit interview indicated that 29 participants (74.4%) preferred HA2 over HA1. Conclusion The study suggests that in-situ self-reports collected using EMA could have a higher sensitivity than retrospective questionnaires. Therefore, EMA is worth considering in clinical trials that aim to compare the outcomes of different hearing aid technologies. The weak to moderate association between in-situ and retrospective self-reports suggests that these two types of measures assess different aspects of hearing aid outcomes.

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Tuning Single-Molecule Conductance by Controlled Electric Field-Induced trans-to-cis Isomerisation

Applied Sciences ◽

10.3390/app11083317 ◽

2021 ◽

Vol 11 (8) ◽

pp. 3317

Author(s):

C.S. Quintans ◽

Denis Andrienko ◽

Katrin F. Domke ◽

Daniel Aravena ◽

Sangho Koo ◽

...

Keyword(s):

Electric Field ◽

Electric Fields ◽

Single Molecule ◽

Quantum Interference ◽

Single Molecule Level ◽

Wet Chemical Synthesis ◽

Single Molecule Junctions ◽

Tunnelling Microscopy ◽

The Difference

External electric fields (EEFs) have proven to be very efficient in catalysing chemical reactions, even those inaccessible via wet-chemical synthesis. At the single-molecule level, oriented EEFs have been successfully used to promote in situ single-molecule reactions in the absence of chemical catalysts. Here, we elucidate the effect of an EEFs on the structure and conductance of a molecular junction. Employing scanning tunnelling microscopy break junction (STM-BJ) experiments, we form and electrically characterize single-molecule junctions of two tetramethyl carotene isomers. Two discrete conductance signatures show up more prominently at low and high applied voltages which are univocally ascribed to the trans and cis isomers of the carotenoid, respectively. The difference in conductance between both cis-/trans- isomers is in concordance with previous predictions considering π-quantum interference due to the presence of a single gauche defect in the trans isomer. Electronic structure calculations suggest that the electric field polarizes the molecule and mixes the excited states. The mixed states have a (spectroscopically) allowed transition and, therefore, can both promote the cis-isomerization of the molecule and participate in electron transport. Our work opens new routes for the in situ control of isomerisation reactions in single-molecule contacts.

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Development of an Easy-to-Operate Underwater Raman System for Deep-Sea Cold Seep and Hydrothermal Vent In Situ Detection

Sensors ◽

10.3390/s21155090 ◽

2021 ◽

Vol 21 (15) ◽

pp. 5090

Author(s):

Qingsheng Liu ◽

Jinjia Guo ◽

Wangquan Ye ◽

Kai Cheng ◽

Fujun Qi ◽

...

Keyword(s):

Deep Sea ◽

Hydrothermal Vent ◽

Methane Hydrate ◽

Sulfur Cycle ◽

Cold Seep ◽

Remotely Operated Vehicle ◽

Bacterial Mats ◽

Optical Module ◽

In Situ Detection

As a powerful in situ detection technique, Raman spectroscopy is becoming a popular underwater investigation method, especially in deep-sea research. In this paper, an easy-to-operate underwater Raman system with a compact design and competitive sensitivity is introduced. All the components, including the optical module and the electronic module, were packaged in an L362 × Φ172 mm titanium capsule with a weight of 20 kg in the air (about 12 kg in water). By optimising the laser coupling mode and focusing lens parameters, a competitive sensitivity was achieved with the detection limit of SO42− being 0.7 mmol/L. The first sea trial was carried out with the aid of a 3000 m grade remotely operated vehicle (ROV) “FCV3000” in October 2018. Over 20,000 spectra were captured from the targets interested, including methane hydrate, clamshell in the area of cold seep, and bacterial mats around a hydrothermal vent, with a maximum depth of 1038 m. A Raman peak at 2592 cm−1 was found in the methane hydrate spectra, which revealed the presence of hydrogen sulfide in the seeping gas. In addition, we also found sulfur in the bacterial mats, confirming the involvement of micro-organisms in the sulfur cycle in the hydrothermal field. It is expected that the system can be developed as a universal deep-sea survey and detection equipment in the near future.

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