Evaluation of an Integrated Smart Sensor System for Real-Time Characterization and Digitalization of Postoperative Abdominal Drain Output: A Pilot Study.

Background: For centuries, surgeons have relied on surgical drains during postoperative care. Despite all advances in modern medicine and the area of digitalization, as of today, most if not all assessment of abdominal secretions excreted via surgical drains are carried out manually. We here introduce a novel integrated Smart Sensor System (Smart Drain) that allows for real-time characterization and digitalization of postoperative abdominal drain output at the patient's bedside. Methods: A prototype of the Smart Drain was developed using a sophisticated spectrometer for assessment of drain output. The prototype measures 10 × 6 × 6 cm and therefore easily fits at the bedside. At the time of measurement with our Smart Drain, the drain output was additionally sent off to be analyzed in our routine laboratory for typical markers of interest in abdominal surgery such as bilirubin, lipase, amylase, triglycerides, urea, protein, and red blood cells. A total of 45 samples from 19 patients were included. Results: The measurements generated were found to correlate with conventional laboratory measurements for bilirubin (r = .658, P = .000), lipase (r = .490, P = .002), amylase (r = .571, P = .000), triglycerides (r = .803, P = .000), urea (r = .326, P = .033), protein (r = .387, P = .012), and red blood cells (r = .904, P = .000). Conclusions: To our best knowledge, for the first time we describe a device using a sophisticated spectrometer that allows for real-time characterization and digitalization of postoperative abdominal drain output at the patient's bedside.

Balance of carbon species combined with stable isotope ratios show critical switch towards bicarbonate uptake during cyanobacteria blooms.

Next to water quality deterioration, cyanobacteria blooms can affect turnover of aqueous carbon, including dissolved inorganic carbon (DIC), dissolved organic carbon (DOC), and particulate organic carbon (POC). We investigated interactions of these three phases and their stable isotopes in a freshwater pond with periodic cyanobacterial blooms over a period of 23 months. This helped to map turnover and sources of aqueous carbon before, during, and after bloom events. During bloom events POC isotope values (δ13CPOC) increased up to -17.4‰, after aqueous CO2 (CO2(aq)) fell below an atmospheric equilibration value of 412 µatm. Additionally, carbon isotope enrichment between CO2(aq) and POC (εCO2-phyto) ranged from 2.0 to 21.5‰ with lowest fractionations observed at pH values above 8.9. The increase of δ13CPOC and decrease of εCO2-phyto values at low pCO2 and high pH was most likely caused by the activation of the carbon concentrating mechanism (CCM). This mechanism correlated with prevalent assimilation of 13C-enriched HCO3-. Surprisingly, CO2(aq) still contributed more than 50% to the POC pool down to pCO2 values of around 150 µatm. Only after this threshold the reduced εCO2-phyto suggested incorporation of 13C-enriched HCO3-.

Geological CO2 quantified by high-temporal resolution stable isotope monitoring in a salt mine.

The relevance of CO2 emissions from geological sources to the atmospheric carbon budget is becoming increasingly recognized. Although geogenic gas migration along faults and in volcanic zones is generally well studied, short-term dynamics of diffusive geogenic CO2 emissions are mostly unknown. While geogenic CO2 is considered a challenging threat for underground mining operations, mines provide an extraordinary opportunity to observe geogenic degassing and dynamics close to its source. Stable carbon isotope monitoring of CO2 allows partitioning geogenic from anthropogenic contributions. High temporal-resolution enables the recognition of temporal and interdependent dynamics, easily missed by discrete sampling. Here, data is presented from an active underground salt mine in central Germany, collected on-site utilizing a field-deployed laser isotope spectrometer. Throughout the 34-day measurement period, total CO2 concentrations varied between 805 ppmV (5th percentile) and 1370 ppmV (95th percentile). With a 400-ppm atmospheric background concentration, an isotope mixing model allows the separation of geogenic (16-27%) from highly dynamic anthropogenic combustion-related contributions (21-54%). The geogenic fraction is inversely correlated to established CO2 concentrations that were driven by anthropogenic CO2 emissions within the mine. The described approach is applicable to other environments, including different types of underground mines, natural caves, and soils.

Influences of seawater intrusion and anthropogenic activities on shallow coastal aquifers in Sri Lanka: evidence from hydrogeochemical and stable isotope data.

Water supplies in coastal aquifers throughout the world are often threatened by salinization due to seawater intrusion and anthropogenic activities. In the Kalpitiya Peninsula in Sri Lanka, agricultural and domestic water supplies entirely depend on groundwater resources extracted from unconfined Holocene sandy aquifers. To differentiate the effects of seawater intrusion and agriculture on the coastal aquifers of this 160 km2 peninsula, 43 groundwater samples were collected. These samples were analyzed for major ions, trace elements, and stable isotopes of water (δ18O and δ2H). The solute compositions were dominated by Cl-, [Formula: see text], and [Formula: see text], which were mostly balanced by Ca2+, Na+, and Mg2+. Among the four main water types, Na+-Cl- and Ca2+-[Formula: see text] classifications were predominant in the investigated aquifers. Modifications of the groundwater due to evaporation during irrigation activities, but also due to seawater intrusion seem most plausible as indicated by the correlation of δ18O with δ2H (δ2H = 5.51 * Î´18O-3.08, r = 0.93) deviating from the local meteoric water line. Particularly in the southern part of the peninsula, Mg2+/Ca2+ ratios and stable isotopes of water attributed salinization of groundwater to agricultural activities. However, especially in the north, seawater intrusions were also evident. Established mass balance calculations revealed that local groundwater had seawater admixtures of up to 12%. Our results indicate that integrated water management is essential and water resources should critically monitor in the Kalpitiya Peninsula in order to avoid over-exploitation and further seawater inflows.

Decoupling of microbial carbon, nitrogen, and phosphorus cycling in response to extreme temperature events.

Predicted changes in the intensity and frequency of climate extremes urge a better mechanistic understanding of the stress response of microbially mediated carbon (C) and nutrient cycling processes. We analyzed the resistance and resilience of microbial C, nitrogen (N), and phosphorus (P) cycling processes and microbial community composition in decomposing plant litter to transient, but severe, temperature disturbances, namely, freeze-thaw and heat. Disturbances led temporarily to a more rapid cycling of C and N but caused a down-regulation of P cycling. In contrast to the fast recovery of the initially stimulated C and N processes, we found a slow recovery of P mineralization rates, which was not accompanied by significant changes in community composition. The functional and structural responses to the two distinct temperature disturbances were markedly similar, suggesting that direct negative physical effects and costs associated with the stress response were comparable. Moreover, the stress response of extracellular enzyme activities, but not that of intracellular microbial processes (for example, respiration or N mineralization), was dependent on the nutrient content of the resource through its effect on microbial physiology and community composition. Our laboratory study provides novel insights into the mechanisms of microbial functional stress responses that can serve as a basis for field studies and, in particular, illustrates the need for a closer integration of microbial C-N-P interactions into climate extremes research.

5-Hydroxymethylcytosine is a nuclear biomarker to assess biological potential in histologically ambiguous heavily pigmented melanocytic neoplasms.

BACKGROUND: 5-Hydroxymethylcytosine (5-hmC) is an epigenetic marker detectable through immunohistochemistry (IHC) that has been shown to distinguish benign nevi from melanoma with high sensitivity and specificity. The purpose of the study was to explore its diagnostic utility in a subset of histologically challenging, heavily pigmented cutaneous melanocytic neoplasms. METHODS: 5-hmC IHC was performed on 54 heavily pigmented melanocytic tumors. Semi-quantitative analysis of immunoreactivity was correlated with clinical, pathologic and follow-up data. RESULTS: Benign melanocytic neoplasms (4 of 4 blue nevi with epithelioid change; 12 of 12 combined nevi; 5 of 5 deep penetrating nevi, DPN) exhibited strong 5-hmC nuclear reactivity. Eight heavily pigmented blue nevus-like melanomas and 7 of 8 pigmented epithelioid melanocytomas (PEM) showed significant 5-hmC loss. Five of 7 atypical DPN cases and 8 of 10 melanocytic tumors of uncertain malignant potential (MELTUMP) showed low to intermediate 5-hmC immunoreactivity. These differences were statistically significant (P-value <.0001). CONCLUSIONS: Loss of 5-hmC may be helpful in differentiating benign, diagnostically challenging, heavily pigmented melanocytic tumors from those with malignant potential. The intermediate to low 5-hmC immunoreactivity in atypical DPNs, PEMs and so-called MELTUMP categories further underscores the need to consider these neoplasms as having some potential for lethal biological behavior.

Connectivity between surface and deep waters determines prokaryotic diversity in the North Atlantic Deep Water.

To decipher the influence of depth stratification and surface provincialism on the dark ocean prokaryotic community composition, we sampled the major deep-water masses in the eastern North Atlantic covering three biogeographic provinces. Their diversity was evaluated using ordination and canonical analysis of 454 pyrotag sequences. Variance partitioning suggested that 16% of the variation in the bacterial community composition was based on depth stratification while 9% of the variation was due to geographic location. General linear mixed effect models showed that the community of the subsurface waters was connected to the dark ocean prokaryotic communities in different biogeographic provinces. Cluster analysis indicated that some prokaryotic taxa are specific to distinct regions in bathypelagic water masses. Taken together, our data suggest that the dark ocean prokaryotic community composition of the eastern North Atlantic is primed by the formation and the horizontal transport of water masses.

Stoichiometric controls of nitrogen and phosphorus cycling in decomposing beech leaf litter.

Resource stoichiometry (C:N:P) is an important determinant of litter decomposition. However, the effect of elemental stoichiometry on the gross rates of microbial N and P cycling processes during litter decomposition is unknown. In a mesocosm experiment, beech (Fagus sylvatica L.) litter with natural differences in elemental stoichiometry (C:N:P) was incubated under constant environmental conditions. After three and six months, we measured various aspects of nitrogen and phosphorus cycling. We found that gross protein depolymerization, N mineralization (ammonification), and nitrification rates were negatively related to litter C:N. Rates of P mineralization were negatively correlated with litter C:P. The negative correlations with litter C:N were stronger for inorganic N cycling processes than for gross protein depolymerization, indicating that the effect of resource stoichiometry on intracellular processes was stronger than on processes catalyzed by extracellular enzymes. Consistent with this, extracellular protein depolymerization was mainly limited by substrate availability and less so by the amount of protease. Strong positive correlations between the interconnected N and P pools and the respective production and consumption processes pointed to feed-forward control of microbial litter N and P cycling. A negative relationship between litter C:N and phosphatase activity (and between litter C:P and protease activity) demonstrated that microbes tended to allocate carbon and nutrients in ample supply into the production of extracellular enzymes to mine for the nutrient that is more limiting. Overall, the study demonstrated a strong effect of litter stoichiometry (C:N:P) on gross processes of microbial N and P cycling in decomposing litter; mineralization of N and P were tightly coupled to assist in maintaining cellular homeostasis of litter microbial communities.

A suite of sensitive chemical methods to determine the δ15N of ammonium, nitrate and total dissolved N in soil extracts.

Natural (15) N abundances (δ(15) N values) of different soil nitrogen pools deliver crucial information on the soil N cycle for the analysis of biogeochemical processes. Here we report on a complete suite of methods for sensitive δ(15) N analysis in soil extracts. A combined chemical reaction of vanadium(III) chloride (VCl(3) ) and sodium azide under acidic conditions is used to convert nitrate into N(2) O, which is subsequently analyzed by purge-and-trap isotope ratio mass spectrometry (PTIRMS) with a cryo-focusing unit. Coupled with preparation steps (microdiffusion for collection of ammonium, alkaline persulfate oxidation to convert total dissolved N (TDN) or ammonium into nitrate) this allows the determination of the δ(15) N values of nitrate, ammonium and total dissolved N (dissolved organic N, microbial biomass N) in soil extracts with the same basic protocol. The limits of quantification for δ(15) N analysis with a precision of 0.5‰ were 12.4 µM for ammonium, 23.7 µM for TDN, 16.5 µM for nitrate and 22.7 µM for nitrite.