Short Turnover Time Research Articles

Separate rooms for patient induction, case set-up and breakdown: Innovative operating room turnover through quality management

Turnover time (TT) is the time it takes to prepare an operating room (OR) between consecutive surgeries. Short TT improves OR efficiency, while maintaining patient and staff safety and satisfaction. Yet the multitude of staff involved and steps required creates process complexity that can hinder this goal. Leveraging a unique case study setting, this study deploys a collection of quality management tools to investigate how the use of separate support rooms for patient induction (the administration of anesthesia), case set-up, and case breakdown can reduce OR TT while maintaining safety and satisfaction. Key results show that separate rooms for patient induction and case breakdown can enable parallel processing, improve patient and staff safety, and patient experience. We use post implementation observations to measure TT reduction when using an induction room, which allows time for an extra case per day. We develop decision-support models practitioners can use to identify the potential benefits of separate support rooms during the OR turnover, based on operating conditions and surgical characteristics. We provide considerations from buffer theory and coordination theory for the separation of physical space, proposing a novel view of the OR turnover process as a set of service modules and interfaces.

Vitamin B12 Deficiency and Hemolytic Anemia Presenting As Pseudo Thrombotic Microangiopathy: A Systematic Review

Introduction: Vitamin B12 deficiency is a common nutritional issue associated with mild anemia and neurological deficits. While rare, hemolytic anemia and low platelet count can be complications of this deficiency, often misdiagnosed as thrombotic microangiopathy (TMA), specifically thrombotic thrombocytopenic purpura (TTP). Pseudo TMA features can occur with B12 deficiency and can be effectively treated with vitamin B12 supplementation. In contrast, true TMA requires plasmapheresis. This systematic review aims to differentiate between pseudo TMA and TMA cases through an analysis of published case reports, providing valuable insights to avoid unnecessary treatments. Methods: We performed systematic review from Pubmed, Web of Science, and Scopus database. Twin independent reviewers (SY and BL) performed the screening using Covidence. Search keywords included “((hemolytic anemia) AND (vitamin B12 deficiency)) OR ((cobalamin deficiency) AND (hemolytic anemia)) Filters: English” for Pubmed, “(((ALL=(Cobalamin deficiency)) OR ALL=(vitamin B12 Deficiency))) AND ALL=(hemolytic anemia) Filter: English” for Web of Science and “( vitamin AND b12 AND deficiency OR cobalamin AND deficiency ) AND hemolytic AND anemia AND ( LIMIT-TO ( LANGUAGE , ”English“ ))” from Scopus. Only case reports in English with full-text availability and adult subjects were selected. Cases without final clinical outcome after treatment were excluded. After a comprehensive review, we identified 43 case reports and series with a total 53 patients that fulfilled our criteria. The details of selection process is illustrated in the prisma diagram (Figure 1). Results: The majority of cases involved males with low hemoglobin and platelet counts upon admission. Evidence of hemolysis was observed, indicated by increased lactate dehydrogenase (LDH), undetectable haptoglobin, and elevated or normal total and direct bilirubin levels. Peripheral blood films confirmed the presence of hemolytic anemia. Due to the co-occurrence of thrombocytopenia and hemolytic anemia, some cases were initially diagnosed as TTP, leading to the initiation of plasmapheresis. In 16 out of 53 reported case reports/series, patient received plasmapheresis. However, low reticulocyte index and normal ADAMTS 13 suggested an alternative diagnosis. Once ADAMTS 13 levels were normal, plasmapheresis was discontinued as TTP was ruled out. Diagnosis of B12 deficiency was confirmed by low B12 levels and elevated methylmalonic acid (MMA) levels. Leading cause for B12 deficiency were pernicious anemia in 28/53 cases, followed by dietary deficiency, and malabsorption due to surgery. Some patients also exhibiting concurrent iron deficiency anemia and folate deficiency. Treatment with subcutaneous B12 injections showed improvement in hemolysis as early as one week. Conclusion: Many cases of Vitamin B12 deficiency presenting with hemolytic anemia and thrombocytopenia are mistakenly diagnosed as TTP, leading to unnecessary and expensive plasmapheresis. Routine B12 level checks should be performed in all patients with hemolytic anemia, as B12 deficiency can be rapidly diagnosed and effectively treated, avoiding misdiagnoses and unnecessary interventions associated with TTP. The short turnover time for B12 levels (hours) compared to ADAMTS 13 activity (1-2 days) further supports the importance of routine B12 assessment in these patients.

Diversifying with grain legumes amplifies carbon in management-sensitive soil organic carbon pools on smallholder farms

Crop diversification with grain legumes has been advocated as a means to increase agroecological resilience, diversify livelihoods, boost household nutrition, and enhance soil health and fertility in cereal-based cropping systems in sub-Saharan Africa and around the world. Soil organic carbon (SOC) is a primary indicator of soil health and there is limited data regarding SOC pools and grain legume diversification on smallholder farms where soils are often marginal. In Malawi, a range of legume diversification options are under investigation, including rotations and a doubled-up legume rotation (DLR) system in which two compatible legumes are intercropped and then rotated with a cereal. The impact of the DLR system on SOC has not yet been determined, and there is a lack of evidence regarding SOC status over a gradient of simple to complex grain legume diversified systems. We address this knowledge gap by evaluating these systems in comparison to continuous sole maize (Zea mays L.) at three on-farm trial sites in central Malawi. After six years of trial establishment, we measured SOC in bulk soils and aggregate fractions and in faster cycling SOC pools that respond more rapidly to management practices, including water extractable organic carbon (WEOC), particulate organic matter carbon (POM-C), potentially mineralizable carbon (C), and macroaggregate C. Cropping treatment differences were not seen in bulk SOC or total N, but they were apparent in SOC pools with a shorter turnover time. The DLR system of intercropped pigeonpea (Cajanus cajan (L.) Millsp.) and groundnut (Arachis hypogaea L.) rotated with maize had higher WEOC, POM-C, potentially mineralizable C, macroaggregate and microaggregate C values than continuous maize. Of the single legume rotations, the pigeonpea-maize rotation had more mineralizable C and microaggregate C compared to continuous maize, while the groundnut-maize rotation had similar C values to the maize system. Overall, this study shows the potential for crop rotations diversified with grain legumes to enhance C in management sensitive SOC pools, and it is one of the first reports to show this effect on smallholder farm sites.

Abstract 5323: Accelerating the drug discovery process with an automated high-throughput protein production and characterization platform for AI-driven antibody development of immunotherapy

Abstract The demonstrated effectiveness and vast potential of large molecule therapeutics have driven biopharmaceutical companies to change the ways by which they discover and develop novel biologic therapies. While the conventional antibody discovery process via animal immunization and in vivo hypermutation can generate sufficient hits for functional screening, this approach can only cover a limited subset of sequence diversity. In silico, artificial intelligence (AI) driven methods, by contrast, have the potential to cover 2-3 orders of magnitude more sequence diversity compared to conventional methods and more rapidly produce a drug candidate with a superior safety and efficacy profile. However, this approach requires wet lab validation of predicted sequences as well as targeted data generation to improve AI-predicted rankings. Traditional wet lab methods for protein generation and characterization are expensive, time consuming, and prone to human error. These limitations restrict the overall potential benefit of the AI-driven antibody discovery process. To accelerate this process, which consists of a complex series of cycles spanning different functional teams, a substantial increase in the throughput of the end-to-end production and characterization workflow is established in-house such that 104 antibodies with property data can be generated and analyzed within a short period of time. BioMap has implemented a highly integrated and automated protein expression, purification, and characterization platform linked with a unified informatics system to eliminate as much manual operation as possible. This high-throughput robotic platform interweaves multiple procedures including plasmid preparation, cell dispensing, mammalian transfection, protein purification, and characterization, and it is coupled to our in-house informatics system and database. Empowered by state-of-the-art liquid handling system and well-established experimental protocols, the integrated facility is capable of the delivery of 103 protein samples from plasmids in ten days within a single batch. Benefiting from our robust transient expression platform, the production scale ranges from 0.5 to 30 mL with an average antibody yield of 300 mg/L. The high-throughput workflow brings a challenge to track the provenance of each protein and manage data flow across different stations. To address this bottleneck, a well-defined informatics platform and database have been developed to provide sample registration, interface with lab instruments, experimental process tracking, and automated data recording and analysis. The implementation of this system provides a massive amount of high-quality data available for AI training and validation with a very short turnover time and enables AI-driven development of next-generation biologics. Citation Format: Zhehao Xiong, Wei Jiang, Lijun Xia, Jianhua Huang, Cheng-chi Chao. Accelerating the drug discovery process with an automated high-throughput protein production and characterization platform for AI-driven antibody development of immunotherapy. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5323.

Effects of tissue decomposition on stable isotope ratios and implications for use of stranded animals in research

AbstractStable isotope analysis (SIA) provides ecological data that can be safely and efficiently collected on endangered, threatened, and cryptic species. Marine mammals are an ecologically important group for which economical and logistical constraints can make data collection challenging. Stranded marine mammals are often used in research, but the causes of strandings and subsequent tissue decomposition could affect SIA. We conducted a three‐part study to test the validity of using δ13C and δ15N values from tissues of stranded bottlenose dolphins (Tursiops truncatus) and West Indian manatees (Trichechus manatus) for ecological studies. First, we quantified isotopic overlap using ellipses based on 95% of the data to compare isotope values in skin between stranded and live‐captured animals. Second, we compared stable isotope values from liver, skin, and muscle of animals that had stranded and were sampled at different decomposition stages. Third, we experimentally exposed each tissue to environmental conditions and sampled tissues as they decomposed. For both dolphins and manatees, isotopic ellipses from skin of stranded carcasses were similar to live‐captured individuals. Among individuals recovered at different decomposition stages, more advanced decomposition affected δ13C values in dolphin liver and skin but not in manatee tissues and had no effect on δ15N values in any tissue for either species. In the experimental manipulation, decomposition resulted in depleted δ13C values, enriched δ15N values, and increased C:N in liver for both species. Skin and muscle from stranded dolphins and manatees are representative of their corresponding live populations and can be used for SIA with appropriate caution. To facilitate the use of tissues from stranded animals, tissues should be dried or frozen for storage as soon as possible after sampling. We recommend liver from stranded animals only be used for SIA when researchers need tissues with short turnover times and can access fresh samples. Without consideration of decomposition effects on isotope values, ecologists may make inaccurate inferences about habitat use, diet, and community structure. Careful use of SIA on tissues from stranded animals can help researchers provide better quality information for managers and policy makers.

Rapid Multiplex RT-PCR for Influenza A and B by Genesoc®, a Microfluidic PCR System.

Rapid antigen tests are widely used to diagnose influenza. However, despite their simplicity and short turnover time, the sensitivity of these tests is relatively low, and molecular tests with greater sensitivity are being sought. In this study, we developed and clinically evaluated a protocol for the rapid multiplex testing of influenza A and B, using a rapid real-time PCR system, GeneSoC®, that is based on microfluidic thermal cycling technology. The specificity of the developed assay was validated using cultured viral strains of influenza A/B, human metapneumovirus, and respiratory syncytial virus. Analytical sensitivity was evaluated using serially diluted RNA synthesized via in vitro transcription and nasopharyngeal swab samples collected from consecutive patients seeking medical attention for a combination of upper respiratory and general symptoms. Cross-validation of GeneSoC® based on comparisons with conventional real-time RT-PCR and rapid antigen tests was performed by parallel testing of influenza-positive clinical specimens. The GeneSoC® assay detected the target sequences of influenza A and B at minimum concentrations of 38 and 65 copies/µL in reaction, respectively. For the analysis of clinical specimens, the positive, negative, and overall agreement between GeneSoC® RT-PCR and a conventional real-time RT-PCR was in all cases 100%, whereas for the comparison between GeneSoC® RT-PCR and the rapid antigen test, the agreements for positive, negative, and overall findings were 100%, 90.9%, and 95.7%, respectively. The mean time for completing GeneSoC® RT-PCR was 16 min 29 s (95% confidence interval, 16 min 18 s to 16 min 39 s). The microfluidic real-time PCR system, GeneSoC®, has an analytical performance comparable to that of conventional real-time RT-PCR with rapid turnover time, and represents a promising alternative to rapid antigen tests for diagnosing influenza A and B.

Soil Microbial and Organic Carbon Legacies of Pre-Existing Plants Drive Pioneer Tree Growth during Subalpine Forest Succession

Fast-growing pioneer tree species play a crucial role in triggering late successional development in forests. Experimental evidence of the soil legacy effects of pre-existing plants on pioneer tree performance is lacking. We explored the legacy effects of soils conditioned by early successional herbs (Poa poophagorum Bor and Potentilla fragarioides L.) and mid-successional shrubs (Rhododendron fortunei Lindl. and Enkianthus quinqueflorus Lour.) on late-successional ectomycorrhizal (ECM) pioneer tree (Betula platyphylla Sukaczev) seedling growth. The soils were analyzed for soil nutrient status and fungal and bacterial compositions using ITS and 16S rRNA gene sequencing. B. platyphylla seedlings produced higher biomass in soils conditioned by shrubs. Soil organic carbon (SOC) and bacterial and fungal legacies most impacted pioneer tree seedling growth. Additionally, the partial least squares path model revealed that soil nutrients, especially SOC, indirectly affected seedling biomass by their direct effects on the bacterial and fungal communities. The changes in bacterial community composition had a stronger effect on seedling biomass than those of fungi because bacteria with shorter turnover times are generally considered to be more efficient than fungi in enhancing nutrient availability. Our study integrates soil microbial and nutrient legacies to explain the potential mechanisms of pioneer tree regeneration.

Clinical decision making is improved by BioFire Pneumonia Plus in suspected lower respiratory tract infection after lung transplantation: Results of the prospective DBATE-IT study.

Lower respiratory tract infections (LRTIs) are a significant cause of morbidity and mortality in lung transplant (LTx) recipients. Timely and precise pathogen detection is vital to successful treatment. Multiplex PCR kits with short turnover times like the BioFire Pneumonia Plus (BFPPp) (manufactured by bioMérieux) may be a valuable addition to conventional tests. We performed a prospective observational cohort study in 60 LTx recipients with suspected LRTI. All patients received BFPPp testing of bronchoalveolar lavage fluid in addition to conventional tests including microbiological cultures and conventional diagnostics for respiratory viruses. Primary outcome was time-to-test-result; secondary outcomes included time-to-clinical-decision and BFPPp test accuracy compared to conventional tests. BFPPp provided results faster than conventional tests (2.3h [2-2.8] vs. 23.4h [21-62], p<0.001), allowing for faster clinical decisions (2.8 [2.2-44] vs. virology 28.1h [23.1-70.6] and microbiology 32.6h [4.6-70.9], both p<0.001). Based on all available diagnostic modalities, 26 (43%) patients were diagnosed with viral LRTI, nine (15 %) with non-viral LRTI, and five (8 %) with combined viral and non-viral LRTI. These diagnoses were established by BFPPp in 92%, 78%, and 100%, respectively. The remaining 20 patients (33 %) received a diagnosis other than LRTI. Preliminary therapies based on BFPPp results were upheld in 90% of cases. There were six treatment modifications based on pathogen-isolation by conventional testing missed by BFPPp, including three due to fungal pathogens not covered by the BFPPp. BFPPp offered faster test results compared to conventional tests with good concordance. The absence of fungal pathogens from the panel is a potential weakness in a severely immunosuppressed population.

Characterize groundwater vulnerability to intensive groundwater exploitation using tritium time-series and hydrochemical data in Shijiazhuang, North China Plain

The deterioration of water quality in shallow groundwater systems over the past decades has attracted increased amounts of attention from hydrogeologists. Groundwater vulnerability and its changes are the factors that cause groundwater deterioration. Combining of the mean residence times (MRTs) with chemical characteristics of groundwater can be applied to understand groundwater vulnerability and its changes. The groundwater MRTs ranged from 6 to 180 years, with MRTs of 6 to 77 years in the shallow aquifer. Spatial distribution of groundwater MRTs suggested that young groundwater trended to extend. Relatively uniform MRTs and concentrations of ions were found above the main pumped well depth. High concentrations of ions (K+, Na+, Ca2+, Mg2+, HCO3−, Cl- and SO42-) were mainly distributed in the western piedmont plain areas with short turnover time but with low productivity, meaning that the aquifer is susceptible to human activities and hardly migrate out. Elevated concentrations of nitrate and others ions (such as K+, Ca2+, Cl- and SO42-) also were observed in moderately old groundwater (20 < MRTs < 80 years), indicating that some mixing with recent water within MRTs < 20 years likely occurs through vertical drainage from the upper to deeper in the single aquifer and that lateral flow occurs along flow paths towards the piezometric depressions caused by the pumping in urban areas. Slightly elevated HCO3− and K+ were found at east of the areas with long residence times suggested that water-salt equilibrium had also been disrupted. Therefore, the anthropogenic influence exceeded the natural attenuation in the current groundwater environment on the piedmont plain. And the Shijiazhuang groundwater system was identified to be tending more vulnerable under anthropogenic influence. Some measures must be taken to significantly reduce groundwater withdrawal and pollutant discharge.

ChromInst: A single cell sequencing technique to accomplish pre-implantation comprehensive chromosomal screening overnight.

Next Generation Sequencing (NGS) is a powerful tool getting into the field of clinical examination. Its preliminary application in pre-implantation comprehensive chromosomal screening (PCCS) of assisted reproduction (test-tube baby) has shown encouraging outcomes that improves the success rate of in vitro fertilization. However, the conventional NGS library construction is time consuming. In addition with the whole genome amplification (WGA) procedure in prior, makes the single cell NGS assay hardly be accomplished within an adequately short turnover time in supporting fresh embryo implantation. In this work, we established a concise single cell sequencing protocol, ChromInst, in which the single cell WGA and NGS library construction were integrated into a two-step PCR procedure of ~ 2.5hours reaction time. We then validated the feasibility of ChromInst for overnight PCCS assay by examining 14 voluntary donated embryo biopsy samples in a single sequencing run of Miseq with merely 13M reads production. The good compatibility of ChromInst with the restriction of Illumina sequencing technique along with the good library yield uniformity resulted superior data usage efficiency and reads distribution evenness that ensures precisely distinguish of 6 normal embryos from 8 abnormal one with variable chromosomal aneuploidy. The superior succinctness and effectiveness of this protocol permits its utilization in other time limited single cell NGS applications.

Epidural versus general anesthesia for open pyloromyotomy in infants: A retrospective observational study.

BackgroundThoracic epidural anesthesia for open infantile hypertrophic pyloric stenosis surgery is a controversial issue in the presence of little comparative data.AimsTo compare this approach to general anesthesia for desaturation events (≤90% oxygen saturation) and absolute values of minimal oxygen saturation, minimal heart frequency, operating‐room occupancy time, and durations of surgery in a retrospective study design.MethodsData were retrieved for patients with infantile hypertrophic pyloric stenosis managed by thoracic epidurals under sedation or general anesthesia with rapid sequence induction between 01/2007 and 12/2017. Oxygen saturation and heart rate were analyzed over eight 5‐minutes intervals relative to the start of anesthesia / sedation (four‐time intervals) and before discharge of the patient from the operating room (four‐time intervals). Fisher's exact tests and mixed model two‐way analysis of variance for repeated measures were employed for intergroup comparisons.ResultsThe epidural and general anesthesia groups included 69 and 32 evaluable infants, respectively. Patients managed under epidural anesthesia had cumulatively higher minimimal mean (SD) oxygen saturation values (98.2 [2.6] % versus 96.6 [5.2] %, p < 0.001) and lower minimal mean (SD) heart rate values (127.9 [15.0] beats per minute versus 140.7 [17.2] beats per minute, p < 0.001) over time. Similarly, the frequency of desaturation events (defined as ≤90% oxygen saturation) was significantly lower for these patients during the period of 5 minutes after induction of sedation or general anesthesia (odds ratio 7.4 [2.1–25.9]; p = 0.001) and during the subsequent period of five minutes (odds ratio 6.2 [1.1–33.9]; p = 0.031). One case of prolonged respiratory weaning was observed in the general anesthesia group. The mean (SD) operating‐room occupancy was 61.9 (16.6) minutes for the epidural anesthesia group versus 73.3 (22.2) minutes for the general anesthesia group (p = 0.005) as a result of shorter emergence from sedation.ConclusionsIn our series, maintaining spontaneous breathing with minimal airway manipulation in patients undergoing open repair of hypertrophic pyloric stenosis under single‐shot epidural anesthesia resulted in fewer desaturation events ≤90% than general anesthesia. In addition, this approach seems to result in shorter turnover times in the operating room.

Smart materials-integrated sensor technologies for COVID-19 diagnosis.

After the first case has appeared in China, the COVID-19 pandemic continues to pose an omnipresent threat to global health, affecting more than 70 million patients and leading to around 1.6 million deaths. To implement rapid and effective clinical management, early diagnosis is the mainstay. Today, real-time reverse transcriptase (RT)-PCR test is the major diagnostic practice as a gold standard method for accurate diagnosis of this disease. On the other side, serological assays are easy to be implemented for the disease screening. Considering the limitations of today’s tests including lengthy assay time, cost, the need for skilled personnel, and specialized infrastructure, both strategies, however, have impediments to be applied to the resource-scarce settings. Therefore, there is an urgent need to democratize all these practices to be applicable across the globe, specifically to the locations comprising of very limited infrastructure. In this regard, sensor systems have been utilized in clinical diagnostics largely, holding great potential to have pivotal roles as an alternative or complementary options to these current tests, providing crucial fashions such as being suitable for point-of-care settings, cost-effective, and having short turnover time. In particular, the integration of smart materials into sensor technologies leverages their analytical performances, including sensitivity, linear dynamic range, and specificity. Herein, we comprehensively review major smart materials such as nanomaterials, photosensitive materials, electrically sensitive materials, their integration with sensor platforms, and applications as wearable tools within the scope of the COVID-19 diagnosis.

Expert consensus on prenatal fluorescence in situ hybridization

Although non-invasive prenatal testing has been widely used, it has certain limitations. As the gold standard of prenatal diagnosis, G-banding karyotype analysis is time-consuming and laborious. Fluorescence in situ hybridization (FISH), as a method for detecting samples with non-radioactive signals, does not require cell culture and has a short turnover time, and can diagnose aneuploidies of chromosomes 13, 18, 21, X, Y with efficiency, which can solve the problems such as insufficient testing ability and long diagnosis period for karyotype analysis. To standardize the procedures of prenatal FISH assay and enhance laboratory quality management, the Expert Committee of the Prenatal Screening and Diagnosis Laboratory of the Clinical Test Center of the National Health Commission and the Inter-laboratory Quality Assessment Committee of the Neonatal Genetic and Metabolic Disease Screening Laboratory have formulated this consensus.

Precision fabrication of flexible microfluidic circuits using direct laser rapid prototyping solution

An effective development platform for custom lab-on-a-chip and lab-on-a-foil solutions has been regarded as a missing element for wider adoption of microfluidic technologies in everyday life. We have used a direct laser structuring device combined with CAD-CAM software and have developed an efficient, fast, and precise procedure for rapid prototyping of widely accessible contemporary materials utilized for flexible microfluidics. Utilization of an ultra-short pulsed laser has enabled us to predict and control the laser ablation process on thin low-temperature co-fired ceramics and Kapton foil. We have demonstrated an agreement between the theoretic predictions and experimental data on ablation rates, paving the way to a fully predictive manufacturing process. Our procedure enables an independent control of microfluidic channel shape, depth, and lateral dimensions down to 10 µm, while maintaining an exceptional process quality achieved by a parametrically optimized laser output at single-picosecond pulse durations. Our novel rapid prototyping solution features short turnover times, minimum material waste, no chemical procedures, and a single-step process free of heat-effects. We demonstrate the improvements to the structuring process on a known difficult-to-manufacture herringbone mixer structures inside a micro-mixer chip application.

The Impact of Organic Matter on Polycyclic Aromatic Hydrocarbon (PAH) Availability and Persistence in Soils.

Polycyclic aromatic hydrocarbons (PAHs) exhibit persistence in soils, and most of them are potentially mutagenic/carcinogenic and teratogenic for human beings but also influence the growth and development of soil organisms. The PAHs emitted into the atmosphere are ultimately deposited (by dry or wet deposition processes) onto the soil surface where they tend to accumulate. Soil organic matter (SOM) plays an important role in the fate and transformation processes of PAHs, affecting their mobility, availability, and persistence. Therefore, the aim of this research was to investigate the influence of SOM fractional diversification (fulvic acids—FA, humic acids—HA, and humins—HN) on PAH availability and persistence in soils. Twenty soil samples (n = 20) were collected from upper horizons (0–30 cm) of agricultural soils exposed to anthropogenic emissions from industrial and domestic sources. The assessment of PAH concentrations included the determination of medium-molecular-weight compounds from the US EPA list: fluoranthene—FLA, pyrene—PYR, benz(a)anthracene—BaA, and chrysene—CHR. The assessment was conducted using the GC-MS/MS technique. Three operationally defined fractions were investigated: total extractable PAHs (TE-PAHs) fraction, available/bioavailable PAHs (PB-PAHs) fraction, and nonavailable/residual PAHs (RE-PAHs) fraction, which was calculated as the difference between total and available PAHs. TE-PAHs were analyzed by dichloromethane extraction, while PB-PAHs were analyzed with a hydrophobic β-cyclodextrin solution. SOM was characterized by total organic carbon content (Turin method) and organic carbon of humic substances including FA, HA, HN (IHSS method). Concentrations of PAHs differed between soils from 193.5 to 3169.5 µg kg−1, 4.3 to 226.4 µg kg−1, and 148.6 to 3164.7 µg kg−1 for ∑4 TE-PAHs, ∑4 PB-PAHs, and ∑4 RE-PAHs, respectively. The ∑4 PB-PAHs fraction did not exceed 30% of ∑4 TE-PAHs. FLA was the most strongly bound in soil (highest content of RE-FLA), whereas PYR was the most available (highest content of PB-PYR). The soils were characterized by diversified total organic carbon (TOC) concentration (8.0–130.0 g kg−1) and individual SOM fractions (FA = 0.4–7.5 g kg−1, HA = 0.6–13.0 g kg−1, HN = 0.9–122.9 g kg−1). FA and HA as the labile fraction of SOM with short turnover time strongly positively influenced the potential ∑4 PAH availability (r = 0.56 and r = 0.52 for FA and HA, respectively). HN, which constitutes a stable fraction of organic matter with high hydrophobicity and poor degradability, was strongly correlated with ∑4 RE-PAHs (r = 0.75), affecting their persistence in soil.

Timeliness of care and adverse event profile in children undergoing general anesthesia or sedation for MRI: An observational prospective cohort study.

Background and Aims:Anaesthesia for children undergoing magnetic resonance imaging (MRI) ranges from moderate to deep sedation in order to facilitate uninterrupted completion of the scan. While various intravenous and inhalational techniques of anaesthesia have their own merits and demerits, there is a paucity of comparative literature between the two in children undergoing diagnostic MRI.Materials and Methods:This prospective observational cohort study was conducted at the Radiology suite of a 2800-bedded tertiary care hospital, wherein 107 unpremedicated children between the ages of 6 months to 15 years received either sedation with propofol infusion (Group GSP, n = 57) or inhalational anaesthesia with a laryngeal mask airway (Group GAL, n = 50). Primary outcome measures included time to induction and time to recovery. Secondary outcomes comprised the incidence of respiratory and non-respiratory adverse events in the two groups.Results:The median time to induction was significantly shorter in GSP than GAL [7.00 (IQR 5.0, 10.0) versus 10.00 minutes (IQR 8.8, 13.0), P < 0.001]; the incidence of desaturation [8 (16.0%) in GAL, 1 (1.8%) in GSP, P = 0.012], laryngospasm [11 (22.4%) in GAL, 1 (1.8%) in GSP, P = 0.001] and emergence delirium (5 (10%) in GAL, 0 in GSP, P = 0.047) were significantly greater in the GAL group. There was no difference in the time to emergence, nausea and vomiting or bradycardia between the two groups.Conclusion:Sedation with propofol infusion during paediatric MRI scan offers a short turnover time and favourable adverse event profile when compared to inhalational anaesthesia with an LMA.

Bioavailability of dissolved organic nitrogen and its uptake by Ulva prolifera: Implications in the outbreak of a green bloom off the coast of Qingdao, China

To investigate bioavailability of dissolved organic nitrogen (DON) and its contribution to nitrogen demand for Ulva prolifera, a cruise was conducted during a bloom of U. prolifera in Qingdao coastal waters, China, dissolved inorganic nitrogen (DIN) and DON components were investigated. Uptakes of both DIN and DON by U. prolifera were synchronously measured onboard using stable isotope techniques. The contribution of DON to total dissolved N (TDN) was >50% and that of labile components (urea and to amino acids, AA) to DON exceeded 30%. Both DIN and DON were utilized by U. prolifera, which uptake NH4-N preferentially, then urea, NO3-N and AA in turn; whereas the ranking of turnover times from short to long was AA, NH4-N, urea and NO3-N. The high uptake rates and short turnover time of AA and urea indicated that DON may play an important role in the nutrition of U. prolifera.

Coupled effect of substrate and light on assimilation and oxidation of regenerated nitrogen in the euphotic ocean

AbstractNitrogen (N), as a critical element for microbial metabolisms, recycles rapidly in the euphotic ocean. Oxidation by nitrifiers is a competing pathway for phytoplankton assimilation of regenerated N (NH4+ and urea). Sharing the overlapping substrates may result in competitive exclusion, thus, niche separation for the two assemblages. Both pathways are sensitive to light, but whether light intensity will intensify or alleviate such resource competition in the euphotic zone remains poorly explored in the field at the community level. By using 15N labeling techniques, paired kinetic responses of uptake and oxidation were conducted in single bottles under manipulated light intensities for both NH4+ and urea. We found light stimulated the maximum rate (Rm) and specific affinities (αU) of both NH4+ and urea uptake. In contrast, light effects were opposite for oxidation kinetics (Rm and αO). As irradiance increased, the rapid increase in αU and concomitant decrease in αO imply a distinctive competition advantage of photosynthetic organisms over oxidizers under substrate‐limited environments. The ratio of αU/αO for NH4+ ranged from 0.8 to 3089 (5.8–46,788 for urea) showing a distinct increasing pattern as ambient light increases, demonstrating that phytoplankton overwhelms nitrifiers throughout the oligotrophic euphotic zone, driving down concentrations and maintaining short turnover times of the two regenerated N substrates. Moreover, phytoplankton relied equally on NH4+ and urea; yet, nitrifiers preferred NH4+ to urea. In the nitrate‐depleted euphotic ocean, light acts as a crucial driver for utilization pathways of regenerated N and vertical niche separation.

After the Fall: Legacy Effects of Biogenic Structure on Wind-Generated Ecosystem Processes Following Mussel Bed Collapse

Blue mussels (Mytilus edulis) are ecosystem engineers with strong effects on species diversity and abundances. Mussel beds appear to be declining in the Gulf of Maine, apparently due to climate change and predation by the invasive green crab, Carcinus maenas. As mussels die, they create a legacy of large expanses of shell biogenic structure. In Maine, USA, we used bottom traps to examine effects of four bottom cover types (i.e., live mussels, whole shells, fragmented shells, bare sediment) and wind condition (i.e., days with high, intermediate, and low values) on flow-related ecosystem processes. Significant differences in transport of sediment, meiofauna, and macrofauna were found among cover types and days, with no significant interaction between the two factors. Wind condition had positive effects on transport. Shell hash, especially fragmented shells, had negative effects, possibly because it acted as bed armor to reduce wind-generated erosion and resuspension. Copepods had the greatest mobility and shortest turnover times (0.15 d), followed by nematodes (1.96 d) and the macrofauna dominant, Tubificoides benedeni (2.35 d). Shell legacy effects may play an important role in soft-bottom system responses to wind-generated ecosystem processes, particularly in collapsed mussel beds, with implications for recolonization, connectivity, and the creation and maintenance of spatial pattern.

Vertical Distribution of Macrobenthos in Hypoxia-Affected Sediments of the Northern Gulf of Mexico: Applying Functional Metrics

Continuing trends of declining bottom-water dissolved oxygen (BWDO) in coastal oceans are a threat to marine organisms, especially the benthos, and in the northern Gulf of Mexico (nGOM), the hypoxic area is expected to expand. Within-sediment vertical functional metric responses of macrobenthos were examined in four depth strata at four sites with different histories of exposure to seasonal hypoxia. The sites H7, D5, E4, and A6 between 30 and 39-m water depth represented a historical oxygen stress gradient from 5.4 to 2.1 mg L−1 BWDO (mid-summer 11-year mean), from which macrobenthos were sampled in spring and late summer 2009 and in mid-summer in 2010. High abundance together with high biomass and production potential within upper strata under low BWDO stress supports the primacy of a numerically driven response in this system. Total abundance decreased along the BWDO stress gradient, and the lowest abundance coincided at the highest stress (MaxStress) site together with the highest proportion of opportunists, the smallest mean size, and the shortest turnover time. Accordingly, the relative abundance of opportunists within the upper two strata increased while surface deposit feeders decreased with greater hypoxic stress. Notwithstanding the proportion of opportunists, functional metrics generally decreased across the BWDO stress gradient within the upper strata, and metrics generally varied inversely between upper and lower strata. The findings underscore how vertical benthos distribution patterns reflect the BWDO exposure regime and how secondary production varies as an indicator of trophic transfer potential and organic matter processing within this system.