A microfluidic biosensor architecture for the rapid detection of COVID-19.

The lack of enough diagnostic capacity to detect severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has been one of the major challenges in the control the 2019 COVID pandemic; this led to significant delay in prompt treatment of COVID-19 patients or accurately estimate disease situation. Current methods for the diagnosis of SARS-COV-2 infection on clinical specimens (e.g. nasal swabs) include polymerase chain reaction (PCR) based methods, such as real-time reverse transcription (rRT) PCR, real-time reverse transcription loop-mediated isothermal amplification (rRT-LAMP), and immunoassay based methods, such as rapid antigen test (RAT). These conventional PCR methods excel in sensitivity and specificity but require a laboratory setting and typically take up to 6 h to obtain the results whereas RAT has a low sensitivity (typically at least 3000 TCID50/ml) although with the results with 15 min. We have developed a robust micro-electro-mechanical system (MEMS) based impedance biosensor fit for rapid and accurate detection of SARS-COV-2 of clinical samples in the field with minimal training. The biosensor consisted of three regions that enabled concentrating, trapping, and sensing the virus present in low quantities with high selectivity and sensitivity in 40 min using an electrode coated with a specific SARS-COV-2 antibody cross-linker mixture. Changes in the impedance value due to the binding of the SARS-COV-2 antigen to the antibody will indicate positive or negative result. The testing results showed that the biosensor's limit of detection (LoD) for detection of inactivated SARS-COV-2 antigen in phosphate buffer saline (PBS) was as low as 50 TCID50/ml. The biosensor specificity was confirmed using the influenza virus while the selectivity was confirmed using influenza polyclonal sera. Overall, the results showed that the biosensor is able to detect SARS-COV-2 in clinical samples (swabs) in 40 min with a sensitivity of 26 TCID50/ml.

The possible relation between temporal muscle mass and glioblastoma multiforme prognosis via sarcopenia perspective.

BACKGROUND: The optimal sarcopenia measurement method in patients with a diagnosis of glioblastoma multiforme (GBM) is unknown. It has been found that temporal muscle thickness (TMT) may reflect sarcopenia and be associated with survival, but the relationship between temporal muscle area (TMA) and GBM prognosis has never been evaluated before. The primary outcome of the study was to evaluate the relationship between TMA/TMT and overall survival (OS) time in newly diagnosed GBM patients. METHODS: The data of patients who presented at the university hospital between January 2009 and January 2019 with a confirmed diagnosis of glioblastoma multiforme at the time of diagnosis were analyzed retrospectively. Temporal muscle thickness and TMA were measured retrospectively from preoperative MRIs of patients diagnosed with GBM. Due to the small number of patients and the failure to determine a cut-off value with acceptable sensitivity and specificity using ROC analysis, the median values were chosen as the cut-off value. The patients were basically divided into two according to their median TMT (6.6 mm) or TMA (452 mm2 ) values, and survival analysis was performed with the Kaplan-Meier analysis. RESULTS: The median TMT value was 6.6 mm, and the median TMA value was 452 mm2 . The median overall survival (OS) was calculated as 25.8 months in patients with TMT < 6.6 mm, and 15.8 months in patients with TMT ≥ 6.6 mm (p = 0.29). The median overall survival (OS) of patients with TMA < 452mm2 was 26.3 months, and the group with TMA ≥ 452mm2 was 14.6 months (p = 0.06). The median disease-free survival was 18.3 months (%95 CI: 13.2-23.4) in patients with TMT < 6.6mm, while mDFS was 10.9 (%95 CI: 8.0-13.8) months in patients with TMT ≥ 6.6mm (p = 0.21). The median disease-free survival was found to be 21.0 months (%95 CI: 15.8-26.1) in patients with TMA < 452 mm2 and 10.5 months (%95 CI: 7.8-13.2) in patients with TMA ≥ 452 mm2 (p = 0.018). DISCUSSION: No association could be demonstrated between TMT or TMA and OS of GBM patients. In addition, the median DFS was found to be longer in patients with low TMA. There is an unmet need to determine the optimal method of sarcopenia in GBM patients.

Do Ultrasound Based Quantitative Hepatic Fat Content Measurements Have Differences Between Respiratory Phases?

RATIONALE AND OBJECTIVES: The recently developed ultrasound based tools using attenuation coefficient (AC) and scatter distribution coefficient (SDC) values can be used to quantify hepatic fat content in patients with non-alcoholic fatty liver disease (NAFLD). However, currently the impact of respiratory phase on these measurements is not known. The purpose of this study is to compare AC and SDC measurements acquired at peak inspiration and end expiration phases. MATERIALS AND METHODS: AC and SDC measurements were obtained in 50 patients with NAFLD. Tissue Attenuation Imaging (TAI) and Tissue Scatter Distribution Imaging (TSI) tools were utilized to measure AC and SDC values, respectively. Five measurements were performed at respiratory phases using TAI and TSI tools and the median values were noted. Subgroup analyses were performed and Wilcoxon signed rank test was used for comparison of the measurements. RESULTS: The median values of the AC measurements at peak inspiration and end expiration phases were 0.87 dB/cm/MHz and 0.89 dB/cm/MHz, respectively. The median values of the SDC measurements at peak inspiration and end expiration phases were 97.91 and 96.62, respectively. There were no statistically significant differences in AC and SDC measurements between the respiratory phases except for AC measurements in BMI <30 kg/m2 subgroup. CONCLUSION: Our results revealed that respiratory phases have no impact on SDC measurements. However, while the AC measurements in BMI ≥30 kg/m2 subgroup showed no significant difference, there was a significant difference in AC measurements in BMI <30 kg/m2 subgroup between the respiratory phases.

Prevalence and associated risk factors of coronary artery disease in patients with a zero coronary calcium score.

PURPOSE: A zero coronary calcium score (CCS) is not able to provide a definite exclusion for coronary artery disease (CAD). The goal of this study was to determine the prevalence and associated cardiovascular risk factors of CAD in patients with zero CCS. METHODS: Six hundred thirteen patients with zero CCS referred to coronary calcium score analysis (CCSA) and coronary computed tomography angiography (CCTA) with suspicion of CAD were included. The descriptive, univariate, and multivariate analyses were used to determine the prevalence and predictors of CAD presence. RESULTS: Among 613 patients, 17 patients (2.7%) have NCCP, and obstructive CAD was found in 3 patients (0.48%). Multivariate analysis revealed that male gender and older age (≥50 years) were significantly associated with the presence of noncalcified coronary plaques (NCCP) (p < 0.05). The receiver operating characteristic (ROC) curve analysis showed that the male gender and older age (≥50 years) model had 70.6% sensitivity and 84.2% specificity for predicting NCCP. CONCLUSION: A non-negligible portion of patients with zero CCS had CAD. Male gender and older age (≥50 years) were independently associated with NCCP. Due to the high specificity value (84.2%) and negative predictive value (99.0%) of the male gender and older age (≥50 years) model, selective use of CCTA is recommended in <50 years old female patients to avoid unnecessary radiation exposure.

Accuracy in tumor size measurements: Comparison of digital mammography, digital breast tomosynthesis and synthetic mammography.

PURPOSE: The aim of this study was to assess the accuracy of digital mammography (DM), digital breast tomosynthesis (DBT) and synthetic mammography (SM) in tumor size measurements compared with histological tumor sizes. MATERIALS AND METHODS: 71 breast cancer patients who underwent DM and DBT acquisitions simultaneously were included in this study. One radiologist with 8 years of experience in breast imaging measured tumor sizes independently in three separate sessions which include DM, DBT and SM images, respectively. The correlations between the measured tumor sizes on each imaging technique and histological sizes were analyzed using Spearman correlation test. The patients were categorized into two subgroups according to assigned breast density categories (dense and non-dense), and histological tumor sizes (≤2 cm and > 2 cm). To assess the agreement levels between the measured tumor sizes and histological sizes Bland-Altman analyses were performed for each imaging technique. RESULTS: The mean of histological size of tumors was 23.85 ±â€¯16.57 mm (median: 20). The means of measured tumor sizes were 21.21 ±â€¯13.59 mm (median: 19), 21.52 ±â€¯13.42 mm (median: 19) and 18.97 ±â€¯11.21 mm (median: 17) in DM, DBT and SM, respectively. The Spearman correlation values with histologic sizes were 0.814 (P < 0.001), 0.887 (P < 0.001), and 0.852 (P < 0.001) for DM, DBT and SM, respectively. In subgroup analyses, the correlation values showed decrement for tumors >2 cm in size compared to tumors ≤2 cm in size. CONCLUSION: DBT provides the most accurate tumor size measurements among mammographic imaging techniques and if mammography will be used in tumor size measurements, DBT should be preferred.

A practitioner's perspective on the application and research needs of membrane bioreactors for municipal wastewater treatment.

The application of membrane bioreactors (MBRs) for municipal wastewater treatment has increased dramatically over the last decade. From a practitioner's perspective, design practice has evolved over five "generations" in the areas of biological process optimization, separating process design from equipment supply, and reliability/redundancy thereby facilitating "large" MBRs (e.g. 150,000 m(3)/day). MBR advantages and disadvantages, and process design to accommodate biological nutrient removal, high mixed liquor suspended solids concentrations, operation and maintenance, peak flows, and procurement are reviewed from the design practitioner's perspective. Finally, four knowledge areas are identified as important to practitioners meriting further research and development: (i) membrane design and performance such as improving peak flow characteristics and decreasing operating costs; (ii) process design and performance such as managing the fluid properties of the biological solids, disinfection, and microcontaminant removal; (iii) facility design such as equipment standardization and decreasing mechanical complexity; and (iv) sustainability such as anaerobic MBRs.

Is it PAO-GAO competition or metabolic shift in EBPR system? Evidence from an experimental study.

Reduced EBPR performance in full and bench-scale EBPR studies was linked to the proliferation of GAOs but often time with the lack of any evidence. In this study, a detailed enzymatic study was coupled with batch tests and electron microscopy results for a realistic explanation. The results eliminated the possibility of population shift from PAO to GAO or other non-PAO due to the short batch test period provided which would not allow a population shift and further justified with the electron microscopy results. The results indicate that glycogen serves not only as source of reducing power for PHA production but also serves as an alternative energy source when the poly-P pool of the PAOs is depleted. Slow generation of ATP via glycolytic pathway at 5 degrees C cannot satisfy energy requirements of EBPR cells to complete several cell functions including acetate uptake and PHA storage. However, the glycolytic pathway is efficiently operable at warm temperatures (> 20 degrees C). The reduced performance of enhanced EBPR facilities operated at warm temperature may not be a result of GAO proliferation; instead it may be related the efficient use of the glycolytic pathway by PAOs which results in more glycogen storage and less P uptake, thereby reducing the EBPR performance.

Recent findings on biosolids cake odor reduction--results of WERF phase 3 biosolids odor research.

The Water Environment Research Foundation (WERF) has sponsored three phases of a long-term project entitled "Identifying and Controlling Odors in the Municipal Wastewater Environment." The current (third) phase focuses on reduction of odors from dewatered biosolids cakes, and is entitled "Biosolids Processing Modifications for Cake Odor Reduction." This phase encompasses nine research agenda items developed from the results of the prior phase of research (Phase 2), which was completed in December 2003 as WERF Report No. 00-HHE-5T and was entitled "Impacts of In-Plant Parameters on Biosolids Odor Quality." The current phase (Phase 3) was a 2.5-year project, the first half of which was dedicated to testing several of the more promising hypotheses from Phase 2 in the laboratory to help determine the cause-effect relationships of odor generation from biosolids, and to develop odor reduction techniques. It is important to note that this research project covers the reduction or prevention of odorous emissions from dewatered biosolids cake, not odor control by means of containment or adsorption or absorption of malodorous emissions. In the remainder of the Phase 3 project, promising laboratory findings are being applied to biosolids handling processes at one or more wastewater treatment plants (WWTPs), with the goal of achieving significant cake odor reduction in a realistic, full-scale setting. The Phase 3 laboratory results were used to identify the relative effectiveness of methods for reducing biosolids cake odors, using techniques and measurements of biosolids cake odor production potential that have been developed by the WERF Project Team. Plans to demonstrate the most promising research findings at full-scale biosolids digestion and dewatering facilities constitute the final, fourth phase of the project. Contacts have been made with wastewater treatment facilities that have an interest or need to reduce their biosolids cake odors. The main goal of the next phase of the project will be to match wastewater or biosolids facilities that need to reduce biosolids odors with specific technologies, chemicals, or biological agents, in order to demonstrate the efficacy of promising laboratory findings full scale at a real WWTP.

Role of protein, amino acids, and enzyme activity on odor production from anaerobically digested and dewatered biosolids.

The main objective of this research was to test the hypothesis that bioavailable protein and, more specifically, the sulfur-containing amino acids within the protein, can be degraded by proteolytic enzymes to produce odor-causing compounds--mainly volatile sulfur compounds (VSCs)--during biosolids storage. To achieve these objectives, samples of digester effluent and cake solids were collected at 11 different wastewater treatment plants in North America, and the samples were analyzed for protein and amino acid content and general protein-degrading enzyme activity. At the same time, cake samples were stored using headspace bottles, the concentration of VSCs were measured using gas chromatography, and olfactometry measurements were made by a trained odor panel. The results showed that the bound cake protein content and methionine content was well-correlated with VSC production and the detection threshold measured by the odor panel.

Generation pattern of sulfur containing gases from anaerobically digested sludge cakes.

Eleven dewatered sludge cakes collected from anaerobic digesters at different treatment plants were evaluated for the amount, type, and pattern of odorous gas production. All but one of the sludge cakes were from mesophilic anaerobic digesters. One was from a thermophilic digester. The pattern and quantities of sulfur gases were found to be unique for each of the samples with regard to the products produced, magnitude, and subsequent decline. The main odor-causing chemicals were volatile sulfur compounds, which included hydrogen sulfide, methanethiol, and dimethyl sulfide. Volatile sulfur compound production peaked in 3 to 8 days and then declined. The decline was a result of conversion of organic sulfur compounds to sulfide. In one side-by-side test, a high-solids centrifuge cake generated more odorous compounds than the low-solids centrifuge cake. The data show that anaerobic digestion does not eliminate the odor potential of anaerobically digested dewatered cakes.

The mechanism of enhanced biological phosphorus removal washout and temperature relationships.

In this study, the combined effects of temperature and solids retention time (SRT) on enhanced biological phosphorus removal (EBPR) performance and the mechanism of EBPR washout were investigated. Two pilot-scale University of Cape Town (South Africa) systems fed with synthetic wastewater were operated at 5 and 10 degrees C. The results showed that the phosphorus removal performance was optimum at total SRT ranges of 16 to 24 days and 12 to 17 days for 5 and 10 degrees C, respectively, and steady-state phosphorus removal was greater at the lower temperature. Higher SRT values of up to 32 days at 5 degrees C and 25 days at 10 degrees C slightly reduced EBPR performance as a result of increased extent of endogenous respiration, which consumed internally stored glycogen, leaving less reducing power for poly-hydroxy alkanoate (PHA) formation in anaerobic stages. The phosphorus-accumulating organism (PAO) washout SRTs of the systems were determined as 3.5 days at 5 degrees C and 1.8 days at 10 degrees C, considerably less than the washout SRTs of nitrifiers. Polyphosphorus, the main energy reserve of the EBPR bacterial consortium, was not completely depleted, even at washout points. The inability of EBPR biomass to use glycogen to generate reducing power for PHA formation was the major reason for washout. The results not only suggest that glycogen mechanism is the most rate-limiting step in EBPR systems, but also that it is an integral part of EBPR biochemistry, as proposed originally by Mino et al. (1987), and later others (Pereira et al., 1996, Erdal et al., 2002; Erdal, Z. K., 2002). The aerobic washout SRT values (2.1 and 1.2 days for 5 and 10 degrees C, respectively) of this study did not fit the linear line for PAO washout developed by Mamais and Jenkins (1992). Perhaps this was because the feeds used during this study were chemical-oxygen-demand-limited (acetate-based synthetic feed), whereas the feeds used for their study were phosphorus-limited (external acetate added to domestic wastewater), resulting in different ratios of PAOs and nonPAOs in the biomass.