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•DIET via conductive materials is a promising technology for anaerobic digestion.•Critical reviews on current understanding of DIET were conducted.•Relevant studies published to date ...were systematically analyzed.•Future perspectives for practical applications are proposed.
Anaerobic digestion (AD) is a microbial process that produces renewable energy in the form of methane by treating organic waste and high-strength wastewater. Recent studies have demonstrated that conductive materials can promote direct interspecies electron transfer (DIET) between exoelectrogenic bacteria and methanogenic archaea. DIET via conductive materials is more effective for methane production than interspecies electron transfer using electron carriers such as hydrogen, a principal route of methane production in conventional AD. This critical review presents the current understanding of DIET via conductive materials for methane production, summarizes the relevant studies published to date, and analyzes these studies with regard to conductive materials, substrates, inocula, performance, and microorganisms. Based on this analysis, possible future directions are suggested for practical DIET applications via conductive materials in AD.
We report the synthesis of centimeter-scale, uniform 1T′- and 2H-MoTe2 thin films via the tellurization of Mo thin films. 1T′-MoTe2 was initially grown and converted gradually to 2H-MoTe2 over a ...prolonged growth time under a Te atmosphere. Maintaining excessive Te was essential for obtaining the stable stoichiometric 2H-MoTe2 phase. Further annealing under a lower partial pressure of Te at the same temperature, followed by a rapid quenching, led to the reverse phase transition from 2H-MoTe2 to 1T′-MoTe2. The orientation of the 2H-MoTe2 film was determined by the tellurization rate. Slow tellurization was the key for obtaining a highly oriented 2H-MoTe2 film over the entire area, while fast tellurization led to a 2H-MoTe2 film with a randomly oriented c-axis.
•Anaerobic batch reactors were operated to characterize cluster II Spirochaetes.•Cluster II Spirochaetes were positively correlated with hydrogenotrophic methanogens.•Activity of cluster II ...Spirochaetes was inhibited by high hydrogen partial pressure.•Cluster II Spirochaetes are frequently observed syntrophic acetate oxidizers.
To search for evidence of syntrophic acetate oxidation by cluster II Spirochaetes with hydrogenotrophic methanogens, batch reactors seeded with five different anaerobic sludge samples supplemented with acetate as the sole carbon source were operated anaerobically. The changes in abundance of the cluster II Spirochaetes, two groups of acetoclastic methanogens (Methanosaetaceae and Methanosarcinaceae), and two groups of hydrogenotrophic methanogens (Methanomicrobiales and Methanobacteriales) in the reactors were assessed using qPCR targeting the 16S rRNA genes of each group. Increase in the cluster II Spirochaetes (9.0±0.4-fold) was positively correlated with increase in hydrogenotrophic methanogens, especially Methanomicrobiales (5.6±1.0-fold), but not with acetoclastic methanogens. In addition, the activity of the cluster II Spirochaetes decreased (4.6±0.1-fold) in response to high hydrogen partial pressure, but their activity was restored after consumption of hydrogen by the hydrogenotrophic methanogens. These results strongly suggest that the cluster II Spirochaetes are involved in syntrophic acetate oxidation in anaerobic digesters.
Hydrochromic materials find great utility in a wide range of applications including humidity sensing and measuring the water contents of organic solvents, as well as substrates for rewritable paper ...and human sweat pore mapping. Herein, an inkjet printable diacetylene (DA) is described that can be transformed by UV irradiation to a hydrochromic‐conjugated polymer on conventional paper. Specifically, an amphiphilic DA that contains an imidazolium ion head‐group is found to be compatible with a common office inkjet printer. Various computer‐designed images are printed on paper using this substance. UV irradiation of the printed images results in the generation of blue‐colored images associated with formation of a polydiacetylene (PDA). The resolutions of the images are almost identical to those generated using a conventional black ink. Importantly, the printed images undergo a blue‐to‐red color change upon exposure to water and the hydrochromism is found to be temperature dependent. The facile color change that occurs near body temperatures enables use of the hydrochromic PDA‐coated paper for rapid and precise mapping of human sweat pores from fingers, palms, and feet.
Inkjet printing of an aqueous solution of amphiphilic diacetylene followed by UV‐irradiation results in the generation of hydrochromic polydiacetylene on conventional paper. The polydiacetylene‐coated paper, which displays temperature‐dependent hydrochromism corresponding to a facile color change at near body temperature, enables a rapid and precise mapping of human sweat pores from fingers, palms, and feet.
Although a variety of stretchable strain sensors based on electrical percolation have been reported, stretchable sensors detecting low strains have been rarely demonstrated. This is because large ...stretchability of a strain sensor conflicts with high strain resolution at low strains. Here, the electrical percolation into 2D is confined and a strain sensor that is highly sensitive at low strains and simultaneously highly stretchable is presented. The 2D confinement of the electrical percolation is accomplished by a close‐packed monolayer assembly of conductive microparticles (MPs) on an elastomer substrate. The current profiles of the MP monolayer at low strains are in situ visualized using conductive atomic force microscopy. When the lattice of the MP monolayer is aligned vertically to the strain direction, the resistance is highly sensitive to low‐strain deformations (ε = 0 – 0.05), but the sensor has reasonable stretchability (ε = 0.3). The simultaneous achievement of the high sensitivity at low strains and the reasonable stretchability is explained by the relationship between the strain‐dependent current profile and the relative position changes of the MPs. A high‐precision pulse sensor clearly showing the representative peaks is demonstrated.
Here, 2D electrical percolation in a monolayer of close‐packed conductive microparticles is analyzed and a correlation between the electrical changes and the lattice orientation and morphology is established. A stretchable sensor with high sensitivity in small strains is demonstrated, which clearly presents the representative three peaks of the heart pulse (P1, P2, P3).
Abstract Background Blood loss occurs significantly more frequently during total hip and knee arthroplasty than among any other type of orthopedic operation, which can sometimes lead to requiring a ...blood transfusion. Although allogeneic blood transfusion has been identified as a risk factor for postoperative surgical-site infection following arthroplasty, results are inconclusive. The purpose of this study was to conduct a systematic meta-analysis to investigate whether having an allogeneic blood transfusion significantly increases the risk for surgical-site infection, particularly after total hip and knee arthroplasty. Methods We performed a systematic review and meta-analysis using random-effect models. Using an electronic database search, we selected 6 studies that included data on 21,770 patients and among these studies compared the postoperative infection rate between an allogeneic blood-transfusion exposure group and a nonexposure group. We calculated the pooled odds ratios and 95% confidence intervals for the groups. Results The prevalences of surgical-site infections in our pooled analyses were 2.88% and 1.74% for the transfusion and nontransfusion groups, respectively. The allogeneic blood transfusion group had a significantly higher frequency of surgical-site infections based on pooled analysis using a random-effect model (pooled odds ratio = 1.71, 95% confidence interval: 1.23-2.40, P = .002). Conclusion Allogeneic blood transfusion is a significant risk factor for increasing the surgical-site infection rate after total hip and knee arthroplasty.
Malnutrition is associated with many adverse clinical outcomes. The present study aimed to identify the prevalence of malnutrition in hospitalized patients in Korea, evaluate the association between ...malnutrition and clinical outcomes, and ascertain the risk factors of malnutrition.
A multicenter cross-sectional study was performed with 300 patients recruited from among the patients admitted in 25 hospitals on January 6, 2014. Nutritional status was assessed by using the Subjective Global Assessment (SGA). Demographic characteristics and underlying diseases were compared according to nutritional status. Logistic regression analysis was performed to identify the risk factors of malnutrition. Clinical outcomes such as rate of admission in intensive care units, length of hospital stay, and survival rate were evaluated.
The prevalence of malnutrition in the hospitalized patients was 22.0%. Old age (≥ 70 years), admission for medical treatment or diagnostic work-up, and underlying pulmonary or oncological disease were associated with malnutrition. Old age and admission for medical treatment or diagnostic work-up were identified to be risk factors of malnutrition in the multivariate analysis. Patients with malnutrition had longer hospital stay (SGA A = 7.63 ± 6.03 days, B = 9.02 ± 9.96 days, and C = 12.18 ± 7.24 days, P = 0.018) and lower 90-day survival rate (SGA A = 97.9%, B = 90.7%, and C = 58.3%, P < 0.001).
Malnutrition was common in hospitalized patients, and resulted in longer hospitalization and associated lower survival rate. The rate of malnutrition tended to be higher when the patient was older than 70 years old or hospitalized for medical treatment or diagnostic work-up compared to elective surgery.
Summary
The aim of this study was to evaluate the feasibility of biological hydrogen production (BHP) in a dynamic membrane bioreactor. Hydraulic retention time (HRT) was varied from 1 to 12 hours, ...and the microbial communities were analyzed. The major hydrogen‐producing bacterium was Clostridium chromiireducens, which was enriched up to 82% of the total bacteria with a 2 hour HRT, while Enterobacter cloacae was also observed in the range of 0.2% to 34.4% of total bacteria. When the level of the substrate in the reactor was low (<0.5 g/L), BHP dropped dramatically, and Sporolactobacillus putidus increased to 8.8% of the total bacteria. Differences in substrate affinity between S. putidus and C. chromiireducens likely promoted the dominance of S. putidus, which is more favorable for growth and metabolism at low substrate concentrations, and caused changes in the microbial community.
In this study, unexpected damage in continuous biohydrogen production using dynamic membrane bioreactor (DMBR) was interpreted based on the change of microbial community structure according to the remaining substrate in the reactor. Remaining substrate was advantageous to Sporolactobacillus sp., a competitive strain of hydrogen‐producing bacteria, with a relatively low substrate affinity. This result means that control of the remaining substrate in the reactor can be a key factor for stable hydrogen production.
We report the synthesis of centimeter-scale monolayer WS2 on gold foil by chemical vapor deposition. The limited tungsten and sulfur solubility in gold foil allows monolayer WS2 film growth on gold ...surface. To ensure the coverage uniformity of monolayer WS2 film, the tungsten source-coated substrate was placed in parallel with Au foil under hydrogen sulfide atmosphere. The high growth temperature near 935 °C helps to increase a domain size up to 420 μm. Gold foil is reused for the repeatable growth after bubbling transfer. The WS2-based field effect transistor reveals an electron mobility of 20 cm2 V–1 s–1 with high on–off ratio of ∼108 at room temperature, which is the highest reported value from previous reports of CVD-grown WS2 samples. The on–off ratio of integrated multiple FETs on the large area WS2 film on SiO2 (300 nm)/Si substrate shows within the same order, implying reasonable uniformity of WS2 FET device characteristics over a large area of 3 × 1.5 cm2.
To evaluate the effect of substrate concentration on competition between hydrogen producing bacteria and lactic acid bacteria during hydrogen fermentation, a series of batch tests was conducted using ...galactose or glucose as a carbon source. Clostridium butyricum, Lactobacillus casei, and mixture of the two species were used for inoculum, respectively. The batch tests based on single species revealed that C. butyricum utilized galactose faster than L. casei, regardless of substrate concentration (0.2–5.7 g/L), while L. casei utilized glucose faster than C. butyricum at low levels of glucose (<1 g/L). These trends were also observed in the batch test based on a mixture of the two species. L. casei outcompeted C. butyricum only when glucose was provided at low concentration. Taken together, the results suggest that failure of biohydrogen production can occur at low glucose concentration via outcompeting of lactic acid bacteria over hydrogen producing bacteria.
•Clostridium used galactose faster than Lactobacillus regardless of initial levels.•Lactobacillus used glucose faster than Clostridium at low initial concentrations.•Lactobacillus had a competitive advantage over Clostridium at low initial glucose.•Low levels of glucose can cause a failure of biohydrogen production.
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