Rapid and In-Field Sensing of Hydrogen Peroxide in Plant by Hydrogel Microneedle Patch.

The rapidly changing climate is exacerbating the environmental stress that negatively impacts crop health and yield. Timely sensing of plant response to stress is beneficial to timely adjust planting conditions, promoting the healthy growth of plants, and improving plant productivity. Hydrogen peroxide (H2O2) is an important molecule of signal transduction in plants. However, the common methods for detecting H2O2  in plants are associated with certain drawbacks, such as long extraction time, cumbersome steps, dependence on large instruments, and difficulty in realizing in-field sensing. Therefore, it is urgent to establish more efficient detection methods to realize the rapid detection of H2O2 content in plants. In this research, poly (methyl vinyl ether-alt-maleic acid) (PMVE/MA) hydrogel microneedle (MN) patch for rapid extraction of leaf sap are prepared, and the extraction mechanism of PEG-crosslinked PMVE/MA hydrogel MN patch is studied. A method of rapid detection of H2O2 content in plants based on MN patch with optical detection technology is constructed. The hydrogel MN patch can be used for timely H2O2 analysis. This application enables new opportunities in plant engineering, and can be extended to the safety and health monitoring of other plants and animals.

Recent advances in hydrogel microneedle-based biofluid extraction and detection in food and agriculture.

Microneedle (MN) technology has been extensively studied for its advantages of minimal invasiveness and user-friendliness. Notably, hydrogel microneedles (HMNs) have garnered considerable attention for biofluid extraction due to its high swelling properties and biocompatibility. This review provides a comprehensive overview of definition, materials, and fabrication methods associated with HMNs. The extraction mechanisms and optimization strategies for enhancing extraction efficiency are summarized. Moreover, particular emphasis is placed on HMN-based biofluid extraction and detection in the domains of food and agriculture, encompassing the detection of small molecules, nucleic acids, and other relevant analytes. Finally, current challenges and possible solutions associated with HMN-based biofluid extraction are discussed.

Alternating polarity as a novel strategy for building synthetic microbial communities capable of robust Electro-Methanogenesis.

Electro-methanogenic microbial communities can produce biogas with high efficiency and have attracted extensive research interest. In this study an alternating polarity strategy was developed to build electro-methanogenic communities. In two-chamber bioelectrochemical systems amended with activated carbon, the electrode potential was alternated between +0.8 V and -0.4 V vs. standard hydrogen electrode every three days. Cumulative biogas production under alternating polarity increased from 45 L/L/kg-activated carbon after start-up to 125 L/L/kg after the 4th enrichment, significantly higher than that under intermittent cathode (-0.4 V/open circuit), continuous cathode (-0.4 V), and open circuit. The communities assembled under alternating polarity were electroactive and structurally different from those assembled under other conditions. One Methanobacterium population and two Geobacter populations were consistently abundant and active in the communities. Their 16S rRNA was up-regulated by electrode potentials. Bayesian networks inferred close associations between these populations. Overall, electro-methanogenic communities have been successfully assembled with alternating polarity.

Linking population dynamics to microbial kinetics for hybrid modeling of bioelectrochemical systems.

Mechanistic and data-driven models have been developed to provide predictive insights into the design and optimization of engineered bioprocesses. These two modeling strategies can be combined to form hybrid models to address the issues of parameter identifiability and prediction interpretability. Herein, we developed a novel and robust hybrid modeling strategy by incorporating microbial population dynamics into model construction. The hybrid model was constructed using bioelectrochemical systems (BES) as a platform system. We collected 77 samples from 13 publications, in which the BES were operated under diverse conditions, and performed holistic processing of the 16S rRNA amplicon sequencing data. Community analysis revealed core populations composed of putative electroactive taxa Geobacter, Desulfovibrio, Pseudomonas, and Acinetobacter. Primary Bayesian networks were trained with the core populations and environmental parameters, and directed Bayesian networks were trained by defining the operating parameters to improve the prediction interpretability. Both networks were validated with Bray-Curtis similarly, relative root-mean-square error (RMSE), and a null model. A hybrid model was developed by first building a three-population mechanistic component and subsequently feeding the estimated microbial kinetic parameters into network training. The hybrid model generated a simulated community that shared a Bray-Curtis similarity of 72% with the actual microbial community at the genus level and an average relative RMSE of 7% for individual taxa. When examined with additional samples that were not included in network training, the hybrid model achieved accurate prediction of current production with a relative error-based RMSE of 0.8 and outperformed the data-driven models. The genomics-enabled hybrid modeling strategy represents a significant step toward robust simulation of a variety of engineered bioprocesses.

Collision Carcinoma Involving Small Cell Neuroendocrine Carcinoma and Squamous Cell Carcinoma of the Ureter: A Case Report and Review of the Literature.

BACKGROUND: Small cell neuroendocrine carcinoma (SCNEC) of the ureter is a rare tumour, accounting for less than 0.5% of all ureteral tumours. SCNEC tumours are highly aggressive and patients have a poor prognosis. Ureteral SCNEC colliding with other pathological types of tumours is extremely rare. In this paper, we present the case of a patient with ureteral small cell carcinoma colliding with squamous cell carcinoma and review the literature regarding the clinicopathological features, treatment and prognosis of thus tumour. To the best of our knowledge, this is the second identified case of ureteral SCNEC colliding with SCC. CASE PRESENTATION: A 64-year-old male patient presented with a history of 1 month of gross haematuria and 3 months of left flank pain. CT urography revealed a soft tissue mass in the upper ureter, which was slightly enhanced on contrast-enhanced CT. Nephroureterectomy was performed after the patient was diagnosed with a tumour in the left ureter. Microscopy and immunohistochemical examination confirmed the mass to be a SCNEC collision with SCC. Two months after the surgery, the patient received adjuvant chemotherapy (cisplatin/etoposide). After 14 months of follow-up, no local recurrence or distant metastasis was found. CONCLUSION: Ureteral collision carcinoma with SCNEC predominantly occurs in Asian individuals, is difficult to diagnose preoperatively and is highly invasive. The current management of ureteral collision carcinoma is a comprehensive treatment based on surgery.

Development and evaluation of a point-of-use UV appliance for fresh produce decontamination.

In-house treatment strategy for fresh produce decontamination has not been emphasized as much as industrial washing. The most common treatment for fresh produce decontamination and cleaning at home and other point-of-use places such as cafeteria is rinsing and/or soaking in a sink. In this study, an appliance utilizing UV and agitated water to decontaminate fresh produce was developed and its effectiveness was investigated in an aim to identify optimum processing parameters. Grape tomato and spinach representing two different surface smoothness were dip-inoculated in a four-strain Salmonella cocktail to reach a final population of 5-8 log CFU/g and air-dried. The produce samples were then washed in 1 gallon tap water under varying conditions, water agitation speed (0-190 RPM), sample size (50-400 g), UV intensity (0-30 mW/cm2) and treatment time (2, 5 and 10 min). In general, increasing the agitation speed and UV intensity enhanced Salmonella inactivation for both grape tomato and spinach. Sample size significantly affected the UV inactivation of Salmonella on grape tomato, but not on spinach. The effect of extending treatment time from 2 to 10 min was insignificant for almost all the UV treatments and the controls. The effect of UV intensity and treatment time on inactivation of Salmonella on spot-inoculated grape tomato and spinach was also determined. The most severe treatment used in this study, 30 mW/cm2 UV for 10 min, resulted in >4 log reductions of Salmonella dip- or spot-inoculated on grape tomato (200 g sample size and 190 RPM agitation speed) and 3.5 log reductions of Salmonella dip- or spot-inoculated on spinach (100 g sample size and 110 RPM agitation speed). We foresee that the UV appliance developed and evaluated in this study could be further fine-tuned and optimized to eventually construct a point-of-use UV appliance that can be used at home, cafeteria, restaurants, and hospitals for fresh produce decontamination and cleaning. The UV appliance could be an inexpensive and effective tool to improve fresh produce safety.

Evaluation of the combined treatment of ultraviolet light and peracetic acid as an alternative to chlorine washing for lettuce decontamination.

The potential of using ultraviolet light (UV) in combination of peracetic acid (PAA) as an alternative to chlorine washing for lettuce was evaluated. Shredded iceberg lettuce was dip-inoculated with a four-strain Salmonella cocktail to final levels of 6-7.5 log CFU/g, following by air-drying and overnight cold storage. The inoculated lettuce (80 g) was then washed in turbid tap water containing 6% lettuce juice extract and silicon dioxide (turbidity of ~60 NTU; COD of ~2000 mg/L) while being treated with 1) 10 or 20 ppm free chlorine, 2) PAA solution (40 and 80 ppm), 3) UV (10, 20 and 30 mW/cm2), 4) a combination of UV and PAA for 1, 2, and 5 min. Among all the single treatments, the 30 mW/cm2 UV treatment achieved the highest Salmonella reduction on lettuce. For the 2-min treatment group, the 30 mW/cm2 UV treatment achieved 1.98 log reduction, while the 80 ppm PAA and 20 ppm free chlorine resulted in 1.52 and 1.23 log reduction, respectively. The combined treatment of 30 mW/cm2 UV and 80 ppm PAA achieved significantly higher (P < .05) Salmonella reduction than the 20 ppm free chlorine washing. For the 5-min treatment group, the combined treatment resulted in 3.24 log reduction, while the 20 ppm free chlorine washing only achieved 1.24 log reduction. The effect of the combined treatment of 30 mW/cm2 UV and 80 ppm PAA was also compared with 20 ppm free chlorine washing on larger sample sizes of 200, 500, and 1000 g lettuce. The increase of sample size from 80 g to 1000 g did not significantly (P < .05) affect the inactivation of Salmonella on lettuce for the combined treatment. In addition, the combined treatment of 80 ppm PAA and 30 mW/cm2 UV was able to maintain the Salmonella population in wash water under the detection limit of 0.3 log CFU/mL. It was therefore concluded that the combined treatment of 30 mW/cm2 UV and 80 ppm PAA could be used as an alternative to chlorine washing for lettuce decontamination.

Field evaluation of a novel UV water disinfection system for use in underserved rural communities.

Reliable, robust, and inexpensive disinfection systems are needed to expand water security in remote and underserviced areas. This paper reports on the deployment and evaluation of a novel UV water disinfection system in a remote rural community. Prior laboratory tests indicated a 7.12 log10 reduction of the bacteriophage MS-2 at a flow rate of 9.46 L/min, which corresponds to a supplied UV dose 215 mJ/cm2 . Further tests in water containing turbidity levels up to 18 NTU showed E. coli removal remaining above the 5 log10 level. Field testing was performed at a Native American reservation in Northern California where the system was used to treat groundwater obtained from a well with a known fecal contamination. The system was powered by solar panel and was operated on-demand for extended periods. Tests on the treated water showed that the system exceeded the standard of disinfection required for drinking water. PRACTITIONER POINTS: A novel system for water disinfection with UV light is described. Laboratory and field tests showed high levels of disinfection achieved even at low UVT and high turbidity. System is robust, reliable and inexpensive to produce thus suitable for use in underserved communities.