Diatom DNA barcodes for forensic discrimination of drowning incidents

GO-CoNiP New Composite Material Modified Separator for Long Cycle Lithium-Sulfur Batteries

Lithium-sulfur batteries with high capacity are considered the most promising candidates for next-generation energy storage systems. Mitigating the shuttle reaction and promoting catalytic conversion within the battery are major challenges in the development of high-performance lithium-sulfur batteries. To solve these problems, a novel composite material GO-CoNiP is synthesized in this study. The material has excellent conductivity and abundant active sites to adsorb polysulfides and improve reaction kinetics within the battery. The initial capacity of the GO-CoNiP separator battery at 1 C is 889.4 mAh g-1 , and the single-cycle decay is 0.063% after 1000 cycles. In the 4 C high-rate test, the single-cycle decay is only 0.068% after 400 cycles. The initial capacity is as high as 828.2 mAh g-1 under high sulfur loading (7.3 mg cm-2 ). In addition, high and low-temperature performance tests are performed on the GO-CoNiP separator battery. The first cycle discharge reaches 810.9 mAh g-1 at a low temperature of 0 °C, and the first cycle discharge reaches 1064.8 mAh g-1 at a high temperature of 60 °C, and both can run stably for 120 cycles. In addition, in situ Raman tests are conducted to explain the adsorption of polysulfides by GO-CoNiP from a deeper level.

Application of Inorganic Quantum Dots in Advanced Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries have emerged as one of the most attractive alternatives for post-lithium-ion battery energy storage systems, owing to their ultrahigh theoretical energy density. However, the large-scale application of Li-S batteries remains enormously problematic because of the poor cycling life and safety problems, induced by the low conductivity , severe shuttling effect, poor reaction kinetics, and lithium dendrite formation. In recent studies, catalytic techniques are reported to promote the commercial application of Li-S batteries. Compared with the conventional catalytic sites on host materials, quantum dots (QDs) with ultrafine particle size (<10 nm) can provide large accessible surface area and strong polarity to restrict the shuttling effect, excellent catalytic effect to enhance the kinetics of redox reactions, as well as abundant lithiophilic nucleation sites to regulate Li deposition. In this review, the intrinsic hurdles of S conversion and Li stripping/plating reactions are first summarized. More importantly, a comprehensive overview is provided of inorganic QDs, in improving the efficiency and stability of Li-S batteries, with the strategies including composition optimization, defect and morphological engineering, design of heterostructures, and so forth. Finally, the prospects and challenges of QDs in Li-S batteries are discussed.

Covalent Organic Frameworks for Separator Modification of Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are regarded as one of the promising energy storage systems. However, rapid capacity attenuation caused by shuttle effect of soluble polysulfides is major challenge in practical application. The separator modification is regarded as one countermeasure besides the construction of sulfur host materials. Covalent organic frameworks (COFs) are one type of outstanding candidates for suppressing shuttle effect of polysulfides. Herein, recent advances of COFs in the application as commercial separator modifiers are summarized. COFs serve as ionic sieves, the importance of porous size and surface environments in inhibiting soluble polysulfides shuttling and promoting lithium ions conduction is highlighted. The superiority of charge-neutral COFs, ionic COFs, and the composites of COFs with conductive materials for improving reversible capacity and cycling stability is demonstrated. Some new strategies for the design of COF-based separator modifiers are proposed to achieving high energy density. The review provides new perspectives for future development of high-performance Li-S batteries.

Optimisation of Biomass Production and Nutritional Value of Two Marine Diatoms (Bacillariophyceae), Skeletonema costatum and Chaetoceros calcitrans

Simple Summary

One of the key constraints that is associated with the production of microalgae biomass and products, is the low yields that are associated with high production costs in microalgae cultivation units. Therefore, the aim of the present work was to improve the biomass productivity of two high-value diatom species, Skeletonema costatum and Chaetoceros calcitrans. To do so, the culture medium that was supplied to the cultures was optimised in a stepwise process, regarding the nutrient’s silicate, nitrate, phosphorus, iron, and micronutrients. For both diatoms, the results that were obtained revealed a significant increase in biomass productivity as well as an improved biochemical profile regarding increased omega-3 fatty acids contents. With this work, the optimise culture media was established for each diatom, thus providing a strategy for lower production costs that were reflected in higher productivities with higher biomass quality. Ultimately this will help improve the application of S. costatum and C. calcitrans in the aquaculture and nutraceutical industries.

Abstract

S. costatum and C. calcitrans are two cosmopolitan high-value centric diatoms, with a rich nutritional profile. The following work optimised the culture medium of S. costatum and C. calcitrans cultures, respectively, in a stepwise process as follows: 2.4 mM and 1.2 mM of silicate, 4 mM of nitrate, 100 µM of phosphate, 20 and 80 µM iron, and 0.5 mL L⁻¹ of micronutrients. The results that were obtained revealed an increase in biomass productivity with a 1.8- and 3.2-fold increase in biomass that was produced by S. costatum and C. calcitrans, respectively. The biochemical profile showed an increase in high-value PUFAs such as 2.6-fold and 2.3-fold increase in EPA for S. costatum and C. calcitrans, respectively, whilst a 2.6-fold increase in DHA was detected in S. costatum cultures. The present work provides the basic tools for the industrial cultivation of S. costatum and C. calcitrans with enhanced productivity as well as improved biomass quality, two factors which are highly relevant for a more effective application of these diatoms to aquaculture and nutraceutical production.

Lithium-Sulfur Battery Cathode Design: Tailoring Metal-Based Nanostructures for Robust Polysulfide Adsorption and Catalytic Conversion

Lithium-sulfur (Li-S) batteries have a high specific energy capacity and density of 1675 mAh g^-1 and 2670 Wh kg^-1 , respectively, rendering them among the most promising successors for lithium-ion batteries. However, there are myriads of obstacles in the practical application and commercialization of Li-S batteries, including the low conductivity of sulfur and its discharge products (Li₂ S/Li₂ S₂ ), volume expansion of sulfur electrode, and the polysulfide shuttle effect. Hence, immense attention has been devoted to rectifying these issues, of which the application of metal-based compounds (i.e., transition metal, metal phosphides, sulfides, oxides, carbides, nitrides, phosphosulfides, MXenes, hydroxides, and metal-organic frameworks) as sulfur hosts is profiled as a fascinating strategy to hinder the polysulfide shuttle effect stemming from the polar-polar interactions between the metal compounds and polysulfides. This review encompasses the fundamental electrochemical principles of Li-S batteries and insights into the interactions between the metal-based compounds and the polysulfides, with emphasis on the intimate structure-activity relationship corroborated with theoretical calculations. Additionally, the integration of conductive carbon-based materials to ameliorate the existing adsorptive abilities of the metal-based compound is systematically discussed. Lastly, the challenges and prospects toward the smart design of catalysts for the future development of practical Li-S batteries are presented.

Determination of a criminal suspect using environmental plant DNA metabarcoding technology

There are criminal cases that no frequently used evidence, for example, human DNAs from the criminal, is available. Such cases usually are unresolvable. With the advent of DNA metabarcoding, evidences are mined from environmental DNA and such cases become resolvable. This study reports how a criminal suspect was determined by environmental plant DNA metabarcoding technology. A girl was killed in a rural wet area in China without a witness or video record. Pants with dried mud was found from one of her classmate's house. The mud was removed from the pants and 11 more mud or soil samples surrounding murder scene were collected. DNA was extracted from the soil. Chloroplast rbcL gene were amplified and sequenced on a next generation sequencing platform. After bioinformatics analysis, ZOTU composition of 12 samples demonstrated that the mud on the suspect's pants was from the criminal scene. The suspect finally made a clean breast of his crime. This case implies that plant DNA in the environment soil is a new source of evidence in determination of suspects using DNA metabarcoding technology and has high potentials of extensive applications in criminal cases.

DNA metabarcoding of forensic mycological samples

Background

DNA metabarcoding and massive parallel sequencing are valuable molecular tools for the characterization of environmental samples. In forensic sciences, the analysis of the sample’s fungal population can be highly informative for the estimation of post-mortem interval, the ascertainment of deposition time, the identification of the cause of death, or the location of buried corpses. Unfortunately, metabarcoding data analysis often requires strong bioinformatic capabilities that are not widely available in forensic laboratories.

Results

The present paper describes the adoption of a user-friendly cloud-based application for the identification of fungi in typical forensic samples. The samples have also been analyzed through the QIIME pipeline, obtaining a relevant data concordance on top genus classification results (88%).

Conclusions

The availability of a user-friendly application that can be run without command line activities will increase the popularity of metabarcoding fungal analysis in forensic samples.

Comparative study on diatom morphology and molecular identification in drowning cases

In the field of criminal investigations, in the event that a body is found in water, the ability to differentiate whether the cause of death was drowning or the body was murdered then dumped into water elsewhere is difficult but important for case detection. Detecting diatoms in human organs can be used to effectively identify if the cause of death was drowning. At present, diatom detection methods are roughly divided into morphological and molecular detection methods, but both methods have different limitations. In this study, a total of 79 samples from 23 victims in 19 known drowning deaths were collected. The diatom morphological identification combined with DNA metabarcoding technology was used to compare the reliability of the diatom detection method. Microscopic observations revealed that the positive detection rate of diatoms was 52.6 %, 26.3 % and 58.8 % respectively in the kidney, liver and lung samples. DNA metabarcoding analysis found that the positive detection rate of diatoms was 31.6 %, 31.6 % and 35.3 % respectively in kidney, liver and lung samples. When compared with barcode BacirbcL, barcode 18S605 detected more diatoms, while diatoms in BacirbcL were more consistent with environmental samples. The comparative analysis found that microscopic observations were not highly correlated with the identification results of DNA barcoding technology. There were no obvious differences in the effect of internal organs on diatom enrichment, and different organs should be tested at the same time. At present, the DNA barcode reference sequence is gravely insufficient and has many errors, which leads to restrictions in the application of this technology, resulting in many OTU not being accurately identified. This explains why the success rate of molecular identification is not higher than that of microscopic identification. Construction of a reliable diatom DNA barcode reference sequence database is an urgent task for drowning forensics.