Microbial diversity analysis of jiaoke from Xilingol, Inner Mongolia.

Jiaoke is a traditional Mongolian fermented dairy product that is nutritious and has a unique taste. It is made from the fat separated from fermented milk. In this study, we collected 24 jiaoke samples from the Xilingol region of Inner Mongolia. The microbiota composition of the collected samples was analyzed using 16S rRNA small-molecule real-time sequencing, and the lactic acid bacteria (LAB) population was enumerated and isolated by laboratory culture techniques. We used an electronic tongue device to assess the taste quality of the products. One hundred fifty LAB isolates (5 genera and 14 species) were recovered and identified by 16S rRNA sequencing across all samples. Lactococcus lactis and Lactobacillus plantarum accounted for 51.33% and 10.67% of the total isolates, respectively. The small-molecule real-time sequencing of full-length 16S rRNAs revealed an overall bacterial microbiota composition of 10 phyla, 121 genera, and 186 species, largely represented by sequences of Lactococcus (68.46%) and Lactococcus lactis (52.92%) at the genus and species levels, respectively. The electronic tongue analysis revealed that the sweetness, bitterness, sourness, and saltiness of jiaoke varied greatly between samples. The presence of Lactococcus lactis correlated positively with bitter aftertaste; the presence of Lactococcus piscium correlated positively with umami and negatively with astringent and bitter aftertastes; and the presence of Lactobacillus helveticus correlated positively with sourness and negatively with other taste qualities. These results suggest that the microbiota composition and product taste are closely related. The novel LAB strains collected in this work represent valuable natural microbial resources.

Shampoo assisted aligning of carbon nanotubes toward strong, stiff and conductive fibers.

High alignment and densification of carbon nanotubes (CNTs) are of key importance for strengthening CNT fibers, whereas direct stretching has a very limited effect when CNTs are highly entangled. We report that by lubricating CNT surfaces with viscous alcohols, the relative motion between CNTs improves because of the reduced sliding energy barrier; thus non-stretched regions are effectively eliminated. Owing to the very efficient optimization of the assembled structure, the stretched CNT fibers exhibited an average tensile strength of 2.33 GPa (1.82 N per tex) and modulus of 70.1 GPa (54.8 N per tex). Other fundamental properties, such as electrical and thermal conductivities, were also remarkably improved. Such a strategy can be readily used for manufacturing high-performance CNT assemblies and composites.

Analyses of physicochemical properties, bacterial microbiota, and lactic acid bacteria of fresh camel milk collected in Inner Mongolia.

Camel milk has significant economic value and is an important food in the region of Alxa Left Banner of Inner Mongolia. Fifteen fresh camel milk samples were collected from domesticated camels in a pasture of Alxa Left Banner. The physicochemical properties and bacterial diversity of camel milk samples were analyzed. The average values of fat, total protein, nonfat milk solids, acidity, and density were 4.40%, 3.87%, 9.50%, 16.95°T, and 1.02 g/cm3, respectively. The bacterial microbiota of the collected fresh camel milk was investigated using PacBio single-molecule real-time (Pacific Biosciences, Menlo Park, CA) sequencing. The camel milk microbiota was highly diverse and comprised 8,513 operational taxonomic units belonging to 32 phyla, 377 genera, and 652 species. The major phyla included Proteobacteria, Firmicutes, Deinococcus-Thermus, Bacteroidetes, and Actinobacteria. A small number of lactic acid bacteria sequences were detected, representing the species Streptococcus thermophilus, Lactobacillus helveticus, Lactococcus lactis, and Leuconostoc mesenteroides. A total of 72 strains of lactic acid bacteria were isolated and identified from 15 samples, including Lactobacillus paracasei, Enterococcus italicus, Enterococcus durans, Lactococcus lactis ssp. lactis, Weissella confusa, and Enterococcus faecium. These results confirm that fresh camel milk has a high bacterial diversity and is a valuable natural resource for isolation of novel lactic acid bacteria.

Millisecond tension-annealing for enhancing carbon nanotube fibers.

Mechanically strong carbon nanotube (CNT) fibers have increasingly become the focus of the present research in the fiber industry. However, the weak or even a lack of interconnections between adjacent CNTs induces much inter-tube slippages during fiber failure, and thus results in their low mechanical strength. Moreover, achieving fast cross-linking between neighbouring CNTs on a large scale to prevent the failure by slip is still a big challenge. Herein we report an ultrafast and continuous tension-annealing process to achieve the considerably improved tube alignment and strong covalent cross-linking of neighbouring CNTs in milliseconds, resulting in great improvement of the fiber performance. The CNT fibers were heated to high temperature (∼2450 °C) by Joule heating under the applied tension and subsequently annealed for just 12 ms. Due to the rapid electromechanical response of the fibers, instant nanotube rearrangements coupled by the formation of cross-links robustly bonding the adjacent CNTs occurred at power-on, which could be attributed to the considerable increases of strength and modulus by factors of 2.9 (up to 3.2 GPa) and 4.8 (up to 123 GPa), respectively. The resultant fibers showed high specific strength (2.2 N per tex), comparable with that of PAN-based carbon fibers, and high specific electrical conductivity higher than that of PAN-based carbon fibers. Moreover, the obtained strongly crosslinked and highly dense structures also endowed the fibers with the significantly improved thermal stability under a high-temperature oxidation atmosphere. Moreover, a continuous tension-annealing process was designed to achieve the large scale production of high performance fibers with the average strength of 2.2 GPa. The high-toughness, lightweight and continuous features together with their outstanding mechanical and electrical properties would certainly boost the large-scale applications of CNT fibers.

Soft and MRI Compatible Neural Electrodes from Carbon Nanotube Fibers.

Soft and magnetic resonance imaging (MRI) compatible neural electrodes enable stable chronic electrophysiological measurements and anatomical or functional MRI studies of the entire brain without electrode interference with MRI images. These properties are important for many studies, ranging from a fundamental neurophysiological study of functional MRI signals to a chronic neuromodulatory effect investigation of therapeutic deep brain stimulation. Here we develop soft and MRI compatible neural electrodes using carbon nanotube (CNT) fibers with a diameter from 20 µm down to 5 µm. The CNT fiber electrodes demonstrate excellent interfacial electrochemical properties and greatly reduced MRI artifacts than PtIr electrodes under a 7.0 T MRI scanner. With a shuttle-assisted implantation strategy, we show that the soft CNT fiber electrodes can precisely target specific brain regions and record high-quality single-unit neural signals. Significantly, they are capable of continuously detecting and isolating single neuronal units from rats for up to 4-5 months without electrode repositioning, with greatly reduced brain inflammatory responses as compared to their stiff metal counterparts. In addition, we show that due to their high tensile strength, the CNT fiber electrodes can be retracted controllably postinsertion, which provides an effective and convenient way to do multidepth recording or potentially selecting cells with particular response properties. The chronic recording stability and MRI compatibility, together with their small size, provide the CNT fiber electrodes unique research capabilities for both basic and applied neuroscience studies.

Ni Nanobuffer Layer Provides Light-Weight CNT/Cu Fibers with Superior Robustness, Conductivity, and Ampacity.

Carbon nanotube (CNT) fiber has not shown its advantage as next-generation light-weight conductor due to the large contact resistance between CNTs, as reflected by its low conductivity and ampacity. Coating CNT fiber with a metal layer like Cu has become an effective solution to this problem. However, the weak CNT-Cu interfacial bonding significantly limits the mechanical and electrical performances. Here, we report that a strong CNT-Cu interface can be formed by introducing a Ni nanobuffer layer before depositing the Cu layer. The Ni nanobuffer layer remarkably promotes the load and heat transfer efficiencies between the CNT fiber and Cu layer and improves the quality of the deposited Cu layer. As a result, the new composite fiber with a 2 µm thick Cu layer can exhibit a superhigh effective strength >800 MPa, electrical conductivity >2 × 107 S/m, and ampacity >1 × 105 A/cm2. The composite fiber can also sustain 10 000 times of bending and continuously work for 100 h at 90% ampacity.

Direct Intertube Cross-Linking of Carbon Nanotubes at Room Temperature.

Carbon nanotubes (CNTs) have long been regarded as an efficient free radical scavenger because of the large-conjugation system in their electronic structures. Hence, despite abundant reports on CNT reacting with incoming free radical species, current research has not seen CNT itself displaying the chemical reactivity of free radicals. Here we show that reactive free radicals can in fact be generated on carbon nanotubes via reductive defluorination of highly fluorinated single-walled carbon nanotubes (FSWNTs). This finding not only enriches the current understanding of carbon nanotube chemical reactivity but also opens up new opportunities in CNT-based material design. For example, spacer-free direct intertube cross-linking of carbon nanotubes was previously achieved only under extremely high temperature and pressure or electron/ion beam irradiation. With the free radicals on defluorinated FSWNTs, the nanotubes containing multiple radicals on the sidewall can directly cross-link with each other under ambient temperature through intertube radical recombination. It is demonstrated that carbon nanotube fibers reinforced via direct cross-linking displays much improved mechanical properties.

New perspectives on schizophrenia in later life: implications for treatment, policy, and research.

Worldwide, in the past few decades, the demographics of older people (ie, people 55 years and over) with schizophrenia have changed completely with respect to absolute numbers of people affected, the proportion of all people with the disorder, life expectancy, and residential status. The ageing schizophrenia population has created vast health-care needs and their medical comorbidity contributes to higher mortality than in the general population. Proposals to classify schizophrenia into early-onset, late-onset, and very-late-onset subtypes now should be tempered by the recognition that comorbid medical and neurological disorders can contribute to psychotic symptoms in later life. The concept of outcome has become more nuanced with an appreciation that various outcomes can occur, largely independent of each other, that need different treatment approaches. Data show that schizophrenia in later life is not a stable end-state but one of fluctuation in symptoms and level of functioning, and show that pathways to improvement and recovery exist. Several novel non-pharmacological treatment strategies have been devised that can augment the clinical options used to address the specific needs of older adults with schizophrenia.

Bio-Inspired Aggregation Control of Carbon Nanotubes for Ultra-Strong Composites.

High performance nanocomposites require well dispersion and high alignment of the nanometer-sized components, at a high mass or volume fraction as well. However, the road towards such composite structure is severely hindered due to the easy aggregation of these nanometer-sized components. Here we demonstrate a big step to approach the ideal composite structure for carbon nanotube (CNT) where all the CNTs were highly packed, aligned, and unaggregated, with the impregnated polymers acting as interfacial adhesions and mortars to build up the composite structure. The strategy was based on a bio-inspired aggregation control to limit the CNT aggregation to be sub 20-50 nm, a dimension determined by the CNT growth. After being stretched with full structural relaxation in a multi-step way, the CNT/polymer (bismaleimide) composite yielded super-high tensile strengths up to 6.27-6.94 GPa, more than 100% higher than those of carbon fiber/epoxy composites, and toughnesses up to 117-192 MPa. We anticipate that the present study can be generalized for developing multifunctional and smart nanocomposites where all the surfaces of nanometer-sized components can take part in shear transfer of mechanical, thermal, and electrical signals.

Electro-induced mechanical and thermal responses of carbon nanotube fibers.

The electromechanical and electrothermal responses of carbon nanotube fibers provide new ways to use energy conversion, including the modulation of assembly structures by alternative densification and relaxation. The most efficient way to strengthen the tensile strength up to 2.32-2.50 GPa is shown as well as a microscale, nanotube-based Chinese calligraphy brush.

Carbon nanotube fibers for electrochemical applications: effect of enhanced interfaces by an acid treatment.

Chemical treatment using concentrated nitric acid (16 M) not only induced significant improvement of mechanical and electrical properties of carbon nanotube fibers due to the enhanced interfacial interaction but also allowed much more efficient deposition of polyaniline for developing fiber-shaped supercapacitors. After the 2 h treatment, the acidized fiber had a tensile strength of 1.52 GPa and an electrical conductivity of 1050 S cm(-1), increased by 52% and 128%, respectively, compared with the untreated one. By depositing polyaniline for 10 min around the fiber, the composite fiber had a volumetric capacitance of 239 F cm(-3), 17% higher than that without the acid treatment. For a long time treatment up to 6 h, although the strength and conductivity decreased slightly, the composite fiber had a super high volumetric capacitance up to 299 F cm(-3). The improvement of electrochemical performance is attributed to the increased deposition rate and structural change of polyaniline due to the existence of functional groups on the fiber surface.

Continuous electrodeposition for lightweight, highly conducting and strong carbon nanotube-copper composite fibers.

Carbon nanotube (CNT) fiber is a promising candidate for lightweight cables. The introduction of metal particles on a CNT fiber can effectively improve its electrical conductivity. However, the decrease in strength is observed in CNT-metal composite fibers. Here we demonstrate a continuous process, which combines fiber spinning, CNT anodization and metal deposition, to fabricate lightweight and high-strength CNT-Cu fibers with metal-like conductivities. The composite fiber with anodized CNTs exhibits a conductivity of 4.08 × 10(4)-1.84 × 10(5) S cm(-1) and a mass density of 1.87-3.08 g cm(-3), as the Cu thickness is changed from 1 to 3 µm. It can be 600-811 MPa in strength, as strong as the un-anodized pure CNT fiber (656 MPa). We also find that during the tensile tests there are slips between the inner CNTs and the outer Cu layer, leading to the drops in electrical conductivity. Therefore, there is an effective fiber strength before which the Cu layer is robust. Due to the improved interfacial bonding between the Cu layer and the anodized CNT surfaces, such effective strength is still high, up to 490-570 MPa.

Double-peak mechanical properties of carbon-nanotube fibers.

The introduction of twist during the spinning of carbon nanotubes from their arrays (forests) has been widely applied in making ultrastrong, stiff, and lightweight nanotube fibers. Here, for the first time, an important observation of a double-peak behavior of the tensile properties, as a function of the twist angle, that is different from the single peak of traditional fibers is reported. Raman spectra show that the new peak arises from the collapse of nanotubes, showing a strong "nano" element in applying the ancient draw-and-twist technique, besides the downsizing. A qualitative continuum model is also presented to describe the collapse-induced enhancement as well as traditional fibers. Our combined experimental and theoretical studies indicate the direction of full utilization of the nano element in improving the mechanical properties of nanotube fibers.