OBJECTIVES/GOALS: Current clinical practice recommends occlusive dressings (e.g., film and hydrocolloid) for wounds with variable regenerative capacities. However, clinical evidence suggests that occlusion may hinder regeneration. Our objective was to test the impact of occlusion on regeneration using animal models. METHODS/STUDY POPULATION: The murine wound-induced hair neogenesis (WIHN) is a well-established model of regeneration characterized by de novo hair follicle (HF) formation in the center of large full-thickness wounds. The quantity of neogenic HFs depends on the robustness of Wnt signaling. Optimal tissue mechanics is also required for WIHN. Utilizing the murine WIHN model, we tested the hypothesis that wound occlusion impedes regeneration. We determined how (i) the timing and duration of wound occlusion impacts WIHN, (ii) Wnt signaling influences the occlusion-induced effects on regeneration and (iii) occlusion alters the tissue mechanics of the wound, which establishes the morphogenetic field needed for WIHN. RESULTS/ANTICIPATED RESULTS: Occlusion completely eliminated WIHN. Only a brief period of occlusion between post-wound days 0-3 or 4-7 was sufficient to abrogate WIHN. Microarray and qPCR of open and occluded wounds demonstrated that occlusion promotes fibrosis by upregulating TGF-β2 and mechanotransduction, a mechanosensitive profibrotic pathway. Recruitment of these potent profibrotic pathways generated a symmetrically rigid wound incapable of de novo HF regeneration. Using transgenic animal models with enhanced Wnt signaling, we determined that the ligand-dependent Wnt signaling protected against the occlusion-induced inhibition of WIHN, as well as the occlusion-induced upregulation of both profibrotic pathways. DISCUSSION/SIGNIFICANCE: In animal models, occlusion promoted fibrosis at the expense of regeneration during acute wound healing. Augmented Wnt signaling protected against this effect. Occluding wounds may reduce regeneration. Further studies are warranted to validate these findings.

Dual-chirped difference frequency generation (DFG) is an advantageous technique for generating the broadband mid-infrared (IR) idler wave, which is inaccessible by a population-inversion-based laser system. In principle, the generated idler wave may even suffer a spectrum broadening compared with the driving pulsed lasers if the pump and signal waves are oppositely chirped. However, broadband phase-matching is always the determining factor for the resulting efficiency and the bandwidth of the generated idler wave. In this study, specific to an oppositely dual-chirped DFG scheme, we derive the precondition to realize broadband frequency conversion, wherein a negative $(1/\unicode[STIX]{x1D710}_{p}-1/\unicode[STIX]{x1D710}_{i})/(1/\unicode[STIX]{x1D710}_{s}-1/\unicode[STIX]{x1D710}_{i})$, in terms of the correlation coefficient of the group velocity ($\unicode[STIX]{x1D70E}$), is necessary. However, most birefringence bulk crystals can only provide the required material dispersions in limited spectral regions. We show that the periodically poled lithium niobate crystal that satisfies an inactive Type-II (eo-o) quasi-phase-matching condition has a stable negative $\unicode[STIX]{x1D70E}$ and exerts the expected broadband gain characteristic across an ultra-broad idler spectral region $(1.7{-}4.0~\unicode[STIX]{x03BC}\text{m})$. Finally, we propose and numerically verify a promising DFG configuration to construct a tunable mid-IR spectrum broader based on the broadband phase-matched oppositely dual-chirped DFG scheme.

This article presents a brief review of our case studies of data-driven Integrated Computational Materials Engineering (ICME) for intelligently discovering advanced structural metal materials, including light-weight materials (Ti, Mg, and Al alloys), refractory high-entropy alloys, and superalloys. The basic bonding in terms of topology and electronic structures is recommended to be considered as the building blocks/units constructing the microstructures of advanced materials. It is highlighted that the bonding charge density could not only provide an atomic and electronic insight into the physical nature of chemical bond of materials but also reveal the fundamental strengthening/embrittlement mechanisms and the local phase transformations of planar defects, paving a path in accelerating the development of advanced metal materials via interfacial engineering. Perspectives on the knowledge-based modeling/simulations, machine-learning knowledge base, platform, and next-generation workforce for sustainable ecosystem of ICME are highlighted, thus to call for more duty on the developments of advanced structural metal materials and enhancement of research productivity and collaboration.

Residents of Hong Kong have undergone a dietary transition from a traditional Chinese diet that is high in seafood to a more Western diet. This may have affected the nutritional composition of breast milk of Hong Kong mothers. The present study aims to investigate the relationship between the dietary pattern and the fatty acid profile of the breast milk of lactating women in Hong Kong. Seventy-three volunteering healthy Hong Kong lactating mothers participated in the study. Their dietary intakes were assessed by using a 3-d dietary record and FFQ. The mean n-3 fatty acid levels were approximately 0·4 % (EPA) and 0·9 % (DHA) of total fatty acids in the breast milk of lactating mothers who had exclusively breastfed their infants aged 2–6 months. Maternal dietary intakes of n-3 fatty acids were positively associated with their levels in the breast milk. The levels of maternal intakes of freshwater and saltwater fish, especially the consumption of salmon, croaker and mandarin, were significantly correlated with the content of DHA in breast milk. The present study is among the very few in the literature to determine the fatty acid profile of breast milk in Hong Kong populations and verify certain dietary factors that influence this profile. High levels of n-3 PUFA, especially DHA, were observed in the breast milk of Hong Kong lactating women. The findings may serve as a dietary reference for lactating mothers to optimise the fatty acid profile of their breast milk.

Graphoglyptids are biogenic structures commonly found in deep-sea flysch deposits and occasionally detected on the modern deep-sea floor. They extend principally horizontally and take a variety of geometric patterns, whose functional morphology remains an enigma in ichnology and paleoceanography. Based on published materials from 1850 to 2017 (79 ichnotaxa from 28 ichnogenera of graphoglyptids) and systematic observations of one of the largest deep-sea trace fossil collections in the world, this paper proposes that topological analysis is an important ingredient in the taxonomy and functional interpretation of graphoglyptids. Accordingly, graphoglyptids are classified into line, tree, and net forms by their key topological architecture, and are further attributed to 19 topological prototypes by detailed secondary topological features. Line graphoglyptids are single-connected structures with uniform tunnel width, representing primarily the feeding patterns of solitary animals. Tree graphoglyptids, the most diverse architectural group of graphoglyptids, are ascribed to 11 topological prototypes according to the connectivity features of burrow segments and the number and distributional pattern of the branching points. Net graphoglyptids are subdivided into three topological prototypes on the basis of the connectivity features and/or the regularity of the meshes. Multiconnected net forms are considered as a continuous morphological spectrum with different levels of complexity in the net formation. The various connected components in multiconnected tree and net graphoglyptids generally exhibit small and uniform tunnel diameter in a given structure (suggesting a tiny trace maker[s]). The whole structure shows relatively extensive linear or surface coverage and overall good preservation, indicating sustained processes of burrow construction. It is highly probable that certain multiconnected tree and net graphoglyptids represent some emergent patterns from self-organized collective behaviors of conspecific animals. Graphoglyptids thus provide us with a new perspective on the study of solitary and collective behaviors of macrobenthos in the deep-sea environment.

Nanopore tuning via atomic layer deposition (ALD) is promising but its conformality on sub-10nm pores and its homogeneity over the whole porous network is still challenging, primarily due to the slow transport within the porous network. Conventional ALD process oftentimes falls into a dilemma: higher temperature and prolonged exposure/purge time are required to overcome the slow transport issue, but higher temperature will cause the instability of surface –OH groups and prolonged exposure/purge time will result in “over purge” at the surface vicinity, leading to another type of non-homogeneity. To resolve this issue, a new dual-stage exposure/purge ALD process was developed. Each exposure/purge step contains a longer exposure/purge stage and a shorter exposure/purge stage, where the longer stage ensures ideal exposure/purge for inner pores, and the shorter stage makes up the surface depletion for the outer pores. By doing so, we’ve been able to extend the ALD nanopore tuning to sub-10nm pores with excellent coating homogeneity and conformality.

The study investigated whether dietary methionine (Met) affects egg weight and antioxidant status through regulating gene expression of ovalbumin (OVAL), nuclear factor erythroid 2 like 2 (Nrf2) and haem oxygenase 1 (HO-1) in laying duck breeders. Longyan duck breeders (n 540, 19 weeks) were randomly assigned to six treatments with six replicates of fifteen birds each. Breeders were fed diets with six Met levels (2·00, 2·75, 3·50, 4·25, 5·00 and 5·75 g/kg) for 24 weeks. The egg weight (g), egg mass (g/d), feed conversion ratio, hatchability, 1-d duckling weight, albumen weight, albumen proportion and OVAL mRNA level improved with dietary Met levels, whereas yolk proportion decreased (P<0·05). The weight of total large yellow follicles increased linearly (P<0·001) and quadratically (P<0·05) with dietary Met concentration, and their weight relative to ovarian weight showed a linear (P<0·05) effect. Dietary Met level had a linear (P<0·05) and quadratic (P<0·001) effect on the gene expression of glutathione peroxidase (GPX1), HO-1 and Nrf2, and quadratically (P<0·05) increased contents of GPX and total antioxidant capacity (T-AOC) in liver of duck breeders. In addition, maternal dietary Met enhanced gene expression of GPX1, HO-1 and Nrf2, increased contents of GPX and T-AOC and reduced carbonylated protein in the brains of hatchlings. Overall, dietary Met concentration affected egg weight and albumen weight in laying duck breeders, which was partly due to gene expression of OVAL in oviduct magnum. A diet containing 4·0 g Met/kg would achieve optimal hepatic GPX1 and Nrf2 expression, maximise the activity of GPX and minimise lipid peroxidation.

Babesiosis is an emerging tick-transmitted zoonosis prevalent in large parts of the world. This study was designed to determine the rates of Babesia microti infection among small rodents in Yunnan province, where human cases of babesiosis have been reported. Currently, distribution of Babesia in its endemic regions is largely unknown. In this study, we cataloged 1672 small wild rodents, comprising 4 orders, from nine areas in western Yunnan province between 2009 and 2011. Babesia microti DNA was detected by polymerase chain reaction in 4·3% (72/1672) of the rodents analyzed. The most frequently infected rodent species included Apodemus chevrieri and Niviventer fulvescens. Rodents from forests and shrublands had significantly higher Babesia infection rates. Genetic comparisons revealed that Babesia was most similar to the Kobe- and Otsu-type strains identified in Japan. A variety of rodent species might be involved in the enzootic maintenance and transmission of B. microti, supporting the need for further serological investigations in humans.