Multipotent vascular stem cells contribute to neurovascular regeneration of peripheral nerve.

BackgroundNeurovascular unit restoration is crucial for nerve regeneration, especially in critical gaps of injured peripheral nerve. Multipotent vascular stem cells (MVSCs) harvested from an adult blood vessel are involved in vascular remodeling; however, the therapeutic benefit for nerve regeneration is not clear.MethodsMVSCs were isolated from rats expressing green fluorescence protein (GFP), expanded, mixed with Matrigel matrix, and loaded into the nerve conduits. A nerve autograft or a nerve conduit (with acellular matrigel or MVSCs in matrigel) was used to bridge a transected sciatic nerve (10-mm critical gap) in rats. The functional motor recovery and cell fate in the regenerated nerve were investigated to understand the therapeutic benefit.ResultsMVSCs expressed markers such as Sox 17 and Sox10 and could differentiate into neural cells in vitro. One month following MVSC transplantation, the compound muscle action potential (CMAP) significantly increased as compared to the acellular group. MVSCs facilitated the recruitment of Schwann cell to regenerated axons. The transplanted cells, traced by GFP, differentiated into perineurial cells around the bundles of regenerated myelinated axons. In addition, MVSCs enhanced tight junction formation as a part of the blood-nerve barrier (BNB). Furthermore, MVSCs differentiated into perivascular cells and enhanced microvessel formation within regenerated neurovascular bundles.ConclusionsIn rats with peripheral nerve injuries, the transplantation of MVSCs into the nerve conduits improved the recovery of neuromuscular function; MVSCs differentiated into perineural cells and perivascular cells and enhanced the formation of tight junctions in perineural BNB. This study demonstrates the in vivo therapeutic benefit of adult MVSCs for peripheral nerve regeneration and provides insight into the role of MVSCs in BNB regeneration

Entropy/Area spectra of the charged black hole from quasinormal modes

With the new physical interpretation of quasinormal modes proposed by Maggiore, the quantum area spectra of black holes have been investigated recently. Adopting the modified Hod's treatment, results show that the area spectra for black holes are equally spaced and the spacings are in a unified form, $\triangle A=8\pi \hbar$, in Einstein gravity. On the other hand, following Kunstatter's method, the studies show that the area spectrum for a nonrotating black hole with no charge is equidistant. And for a rotating (or charged) black hole, it is also equidistant and independent of the angular momentum $J$ (or charge $q$) when the black hole is far from the extremal case. In this paper, we mainly deal with the area spectrum of the stringy charged Garfinkle-Horowitz-Strominger black hole, originating from effective action that emerges in the low-energy string theory. We find that both methods give the same results-that the area spectrum is equally spaced and does not depend on the charge $q$. Our study may provide new insights into understanding the area spectrum and entropy spectrum for stringy black holes.Comment: 13 pages, no figure

Silicon nitride metalenses for unpolarized high-NA visible imaging

As one of nanoscale planar structures, metasurface has shown excellent superiorities on manipulating light intensity, phase and/or polarization with specially designed nanoposts pattern. It allows to miniature a bulky optical lens into the chip-size metalens with wavelength-order thickness, playing an unprecedented role in visible imaging systems (e.g. ultrawide-angle lens and telephoto). However, a CMOS-compatible metalens has yet to be achieved in the visible region due to the limitation on material properties such as transmission and compatibility. Here, we experimentally demonstrate a divergent metalens based on silicon nitride platform with large numerical aperture (NA~0.98) and high transmission (~0.8) for unpolarized visible light, fabricated by a 695-nm-thick hexagonal silicon nitride array with a minimum space of 42 nm between adjacent nanoposts. Nearly diffraction-limit virtual focus spots are achieved within the visible region. Such metalens enables to shrink objects into a micro-scale size field of view as small as a single-mode fiber core. Furthermore, a macroscopic metalens with 1-cm-diameter is also realized including over half billion nanoposts, showing a potential application of wide viewing-angle functionality. Thanks to the high-transmission and CMOS-compatibility of silicon nitride, our findings may open a new door for the miniaturization of optical lenses in the fields of optical fibers, microendoscopes, smart phones, aerial cameras, beam shaping, and other integrated on-chip devices.Comment: 16 pages, 7 figure

Study on aphid control by applying Harmonia (Leis) axyridis

The larvae of the varied color ladybug Harmonia (Leis) axyridis eat aphids. The first larval instar can eat 32 aphids a day. The second larval instar can eat 85 aphids per day. The third and the fourth larval instars can consume 169 and 203 aphids every day, respectively. Each larval instar can eat 120 aphids on average. The adult can eat 160 aphids every day.[1] The amount of aphids consumed by the adult of the varied color ladybug Harmonia (Leis) axyridis is higher than that of other ladybugs. The ladybugs have a broad appetite (wide eating patterns). They can eat almost all kinds of aphids. They aggregate during hibernation. The population of this ladybug is very large. Therefore, it is a natural enemy worthy of development and utilization. Since the aggregation habit of the ladybug in hibernation was reported in the 1960's, [2] many valuable studies about the ladybug have been done. The investigation on site hibernation[3] , occurrence and habits[4-5] and the study of controlling cucumber aphid and cotton aphid etc. were included in this research. However, because the adult has a habit of disperal toward higher elevations, it is difficult to establish a source of ladybug colonies in flatlands. Moreover the larvae are suicidal. It is not easy to raise the ladybug on a large scale. Therefore, for a long time the ladybug has not played an important role in controlling aphids in the field. Changbai Mountain is a region with the largest quantity of hibernating ladybugs [3]. It is also the place where the aggregation habit of adults in hibernation was first discovered [1]. We have done some experiments and research in Changbai Mountain since 1987 on biological characteristics of the varied color ladybug Harmonia (Leis) axyridis, such as oviposition of hibernating adults and hatching behavior from eggs to larvae. While we summarize previous research evidence, we base our work on the principle of “taking from nature, applying to field, developing in laboratory and releasing to nature”. We have done some release experiments to control soybean aphid and have simulated experiments for farmers rearing ladybugs by themselves. Now the data is presented as follows.Originating text in Chinese.Citation: Yuan, Rongcai, Yu, Ming, Wen, Guizhu. (1994). Study on aphid control by applying Harmonia (Leis) axyridis. Journal of Jilin Agricultural Sciences, 44(1), 30-57

Width-tuned magnetic order oscillation on zigzag edges of honeycomb nanoribbons

Quantum confinement and interference often generate exotic properties in nanostructures. One recent highlight is the experimental indication of a magnetic phase transition in zigzag-edged graphene nanoribbons at the critical ribbon width of about 7 nm [G. Z. Magda et al., Nature \textbf{514}, 608 (2014)]. Here we show theoretically that with further increase in the ribbon width, the magnetic correlation of the two edges can exhibit an intriguing oscillatory behavior between antiferromagnetic and ferromagnetic, driven by acquiring the positive coherence between the two edges to lower the free energy. The oscillation effect is readily tunable in applied magnetic fields. These novel properties suggest new experimental manifestation of the edge magnetic orders in graphene nanoribbons, and enhance the hopes of graphene-like spintronic nanodevices functioning at room temperature.Comment: 22 pages, 9 figure