Recent Advances in the Preparation of Protein/peptide Microspheres by Solvent Evaporation Method.

Protein/peptide drugs are extensively used to treat various chronic and serious diseases. The short half-life in vivo of protein and peptide as therapeutics drug limit the realization of complete effects. Encapsulating drugs in microspheres can slow the speed of drug release and prolong the efficacy of drugs. The solvent evaporation method is widely used to prepare protein/peptide microspheres because of its facile operation and minimal equipment requirements. This method has several challenges in the lower encapsulation efficiency, fluctuant release profiles and the stabilization of protein/peptides, which researchers believe may be solved by adjusting the preparation parameter or formulation of microspheres. The article discusses the formulation parameters that govern the preparation of protein/peptide-loaded microspheres by the solvent evaporation method, which provides an overview of the current promising strategies for solvent evaporation for protein/peptide microspheres. The article takes parameter evaluation as the framework, facilitating subsequent researchers to quickly find possible solutions when encountering problems.

Aquilaria sinensis leaf tea affects the immune system and increases sleep in zebrafish.

The importance of adequate sleep for good health cannot be overstated. Excessive light exposure at night disrupts sleep, therefore, it is important to find more healthy drinks that can promote sleep under sleep-disturbed conditions. The present study investigated the use of A. sinensis (Lour.) Spreng leaf tea, a natural product, to reduce the adverse effects of nighttime light on sleep. Here, Aquilaria sinensis leaf tea at 1.0 and 1.5 g/L significantly increased sleep time in zebrafish larvae (5-7 dpf) with light-induced sleep disturbance. Transcriptome sequencing and qRT-PCR analysis revealed a decrease in the immune-related genes, such as nfkbiab, tnfrsf1a, nfkbiaa, il1b, traf3, and cd40 in the 1.5 g/L Aquilaria sinensis leaf tea treatment group. In addition, a gene associated with sleep, bhlhe41, showed a significant decrease. Moreover, Aquilaria sinensis leaf tea suppressed the increase in neutrophils of Tg(mpo:GFP) zebrafish under sleep-disturbed conditions, indicating its ability to improve the immune response. Widely targeted metabolic profiling of the Aquilaria sinensis tea using ultra-performance liquid chromatography coupled with electrospray tandem mass spectrometry (UPLC-ESI-MS/MS) revealed flavonoids as the predominant component. Network pharmacological and molecular docking analyses suggested that the flavonoids quercetin and eupatilin in Aquilaria sinensis leaf tea improved the sleep of zebrafish by interacting with il1b and cd40 genes under light exposure at night. Therefore, the results of the study provide evidence supporting the notion that Aquilaria sinensis leaf tea has a positive impact on sleep patterns in zebrafish subjected to disrupted sleep due to nighttime light exposure. This suggests that the utilization of Aquilaria sinensis leaf tea as a potential therapeutic intervention for sleep disturbances induced by light may yield advantageous outcomes.

Photoelectric Target Detection Algorithm Based on NVIDIA Jeston Nano.

This paper proposes a photoelectric target detection algorithm for NVIDIA Jeston Nano embedded devices, exploiting the characteristics of active and passive differential images of lasers after denoising. An adaptive threshold segmentation method was developed based on the statistical characteristics of photoelectric target echo light intensity, which effectively improves detection of the target area. The proposed method's effectiveness is compared and analyzed against a typical lightweight network that was knowledge-distilled by ResNet18 on target region detection tasks. Furthermore, TensorRT technology was applied to accelerate inference and deploy on hardware platforms the lightweight network Shuffv2_x0_5. The experimental results demonstrate that the developed method's accuracy rate reaches 97.15%, the false alarm rate is 4.87%, and the detection rate can reach 29 frames per second for an image resolution of 640 × 480 pixels.

Simulation and Experimental Research on a Beam Homogenization System of a Semiconductor Laser.

Aiming at the application of laser active imaging detection technology, this paper studied the beam homogenization system of a semiconductor laser based on a homogenizing pipe. Firstly, the principle of the homogenizing pipe was introduced. Secondly, the homogenization effect, which was influenced by several geometric parameters (aperture size, length, and taper) of the homogenizing pipe using the optical design software, was simulated for the fiber-coupled semiconductor laser. Finally, according to the simulated results, a laser illumination system composed of a fiber-coupled semiconductor laser, a homogenizing pipe, and an aspheric lens was designed, which can obtain a rectangular uniform light spot in a long distance. The effectiveness of the illumination system was verified by simulation and experiment, respectively. Simulation results suggested that the uniformity of the spot at a distance of 20 m was 85.6%, while divergence angle was 10 mrad. The uniformity of the spot at a distance of 120 m was 91.5%, while divergence angle was 10 mrad. Experimental results showed that the uniformity of the spot at a distance of 20 m was 87.7%, while divergence angle was 13 mrad. The uniformity of the spot at a distance of 120 m was 93.3%, while divergence angle was 15 mrad. The laser illumination system designed in this paper was simple and easy to assemble, and has strong practicability. The results in this paper have certain reference value and guiding significance for the homogenization design of semiconductor lasers.

Preparation and Evaluation of BDNF Composite Conduits for Regeneration of Sciatic Nerve Defect in Rats.

The treatment of peripheral nerve injury is still a challenge. The present study was aimed to fabricate a composite nerve conduit containing slow-released brain-derived neurotrophic factor (BDNF) and evaluate its therapeutic effects on peripheral nerve defect. BDNF and polylactic acid were mixed together and a BDNF-loaded composite conduit was fabricated by solvent evaporation method. The bioactivity of BDNF released from the composite conduit was measured by MTT assay. A rat sciatic nerve defect model was used to compare regeneration potentials of autologous nerve graft, conduit filled with saline, conduit filled with BDNF solution and BDNF composite conduit. Nerve-regeneration was evaluated 3 months after surgery. The results demonstrated BDNF composite conduits prepared in this study remained bioactive for at least 3 months, and can promote the regeneration of sciatic nerve with a 10-mm gap in rats.

The Effect of Light Source Line Width on the Spectrum Resolution of Dual-Frequency Coherent Detection Signals.

In this paper, the power spectrum resolution problem of dual-frequency coherent mixing signals is analyzed when the Doppler frequency difference is small. The power spectrum function formula of the four optical coherent mixing signals is obtained using statistical theory and the Wiener-Khinchin theorem. The influence of delay time and light source line width on the power spectrum of dual-frequency coherent signals is analyzed using this formula. The results show that delay time only affects the peak of the power spectrum of the coherent signal. An increase in the line width of the light source broadens the signal power spectrum and reduces the peak value. The necessary condition for distinguishing the Doppler frequency difference is that the theoretical Doppler frequency difference is greater than 1/5 times the line width of the light source.

Multi-View Laser Point Cloud Global Registration for a Single Object.

Global registration is an important step in the three-dimensional reconstruction of multi-view laser point clouds for moving objects, but the severe noise, density variation, and overlap ratio between multi-view laser point clouds present significant challenges to global registration. In this paper, a multi-view laser point cloud global registration method based on low-rank sparse decomposition is proposed. Firstly, the spatial distribution features of point clouds were extracted by spatial rasterization to realize loop-closure detection, and the corresponding weight matrix was established according to the similarities of spatial distribution features. The accuracy of adjacent registration transformation was evaluated, and the robustness of low-rank sparse matrix decomposition was enhanced. Then, the objective function that satisfies the global optimization condition was constructed, which prevented the solution space compression generated by the column-orthogonal hypothesis of the matrix. The objective function was solved by the Augmented Lagrange method, and the iterative termination condition was designed according to the prior conditions of single-object global registration. The simulation analysis shows that the proposed method was robust with a wide range of parameters, and the accuracy of loop-closure detection was over 90%. When the pairwise registration error was below 0.1 rad, the proposed method performed better than the three compared methods, and the global registration accuracy was better than 0.05 rad. Finally, the global registration results of real point cloud experiments further proved the validity and stability of the proposed method.

Fabrication of Alginate/Calcium Carbonate Hybrid Microparticles for Synergistic Drug Delivery.

A hybrid drug delivery system coloaded with different drugs for synergistic drug delivery was developed. Alginate/calcium carbonate (CaCO3) hybrid microparticles (MPs) were fabricated via a facile coprecipitation method under mild conditions without using any organic solvent and surfactant. Due to the incorporation of negatively charged alginate chains onto the surface, the obtained hybrid MPs with spherical morphology showed good colloidal stability in an aqueous solution. An antitumor drug (doxorubicin, DOX) and a drug resistance reversal agent (verapamil, VP) were coloaded in the hybrid MPs simultaneously to obtain dual-drug-loaded MPs (DOX/VP/MP). Due to the presence of inorganic CaCO3 (∼54 wt%), the drugs could be loaded in the hybrid MPs with high encapsulation efficiency and the drug release could be effectively sustained. The cell growth inhibition of the drug-loaded MPs was evaluated in HeLa cells. An in vitro study showed DOX/VP/MP exhibited higher cell growth inhibition as compared with DOX monodrug-loaded MPs (DOX/MP). These results suggest the hybrid MPs can potentially be used as a synergistic drug delivery platform for cancer chemotherapy.

Integrin ß4 regulation of PTHrP underlies its contribution to mammary gland development.

The integrin α6ß4 (referred to as ß4) is expressed in epithelial cells where it functions as a laminin receptor. Although in vitro studies have implicated ß4 in the biology of mammary epithelial cells, its contribution to mammary gland development has not been settled. To address this problem, we generated and analyzed itgb4(flox/flox)MMTV-Cre(-) and itgb4(flox/flox)MMTV-Cre(+) mice. The salient features of embryonic mammary tissue from itgb4(flox/flox)MMTV-Cre(+) mice were significantly smaller mammary buds and increased apoptosis in the surrounding mesenchyme. Also, compared to control glands, the itgb4-deleted mammary buds lacked expression of the progenitor cell marker CK14 and they were unable to generate mammary glands upon transplantation into cleared fat pads of recipient mice. Analysis of mammary glands at puberty and during pregnancy revealed that itgb4-diminished mammary tissue was unable to elongate and undergo branching morphogenesis. Micro-dissection of epithelial cells in the mammary bud and of the surrounding mesenchyme revealed that loss of ß4 resulted in a significant decrease in the expression of parathyroid hormone related protein (PTHrP) in epithelial cells and of target genes of the PTHrP receptor in mesenchymal cells. Given that the phenotype of the itgb4-deleted mammary tissue mimicked that of the PTHrP knockout, we hypothesized that ß4 contributes to mammary gland development by sustaining PTHrP expression and enabling PTHrP signaling. Indeed, the inability of itgb4-deleted mammary buds to elongate was rescued by exogenous PTHrP. These data implicate a critical role for the ß4 integrin in mammary gland development and provide a mechanism for this role.

A requirement of dendritic cell-derived interleukin-27 for the tumor infiltration of regulatory T cells.

Tregs (Foxp3+CD4+) are enriched in tumors to foster a tolerant microenvironment that inhibits antitumor immune response. IL-27 is reported to regulate the development and function of Tregs in vitro and in vivo; however, the effects of endogenous IL-27 on Tregs in the tumor microenvironment remain elusive. We demonstrated that in the absence of DC-derived IL-27, Tregs were decreased significantly in transplanted B16 melanoma, transplanted EL-4 lymphoma, and MCA-induced fibrosarcoma by using IL-27p28 conditional KO mice. Further studies revealed that IL-27 promoted the expression of CCL22, which is established to mediate the recruitment of peripheral Tregs into tumors. Tumor-associated DCs were identified as the major source of CCL22 in tumor sites, and IL-27 could induce CCL22 expression in an IL-27R-dependent manner. Intratumoral reconstitution of rmCCL22 or rmIL-27, but not rmIL-27p28, significantly restored the tumor infiltration of Tregs in IL-27p28 KO mice. Correlated with a decreased number of Tregs, tumor-infiltrating CD4 T cells were found to produce much more IFN-γ in IL-27p28 KO mice, which highlighted the physiological importance of Tregs in suppressing an antitumor immune response. Overall, our results identified a novel mechanism of action of IL-27 on Tregs in the context of cancers.

In vitro evaluation of the effects of various additives and polymers on nerve growth factor microspheres.

OBJECTIVE: To evaluate the effects of various additives or polymers on the in vitro characteristics of nerve growth factor (NGF) microspheres. MATERIALS AND METHODS: NGF microspheres were fabricated using polyethylene glycol (PEG), ovalbumin (OVA), bovine serum albumin (BSA) or glucose as protein protectors, and poly(lactide-co-glycolide) (PLGA) or poly(lactic acid) (PLA)/PLGA blends as encapsulation materials. RESULTS: Encapsulation efficiencies of the NGF microspheres with various additives or polymers were not more than 30%. A comparative study revealed that OVA was somewhat superior over others, and was thus chosen as the protective additive in subsequent experiments. Polymer analysis showed that NGF release from 1:1 PLA (η = 0.8):PLGA (75/25, η = 0.45) microspheres lasted for 90 d with a burst release rate of 12.7%. About 40% of the original bioactivity was retained on the 28th day, while 10% was left on the 90th day. DISCUSSION AND CONCLUSION: The combination of OVA as an additive and the PLA/PLGA blend as the coating matrix is suitable for encapsulation of NGF in microspheres for extended release.

Critical role of dendritic cell-derived IL-27 in antitumor immunity through regulating the recruitment and activation of NK and NKT cells.

Critical roles of IL-27 in autoimmune diseases and infections have been reported; however, the contribution of endogenous IL-27 to tumor progression remains elusive. In this study, by using IL-27p28 conditional knockout mice, we demonstrate that IL-27 is critical in protective immune response against methyl-cholanthrene-induced fibrosarcoma and transplanted B16 melanoma, and dendritic cells (DCs) are the primary source. DC-derived IL-27 is required for shaping tumor microenvironment by inducing CXCL-10 expression in myeloid-derived suppressor cells and regulating IL-12 production from DCs, which lead to the recruitment and activation of NK and NKT cells resulting in immunological control of tumors. Indeed, reconstitution of IL-27 or CXCL-10 in tumor site significantly inhibits tumor growth and restores the number and activation of NK and NKT cells. In summary, our study identifies a previous unknown critical role of DC-derived IL-27 in NK and NKT cell-dependent antitumor immunity through shaping tumor microenvironment, and sheds light on developing novel therapeutic approaches based on IL-27.

Fast calculation method of complex space targets' optical cross section.

This paper utilizes the optical cross section (OCS) to characterize the optical scattering characteristics of a space target under the conditions of Sun lighting. We derive the mathematical expression of OCS according to the radiometric theory, and put forward a fast visualization calculation method of complex space targets' OCS based on an OpenGL and 3D model. Through the OCS simulation of Lambert bodies (cylinder and sphere), the computational accuracy and speed of the algorithm were verified. By using this method, the relative error for OCS will not exceed 0.1%, and it only takes 0.05 s to complete a complex calculation. Additionally, we calculated the OCS of three actual satellites with bidirectional reflectance distribution function model parameters in visible bands, and results indicate that it is easy to distinguish the three targets by comparing their OCS curves. This work is helpful for the identification and classification of unresolved space target based on photometric characteristics.

Mouse embryonic head as a site for hematopoietic stem cell development.

In the mouse embryo, the aorta-gonad-mesonephros (AGM) region is considered to be the sole location for intraembryonic emergence of hematopoietic stem cells (HSCs). Here we report that, in parallel to the AGM region, the E10.5-E11.5 mouse head harbors bona fide HSCs, as defined by long-term, high-level, multilineage reconstitution and self-renewal capacity in adult recipients, before HSCs enter the circulation. The presence of hemogenesis in the midgestation head is indicated by the appearance of intravascular cluster cells and the blood-forming capacity of a sorted endothelial cell population. In addition, lineage tracing via an inducible VE-cadherin-Cre transgene demonstrates the hemogenic capacity of head endothelium. Most importantly, a spatially restricted lineage labeling system reveals the physiological contribution of cerebrovascular endothelium to postnatal HSCs and multilineage hematopoiesis. We conclude that the mouse embryonic head is a previously unappreciated site for HSC emergence within the developing embryo.

Preparation and evaluation of NGF-microsphere conduits for regeneration of defective nerves.

OBJECTIVES: To fabricate nerve growth factor (NGF) microsphere conduits and evaluate their promotional effects on regeneration of defective nerves. METHODS: NGF microspheres containing ovalbumin were prepared using a double-emulsion method. The total amount of NGF was determined by enzyme-linked immunosorbent assay, and bioactive NGF was quantified by the PC12 cell line method; the NGF bioactivity present during the release period was monitored. Conduits made of polylacticacid were added to the NGF microspheres to bridge and repair the nerve injury. The sciatic nerve of Wistar rats was used to evaluate nerve-regeneration efficacy. RESULTS: NGF microspheres were spherical, with smooth and compact surfaces. The fabrication yield, encapsulation efficiency, and drug loading of the microspheres were 58.3, 29.72, and 0.003%, respectively. The monitoring of NGF bioactivity remaining during the release period showed that ~40% of the original bioactivity was kept on the twenty-eighth day and 10% left on the ninetieth day. Polylacticacid conduits are lowly antigenic, porous (facilitates oxygen diffusion), and able to prevent long-term compression. After 15 days, the length of nerve regenerated from NGF-microsphere conduits was statistically different from that of the control groups (P<0.05). NGF microspheres can accelerate the early nerve-regeneration rate, although the rate was not as good as that caused by autografts. Three months later, the recovery rate of the regenerated nerve collected from NGF-microsphere conduits showed lower values of nerve-conduction velocity, muscular tension, and muscle weight. However, poorer rates of regeneration were observed in the self-mutilation foot compared with those of the control group. The control group had no statistical difference from the sodium chloride and NGF-solution conduits, the best in the autograft group. DISCUSSION: A long-term promoting effect of microsphere-bound exogenous NGF on the functional repair of peripheral nerves could not be confirmed, although the nerve-regeneration rate was rapid in the early stage. Better methods are needed to incorporate protein-release systems into nerve conduits to improve functional recovery in patients with injured nerves.

[Effect of controlled release nerve growth factor on repairing peripheral nerve defect by acellular nerve graft].

OBJECTIVE: To explore the effect of controlled release of nerve growth factor (NGF) on peripheral nerve defect repaire by acellular nerve graft. METHODS: The microspheres of NGF were prepared with drug microsphere technology and fixed with the fibrin glue to make the complicated controlled release NGF. Twenty healthy male SD rats weighing 280-300 g were adopted to prepare acellular xenogenous nerve, 52 male Wistar rats weighing 250-300 g were adopted to prepare the 10 mm defect model of left sciatic nerve, and thereafter were randomly divided into 4 groups: autograft group (group A), acellular nerve allograft combined with the double controlled release NGF (group B), acellular nerve allograft (group C) and acellular nerve allograft combined with fibrin glue (group D). Without any operation, the right sciatic nerve was regarded as control group. General observation was conducted after operation. The nerve axon regeneration length was measured 2 weeks after operation. The effects of peripheral nerve regeneration were evaluated by neural electrophysiology, the recovery rate of triceps surae muscular tension and weight and histological assessment 16 weeks after operation. RESULTS: All the animals survived till the end of experiment. The length of nerve regeneration was measured at 2 weeks after transplantation. The regeneration nerve of group A was longer than that of other groups (P < 0.05), group B longer than groups C and D (P < 0.05), and there were no difference between group C and group D (P > 0.05). At 16 weeks after operation, the recovery rates of nerve conduction velocity of groups A and B (73.37% +/- 7.82% and 70.39% +/- 8.45%) were larger than that of groups C and D (53.51% +/- 6.31% and 55.28% +/- 5.37%) (P < 0.05). The recovery rates of the triceps surae muscular tension in group A (85.33% +/- 5.59%) were larger than that in groups B, C and D (69.79% +/- 5.31%, 64.46% +/- 8.49% and 63.35% +/- 6.40%) (P < 0.05). There were no significant differences among groups B, C and D (P > 0.05). The recovery rates of the triceps surae weight in group A (62.54% +/- 8.25%) were larger than that in groups B, C and D (53.73% +/- 4.56%, 46.37% +/- 5.68% and 45.78% +/- 7.14%, P < 0.05). There was significant difference between group B and groups C, D (P < 0.05) and no significant differences between group C and group D (P > 0.05). The histological observation indicated that axon number and myelin thickness in group B were larger than those in group C and group D (P < 0.05). The axonal diameter in group B was significantly less than that in group A (P < 0.05). CONCLUSION: Acellular nerve graft combined with the controlled release NGF is a satisfactory alternative to repair the peripheral nerve defect.