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Background Chemotherapeutic drugs used for tumor treatments often show limited efficiency due to their short lifetime, nonspecific delivery, and slow or insufficient intracellular drug release, and also, they can cause severe system or organ toxicity. The development of chemotherapeutic nanomedicines with high efficacy and satisfactory safety still remains a challenge for current tumor chemotherapy. Methods A novel type of conjugate was synthesized using hydroxyethyl starch (HES) as a carrier while binding doxorubicin (DOX) onto HES backbone through a pH/redox responsive linker containing both disulfide and hydrazone bonds in series. The built conjugates were self-assembled into nanoparticles (NPs) (HES-SS-hyd-DOX NPs) for achieving enhanced antitumor therapy and adequate safety. Results HES-SS-hyd-DOX NPs had a certain ability for the tumor-orientated drug accumulation and were capable of releasing DOX itself rather than DOX derivatives. It was found that the pH/redox responsive linkage enabled the NPs to achieve fast and sufficient intracellular drug release. Based on the tumor-bearing mouse model, antitumor results demonstrated that these NPs were able to inhibit the growth of the advanced tumors with significantly enhanced efficacy when compared to free DOX, and to those conjugate NPs containing only a single responsive or unresponsive bond. Besides, HES-SS-hyd-DOX NPs also showed adequate safety to the normal organs of the treated mice. Conclusion The pH/redox responsive linkage in HES-SS-hyd-DOX was found to play a critical role in mediating the drug accumulation and the fast and sufficient intracellular drug release. The HES-exposed surface of HES-SS-hyd-DOX NPs endowed the NPs with long circulation capability and remarkably reduced the DOX-induced side effects., Graphical Abstract pH/redox responsive doxorubicin-bound hydroxyethyl starch conjugate nanoparticles.

Thiolated hyaluronic acid(THA) conjugates were synthesized and the selected THA was combined with silk fibroin(SF) and bioactive glass nanoparticles to build a novel type of composite hydrogel with dual-network structure. The optimally achieved gels showed greatly enhanced strength and stiffness compared to the gels built from either THA or SF while having well-defined elasticity and injectability. They were able to sustainably release Si ions in approximately linear manners for around three weeks. In vitro cell culture revealed that they supported the in-growth and proliferation of seeded cells, and showed the ability to markedly stimulate the migration of both fibroblasts and human umbilical vein endothelial cells. In vivo results based on the 10 mm mouse full-thickness skin defect demonstrated that they were able to fully restore the skin defects with formation of vascularized tissues and complete appendages during two weeks, suggesting their highly promising potency in use for wound healing.

In order to adapt to strict emission regulations and reduce particulate emissions from gasoline engines, continuous research on GPF is needed to improve particulate capture efficiency. The structure and working principle of gasoline engine particle catchers are studied. A new type of GPF is designed based on the Sierpinski triangle structure. The GPF shell is designed according to the structure of the filter body, and the flow guide plate is designed to make the gas flow rate uniform. The model and accessories of the filter body are modeled in Solid Works. Based on the repeated characteristics of the filter body structure, a unit body is extracted to simplify the analysis. The simulation was performed using the filter unit. The flow rate of exhaust gas between the new filter structure and the traditional filter body was compared in addition to the pressure of the filter body and the trapping effect of small molecular particles in the exhaust gas. Through analysis and comparison, it can be concluded that the new GPF filter structure has better trapping efficiency than the traditional filter structure.

Copper-containing bioactive glass nanoparticles (Cu-BG NPs) with designed compositions and sizes were synthesized and incorporated into chitosan (CH)/silk fibroin (SF)/glycerophosphate (GP) composites to prepare injectable hydrogels for cell-free bone repair. The resulting Cu-BG/CH/SF/GP gels were found to exhibit well-defined injectability and to undergo rapid gelation at physiological temperature and pH. They were highly porous and showed the ability to administer Si, Ca and Cu ions at their respective safe doses in a sustained and controlled manner. In vitro studies revealed that the gels supported the growth of seeded MC3T3-E1 and human umbilical vein endothelial cells, and effectively induced them toward osteogenesis and angiogenesis, respectively. In vivo bone repair based on a critical-size rat calvarial bone defect model demonstrated that the optimal Cu-BG/CH/SF/GP gel was able to fully restore the bone defect with formation of vascularized bone tissue and mineralized collagen deposition during a treatment period of 8 weeks without utilization of any cells and/or growth factors. The results suggest that the presently developed Cu-BG/CH/SF/GP composite hydrogels have great potential and translation ability for bone regeneration owing to their thermo-sensitive properties, cell-free bioactivity, and cost-effectiveness. Statement of Significance Hydrogels loaded with cells and/or growth factors exhibit potential in bone repair. However, they have been facing obstacles related to the clinic translation. Here, a novel type of hydrogel system consisting of copper-containing bioactive glass nanoparticles and chitosan/silk fibroin composite was developed. These gels showed injectability and thermally triggered in situ gelation properties and were able to administer the release of ions at safe but effective doses in a controlled manner while inducing the seeded cells toward osteogenesis and angiogenesis. The optimal gel showed the ability to fully repair critical-size rat calvarial bone defects without involving time consuming cell processing and/or the use of expensive growth factors, confirming that this novel hydrogel system has great potential for translation to the clinic.

Previous experimental results on full-scale jet fires induced by high-pressure hydrogen/natural gas transient leakage can only be suitable for solving practical engineering problems, or testing the limitation of previous models. Thus, this paper presents a theoretical framework for the high-pressure hydrogen/natural gas leakage and the subsequent jet fire. The proposed framework consists of a transient leakage model, a notional nozzle model, a jet flame size model, a radiative fraction correlation and a line source radiation model. The framework is validated by comparing the model predictions and experimental measurements of mass flow rate, total flame height and thermal radiation field of hydrogen, natural gas, hydrogen/natural gas mixture jet fires with a flame height up to 100 m. The comparison shows that the theoretical framework can give considerable predictions to properties of full-scale jet fires induced by high-pressure hydrogen/natural gas transient leakage.

Thermosensitive alginate&ndash, poloxamer (ALG&ndash, POL) copolymer with an optimal POL content was synthesized, and it was used to combine with silk fibroin (SF) for building ALG&ndash, POL/SF hydrogels with dual network structure. Mesoporous bioactive glass (BG) nanoparticles (NPs) with a high level of mesoporosity and large pore size were prepared and they were employed as a vehicle for loading insulin-like growth factor-1 (IGF-1). IGF-1-loaded BG NPs were embedded into ALG&ndash, POL/SF hydrogels to achieve the controlled delivery of IGF-1. The resulting IGF-1-loaded BG/ALG&ndash, POL/SF gels were found to be injectable with their sol-gel transition near physiological temperature and pH. Rheological measurements showed that BG/ALG&ndash, POL/SF gels had their elastic modulus higher than 5kPa with large ratio of elastic modulus to viscous modulus, indicative of their mechanically strong features. The dry BG/ALG&ndash, POL/SF gels were seen to be highly porous with well-interconnected pore characteristics. The gels loaded with varied amounts of IGF-1 showed abilities to administer IGF-1 release in approximately linear manners for a few weeks while effectively preserving the bioactivity of encapsulated IGF-1. Results suggest that such constructed BG/ALG&ndash, POL/SF gels can function as a promising injectable biomaterial for bone tissue engineering applications.

Poloxamer was grafted onto alginate and the optimally synthesized alginate-poloxamer (ALG-POL) copolymer was combined with silk fibroin (SF) to produce thermosensitive ALG-POL/SF hydrogels with covalently and physically crosslinked networks. The formulated ALG-POL/SF gels were found to be injectable with sol-gel transitions near physiological temperature and pH. Rheological measurements showed that some ALG-POL/SF gels had their elastic modulus of around 5 kPa or higher with large ratio of elastic modulus to viscous modulus, indicative of their mechanically strong feature. The achieved ALG-POL/SF gels exhibited concurrent enhancement in strength and elasticity when compared to the gels built with either ALG-POL or SF alone. The microscopic insight into dry ALG-POL/SF gels validated that they were highly porous with well-interconnected pore characteristics. These ALG-POL/SF gels showed abilities to support the in-growth of seeded chondrocytes while effectively maintaining their chondrogenic phenotype. Results suggest promising attributes of ALG-POL/SF gels as alternative biomaterial for cartilage tissue engineering.

The accidental leakage of high-pressure gas storage systems including tank, pipe, etc. can lead to hazardous jet fires resulting in a serious of disastrous events. With the isentropic process assumption on the high-pressure gas leakage or release, the ideal gas equation of state is firstly used to solve the gas transfer problem, and then the Abel-Noble equation of state (AN-EOS) is adopted for the effect of gas molecule volume. Given both the molecule volume and intermolecular attraction should not be ignored for the high-pressure gas, this paper attempts to build the high-pressure gas leakage process model based on the van der Waals equation of state. Together with the available notional nozzle model and the flame size model, the gas leakage process model is used to calculate the gas state property and flow parameter of hydrogen tank leakage and its subsequent jet flame height. The predicted gas mass flow rate, flame height, and gas pressure and temperature are compared to the experimental measurements for validation and the predictions of the model based on ideal gas equation of state and AN-EOS. It is found that the proposed model can give more encouraging results compared to the previous models. The proposed theoretical model shows a great implication for the calculation of other gas tank leakage and can help to predict the thermal radiation field of jet fires.

Silk fibroin (SF) and hydroxyapatite (HA) were incorporated into chitosan/glycerophosphate (GP) system to prepare new types of hydrogels. The formulated chitosan/SF/GP and chitosan/SF/HA/GP solutions were found to be injectable at room temperature, and able to form into hydrogels at near-physiological temperature and pH. Rheological measurements showed that elastic modulus of certain chitosan/SF/GP and chitosan/SF/HA/GP gels could reach around 1.8 and 15kPa, respectively, and was much higher than their respective viscous modulus. Compressive measurements revealed that some chitosan/SF/GP and chitosan/SF/HA/GP gels had 8 and 20-fold modulus and strength higher than the chitosan/GP gel, respectively, confirming that compressive properties of these gels were greatly improved. Results obtained from in vivo degradation demonstrated that degradation endurance of the optimized chitosan/SF/GP and chitosan/SF/HA/GP gels was significantly enhanced as compared to the chitosan/GP gel, and the degradation rate of the gels could be regulated by the SF component alone or by the combination of SF and HA components.

Thiolated chitosan (CS-NAC) was synthesized and the selected CS-NAC was used together with silk fibroin (SF) to produce dual network CS-NAC/SF hydrogels. The CS-NAC/SF solutions with formulated compositions were able to form hydrogels at physiological temperature and pH. Rheological measurements showed that elastic modulus of some CS-NAC/SF gels could reach around 3 kPa or higher and was much higher than their respective viscous modulus, indicating that they behaved like strong gels. Deformation measurements verified that CS-NAC/SF gels had well-defined elasticity. The optimized CS-NAC/SF gels exhibited jointly enhanced properties in terms of strength, stiffness and elasticity when compared to the gels resulted from either CS-NAC or SF. Examinations of dry CS-NAC/SF gels revealed that they were highly porous with well-interconnected pore features. Cell culture demonstrated that CS-NAC/SF gels supported the growth of chondrocytes while effectively maintaining their phenotype. Results suggest that these dual network gels have promising potential in cartilage repair.

Local administration of platelet-derived growth factor-BB (PGDF-BB) and bone morphogenetic protein-2 (BMP-2) in a sequential release manner could substantially promote bone healing. To achieve this goal, a delivery system that could sustain the release of PGDF-BB and BMP-2 by way of temporal separation was developed. One type of PGDF-BB-encapsulated alginate microsphere and another type of BMP-2-encapsulated microsphere with a core-shell structure were respectively produced using emulsification methods. These two types of microspheres were then embedded into chitosan/glycerophosphate hydrogel for constructing composite gels. Some of them were found to be injectable at ambient temperature and had thermo-sensitive features near physiological temperature and pH. The optimally formulated composite gels showed the ability to control the release of PGDF-BB and BMP-2 in a sequential fashion in which PDGF-BB was released earlier than BMP-2. In vitro release patterns indicated that the release rates could be significantly regulated by varying the embedded amount of the factor-encapsulated microspheres, which can in turn mediate the temporal separation release interval between PGDF-BB and BMP-2. The released PDGF-BB and BMP-2 were detected to be bioactive based on their respective effects on Balb/c 3T3 and C2C12 cells. These results suggest that the presently developed composite gels have the potential for bone repair by synergistically utilizing the early chemotactic effect of PDGF-BB and the subsequent osteogenic and angiogenic functions of PDGF-BB and BMP-2.

Jet fires are often reported to occur in process industry with lots of hazardous heat energy released. A line source model describing the flame emissive power and subsequent heat flux radiated from a horizontal propane jet fire is evaluated through a testing against experimental fire data and comparison against other models. By a review on the jet flame behavior, the correlations of the lift-off distance, flame length and radiative fraction are proposed to close the line source model in theory. It is found that the fuel jet direction holds a considerable effect on the flame behavior by comparison between horizontal and vertical jet fires. Results indicate that the lift-off distance and the flame shape influence the model prediction to some extent. Comparison of model predictions against data collected in the near field and predictions from the point source model and multipoint source model gives encouraging results relative to the validity of model system.

A laboratory experiment visually exploring two opposite basic principles of fluorescence of aggregation-caused quenching (ACQ) and aggregation-induced emission (AIE) is demonstrated. The students would prepared two salicylaldehyde-based Schiff bases through a simple one-pot condensation reaction of one equiv of 1,2-diamine with 2 equiv of salicylaldehyde. The resulting fluorescent dyes have similar chemical structures but possess ACQ and AIE properties, respectively. Their ACQ/AIE properties and pH sensing applications would then examined by visually qualitative analysis (UV lamp, light-emitting diode, and naked eye) and quantitative analysis (fluorometer). Finally, in a deeper level, X-ray single crystal structure analysis was utilized to reveal the inherent relationships between molecular structures/molecular arrangements and ACQ/AIE properties. This lesson is suitable for many areas of chemistry, especially for organic and analytical chemistry.

The photophysical properties, density functional theory calculations, and pH sensing applications of a series of salicylaldehyde derivatives that contain only one small π-conjugated benzene ring system are reported. The steric, electronic and π-extended effects on their photophysical properties are fully investigated. The presence of a donor–acceptor (DA) system ensures not only blue, green, and yellow emission, but also high fluorescence quantum yields up to 0.35 in dimethylformamide (DMF) at room temperature. The absorption and fluorescence properties of the salicylaldehyde derivatives are highly dependent on the pH value of the solution, which realize their applications in pH sensing and living cell imaging. The pK a values of these compounds ranging from 4.6 to 9.6 can be well-tuned by their structures. Moreover, in order to achieve good solubility in water, a sodium sulfonato group was introduced into the salicylaldehyde derivatives, which are very useful for tuning pK a values and detecting pH values in water.

Chitosan (CH), silk fibroin (SF), and hydroxyapatite (HA) were used to prepare CH/SF/HA composites and the resulting composites were electrospun into nanofibrous membrane units with gradient compositional and structural features. The optimal membrane unit was used together with CH/HA and CH/SF composites to fabricate a type of three-layer scaffold that is intended for osteochondral repair. The bottom layer of the scaffold was built with CH/HA composites and it served as a subchondral layer, the integrated nanofibrous membrane unit functioned as the middle layer for mimicking the calcified layer and the top layer was constructed using CH/SF composites for acting as a chondral layer. The nanofibrous membrane unit was found to be permeable to some molecules with limited molecular weight and was able to prevent the seeded cells from migrating cross the unit, functioning approximately like the calcified layer in the osteochondral matrix. Layered scaffolds showed abilities to promote the growth of both chondrocytes and osteoblasts that were seeded in their chondral layer and bony layer, respectively, and they were also able to support the phenotype preservation of seeded chondrocytes and the mineralization of neotissue in the bony layer. Results suggest that this type of layered scaffolds can function as an analogue of the osteochondral matrix and it has potential in osteochondral repair.

Dextran-polylactide (Dex-PLA) copolymers were synthesized and the selected Dex-PLA with water-soluble characteristics was used together with chitosan and glycerophosphate (GP) to produce injectable chitosan/Dex-PLA/GP hydrogels. Some chitosan/Dex-PLA/GP solutions with designated compositions were able to form into hydrogel in a temperature range between around 32 and 35 °C, and their pH values were found to alter between 7.0 and 7.2. Elastic modulus of the optimal chitosan/Dex-PLA/GP gel could reach about 1.0 kPa or higher, and meanwhile, it was much higher than their viscous modulus, revealing that these chitosan/Dex-PLA/GP gels behave like mechanically strong ones. Compression measurements indicated that the certain chitosan/Dex-PLA/GP gels had around 8-fold modulus and strength higher than the chitosan/GP gel, confirming that greatly enhanced compressive properties for chitosan/Dex-PLA/GP gels have been achieved. After 8-week subcutaneous degradation in rats, some chitosan/Dex-PLA/GP gels showed significantly extended degradation endurance compared to the chitosan/GP gel, and the PLA content in the chitosan/Dex-PLA/GP gels was able to regulate the degradation rate of the gels in a controllable manner. These results suggest that the presently developed chitosan/Dex-PLA/GP gels have promising potential for injectable gelling applications where the gel with mechanically strong features and degradation tolerance is needed.

A series of novel, simple, and colorful Salen ligands (56 samples), salicylaldehyde-based bis-Schiff bases, linking with different non-conjugated alkyl bridges ((CH2)n, n = 2–9, 12; cyclohexyl) and containing different electron-accepting (–NO2, –F, and –Cl), electron-donating (–OMe, –OH, and –NEt2), or sterically hindering (–t-butyl) substituents or a π-extended system (naphthalene ring) have been designed and synthesized. The photophysical properties of these Salen ligands can be well-tuned by the introduction of side functional substituents, π-extended systems, and central N-alkyl chain bridges. It is unusual that they contain a small π-conjugated system but display strong blue, green, and red aggregation-induced emission (AIE) with large Stokes shifts (up to 162 nm) and high fluorescence quantum yields (up to 0.44 and 0.75 in water and in solid, respectively). Combining with their advantages of AIE and good stability and biocompatibility, the Salen ligands can be potentially used in mechanofluorochromism (crystal-defect-induced emission) and living cell imaging. Moreover, the inherent relationships between their chemical structures and AIE properties are studied, which provide unequivocal insights for the design of AIE-active dyes.

A series of luminescent salicylaldehyde azines (SAs) containing different electron-accepting substituents (–NO2, –F, and –Cl), electron-donating substituents (–OMe and –NEt2), and a π-extended system (naphthalene ring) are prepared for the application of fluorescent pH probes. These SAs inheriting the aggregation-induced emission (AIE) features display strong blue, green, and red fluorescence with large Stokes shifts in water and solid medium. Combining the advantages of AIE and the chemical reactivity of phenol towards OH−/H+, most of the SAs can be used as ratiometric fluorescent pH probes with a broad pH range (2–14) in water and solid medium (test paper). Moreover, the inherent relationship between their chemical structures and AIE properties/pKa values (7.5–13.3) is studied, which provides unequivocal insights into the design of AIE-active dyes and their applications.

Chitosan/silk fibroin/glycerophosphate gels were loaded with nerve growth factor (NGF) and further processed into multi-tubule fillers. NGF was loaded into the fillers in such a way so that a NGF gradient was established longitudinally along the filler length. A type of poly(lactide-co-glycolide)(PLGA)/chitosan(CH) porous conduit was fabricated using a pre-crosslinking method. The filler was fully filled into the lumen of conduits to build multi-tubule conduit-filler constructs that are intended for long-gap peripheral nerve repair. In vitro degradation in a lysozyme-contained medium revealed that constructs had degradation-tolerant features and the optimized multi-tubule filler was capable of maintaining its multi-tubules unblocked for around 10-week. After being degraded for various periods up to 8 weeks, the optimal conduit-filler constructs showed confirmative ability to retain their compressive load, deformation recovery and tensile strength at about 80 N/m, 75% and 15 N/cm2 in wet state, respectively. The constructs were able to administer NGF release and to maintain persistent NGF gradients longitudinally distributed inside the PLGA/CH conduit for about 6 weeks or even longer. The PC12 cell neurite extension assay confirmed that the presently developed multi-tubule conduit-filler constructs were reliable for effectively preserving the bioactivity of released NGF.

Nerve conduits containing aligned fibrous fillers with gradiently distributed signal molecules are essential for long-gap nerve repair. This study was to develop an approach for establishing nerve growth factor (NGF) gradients onto the aligned chitosan-polylactide (CH-PLA) fibers. CH-PLA containing 37wt% of PLA was spun into fibers using a wet-spinning technique. CH-PLA fibers showed much higher wet-state tensile strength, enhanced degradation tolerance and significantly lower swelling degree in comparison to chitosan fibers. The CH-PLA fibers with diameters from 40 to 60μm were selected and segmentally coated in bundles using NGF-contained alginate solutions to establish NGF gradients lengthwise along fibers. The diameter of resulting NGF-loaded CH-PLA/alginate fibers was well controlled within a range between 60 and 120μm. Calcium ion crosslinked alginate coating layers on fibers showed abilities to administer the sustainable NGF release in a gradient distribution manner for at least 5 weeks. NGF-induced neurite outgrowth of PC12 cells confirmed that bioactivity of NGF released from fibers was well retained.

We report our systematic studies of novel, simple, selective, and sensitive optical (both colorimetric and fluorescent) chemosensors for detecting Al(3+) based on transmetalation reactions (metal displacement or exchange reactions) of a series of K(I), Ca(II), Zn(II), Cu(II), and Pt(II) complexes containing different ligands of salen-based Schiff bases. Both the chemical structure of the salen ligand and the identity of the central metal ion have a tremendous impact on the sensing performance, which is mainly determined by the stability constant of the complex. Moreover, the selectivities of the salen-complex-based chemosensors are much better than those of the corresponding free salen ligands because of the shielding function of the filled-in metal ion in the complex. Therefore, the present work potentially provides a new and simple way to design optical probes via complex-based transmetalation reactions.

Chitosan(CH)-poly(dioxanone) (CH-PDO) copolymers containing varied amounts of PDO and having free amino groups at their CH backbone were synthesized using a group protection method. The selected CH-PDO with soluble characteristics in aqueous media was used together with hyaluronic acid (HA) to prepare HA/CH-PDO polyelectrolyte complex nanoparticles (NPs) via an ionotropic gelation technique, and such a type of HA/CH-PDO NPs was employed as a carrier for delivering bone morphogenetic protein-2 (BMP-2). The optimal BMP-2-encapsulated HA/CH-PDO NPs with high encapsulation efficiency were embedded into CH/glycerophosphate composite solutions to form different hydrogels in order to achieve long-term BMP-2 release. The formulated gels were found to be injectable at room temperature and had its thermosensitive phase transition near physiological temperature and pH. They also showed abilities to administer the release of BMP-2 in approximately linear manners for a few weeks while effectively preserving the bioactivity of the encapsulated BMP-2. In view of their fully biocompatible and biodegradable components, the presently developed gel systems have promising potential for translation to the clinic use in bone repair and regeneration where the sustained and controlled stimuli from active signaling molecules and the stable biomechanical framework for housing the recruited cells are often concurrently needed.

Platelet-derived growth factor-BB (PGDF-BB) loaded gelatin microspheres with an average size of about 2μm was incorporated into chitosan/silk fibroin/glycerophosphate (GP) solutions to prepare composites. The formulated composite solutions were able to form into hydrogels in a temperature range between 32 and 37°C at a pH of ca.7. They had good fluidity at 25°C and showed shear-thinning features at both 25 and 37°C, revealing that they are injectable at room temperature. Elastic modulus of some composites at 37°C was about 10-fold higher than that of chitosan/GP gel, confirming that these composites behave like mechanically strong gels. Optimal composites showed abilities to administrate PDGF-BB release in an approximately linear manner up to 5 weeks. The PDGF-BB release could be regulated by the PDGF-BB load and the silk fibroin content in the composites in an individual or cooperative way. In vivo degradation of composites demonstrated that some of them had markedly enhanced degradation endurance as compared to the chitosan/GP gel. PDGF-BB-stimulated DNA synthesis in Balb/c 3T3 fibroblasts and PDGF-BB-induced cell migration suggested that the bioactivity of released PDGF-BB was well retained.

To understand the influential factors for depression in patients with facial acne vulgaris and to provide scientific evidence for a comprehensive and systematic treatment for acne vulgaris. A total of 287 outpatients with facial acne vulgaris, who visited the dermatology of the Third Xiangya Hospital, were surveyed by Beck Depression Inventory (BDI). The data was collected by Epidata software (version 3.1) and processed by SPSS software package (version 18.0). The influential factors for the depression of outpatients with facial acne vulgaris were analyzed by multinomial logistic regression. A total of 181 patients with facial acne vulgaris showed various degrees of depression (BDI score≥5) and the rate was 63.1%. The symptoms for depression included sad and pessimistic attitude as well as the decreased attention to others (social withdrawal). The influential factors for mild, moderate or severe depression were gender, the degree and the course of acne. Female patients were more likely to suffer mild, moderate or severe depression (OR=3.62, 2.63, respectively); the risk of depression in acne patients was increased with the increase in degree of the severity (OR=2.31, 4.51, respectively); the patients with the acne course more than a year were more likely to show mild depression than those with a course less than a year (OR=4.30, 7.44, respectively). The patients with acne course more than 3 years were more likely to show moderate or severe depression compared to those with a course less than a year (OR=3.60). Most of facial acne patients show a different degree of depression. The acne course is longer in female patients. The more severe the acne vulgaris is, the more suffering of the depression is. Psychological care should be considered to improve the treatment and quality of life.目的：了解颜面部寻常性痤疮患者的抑郁情绪及其影响因素，为综合、系统地治疗痤疮，提高患者的生活质量提供参考依据。方法：采用Beck抑郁问卷对中南大学湘雅三医院皮肤科287名颜面部寻常性痤疮门诊患者的抑郁情绪进行问卷调查。使用Epidata 3.1软件建立数据库，并采用SPSS18.0对资料进行统计分析，采用无序多分类logistic回归分析患者抑郁情绪的影响因素。结果：287名颜面部寻常性痤疮患者中有181例存在不同程度的抑郁(BDI总 分≥5分)、检出率为63.1%，抑郁主要表现为忧郁、悲观、社会退缩等症状。与寻常性痤疮患者轻度和中重度抑郁均相关的因素为性别、病情严重程度和病程，女性患者相对于男性患者更易出现轻度和中重度抑郁(OR=3.62与2.63)；随着痤疮病情的加重，患者出现轻度和中重度抑郁的风险也相应增加(OR=2.31与4.51)；病程在1~3年和3年以上的患者相对于病程不满1年的患者更容易出现轻度抑郁(OR=4.30与7.44)，病程在3年以上的患者相对于病程不满1年的患者更容易出现中重度抑郁(OR=3.60)。结论：大部分颜面部寻常性痤疮患者存在不同程度的抑郁，病情越严重、病程越长及性别为女性的患者抑郁程度越严重，应对其提供心理照顾，从而提高治疗效果及生活质量。.

Si-doped hydroxyapatite (Si-HA) has been intensively investigated as a promising bone biomaterial because of the biomineralization and bone formation benefit from silicon addition. In the current work, Si-HA samples were synthesized by the aqueous precipitation method. The sintering property of Si-HA was studied in terms of phase composition and transition, which was influenced by the Si doping percentage and sintering temperature. The results indicate that all the as-prepared and sintered low Si doping samples (Si% ≤ 1.6 wt%) possess HA phases; while the high Si doping samples (Si% ≥ 2 wt%) present amorphous phases as prepared, and largely or even completely transform to β-tricalcium phosphate (β-TCP) phase after sintering at 1250 °C. The Rietveld refinement on x-ray diffraction patterns was conducted to determine the particle sizes, microstrain factors and anisotropic distributions. According to the refined results, the calculated anisotropic particle sizes correspond to the observations made by transmission electron microscopy. The microstrains also present anisotropic distributions in all refinements. The accurate variation in the fine structure of Si-HA has been studied by the improved refinements after considering the anisotropic distribution.

Chitosan/nano-hydroxyapatite (HA) composites were first prepared and then used together with chitosan and silk fibroin (SF) to produce a type of four-layer porous scaffold that is potentially applicable for articular cartilage repair. The bottom layer of the scaffold was built with the chitosan/HA composite and the other three layers of the scaffold were fabricated using chitosan/SF composites in which the content of the chitosan and SF was altered in a mutually reversed trend. The so-produced chitosan/SF/HA scaffolds were further crosslinked using tripolyphosphate to achieve enhanced mechanical properties. Interconnected porous microstructures throughout the scaffolds were constructed using a temperature gradient processing technique, and the resultant scaffolds were endowed with graded pore-sizes and porosities as well as porous interface zones between contiguous layers without visual clefts. The compressive modulus and stress at 10% strain of the scaffolds in wet state showed a gradient-changed trend which partially mimics the compressive mechanical properties of an articular cartilage matrix. Cell culture on some chitosan/SF/HA scaffolds for a period of time of up to 14 d showed that the scaffolds were able to well support the growth and infiltration of cells, suggesting that the presently developed chitosan/SF/HA scaffolds have promising potential for articular cartilage repair.