High-Rate Printing of Micro/Nanoscale Patterns Using Interfacial Convective Assembly.

Printing of electronics has been receiving increasing attention from academia and industry over the recent years. However, commonly used printing techniques have limited resolution of micro- or sub-microscale. Here, a directed-assembly-based printing technique, interfacial convective assembly, is reported, which utilizes a substrate-heating-induced solutal Marangoni convective flow to drive particles toward patterned substrates and then uses van der Waals interactions as well as geometrical confinement to trap the particles in the pattern areas. The influence of various assembly parameters including type of mixing solvent, substrate temperature, particle concentration, and assembly time is investigated. The results show successful assembly of various nanoparticles in patterns of different shapes with a high resolution down to 25 nm. In addition, the assembly only takes a few minutes, which is two orders of magnitude faster than conventional convective assembly. Small-sized (diameter below 5 nm) nanoparticles tend to coalesce during the assembly process and form sintered structures. The fabricated silver nanorods show single-crystal structure with a low resistivity of 8.58 × 10-5 Ω cm. With high versatility, high resolution, and high throughput, the interfacial convective assembly opens remarkable opportunities for printing next generation nanoelectronics and sensors.

Effects of intramuscular parecoxib administration on vasospasm in an experimental subarachnoid hemorrhage model.

AIM: We examined whether intramuscular parecoxib administration has a preventive or therapeutic effect on vasospasm following experimental subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: Twenty New Zealand White Rabbits were assigned randomly to one of four groups. Animals in Group I were not subjected to SAH (control group). Animals in all other groups were subjected to SAH. Animals in Group II received no treatment after SAH induction (SAH group). Animals in Group III received intramuscular parecoxib (diluted with saline) injection at 6 and at 30 hours after SAH (treatment group). Animals in Group IV received only intramuscular saline injection at 6 and at 30 hours after SAH (vehicle group). Animals were euthanized by perfusion and fixation 48 hours after SAH induction. Basilar artery cross-sectional areas and wall thicknesses were measured. Statistical comparisons were performed using Kruskal-Wallis and Mann-Whitney U tests. RESULTS: Basilar artery cross-sectional areas in the treatment group were significantly higher than in the SAH or vehicle group (p<.05). Basilar artery wall thickness in the treatment group was significantly smaller than in the SAH or vehicle group (p<.05). CONCLUSION: Our study revealed that intramuscular administration of parecoxib significantly attenuates vasospasm following experimental SAH.

Effects of simvastatin on mandibular distraction osteogenesis.

PURPOSE: The aim of this study was to evaluate the effects of local and systemic simvastatin application on distraction osteogenesis. MATERIALS AND METHODS: Eighteen New Zealand white rabbits underwent unilateral mandibular distraction osteogenesis. After 7 days of neutral fixation, 0.4 mm twice per day, distraction was performed for 10 days. Simvastatin was applied locally during the osteotomy phase with a gelatin sponge carrier and systemically during the distraction osteogenesis period by oral gavage. All animals were killed at the end of the consolidation period of 14 days. The distracted mandibles were harvested and evaluated by plain radiography, by peripheral quantitative computed tomography, and with histomorphometry. RESULTS: Radiographic evaluation with peripheral quantitative computed tomography showed that the area of the regenerate increased by 9.6% in the local simvastatin group and by 19.3% in the systemic simvastatin group as compared with the control group. In both experimental groups the density of the regenerate increased by 6.7% as compared with the control group. Statistical evaluation of radiographic data showed that all of these changes were not significant. Histomorphometric evaluation determined that there was no statistical difference among groups with regard to the ratios of bone tissue volume to fibrous tissue volume and bone tissue volume to marrow tissue volume. CONCLUSIONS: The results of this study suggest that simvastatin's effect on enhancing distraction regenerate is limited with the applied doses and methods.

Influence of diabetes on critical flaps based on the vascular axis of a sensory nerve.

Delayed sural flap based on the vascular axis of the sural nerve has been advocated for coverage of diabetic foot ulcers. In this study we compared the survival of neurovenous and standard inferior epigastric island flaps in diabetic and non-diabetic rats. VEGF concentrations and electrolyte balance of the flaps were also investigated during elevation and on the fifth day to explore the possible mechanisms that influence ischaemia of the flap during the hyperglycaemic state. There were no statistical differences in area surviving between diabetic and control rats for either flap. The VEGF concentrations were also similar in the two flaps in the two groups during elevation. On the fifth day, VEGF concentrations had decreased significantly in all of the flaps. Electrolyte balance paralleled VEGF concentrations. We conclude that flaps based on the vascular axis of a superficial nerve deserve further experimental and clinical attention as potential options for reconstruction of ulcers on diabetic feet.

The effect of cyclosporin A on alveolar bone in rats subjected to experimental periodontal disease.

Cyclosporine A (CsA), broadly used in organ transplantation, may contribute to pathogenesis of osteoporosis. The aim of this study was to investigate the effects of CsA on alveolar bone in rats subjected or not to experimental periodontal disease using biochemical, radiographic, and histometric analysis. Forty Wistar rats were divided into 4 equal groups: Group I (Control), Group II (CsA was injected subcutaneously in a daily dose of 10 mg/kg), Group III (Ligature was placed around the mandibular molars), Group IV (Ligature+CsA). After 60 days, rats were decapitated, serum alkaline phosphatase and calcium levels were measured. Radiographic-alveolar bone loss (ABL), histometric-ABL, and percentage of new alveolar bone formation (NABF%) were determined on mandibular molars. Significant increase in serum alkaline phosphatase levels (p < 0.001), no significant difference in calcium levels were observed (p > 0.05) in Group IV compared to Group III. Radiographic and histometric-ABL were significantly less (p < 0.001), NABF% was significantly greater (p < 0.05) in Group IV than in Group III. No significant difference in any of the parameters between Group II and Group I was found. It can be concluded that in the presence of periodontal disease, CsA treatment may bring out an imbalance in the alveolar bone homeostasis by decreasing resorption and stimulating formation of alveolar bone in rats.

The relationship between proliferating cell nuclear antigen expression and histomorphometrical alterations in cyclosporin A-induced gingival overgrowth in rats.

The aim of this study was to investigate the relationship between Proliferating Cell Nuclear Antigen (PCNA) expression and histomorphometrical alterations in cyclosporin A (CsA)-induced gingival overgrowth with or without microbial dental plaque accumulation. Forty male Wistar rats were equally divided into 4 groups; Group I (control); Group II (CsA); Group III (ligature); Group IV (ligature and CsA). After 8 weeks of experimental period, rats were subsequently decapitated and mandibular molars were dissected. Gingival overgrowth was determined by measuring depth of the gingival sulcus, then the mandible were decalcified and serial sections were obtained for histomorphometric and immunohistochemical analysis. Histomorphometric analysis included the measurement of epithelial thickness; immunohistochemical analysis included the assessment of PCNA expression in the oral and sulcular epithelium of buccal and lingual gingiva. Epithelial thickness and PCNA expression were significantly increased in buccal oral epithelium of Group II (p < 0.05) and in all regions in Group IV (p < 0.05) compared to control group. Also gingival overgrowth was more prominent in Group IV in comparison to Group II. These results indicate that CsA-induced gingival alterations are closely associated with increased epithelial proliferative activity, and dental plaque accumulation seems not to be an essential but to be an aggrevating factor for the progression of the lesion.

A perichondrial flap for functional purposes in rhinoplasty.

Recent trends in rhinoplasty techniques have focused on anatomic repair as well as respect and preservation of soft tissue integrity. In this article, the authors describe the use of a perichondrial flap, then discuss technical considerations and clinical perspectives of their advantages. A perichondrial flap helps to restore the stability of the upper lateral cartilage, to achieve extra padding, and to secure osteocartilagenous grafts. The method described has been used for 60 consecutive patients. The majority of these patients were satisfied with the results. To obtain detailed information about the perichondrial flap, the authors performed an anatomic study of 13 cadavers. The average thickness of the perichondrium was 186+/-146.1 microm (range, 90--596 microm). On the basis of the results, it was concluded that elevation of the perichondrial flap with loupe magnification could improve the outcome of rhinoplasty.

Compensatory brow asymmetry: anatomic study and clinical experience.

To obtain detailed information about the interdigitation between the frontalis muscle and the orbicularis oculi muscle, the authors performed an anatomic study involving 9 cadavers (17 specimens). Three types of interdigitation were recognized. Complete interdigitation was noted in 13 specimens, and partial interdigitation in 13 specimens. In one specimen, there was no interdigitation between the frontalis muscle and the orbicularis oculi muscle. Although most of the specimens showed complete interdigitation between the frontalis muscle and the orbicularis oculi muscle, the interdigitation area exhibited architectural heterogeneity. The study findings provide a basis for a better understanding of compensatory eyebrow ptosis. In addition, two cases supporting the theory that compensatory eyebrow asymmetry may resolve when the palpebral ptosis is treated are presented.