Novel Methods of Modification in Isocyanurate Foams

This paper describes novel methods of producing modified isocyanurate foams having low combustibility, high thermal stability and low smoke density.

The research philosophy in this study is based on a hypothesis that by increasing the thermal stability of polymeric linkages, less flammable gases are generated which result in foams having lower combustibility, higher flame resistance, and higher thermal stability.

The thermally-stable linkages employed in this study are amide-, imide-, and imide/carbodiimide linkages.

Amide-modified isocyanurate foams were prepared by either a one step process or a two step process, using dimer acid, adipic acid or di-ketimine as modifier. The foams prepared by the two step process using adipic acid exhibited high closed cell content and therefore higher thermal insulation and high temperature stability.

Imide-modified isocyanurate foams exhibited high flame-resistance and high closed cell content.

Construction of finite element model and stress analysis of anterior cruciate ligament tibial insertion

Objective:

The aim of the present study was to develop a more realistic finite element (FE) model of the human anterior cruciate ligament (ACL) tibial insertion and to analyze the stress distribution in the ACL internal fibers under load.

Methods:

The ACL tibial insertions were processed histologically. With Photoshop software, digital images taken from the histological slides were collaged, contour lines were drawn, and different gray values were filled based on the structure. The data were exported to Amira software and saved as “.hmascii” file. This document was imported into HyperMesh software. The solid mesh model generated using HyperMesh software was imported into Abaqus software. The material properties were introduced, boundary conditions were set, and load was added to carry out the FE analysis.

Results:

The stress distribution of the ACL internal fibers was uneven. The lowest stress could be observed in the ACL lateral fibers under tensile and shear load.

Conclusion:

The establishment of ACL tibial insertion FE model and mechanical analysis could reveal the stress distribution in the ACL internal fibers under load. There was greater load carrying capacity in the ACL lateral fibers which could sustain greater tensile and shear forces.

Regional fibrocartilage variations in human anterior cruciate ligament tibial insertion: a histological three-dimensional reconstruction

PURPOSE

We studied anterior cruciate ligament (ACL) tibial insertion architecture in humans and investigated regional differences that could suggest unequal force transmission from ligament to bone.

MATERIALS AND METHODS

ACL tibial insertions were processed histologically. With Photoshop software, digital images taken from the histological slides were collaged, contour lines were drawn, and different gray values were filled based on the structure. The data were exported to Amira software for three-dimensional reconstruction.

RESULTS

The uncalcified fibrocartilage (UF) layer was divided into three regions: lateral, medial and posterior according to the architecture. The UF zone was significantly thicker laterally than medially or posteriorly (p < 0.05). Similarly, the calcified fibrocartilage (CF) thickness was significantly greater in the lateral part of the enthesis compared to the medial and posterior parts (p < 0.05).

CONCLUSIONS

The UF quantity (more UF laterally) corresponding to the CF quantity (more CF laterally) at the ACL tibial insertion provides further evidence suggesting that the load transferred from the ACL to the tibia was greater laterally than medially and posteriorly.

Power driven tunable white upconversion luminescence from Lu2TeO6 tri-doped with Yb3+, Tm3+ and Ho3+

Tunable power driven white upconversion luminescence was realized in the Yb³⁺, Tm³⁺, and Ho³⁺ tri-doped Lu₂TeO₆.

Randomized clinical trial of Chinese herbal medications to reduce wound complications after mastectomy for breast carcinoma

BACKGROUND

Ischaemia and necrosis of skin flaps is a common complication after mastectomy. This study evaluated the influence of anisodamine and Salvia miltiorrhiza on wound complications after mastectomy for breast cancer.

METHODS

Ninety patients undergoing mastectomy for breast carcinoma were divided into three groups. Group 1 received routine wound care, group 2 received intravenous Salvia miltiorrhiza after surgery for 3 days and group 3 similarly received intravenous anisodamine. Skin flaps were observed on postoperative days 4 and 8; areas of wound ischaemia and necrosis were graded and adverse events recorded.

RESULTS

There was no difference in demographic characteristics between the groups. At 4 days after surgery the rate of ischaemia and necrosis in groups 2 and 3 was significantly reduced compared with that in control group 1 (median wound score 6·80 versus 23·38, P = 0·002, and 3·76 versus 23·38, P < 0·001, respectively). This improvement in groups 2 and 3 continued to postoperative day 8 (both P < 0·001), but wound scores at this stage were better in group 3 than in group 2 (1·82 versus 6·92 respectively; P = 0·022). The volume of wound drainage was lower in group 3 than in group 1 (P = 0·004). The incidence of adverse effects was highest in group 3, and two patients in this group discontinued treatment. No significant complications were noted in group 2.

CONCLUSION

Anisodamine and S. miltiorrhiza were both effective in reducing skin flap ischaemia and necrosis after mastectomy, although anisodamine was associated with a higher rate of adverse effects.

Surface coating of carbon nanofibers/nanotubes by electrodeposition for multifunctionalization

Carbon nanomaterials in the form of paper sheets have been used as platforms to achieve multifunctionality. Combined with electrochemical deposition, room temperature synthesis of magnetic Ni coatings on individual carbon nanofibers (CNF) and/or carbon nanotubes (CNT) has been realized through solution penetration and ion diffusion. In addition to significant electrical conductivity improvement, the magnetic responses of the Ni coated carbon nanopaper sheets can be tuned within large ranges in terms of saturation magnetic field, remnant magnetization and coercivity. After being re-suspended in liquids, the magnetized CNFs/CNTs can be aligned with small external magnetic fields.

[Experimental study of vascular gene transfer using soluble stent]

We assessed the possibility of gene transfer into anastomotic arteries in vivo using soluble stent containing Adv5-CMV/LacZ. After being soaked in a high concentration solution of glucose containing Adv5-CMV (control group) or Adv5-CMV/LacZ (treatment group) for 30 minutes, we inserted soluble stents into the lumina of cut rat carotid arteries, and end-to-end anastomoses of cut rat carotid were performed with standard microvascular surgical technique. 16 rats were killed after two weeks, the segments of anastomotic carotid arteries were prepared for assessing beta-galactosidase activity and histochemical staining. In the control group, the anastomotic arteries did not have detectable level of beta-galactosidase expression. In the treatment group, the amount of beta-galactosidase expression was 9.80 x 10-3 u/g tissue. Microscopic examination of histochemically stained arteries demonstrated that gene transfered not only to endothelial cells but also to smooth muscle cells, and all anastomotic arteries were transfered in the treatment group, but none of arteries revealed blue in the control group. The results of this experimental study suggested that soluble stent be a new method of direct gene transfer into arteries in vivo.

[The role of oxygen radicals in adult respiratory distress syndrome]

A traumatic adult respiratory distress syndrome (ARDS) model was made with 3 intravenous bolus of homologous bone marrow extract in rabbits. Variables were then measured including the metabolites of oxygen radicals in plasma and expired gases, serum lactic dehydrogenase (LDH) isoenzymes and plasma fibronectin (Fn). A two peak increase was found in expired ethane and plasma conjugated dienes following decrease of periphery white blood and polymorphonuclear neutrophil (PMN) differential count; continuous increase of serum LDH3 and severe descent of plasma Fn were also found after the trauma. The above results suggest that PMN releasing oxygen radicals play an important role in RDS pathogenesis; and expired ethane, circulating conjugated dienes, LDH3 and Fn may be useful for making diagnosis and prognosis assessment of ARDS.