Group 13 salphen compounds (In, Ga and Al): a comparison of their structural features and activities as catalysts for cyclic carbonate synthesis.

Many complexes based on group 13 elements have been successfully applied as catalysts for the synthesis of cyclic carbonates from epoxides and CO2 and to date these have provided some of the most active catalysts developed. It is notable that most reports have focused on the use of aluminium-based compounds likely because of the well-established Lewis acidity of this element and its cost. In comparison, relatively little attention has been paid to the development of catalysts based on the heavier group 13 elements, despite their known Lewis acidic properties. This study describes the synthesis of aluminium, gallium and indium compounds supported by a readily prepared salphen ligand and explores both their comparative structures and also their potential as catalysts for the synthesis of cyclic carbonates. In addition, the halide ligand which forms a key part of the compound has been systematically varied and the effect of this change on the structure and catalytic activity is also discussed. It is demonstrated that the indium compounds are actually, and unexpectedly, the most active for cyclic carbonate synthesis, despite their lower Lewis acidity when compared to their aluminium congeners. The experimental observations from this work are fully supported by a Density Functional Theory (DFT) study, which provides important insights into the reasons as to why the indium catalyst with bromide, [InBr(salphen)], is most active.

Demography of the Intertidal Fucoid Hormosira banksii: Importance of Recruitment to Local Abundance.

Canopy-forming macroalgae form the basis of diverse coastal ecosystems globally. The fucoid Hormosira banksii is often the dominant canopy-forming macroalga in the temperate intertidal of southern Australia and New Zealand, where it is commonly associated with an understory of coralline turf. Hormosira banksii is susceptible to both natural and anthropogenic disturbance and despite its abundance, few studies have examined the demography of this important species. This study determined the demographic response of H. banksii to different gradients of disturbance to both its canopy and to the understory coralline turf. We established plots in which the density of H. banksii and/or understory coralline turf was manipulated in a pulse perturbation to simulate a disturbance event. The manipulated plots contained eight treatments ranging from 100% removal of H. banksii to 100% removal of the understory coralline turf. We then measured recruitment and followed individual recruits for up to 18 months to determine growth and survivorship. We found that H. banksii recruitment was seasonally variable throughout the experiment and highest over summer, survivorship of recruits was generally high, and the species was slow-growing and long-lived. Moreover, the level of disturbance did not seem to affect recruitment, growth, or survivorship and post-recruitment mortality was independent of H. banksii density. In this system, it appears that H. banksii is a relatively long-lived perennial species whose demography is density-independent which appears to allow recovery from disturbance.

Healing comparison of porcine cutaneous incisions made with cold steel scalpel, standard electrosurgical blade, and a novel tissue dissector.

BACKGROUND: Standard electrosurgery provides superior hemostasis compared to a cold steel scalpel, but inferior tissue healing. A novel electrosurgical blade with an advanced waveform, the MEGADYNE ACE BLADE™ 700 Soft Tissue Dissector (ACE), was designed to provide both excellent hemostasis and wound healing. This study compared ACE to scalpel and standard electrosurgery in a porcine model of wound healing. METHODS: Skin incisions from six pigs were evaluated at time points of 0, 1, 2, 3 and 6 weeks after application of the three devices. Histopathology was performed on samples from each time point. For each non-initial time point, the healing incisions were photographed for later evaluation by expert graders, and excised for wound strength testing. RESULTS: Time 0 photomicrographs showed a gradient of thermal tissue damage by initial incision, ranging from no damage made by the scalpel, minimal damage made by ACE, and twice the ACE damage made by a nonstick PTFE-coated electrosurgical blade. Histopathologic analysis at 6 weeks showed comparable dermal scar width measurements for scalpel and ACE incisions. Scars were wider for incisions made by standard electrosurgical blade. Wound strength was greater for scalpel and ACE than for standard electrosurgery. Cosmetic results at 6 weeks were not significantly different between scalpel and ACE incisions, while standard electrosurgical blade incisions were significantly inferior to ACE (odds ratio: 53.4, p<0.001). CONCLUSION: The MEGADYNE ACE BLADE™ 700 Soft Tissue Dissector represents a significant improvement in electrosurgical technology for skin incisions and dispels the traditional concerns of delayed healing and poor cosmetic result that have been attributed to using conventional electrosurgical blades for skin incisions.

Automated algorithm for CBCT-based dose calculations of prostate radiotherapy with bilateral hip prostheses.

OBJECTIVE: Cone beam CT (CBCT) images contain more scatter than a conventional CT image and therefore provide inaccurate Hounsfield units (HUs). Consequently, CBCT images cannot be used directly for radiotherapy dose calculation. The aim of this study is to enable dose calculations to be performed with the use of CBCT images taken during radiotherapy and evaluate the necessity of replanning. METHODS: A patient with prostate cancer with bilateral metallic prosthetic hip replacements was imaged using both CT and CBCT. The multilevel threshold (MLT) algorithm was used to categorize pixel values in the CBCT images into segments of homogeneous HU. The variation in HU with position in the CBCT images was taken into consideration. This segmentation method relies on the operator dividing the CBCT data into a set of volumes where the variation in the relationship between pixel values and HUs is small. An automated MLT algorithm was developed to reduce the operator time associated with the process. An intensity-modulated radiation therapy plan was generated from CT images of the patient. The plan was then copied to the segmented CBCT (sCBCT) data sets with identical settings, and the doses were recalculated and compared. RESULTS: Gamma evaluation showed that the percentage of points in the rectum with γ < 1 (3%/3 mm) were 98.7% and 97.7% in the sCBCT using MLT and the automated MLT algorithms, respectively. Compared with the planning CT (pCT) plan, the MLT algorithm showed -0.46% dose difference with 8 h operator time while the automated MLT algorithm showed -1.3%, which are both considered to be clinically acceptable, when using collapsed cone algorithm. CONCLUSION: The segmentation of CBCT images using the method in this study can be used for dose calculation. For a patient with prostate cancer with bilateral hip prostheses and the associated issues with CT imaging, the MLT algorithms achieved a sufficient dose calculation accuracy that is clinically acceptable. The automated MLT algorithm reduced the operator time associated with implementing the MLT algorithm to achieve clinically acceptable accuracy. This saved time makes the automated MLT algorithm superior and easier to implement in the clinical setting. ADVANCES IN KNOWLEDGE: The MLT algorithm has been extended to the complex example of a patient with bilateral hip prostheses, which with the introduction of automation is feasible for use in adaptive radiotherapy, as an alternative to obtaining a new pCT and reoutlining the structures.

Advanced Cutting Effect System versus Cold Steel Scalpel: Comparative Wound Healing and Scar Formation in Targeted Surgical Applications.

BACKGROUND: Use of electrosurgery for skin incisions has been controversial due to concerns of delayed healing, excessive scarring, and increased infection. Recent studies using modern electrosurgical generators that produce pure sinusoidal "CUT" waveforms have shown reductions in thermal damage along incisions made with these devices compared with their predecessors. This study compares scar formation in incisions made using a cold steel scalpel (CSS) or the ACE Blade and Mega Power Generator (ACE system, Megadyne Medical Products, Draper, Utah) from patient and blinded observer perspectives. METHODS: Subjects seeking plastic surgery were enrolled in the study. Incisions on one side of each subject's body were made with a CSS while equivalent incisions on the contralateral side were made with the ACE system. Differences between incision methods were evaluated by assessment of scar formation by observers and assessment of patient satisfaction relating to scar formation at 120 days postsurgery. RESULTS: Observers rated incision vascularization, pigmentation, thickness, and relief. The mean observer score (± SD) of incisions made with the ACE system was 11.1 ± 4.4 while that of incisions made with the CSS was 10.8 ± 3.7 (P < 0.0001). Patients rated incision pain, itching, discoloration, stiffness, thickness, and irregularity. The mean patient score of incisions made with the ACE system was 9.4 ± 9.2 while that of incisions made with the CSS was 9.3 ± 8.5 (P < 0.0001). CONCLUSIONS: Results showed noninferior wound healing/scar formation in skin incisions made with the ACE system compared with incisions made with a CSS.