Syndesmotic Fixation With Suture Button: Neurovascular Structures at Risk: A Cadaver Study

Objectives: The objective of this study was to describe the anatomic variations in the saphenous nerve and risk of direct injury to the saphenous nerve and greater saphenous vein during syndesmotic suture button fixation. Methods: Under fluoroscopic guidance, syndesmotic suture buttons were placed from lateral to medial at 1, 2, and 3 cm above the tibial plafond on 10 below-knee cadaver leg specimens. The distance and position of each button from the greater saphenous vein and saphenous nerve were evaluated. Results: The mean distance of the saphenous nerve to the suture buttons at 1, 2, and 3 cm were 7.1 ± 5.6, 6.5 ± 4.6, and 6.1 ± 4.2, respectively. Respective rate of nerve compression was as follows, 20% at 1 cm, 20% at 2 cm, and 10% at 3 cm. Mean distance of the greater saphenous vein from the suture buttons at 1, 2, and 3 cm was 8.6 ± 7.1, 9.1 ± 5.3, and 7.9 ± 4.9 mm, respectively. Respective rate of vein compression was 20%, 10%, and 10%. A single nerve branch was identified in 7 specimens, and 2 branches were identified in 3 specimens. Conclusion: There was at least one case of injury to the saphenous vein and nerve at every level of button insertion at a rate of 10% to 20%. Neurovascular injury may occur despite vigilant use of fluoroscopy and adequate surgical technique. Further investigation into the use of direct medial visualization of these high-risk structures should be done to minimize the risk. Levels of Evidence: Therapeutic, Level II: Prospective, comparative study

Trends in Indications and Techniques of Corneal Transplantation from 1999 through 2015 at a Tertiary Referral Center in Athens, Greece

Introduction. During the past decade, novel techniques of corneal transplantation allowing faster and better restoration of vision have emerged. The present cohort study describes a shift of indications and techniques that has occurred in the field of corneal transplantation over a 17-year period in Greece. Methods. All patients undergoing keratoplasty between January 1999 and December 2015 at an academic tertiary referral center in Athens, Greece, were retrospectively reviewed. The annual incidence of keratoplasty indications and techniques was recorded and analyzed. Results. A total of 1382 keratoplasty procedures were included. Leading indications were bullous keratopathy (BK) (37.5%), followed by allograft rejection (17.7%), corneal scar (12%), keratoconus (KC) (10.3%), and Fuchs endothelial dystrophy (FED) (8.8%). A decreasing trend was observed for KC (P=0.009) and an increasing trend for BK (P=0.003) and FED (P=0.001). In 2015, the incidence of penetrating keratoplasty (PK) had decreased from 100% (1999 to 2009) to 21.4%; for cases with isolated pathology of the corneal endothelium, DSAEK was the preferred technique (59.8%), while the respective rate of DMEK was 18.8%. Conclusion. Herein, we observed an increasing trend of endothelial pathology among keratoplasty indications as well as a major shift in preferred techniques due to a wide adoption of the new EK procedures.

Modelling of Fischer-Tropsch Synthesis in a Fluidized Bed Reactor

The FT reaction involves the conversion of syngas which is derived from natural gas or coal to different kinds of products according to the operating conditions and the type of the catalyst. In other words, it is a practical way to convert solid fuel (coal) and natural gas to various hydrocarbons (C1-C60) and oxygenates such as alkanes, alkenes etc. The main products of the reaction are naphtha and gasoline. This paper deals with developing a proper product distribution model for FT process using the appropriate kinetic model, optimizing the respective rate constants while applying them in product distribution equations. The results revealed only 8.09% deviations from the olefin experimental data and 10.27% deviations from the paraffin experimental data being acceptable when compared with previous open literature data.

EFFECT OF Cr(VI) IONS ON THE EFFECTIVENESS OF CHLOROPHENOL PHOTODEGRADATION

In order to solve environmental problems due to chlorophenol compound and which is hazardous and carcinogenic, the effect of Cr(VI) ions on the chlorophenol photodegradation effectiveness has been evaluated. Photodegradation process was carried out in a closed reactor by batch sistem, by exposing the UV lamp into a solution containing chlorophenol and Cr(VI) ions for a period of time. Then the solution was analyzed by gas chromatography for determination of the residual chlorophenol concentration. In this research, the influences of reaction time, Cr(VI) ions concentration, and solution pH on the photodegradation results were also evaluated. The research results indicated that the effectiveness of the photodegradation increases when ion Cr(VI) was added. The improvement of the effectiveness is proportional with the increase of the concentration of Cr(VI) added. The effectiveness of the photodegradation is also influenced by solution pH, and the highest is reached at pH < 2. Chlorophenol photodegradation follows first order reaction. The respective rate reaction constants for chlorophenol photodegradation in the absence and in the presence of Cr(VI) ions are 4.91x 10-2 and 11.41x 10-2 hours-1 Keywords: photodegradation, chlorophenol, Cr(VI) ion

Kinetics of catalytic Meerwein-Ponndorf-Verley reduction of aldehydes and ketones using boron triethoxide

Catalytic Meerwein-Ponndorf-Verley (MPV) reduction of various aliphatic, aromatic, and unsaturated aldehydes and ketones to corresponding alcohols (analyzed by GC-MS) in the presence of boron triethoxide (B(OEt)3) were studied. Kinetics of this reduction reaction was also studied and the respective rate constants were determined. It was found that B(OEt)3 catalyzes the reduction of aliphatic aldehydes and ketones to alcohols at room temperature while aromatic aldehydes and ketones were not reduced under the same conditions. In addition, MPV reduction using B(OEt)3 was found to be chemoselective as unsaturated aldehydes and ketones afforded the corresponding alcohols without affecting unsaturated groups. The mechanism proposed involves a six-membered transition state in which both the alcohol and the carbonyl are coordinated to the same boron centre of a boron alkoxide catalyst.

Cancer and immune-mediated disease in people who have had meningococcal disease: record-linkage studies

SUMMARYThe mechanisms that cause susceptibility to invasive meningococcal disease are largely unknown, but are likely to have important genetic and immunological components. We postulated that susceptibility to meningococcal disease might be associated with altered risks of development of other clinical disease. We studied cancer and immune-mediated disease in people who have been hospitalized with meningococcal disease. In cohorts of people who had invasive meningococcal disease, compared with reference cohorts, the rate ratio for cancer in an Oxford dataset studied from 1963 to 1998 was 0·88 [95% confidence interval (CI) 0·42–1·61] and in an all-England dataset studied from 1999 to 2005 it was 1·02 (95% CI 0·80–1·27). The respective rate ratios for immune-mediated disease were 1·49 (95% CI 0·81–2·50) and 0·69 (95% CI 0·53–0·89). Susceptibility to meningococcal disease was not associated with an altered risk of cancer. Occurrence of immune-mediated disease was, if anything, low in the large all-England cohort of people who had meningococcal disease.

Bird mixed-flocks and nuclear species in a tecoma savanna in the Pantanal

In bird mixed flocks, a prominent species, the so-called nuclear species, improves the cohesion and maintenance of the flocks, while other less conspicuous species are assumed as satellite. In this study we described the composition, as well as examined the existence of both nuclear and satellite species in mixed flocks of a savanna in the Pantanal. The observations were developed using three transects during the dry season of 2002. Bird species abundance and respective rate of participation in mixed flocks were surveyed by transects, while intraspecific sociality, communication, foraging maneuvers of species, and responses to predators were sampled by direct observations. These parameters were evaluated to distinguish nuclear from satellite species. We observed 41 bird mixed flocks, which included from 2 to 17 species of which Suiriri suiriri (Vieillot), one of the most abundant species, was present in most flocks, often represented by 2-4 individuals, whereas most other species occurred lone or in pairs. While foraging by acrobatic maneuvers S. suiriri often gave contact calls, as well as earlier giving alarm calls if faced with a risk of predation. In addition, S. suiriri always started mixed flocks movements. Conversely, most other species were silent and closely inspected the vegetation while foraging. Such species always followed S. suiriri and seldom gave contact calls. Hence, the conspicuous traits exhibited by S. suiriri, potentially, are exploited by the other bird species as cues, which are important references for bird mixed flock cohesion in a savanna in the southern Pantanal.

Glufosinate Antagonizes Clethodim Control of Goosegrass (Eleusine indica)

Because of a previously reported antagonism of clethodim activity by other herbicides, greenhouse experiments were conducted to determine goosegrass control with clethodim and glufosinate postemergence alone, in tank mixtures, and as sequential treatments. Herbicide treatments consisted of glufosinate at 0, 290, or 410 g ai/ha and clethodim at 0, 105, or 140 g ai/ha, each applied alone, in all possible combinations of the above application rates, or sequentially. Glufosinate at either rate alone controlled goosegrass at the two- to four-leaf growth stage <44%, and control was less for goosegrass at the one- to two- and four- to six-tiller growth stages. Clethodim controlled two- to four-leaf and one- to two-tiller goosegrass 91 and 99% at application rates of 105 and 140 g/ha, respectively, and controlled four- to six-tiller goosegrass 68 and 83% at application rates of 105 and 140 g ai/ha, respectively. All tank mixtures of glufosinate with clethodim reduced goosegrass control at least 52 percentage points when compared to the control with clethodim alone. Glufosinate at 290 or 410 g/ha when applied sequentially 7 or 14 d prior to clethodim reduced goosegrass control at least 50 percentage points compared to the control obtained with clethodim applied alone. Clethodim at rates of 105 or 140 g/ha when applied 7 or 14 d prior to glufosinate controlled goosegrass equivalent to the control obtained with each respective rate of clethodim applied alone at the two- to four-leaf and one- to two-tiller growth stage. Clethodim should be applied to goosegrass no larger than at the one- to two-tiller growth stage at least 7 d prior to glufosinate application or 14 d after a glufosinate application for effective goosegrass control.

Binding Sites, Singly Bound States, and Conformation Coupling Shape GABA-Evoked Currents

The time course of GABA-evoked currents is the main source of information on the GABAAreceptor gating. Since the kinetics of these currents depends on the transitions between several receptor conformations, it is a major challenge to define the relations between current kinetics and the respective rate constants of the microscopic gating scheme. The aim of this study was to further explore the impact of different GABAA receptor conformations on the kinetics of currents elicited by ultra-fast GABA applications. We show that the rising phase and amplitude of GABA-evoked currents depend on desensitization and singly bound states. The occupancy of bound receptors depends not only on binding properties but also on opening/closing and desensitization. The impact of such functional coupling between channel states is critical in conditions of high non-equilibrium typical for synaptic transmission. The concentration dependence of the rising phase of the GABA-elicited current indicates positive cooperativity between agonist binding sites. We provide evidence that preequilibration at low GABA concentrations reduce GABA-evoked currents due to receptor trapping in a singly bound desensitized state.

Synchronous direct gradient layer and indirect room calorimetry

Rumpler, James L., and William V. Seale. Synchronous direct gradient layer and indirect room calorimetry. J. Appl. Physiol. 83(5): 1775–1781, 1997.—A dual direct/indirect room-sized calorimeter is used at the Beltsville Human Nutrition Research Center to measure heat emission and energy expenditure in humans. Because the response times of a gradient layer direct calorimeter and an indirect calorimeter are not equivalent, the respective rate of heat emission and energy expenditure cannot be directly compared. A system of equations has been developed and tested that can correct the respective outputs of the direct gradient layer calorimeter and indirect calorimeter for delays due to the response times of the measurement systems. Performance tests using alcohol combustion to simulate a human subject indicate accurate measurements of heat production from indirect (99.9 ± 0.4%), indirect corrected for response time (99.9 ± 0.5%), direct (99.9 ± 0.8%), and direct corrected for response time (99.9 ± 0.8%) calorimetry systems. Results from 24-h measurements in 10 subjects indicate that corrected heat emission is equivalent to (99.8 ± 2.0%) corrected energy expenditure. However, heat emission measured during sleep was significantly greater (14%) than energy expenditure, suggesting a change in the energy stored as heat in the body. This difference was reversed during the day. These results illustrate how the simultaneous measurement of heat emission and energy expenditure provides insights into heat regulation.