Factors in circulating air may play a role in immune responses after surgery through induction of gut-derived lipopolysaccharide (LPS) translocation across the gut. CD-1 mice were randomized to one of four treatment groups: controls, laparoscopy with carbon dioxide inflation, laparoscopy with air inflation and laparotomy. The peritoneal and systemic immune response was assessed by evaluating peritoneal macrophage, blood monocyte and neutrophil activity. In a second study, the effect of each of the treatments on fluorescein isothiocyanate (FITC)-LPS translocation across the gut was assessed. There were significant (P < 0.05) increases in peritoneal tissue macrophage release of superoxide and tumour necrosis factor after laparoscopy with air and laparotomy compared with control procedures and carbon dioxide laparoscopy. However, peritoneal macrophage FITC-Candida albicans ingestion was significantly decreased after air laparoscopy and laparotomy compared with controls and carbon dioxide laparoscopy (P < 0.05). These findings correlated with a significant (P < 0.05) decrease in CD11b expression. Significant translocation into the peritoneal cavity and systemic circulation occurred after air laparoscopy and laparotomy only. Factors in circulating air can induce LPS translocation and subsequent stimulation of postoperative immune responses. The beneficial effects of laparoscopic surgery may be explained by the minimal air contamination of the peritoneal cavity.

Performing either single endoscopic port or open CTS in the operating room is more expensive and less efficient than in the clinic setting.

Fuel efficient thermal management of diesel engine aftertreatment is a significant challenge, particularly during cold start, extended idle, urban driving, and vehicle operation in cold ambient conditions. Aftertreatment systems incorporating NO xmitigating selective catalytic reduction and diesel oxidation catalysts must reach ;250°C to be effective. The primary engine-out condition that affects the ability to keep the aftertreatment components hot is the turbine outlet temperature; however, it is a combination of exhaust flow rate and turbine outlet temperature that impact the warm-up of the aftertreatment components via convective heat transfer. This article demonstrates that cylinder deactivation improves exhaust thermal management during both loaded and lightly loaded idle conditions. Coupling cylinder deactivation with flexible valve motions results in additional benefits during lightly loaded idle operation. Specifically, this article illustrates that at loaded idle, valve motion and fuel injection deactivation in three of the six cylinders enables the following: (1) a turbine outlet temperature increases from ;190°C to 310°C with only a 2% fuel economy penalty compared to the most efficient six-cylinder operation and (2) a 39% reduction in fuel consumption compared to six-cylinder operation achieving the same ;310°C turbine out temperature. Similarly, at lightly loaded idle, the combination of valve motion and fuel injection deactivation in three of the six cylinders, intake/exhaust valve throttling, and intake valve closure modulation enables the following: (1) a turbine outlet temperature increases from ;120°C to 200°C with no fuel consumption penalty compared to the most efficient six-cylinder operation and (2) turbine outlet temperatures in excess of 250°C when internal exhaust gas recirculation is also implemented. These variable valve actuation-based strategies also outperform six-cylinder operation for aftertreatment warm-up at all catalyst bed temperatures. These benefits are primarily realized by reducing the air flow through the engine, directly resulting in higher exhaust temperatures and lower pumping penalties compared to conventional six-cylinder operation. The elevated exhaust temperatures offset exhaust flow reductions, increasing exhaust gas-to-catalyst heat transfer rates, resulting in superior aftertreatment thermal management performance.

Most diesel engines meet today’s strict NOx and particulate matter emission regulations using after-treatment systems. A major drawback of these after-treatment systems is that they are efficient in reducing emissions only when their catalyst temperature is within a certain range (typically between 250  °C and 450 °C). At lower engine loads this is a major problem as the exhaust temperatures are usually below 250 °C. The primary objective of this study was to analyze “cylinder throttling” via both delayed and advanced intake valve closure timing. The effect of cylinder throttling on exhaust gas temperatures, fuel consumption, in-cylinder combustion and emissions is outlined. A significant increase in turbine outlet temperature accompanied by a decrease in fuel consumption, NOx, and particulate matter emissions was observed. Both delayed and advanced intake valve closure timings were equally effective. The increase in exhaust gas temperatures was attributed to a drop in air flow through the engine, which resulted from a reduction in the volumetric efficiency via cylinder throttling. The increase in fuel efficiency resulted from a decrease in the pumping work through a reduction in air flow through the engine. Reductions in NOx are attributed to the combined effect of a lower in-cylinder temperature due to a reduction in piston-motion-induced compression and a shift to a more premixed combustion mode. Particulate matter emissions were also reduced as a result of additional premixing. At the 1200 RPM and 2.5 bar brake mean effective pressure (BMEP) operating point, both delayed and advanced intake valve closure timings resulted in a turbine outlet temperature increase from 195 °C to 255 °C accompanied by an increase in brake thermal efficiency of 1.5% (absolute) and a reduction in brake-specific NOx and particulate matter emissions by 40% and 30%, respectively.

Modern on-road diesel engine systems incorporate flexible fuel injection, variable geometry turbocharging, high pressure exhaust gas recirculation, oxidation catalysts, particulate filters, and selective catalytic reduction systems in order to comply with strict tailpipe-out NOx and soot limits. Fuel consuming strategies, including late injections and turbine-based engine exhaust throttling, are typically used to increase turbine-outlet temperature and flow rate in order to reach the aftertreatment component temperatures required for efficient reduction of NOx and soot. The same strategies are used at low load operating conditions to maintain aftertreatment temperatures. This paper demonstrates that cylinder deactivation (CDA) can be used to maintain aftertreatment temperatures in a more fuel-efficient manner through reductions in airflow and pumping work. The incorporation of CDA to maintain desired aftertreatment temperatures during idle conditions is experimentally demonstrated to result in fuel savings of 3.0% over the HD-FTP drive cycle. Implementation of CDA at non-idle portions of the HD-FTP where BMEP is below 3 bar is demonstrated to reduce fuel consumption further by an additional 0.4%, thereby resulting in 3.4% fuel savings over the drive cycle.

Approximately 30% of the fuel consumed during typical heavy-duty vehicle operation occurs at elevated speeds with low-to-moderate loads below 6.5 bar brake mean effective pressure. The fuel economy and aftertreatment thermal management of the engine at these conditions can be improved using conventional means as well as cylinder deactivation and intake valve closure modulation. Airflow reductions result in higher exhaust gas temperatures, which are beneficial for aftertreatment thermal management, and reduced pumping work, which improves fuel efficiency. Airflow reductions can be achieved through a reduction of displaced cylinder volume by using cylinder deactivation and through reduction of volumetric efficiency by using intake valve closure modulation. This paper shows that, depending on load, cylinder deactivation and intake valve closure modulation can be used to reduce the fuel consumption between 5% and 25%, increase the rate of warm-up of aftertreatment, maintain higher temperatures, or achieve active diesel particulate filter regeneration without requiring dosing of the diesel oxidation catalyst.

Level I studies in plastic surgery continue to increase in number; however, most are not randomized or blinded, do not have power analyses, and do not consider cost. Future studies should be designed to produce high-quality evidence and should address cost and comparative effectiveness.

Background:The purpose of this article is to describe the indications, operative technique, outcomes, and systematic review of the literature on the reconstruction of patients with end-stage pressure ulcers using a fillet flap technique. In this technique, the femur, tibia, and fibula are removed from the thigh and leg, and the soft tissue is used as a pedicled, or free, myocutaneous flap for reconstruction. Long-term outcomes, salient surgical technique of flap elevation, and design are detailed for patients who had a fillet of leg flap for reconstruction of extensive pressure ulcers.Methods:The indications, surgical technique, and postoperative outcomes of 5 patients who had pedicled fillet flaps are reviewed including patient age, sex, underlying comorbidities, duration of paraplegia, operative technique, and complications. A systematic review of the literature was performed searching PubMed, Cochrane Database, and Medline with the following MeSH terms: pressure ulcer, pressure sore, decubitus ulcer, fillet flap, and fillet flap. Inclusion criteria were use of a fillet technique, article data on the number of reconstructions before fillet flap, complications, and English language.Results:Most of our patients were male 75% (n = 3) with an average age of 47.5 years, had been paralyzed for an average of 16 years, and had few medical comorbidities. Two patients (3 flaps) required hip disarticulation, 1 patient had a bilateral fillet flaps, and 3 patients had resection of tibia/fibula. After following patients for an average of 1.4 years (4 mo to 2 yr), complications were limited to 1 patient who had partial-thickness flap loss at the distal skin flap that healed by secondary intention and 1 patient who had ulcer recurrence because of noncompliance. Four articles met inclusion criteria for systematic review and 3 were excluded.Conclusions:The fillet of leg flap remains a useful and reliable method of reconstructing end-stage pressure ulcers.