Historical perspectives on injuries of the ligaments of the ankle

As is readily apparent, there is not a consensus regarding the treatment of lateral ligamentous ruptures of the ankle. Certainly, the elimination of functional instability is the goal of treatment. What actually causes this is still open to debate, but from Harrington's work, it appears that degenerative changes can result from mechanical instability. We are all aware that many athletes compete actively with "two-plane" instability of the ankle, but it remains to be seen if they will also suffer the late degenerative changes that Harrington describes. In the meantime, each physician must decide which diagnostic technique to rely upon and which treatment regimen will provide the most consistent results with the least incidence of functional instability.     

Modeling shallow marine carbonate depositional systems

Geological Process Models (GPMs) have been used in the past to simulate the distinctive stratigraphies formed in carbonate sediments, and to explore the interaction of controls that produce heterogeneity. Previous GPMs have only indirectly included the supersaturation of calcium carbonate in seawater, a key physicochemical control on carbonate production in reef and lagoon environments, by modifying production rates based on the distance from open marine sources. We here use the residence time of water in the lagoon and reef areas as a proxy for the supersaturation state of carbonate in a new process model, Carbonate GPM. Residence times in the model are calculated using a particle-tracking algorithm. Carbonate production is also controlled by water depth and wave power dissipation. Once deposited, sediment can be eroded, transported and re-deposited via both advective and diffusive processes. We show that using residence time as a control on production might explain the formation of non-ordered, three-dimensional carbonate stratigraphies by lateral shifts in the locus of carbonate deposition on timescales comparable to so-called 5th-order sea-level oscillations. We also show that representing supersaturation as a function of distance from open marine sources, as in previous models, cannot correctly predict the supersaturation distribution over a lagoon due to the intricacies of the flow regime.     

太阳能热利用在欧美的衰落与在中国的崛起

纵观全球太阳能热利用行业的发展,东西方的差异性明显。不少人认为,这种差异正是西方衰落的信号。目前正值人们应对能源安全和气候变化的紧要关头,欧盟和美国政府却恢复旧的能源政策,已经或者即将终止所有可持续性发展的措施。对他们来说能源安全意味采取古老的军事     

Working Alliance, Treatment Satisfaction, and Patterns of Posttreatment Use Among Adolescent Substance Users.

This longitudinal study examined the relationships among the working alliance, treatment satisfaction, and posttreatment use among adolescents in treatment for substance abuse. Adolescents (N = 600) from the Cannabis Youth Treatment study (M. L. Dennis et al., 2002) completed measures of working alliance and treatment satisfaction as well as substance use and substance-related problems at intake and 3, 6, 9, 12, and 30 months' postintake. When controlling for initial substance use and substance-related problems, working alliance, but not treatment satisfaction, predicted use at 3 and 6 months' postintake. Neither working alliance nor treatment satisfaction were predictive of longitudinal patterns of posttreatment use. Implications for the assessment of working alliance and treatment satisfaction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Spinal anesthesia for elective lumbar spine surgery

STUDY OBJECTIVE: To evaluate a large series of elective lumbar spine surgical procedures by a single surgeon whose patients were all offered spinal anesthesia. DESIGN: Retrospective chart review. SETTING: Tertiary-care teaching hospital. MEASUREMENTS AND MAIN RESULTS: The records of all elective lumbar spine procedures between 1984 and 1995 performed by one surgeon (GRB) were obtained, and 803 were identified. Of those 803 patients, 611 accepted spinal anesthesia. Data collected included patient demographics, details of the spinal and general anesthesia, perioperative complications, and impact of the spinal anesthetic options on the outcome of spinal anesthesia. General and spinal anesthesia patients were comparable for age, gender, height, and ASA physical status. Patients who received spinal anesthesia were significantly heavier than the general anesthesia patients. Among perioperative complications, nausea and deep venous thrombosis occurred significantly more often in the general than spinal anesthesia patients. Mild hypotension and decreased heart rate (HR) were the most common hemodynamic changes with spinal anesthesia, whereas hypertension and increased HR were the result of general anesthesia. Among spinal anesthetic drugs, plain bupivacaine was associated with the lowest incidence of supplemental local anesthetic use intraoperatively compared to hyperbaric bupivacaine or hyperbaric tetracaine. CONCLUSION: Spinal anesthesia is an effective alternative to general anesthesia for lumbar spine surgery and has a reduced rate of minor complications.     

Severe perioperative lactic acidosis: how clinically significant is it?

BACKGROUND: Lactic acidosis, generally defined as a plasma lactate concentration in excess of 5 mmol/L with a concomitant blood pH less than 7.25, is reported to have a direct association with mortality. OBJECTIVE: To report a case of unexplained perioperative lactic acidosis and to discuss the etiology, recognition, treatment, and importance of a transient rise in plasma lactate concentration. SUMMARY: Severe lactic acidosis developed in a 40-year-old man with Crohn's disease during major abdominal surgery. The plasma lactate concentration reached 16.9 mmol/L (normal range 1.5 to 2.2 mmol/L). This condition resolved within 14 hours without harm to the patient. CONCLUSIONS: When lactate accumulates in the perioperative period, the responsible condition is most often self-limiting. Reversible, subacute, marked lactic acidosis should not be assumed to predict mortality as it does in patients whose plasma lactate concentrations remain chronically elevated during severe systemic diseases such as sepsis.     

Microstructure and High‐Temperature Strength of Monocrystalline Nickel‐Base Superalloys

The progress in the further development of monocrystalline nickel‐base superalloys as the most advanced turbine‐blade materials has been the result of combined efforts in alloy development and microstructural refinement. Some aspects of these developments are reviewed. The questions of microstructural stability with respect to the formation of brittle topologically closed‐packed (TCP) phases and, in particular, directional coarsening, i.e., γ/γ′ rafting under service‐near high‐temperature creep conditions are addressed. Since γ/γ′ rafting is usually accompanied by creep acceleration, attempts have been made to avoid rafting by modifying the microstructure by appropriate thermal/mechanical treatments. These attempts were not successful. On the other hand, it could be shown that pre‐rafting in compression, leading to the formation of rafts parallel to the stress axis in the case of alloys with negative γ/γ′ lattice mismatch, enhances both the isothermal high‐temperature creep and fatigue strengths. According to current understanding, there exists no optimum γ/γ′ lattice mismatch in the case of negative mismatch but, at best, an optimum compromise between low‐ and high‐temperature behavior. It is speculated that a more suitable situation could be found in alloys with positive lattice mismatch.     

Selective and self-validating breath-level detection of hydrogen sulfide in humid air by gold nanoparticle-functionalized nanotube arrays

We demonstrate the selective detection of hydrogen sulfide at breath concentration levels under humid airflow,using a self-validating 64-channel sensor array ba...