It is nearly two decades since a formal terminology and a classification scheme were proposed for rock reinforcement hardware and applications. That combined framework was used to clearly identify ...concepts associated with reinforcement mechanics in a manner that was consistent and robust enough to characterise all reinforcement systems. Since that time, many new reinforcement systems have been developed and it can be shown that they all fit within the proposed classification scheme. Most recently, a complementary new terminology and a classification scheme for surface support, also based on mechanics, have been developed. This framework is invaluable in the design of ground support schemes, the planning of testing and instrumentation programs and the development of software used to simulate the static and dynamic response of rock reinforcement and support systems. It will be shown that the terminology and classification schemes are valid today and will so remain into the future because of the laws of mechanics.
Laboratory testing of steel fibre reinforced shotcrete Saw, H.; Villaescusa, E.; Windsor, C.R. ...
International journal of rock mechanics and mining sciences (Oxford, England : 1997),
January 2013, 2013, 2013-1-00, 20130101, Letnik:
57
Journal Article
Recenzirano
Odprti dostop
Uniaxial and triaxial compression tests on steel fibre reinforced shotcrete (SFRS) have been used to quantify the elastic–plastic response behaviour for both the peak and post-peak regions. The ...laboratory tests were conducted with a servo-controlled testing machine to obtain complete stress–strain curves. The test results include unconfined and triaxial compressive strengths, shear strengths and tensile strengths together with the elastic and plastic mechanical properties of SFRS. A method is also suggested for obtaining the plasticity parameters for non-linear modelling of SFRS.
► Uniaxial and triaxial compression tests on steel fibre reinforced shotcrete. ► Conducted with a servo-controlled machine to obtain complete stress–strain curves. ► Test results include strengths, elastic and plastic mechanical properties. ► Suggested for obtaining the plasticity parameters for non-linear modelling.
Background: Marked eosinophilic meningitis or meningoencephalomyelitis (EME) is rarely reported in dogs and the cause is usually undetermined. Long‐term prognosis for dogs with cerebrospinal fluid ...(CSF) eosinophilia is variable.
Animals: Twenty‐three client‐owned dogs.
Methods: Retrospective case series. Dogs with eosinophilic CSF, defined as total nucleated cell count (TNCC) >3 cells/μL with >20% eosinophils, were identified by a computerized search of all dogs having cisternal and/or lumbar CSF analyzed as part of the diagnostic workup between 1992 and 2007.
Results: TNCC in CSF ranged from 4 to 4,740 cells/μL (median 84 cells/μL, reference range ≤3 cells/μL), with 22 to 95% (median 78%) eosinophils in the differential count. An infectious agent was identified on necropsy in 4 of 23 (17%) dogs (Cryptococcus neoformans n = 2, Neospora caninum n = 1, and Baylisascaris procyonis n = 1). Each of these dogs had progressive neurologic deterioration. Sixteen dogs had idiopathic EME. Magnetic resonance imaging (MRI) findings were abnormal in 7 of 13 dogs with EME; 2 dogs had focal lesions and 5 dogs had multifocal lesions. Clinical signs in 12 of 16 (75%) dogs with idiopathic EME resolved with prednisone treatment. Three dogs with acute intervertebral disc herniations recovered after decompressive surgery alone.
Conclusions: Idiopathic EME is a common cause of eosinophilic pleocytosis in dogs. MRI findings are variable. Infectious causes of EME were less common and had a poor prognosis.
To develop a new international classification of acute pancreatitis severity on the basis of a sound conceptual framework, comprehensive review of published evidence, and worldwide consultation.
The ...Atlanta definitions of acute pancreatitis severity are ingrained in the lexicon of pancreatologists but suboptimal because these definitions are based on empiric description of occurrences that are merely associated with severity.
A personal invitation to contribute to the development of a new international classification of acute pancreatitis severity was sent to all surgeons, gastroenterologists, internists, intensivists, and radiologists who are currently active in clinical research on acute pancreatitis. The invitation was not limited to members of certain associations or residents of certain countries. A global Web-based survey was conducted and a dedicated international symposium was organized to bring contributors from different disciplines together and discuss the concept and definitions.
The new international classification is based on the actual local and systemic determinants of severity, rather than description of events that are correlated with severity. The local determinant relates to whether there is (peri)pancreatic necrosis or not, and if present, whether it is sterile or infected. The systemic determinant relates to whether there is organ failure or not, and if present, whether it is transient or persistent. The presence of one determinant can modify the effect of another such that the presence of both infected (peri)pancreatic necrosis and persistent organ failure have a greater effect on severity than either determinant alone. The derivation of a classification based on the above principles results in 4 categories of severity-mild, moderate, severe, and critical.
This classification is the result of a consultative process amongst pancreatologists from 49 countries spanning North America, South America, Europe, Asia, Oceania, and Africa. It provides a set of concise up-to-date definitions of all the main entities pertinent to classifying the severity of acute pancreatitis in clinical practice and research. This ensures that the determinant-based classification can be used in a uniform manner throughout the world.
Populations of fishes provide valuable services for billions of people, but face diverse and interacting threats that jeopardize their sustainability. Human population growth and intensifying ...resource use for food, water, energy and goods are compromising fish populations through a variety of mechanisms, including overfishing, habitat degradation and declines in water quality. The important challenges raised by these issues have been recognized and have led to considerable advances over past decades in managing and mitigating threats to fishes worldwide. In this review, we identify the major threats faced by fish populations alongside recent advances that are helping to address these issues. There are very significant efforts worldwide directed towards ensuring a sustainable future for the world's fishes and fisheries and those who rely on them. Although considerable challenges remain, by drawing attention to successful mitigation of threats to fish and fisheries we hope to provide the encouragement and direction that will allow these challenges to be overcome in the future.
Background. Stroke complicates the postoperative course in 1% to 6% of patients undergoing coronary revascularization. There has been no large scale mandatory database reporting on the incidence of ...stroke after coronary revascularization.
Methods. A multicenter regional database from the Bureau of Health Care Research Information Services, New York State Department of Health, on 19,224 patients who underwent coronary revascularization in 31 hospitals within New York State during 1995 was analyzed to determine the risk factors for postoperative stroke.
Results. The incidence of postoperative stroke was 1.4% (n = 270). Hospital mortality for patients who had a stroke was 24.8%, compared with 2.0% for the rest of the patient population. Postoperative stroke increased the hospital length of stay threefold (27.9 ± 1.9 versus 9.1 ± 0.9 days, p < 0.0001). Multivariable logistic regression identified the following variables to be significantly associated with a postoperative stroke: calcified aorta (p < 0.0001; odds ratio OR, 3.013), prior stroke (p = 0.0003; OR, 1.909), age (p < 0.0001; OR, 1.522 per 10 years), carotid arterial disease (p = 0.002; OR, 1.590), duration of cardiopulmonary bypass (p = 0.0004; OR, 1.27 per 60 minutes), renal failure (p = 0.0062; OR, 2.032), peripheral vascular disease (p = 0.0157; OR, 1.62), cigarette smoking (p = 0.0197; OR, 1.621), and diabetes mellitus (p = 0.0158; OR, 1.373).
Conclusions. Postoperative stroke increases mortality and length of stay after coronary revascularization. Several risk factors can be identified, and some of these factors are potentially amenable to intervention, either before or during coronary revascularization, and should also influence patient selection.
Summary
We present a randomised, controlled, crossover trial of the Caudwell Xtreme Everest (CXE) closed circuit breathing system vs an open circuit and ambient air control in six healthy, hypoxic ...volunteers at rest and exercise at Everest Base Camp, at 5300 m. Compared with control, arterial oxygen saturations were improved at rest with both circuits. There was no difference in the magnitude of this improvement as both circuits restored median (IQR range) saturation from 75%, (69.5–78.9 68–80%) to > 99.8% (p = 0.028). During exercise, the CXE closed circuit improved median (IQR range) saturation from a baseline of 70.8% (63.8–74.5 57–76%) to 98.8% (96.5–100 95–100%) vs the open circuit improvement to 87.5%, (84.1–88.6 82–89%; p = 0.028). These data demonstrate the inverse relationship between supply and demand with open circuits and suggest that ambulatory closed circuits may offer twin advantages of supplying higher inspired oxygen concentrations and/or economy of gas use for exercising hypoxic adults.
Background: Cerebrospinal fluid (CSF) in dogs with Hansen type I intervertebral disc herniation (IVDH) is classically described as normal or mildly inflammatory with a predominance of large ...mononuclear cells or neutrophils in severe acute herniations. However, we have observed a moderate to marked pleocytosis with a predominance of lymphocytes in some dogs with IVDH.
Hypothesis: Moderate to marked CSF pleocytosis occurs more commonly in dogs with type I IVDH than is reported in the literature. Lymphocytic predominance is more common than nonlymphocytic pleocytosis in dogs with chronic IVDH.
Animals: Four hundred twenty‐three client‐owned dogs with type I IVDH.
Methods: Retrospective study. Lumbar CSF of dogs with surgically confirmed type I IVDH was evaluated cytologically. Information obtained from medical records included signalment, prior clinical history, time from onset of signs to presentation, neurologic status, and intraoperative findings. Dogs with prior history and/or intraoperative evidence consistent with chronic IVDH before an acute herniation were termed acute‐on‐chronic (AOC).
Results: Pleocytosis (> 5 cells/uL) was present in 51% of dogs, including 23% with cervical IVDH and 61% with thoracolumbar IVDH. Moderate or marked inflammation (≥ 20 cells/uL) was identified in the CSF of 51% of dogs with thoracolumbar IVDH and pleocytosis. A predominance of lymphocytes was significantly more common in dogs examined > 7 days from onset of signs (P= .032) and in dogs with AOC IVDH (P= .0013).
Conclusions and Clinical Importance: Moderate to marked CSF pleocytosis in dogs with type I IVDH is more common than previously reported. Lymphocytic pleocytosis is most common in dogs with chronic progression or AOC IVDH. Lymphocytic inflammation in the CSF of some dogs might suggest an immune‐mediated response to chronically herniated disc material.
Summary
We describe a unique ambulatory closed circuit for delivering high fractions of inspired oxygen to an exercising user who does not require isolation from their environment. We describe the ...major components and their function and suggest potential applications for such a circuit. This circuit may benefit patients who are chronically dependant on oxygen, are unable to exercise due to hypoxia, or require oxygen supplementation at high altitude.
Background
Complex anal fistulas remain a challenge for the colorectal surgeon. The anal fistula plug has been developed as a simple treatment for fistula-in-ano. We present and evaluate our ...experience with the Surgisis anal fistula plug from two centres.
Methods
Data were prospectively collected and analysed from consecutive patients undergoing insertion of a fistula plug between January 2007 and October 2009. Fistula plugs were inserted according to a standard protocol. Data collected included patient demographics, fistula characteristics and postoperative outcome.
Results
Forty-four patients underwent insertion of 62 plugs (27 males, mean age 45.6 years), 25 of whom had prior fistula surgery. Mean follow-up was 10.5 months Twenty-two patients (50%) had successful healing following the insertion of plug with an overall success rate of 23 out of 62 plugs inserted (35%). Nineteen out of 29 patients healed following first-time plug placement, whereas repeated plug placement was successful in 3 out of 15 patients (20%;
p
= 0.0097). There was a statistically significant difference in the healing rate between patients who had one or less operations prior to plug insertion (i.e. simple fistulas) compared with patients who needed multiple operations (18 out of 24 patients vs. 4 out of 20 patients;
p
= 0.0007).
Conclusions
Success of treatment with the Surgisis anal fistula plug relies on the eradication of sepsis prior to plug placement. Plugs inserted into simple tracts have a higher success rate, and recurrent insertion of plugs following previous plug failure is less likely to be successful. We suggest the fistula plug should remain a first-line treatment for primary surgery and simple tracts.
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