Table Of Instruments Research Articles

Analysis of forces, accuracy and formability in positive die sheet incremental forming

Sheet Incremental Forming (IF) is a forming technology which consists of a sheet clamped along its edges by a suitable blank-holder while an hemispherical head punch is moved along a defined path and locally deforms the sheet. To improve the part geometrical accuracy, a die (which can be positive or negative) is placed behind the sheet with respect to the punch position. In this case, the process is called Two Point Incremental Forming (TPIF). In the present paper TPIF with positive die was studied through an experimental tests campaign using deep drawing steel sheets. The die geometry used in this research was chosen so to be representative of the process and it was tested using different tool paths. Forming forces were measured using self designed instrumented punch and table while the final workpiece geometry was detected using a coordinate measuring machine (CMM). The collected data allowed to study the effects of the different tool paths on the maximum forming forces, the geometry errors, the maximum reachable wall angle and the drawing depth during forming and after springback. The results were also compared with a previously performed experimental campaign where similar tests with negative die were conducted.

Real-time feedback improves accuracy of manually applied forces during cervical spine mobilisation

Purpose To determine if real-time feedback enables students to apply mobilisation forces to the cervical spine that are similar to an expert physiotherapist. Methods An instrumented treatment table collected mobilisation force data with feedback about forces displayed on a computer screen. An expert physiotherapist performed posteroanterior mobilisation of C7 on 21 asymptomatic subjects while forces were recorded. These data were used as force targets for 51 students who mobilised one of the asymptomatic subjects on two occasions. Students' forces were recorded before and after practice either with (experimental group) or without real-time feedback (control group). Improved performance was defined as a smaller difference between expert and student forces, comparing groups with non-parametric statistics. Results Students receiving feedback applied more accurate forces than controls (median difference between student and expert forces in the experimental group, 4.0 N, inter-quartile range (IQR) 1.9–7.7; in controls, 14.3 N, IQR 6.2–26.2, difference between groups p < 0.001). One week later, these students still applied forces that more closely matched the expert's compared to controls ( p < 0.01), but the differences between the students' and expert's forces were greater (6.4 N, IQR 3.1–14.7). Conclusion Practice with real-time objective feedback enables students to apply forces similar to an expert, supporting its use in manual therapy training.

The Medical Library Association Guide to Health Literacy

The Medical Library Association Guide to Health Literacy

Table of UK statutes and statutory instruments

Table of UK statutes and statutory instruments

Potential for infection in orthopaedic practice due to individually packaged screws

The use of implants is widespread in orthopaedic practice. In recent times screws and plates have increasingly been supplied individually pre-packaged. We hypothesised that there is a potential for an increased risk of infection associated with the practice of using individually packaged screws. In this study an attempt was made to recreate as closely as possible the standard practice of opening screw packets in the operating theatre. The exterior of 50 screw packets was cultured. The outer screw packets were then opened over a draped instrument table above a petri dish. As a control, petri dishes were left open to the air in the same theatre environment. The packet exteriors grew cultures of organisms in 24/50 cases. The act of opening the packets yielded a growth in 7/50 cases. There was no growth on the control petri dishes. The significance of the result and potential solutions are discussed.

Table of UK statutes and statutory instruments

Table of UK statutes and statutory instruments

A mobile laminar airflow unit to reduce air bacterial contamination at surgical area in a conventionally ventilated operating theatre

The aim of this study was to evaluate the efficacy of a mobile laminar airflow (LAF) unit in reducing bacterial contamination at the surgical area in an operating theatre supplied with turbulent air ventilation. Bacterial sedimentation was evaluated during 76 clean urological laparotomies; in 34 of these, a mobile LAF unit was added. During each operation, settle plates were placed at four points in the operating theatre (one at the patient area and three at the perimeter), a nitrocellulose membrane was placed on the instrument table and an additional membrane near the wound. During four operations, particle counting was performed to detect particles > or =0.5 microm. Mean bacterial sedimentation on the nitrocellulose membrane on the instrument table was 2730 cfu/m(2)/h under standard ventilation conditions, whereas it decreased significantly to a mean of 305 cfu/m(2)/h when the LAF unit was used, i.e. within the suggested limit for ultraclean operating theatres (P=0.0001). The membrane near the wound showed a bacterial sedimentation of 4031 cfu/m(2)/h without the LAF unit and 1608 cfu/m(2)/h with the unit (P=0.0001). Particle counts also showed a reduction when the LAF unit was used. No significant difference was found at the four points in the operating theatre between samplings performed with, and without, the LAF unit. Use of a mobile LAF unit with turbulent air ventilation can reduce bacterial contamination at the surgical area in high-risk operations (e.g. prosthesis implant).

Calibration of an instrumented treatment table for measuring manual therapy forces applied to the cervical spine

Manual therapy techniques are commonly used to treat musculoskeletal neck disorders, but little is known about the manual forces applied during cervical spine treatment. Forces may vary between practitioners, and this may affect patient outcomes. This study reports the development of an instrumented treatment table and its calibration for measuring posteroanterior-directed forces applied during cervical spine mobilisation. A treatment table surface was instrumented with seven biaxial load cells to measure manually applied forces in three planes. Accuracy of the system was evaluated using known weights (unloaded and loaded to represent a patient's body weight), selected to be consistent with the level of forces expected to be applied during cervical mobilisation. Recorded force values strongly correlated with known weights (Pearson's r=0.999 to 1.000 for forces applied in different directions and locations, unloaded and loaded). The accuracy of forces in the unloaded condition was very good for vertical forces (mean absolute error 1.1 N, SD 1.5), and reasonably good for horizontal forces (2.8 N, SD 2.4 for mediolateral, 3.4 N, SD 1.5 for caudad-cephalad). In the loaded condition absolute error increased slightly for horizontal forces. The accuracy of measured forces indicates the instrumented table is acceptable for measuring cervical mobilisation forces. Using it allows practitioners to perform manual techniques using their usual clinical technique, however interpretation of force data is limited because it represents force applied to the table rather than at a specific joint.

Manual Forces Applied During Cervical Mobilization

Objective Manual therapists routinely use passive accessory mobilization techniques to treat patients with mechanical neck disorders, but little is known about the manual forces applied. The aim of this study was to quantify the manual forces applied to the cervical spine during joint mobilization. Methods Ten physiotherapists performed posterior-to-anterior mobilizations to C2 and C7 (both centrally and unilaterally, 1 right and 1 left, grades I-IV) on a single asymptomatic male subject. Manual forces were measured in 3 planes using an instrumented treatment table. Results The instrumented table showed excellent reliability (intraclass correlation coefficient [2,1], 0.99; 95% confidence interval, 0.97-1.00) and accuracy (mean absolute error; vertical force, 1.1 N; SD, 1.5). There were considerable differences between therapists for mean peak force, force amplitude, and oscillation frequency for each technique and grade. Mean peak forces (grade I, 21.8 N; SD, 15.0; grade II, 34.9 N; SD, 20.9; grade III, 58.2 N; SD, 27.5; grade IV, 61.0 N; SD, 29.9) were considerably lower than previously reported lumbar mobilization forces. Intratherapist repeatability for all mobilization parameters was high. Force amplitude and oscillation frequency measures indicated that therapists generally adhered to the published definitions of the grades of mobilization when applying force, but when asked, provided quite different definitions of the grades. Conclusions This study provides preliminary evidence that cervical mobilization forces vary considerably between therapists, but intratherapist repeatability is high.

Table of UK statutes and statutory instruments

Table of UK statutes and statutory instruments

Further bacteriological evaluation of the TOUL mobile system delivering ultra-clean air over surgical patients and instruments

Two mobile TOUL-400 units (types 1 and 2) that produce an exponential ultra-clean air flow (EUA) via a mobile screen were evaluated (maximum height from floor to centre of screen: type 1, 1.4m; type 2, 1.6m). Bacterial deposition rates were lowered by >60% (P=0.001) over a table area of 1.7 m (length)x1.0m (width) with the TOUL-400 type 1 unit, and the mean air count at 1.0m from the screen was reduced from 23 to 1.6 colony-forming units (CFU)/m3 in experiments in a room with six air changes/h (ACH). The corresponding reductions were two- to three-fold greater in an operating room (OR) with 16 ACH due to higher bacterial contamination levels in the control experiments. The dramatic but localized reduction of the deposition rate recorded on one 14-cm settle plate (>2376-fold at 0.8m from the screen in the OR) apparently reflected the focus of the EUA. The impact of the TOUL-400 unit was underestimated by almost 100-fold by the air counts of bacteria recorded in parallel at the same sampling point (26.5-fold reduction). During sham coronary angiography and sham hip arthroplasty performed in a room with six ACH, ultra-clean air (<10 CFU/m3) was obtained over the incision area with the TOUL-400 type 2 unit when the EUA was undisturbed (maximum screen-wound distance 1.7 m). In actual coronary angiography (room with six ACH, screen-wound distance 2.0-2.3m) and various surgical procedures in the OR (screen-wound distance 1.4-1.8m), ultra-clean air was obtained at the wound in three of 18 instances, characterized by undisturbed air flow and a maximum distance of 1.8 m. The newly developed TOUL-300 surgical instrument table (1.3-1.7 x 0.6m), equipped at one end with the same EUA unit as the TOUL-400 unit, was evaluated for a room with six ACH and an OR with 16 ACH. It yielded ultra-clean air at 0.8m (1.9 CFU/m3, 96% reduction, P=0.01) and reduced the deposition rate by >60% over most of the table surface. Simplified positioning of the screen or a longer reach, plus a mechanism for precise focusing of the air flow on to the wound area would increase the clinical utility of the TOUL EUA system.

Identifying Error Pathways during Elbow and Knee Replacements

The aim of our study was to identify errors and error pathways during joint replacements and to propose improvements. A time-action and error analysis method was adapted for use during surgery. The error analysis consisted of identifying all possible errors, determining error paths presented in an error chart, quantifying errors, and determining the impact of errors. This method was used to evaluate joint replacements. We evaluated five knee and 11 elbow replacements done by two experienced surgeons. The main error for elbow replacements was caused by inadequate instruments. The main error for knee replacements was caused by inexperienced nurses being unfamiliar with guiding instruments. The time-action analysis showed a large variation in procedure duration. The main surgical limitations for both procedures were waiting caused by the cementing process and waiting caused by inexperienced scrub nurses. Our study identified errors and surgical limitations during joint replacements by using time-action and error analysis. Placement of both prostheses will benefit from new fixation techniques, a more experienced nursing staff, and more organized instrument tables.

Ergonomic evaluation of the work area of the scrub nurse

Current ergonomic solutions in the operating room focus on patients and surgeons. The work environment of the scrub nurse has not been studied before. In this article the work environment is described and the potential ergonomic problems are addressed. Practical short‐term solutions are provided and our design vision for future operating rooms is presented. Neck and back problems result from attempts of the scrub nurse to create an unobstructed view of the operating field and from reaching for instruments on instrument tables. Height‐adjustable foot stools, better monitor placement and ergonomically designed instrument tables will help to decrease neck and back torsion. Soft supports placed on resting points of instrument tables will decrease pressure on arms, abdomen, and legs. Standing supports, allowing semi‐standing postures will decrease leg fatigue. The current state of the work environment of the scrub nurse is not optimal. Future studies should focus on problems in the ergonomics of their work environment to enable optimal product design for the scrub nurse.

The use of handheld cement sample as a guide to the setting of In Situ cement mantle

During cemented joint arthroplasties, it is necessary to monitor the hardening of the cement to know when it is soft enough to allow insertion of the prosthesis but viscous enough to maintain bone interlock. Most often, a small piece of cement is left out and checked for hardening. These cement pieces are exposed to different fates, which include being held in the hand, held between fingers and kneaded, and left on the instrument table. The value of any of these techniques for predicting the cement's hardening has not been investigated formally. During 9 total hip arthroplasties, polymethyl methacrylate bone-cement was used in cementing the femoral component. Three 1-cm3 samples collected from each operation site were exposed to the aforementioned 3 different conditions. The fingertip-held and kneaded cement specimens most closely predicted the time to setting of the cement mantle at the operation site.

Counseling Women With AIDS: Skills andTools Every Nurse Needs

Bacteria-carrying particles (BCPs) shed from surgical staff during surgery are one of the main causes of postoperative surgical site infections (SSIs), and the dynamic nature of personnel during surgery make indoor airflow and the distribution of BCPs complicated and difficult to characterize. To investigate the effect of a circulating nurse walking on the airflow and BCP concentration, the Realizable k-ϵ turbulence model and Lagrangian particle tracking model were adopted and validated using airflow velocity and normalized particle concentration obtained from data obtained in an operating room environment cabin. A walking circulating nurse was described by the dynamic mesh model. It was found that when the circulating nurse was not walking, the surgical lamps and thermal plume of surgical staff had a considerable influence on the airflow, resulting a high BCP concentration. This situation did not change when the circulating nurse walked. With increased walking speed, the disturbance of the airflow by the circulating nurse increased significantly, and the length of the wake behind the circulating nurse became longer. Although the walking of the circulating nurse made no difference to the airflow above the operating table, the BCP concentration above nearby instrument tables increased as the circulating nurse passed, resulting in an increased risk of SSI.

Inefficiency of upward displacement operating theatre ventilation

A new thermally based ventilation system (‘Floormaster’) with inlet of cool clean air at floor level, and evacuation at the ceiling of the air warmed by activity in the room (upward displacement ventilation, 17 air changes/h) was compared with a standard positive pressure (plenum) ventilation system with air supply through an inclined perforated screen along one wall at the ceiling and evacuation at floor level (conventional turbulent or mixing system, 16 air changes/h). The study was made during rigidly standardized sham operations ( N = 20) performed in the same operating room by a six-member team wearing non-woven disposable or cotton clothing. In general the upward displacement system removed dust particles too small to carry bacteria (0·16−0·3 μm, 0·001 < P < 0·01) more efficiently than the conventional system. However, the displacement system also yielded two to threefold higher air and surface bacterial counts in areas important for surgical asepsis (wound area, instrument table) especially with regard to bacterial sedimentation (0·001 < P < 0·05). The major shortcoming of the displacement system was insufficient elimination of the larger bacteria-carrying particles. The type of clothing worn by the members of the team did not influence the overall results. We conclude that an upward displacement system will lead to increased counts of airborne and sedimenting bacteria and thus increase the risk of postoperative infection in comparison with conventional operating room ventilation systems.

Peoples and Minorities in International Law. Edited by Catherine Brölmann, René Lefeber, and Marjoleine Zieck. Dordrecht, Boston, London: Martinus Nijhoff Publishers, 1993. Pp. xiii, 347. Index. Dfl.195; $116.50; £79.00.

Preface. Table of Abbreviations. Part One: Evolution. Postmodern Tribalism and the Right to Secession T.M. Franck. Postmodern Tribalism and the Right to Secession, Comments R. Higgins. Africa: Lost between Self-Determination and Uti Possidetis J. Klabbers, R. Lefeber. The Evolution of Minority Rights in International Law N. Lerner. The Evolution of Minority Rights in International Law, Comments M. Nowak. Third Generation Rights J. Donnelly. Part Two: Levels of Identification and Protection. The Emergence of New Minorities as a Result of Migration R. Wolfrum. The European Communities and its Minorities B. de Witte. Indigenous Peoples C.M. Broelmann, M.Y.A. Zieck. The Degree of Self-Rule in Unitarian and Federal States Y. Dinstein. Part Three: Means of Enforcement. Fact-Finding into the Problems of Minorities B.G. Ramcharan. The International Judicial Protection of Peoples and Minorities A.M. de Zayas. The Legitimacy of the Use of Force to Protect Peoples and Minorities M. Bothe. International Representation of Peoples and Minorities A.C. Zoller. The Position of the UNPO in the International Legal Order M. van Walt van Praag. The Second Amsterdam International Law Conference. Synthesis H. Hannum. Table and Index of Treaties and Other International Instruments. Index.

The Near-Infrared Capabilities of LEST

The Large Earth-based Solar Telescope (LEST) will be a powerful, next-generation telescope with unprecedented angular resolution, capable of highly accurate polarimetry of the Sun, covering the optical spectral range from about 300 nm into the near infrared to about 2.5 μm.The telescope is a 2.4-m aperture, “polarization-free” concept based on a modified Gregorian optical system. A fast polarization modulator will be located close to the secondary focus of the system. An actively controlled NTT-type main mirror, a high precision pointing and tracking system, a helium-filled light path and a thin entrance window, together with an integrated adaptive optics system, will give the telescope near diffraction-limited performance in the visible. LEST will be sited on La Palma, in the Canary Islands, near the caldera rim on the Roque de los Muchachos Observatory, which often offers excellent seeing. A frequently occurring seeing parameter of ro = 15–20 cm in the visible will correspond to ro ≥ 1 m in the near IR.The construction of LEST will begin in 1993, and the telescope is to be ready for “first light” in 1997. The telescope facility will accommodate a large number of focal plane instruments on a spacious instrument table. LEST will be made available for near-IR instrumentation from the start of its regular operation.

Aspects of the Administration of International Justice by Elihu Lauterpact

Aspects of the Administration of International Justice, by Elihu Lauterpact Published by Grotius Publications Limited, Cambridge, U.K. (1991, 166 pp., incl. Contents, Preface, Table of Cases, Table of Treaties and other International Instruments, and Index ). Hardback. Price UK £35, US $70. The objective of this book, which is not readily apparent from the title, is to analyse certain underlying aspects of the present international adjudicatory. system. The desire of the author, who is the Director of the Research Centre for International Law at Cambridge University and an experienced teacher and practitioner of international law, is to take the opportunity to make suggestions that may ‘improve and perfect the international legal system’ (p. xiii). The book, being based on a series of lectures, is of a generalised nature, and can be easily criticised for its lack of depth and completeness, but this reviewer at least found that its refreshingly straightforward style, uncluttered by repetitious examples, helped to further the understanding of a complex area. The author makes it clear from the outset that he has a realistic approach to the subject recognising that ‘litigation is not the only, or even the best way of settling disputes. It is an inescapable fact that issues that divide States are best settled by negotiation and agreement’ (p. 6). Indeed, the author is quite rightly of the opinion that so called non-judicial methods of settling disputes: negotiation, good offices, mediation, conciliation, not only merge into one another but also spill over into judicial settlement, a concept which includes arbitration as well as decisions by an established court such as the International Court of Justice. One can readily see non-legal factors playing a role in arbitration, particularly in the formulation of the compromis and in the choice of arbitrators (see Chapter V), but the author is going further by suggesting that the judicial function at the international level, whether by an arbitrator or by a World Court judge, involves a far greater degree of discretion than its equivalent in the municipal sphere (p. 146). This point is …

Distribution of bacteria in the operating room environment and its relation to ventricular shunt infections: a prospective study

In order to study the distribution of bacteria in the operating room environment, cultures were obtained during 111 unselected shunt operations throughout a 10-month period. After routine skin preparation, bacteria were collected by placing Millipore filters on the patient's prepped skin underneath the drapes, on top of the drapes in the operative field, and/or on the sterile instrument table, and left in place for the duration of the case. In 48 patients, full-thickness skin biopsies taken at the initial incision were cultured in lieu of skin surface cultures. Perioperative cerebrospinal fluid cultures and subsequent shunt infections were monitored. Of the 288 environmental (skin and surfaces) cultures, 24 were positive (20 coagulase-negative Staphylococcus and 4 Staphylococcus aureus). Positive cultures were found in 15 of 111 drape cultures (13.5%), 7 of 77 instrument table cultures (9.1%), and 2 of 97 skin cultures (2.1%). Positive environmental cultures were not correlated with the surgeon, length of case, time of day, or type of shunt operation, but were more likely to occur in a room other than the designated neurosurgical operating room. There was a correlation between the occurrence of positive environmental cultures and positive cerebrospinal fluid cultures, although the organisms were not always the same. Coagulase-negative Staphylococcus was the most common organism isolated from all sites. We conclude that bacteria most often associated with shunt infections are airborne in the operating room, rather than originating from the patient's skin, and are distributed in the highest concentration near the surgical team.(ABSTRACT TRUNCATED AT 250 WORDS)