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[Step-by-step mobilization with upwards transposition of the intestinal complex in total esophagoplasty using the right half of the large intestine].

An experience of performing total esophagoplasty with high esophagus strictures and 30 anatomo-experimental investigations on corpses enabled the authors to develop a new method of extraction of a transplant which was called a step-by-step mobilization with a displacement of the intestinal complex with fixation of the small intestine mesentery root to the posterior wall of the rectus abdominis sheath. The essence of the step-by-step mobilization with a displacement of the intestinal complex upwards is the following: if the first step of usual mobilization of the right half of the large intestine with a process of ileum proves to be not sufficient for making high anastomosis, the second step should be fulfilled consisting in mobilization of the small intestine mesenterium root which gives more opportunity to displace the large intestine transplant. If this measure still seems to be insufficient the third step is necessary such as a mobilization of the terminal portion of the duodenum. It allows the transplant to be made as high as the pharynx practically in all cases.

Adult↗

Spectral sensitivity as revealed by isolated step onsets and step offsets.

Opponent-colour spectral sensitivity functions are traditionally elicited with increments; the temporal presentation of these increments is usually step onset and step offset. However, there are both physiological and psychophysical data suggesting differences in sensitivity for spectral step onsets and step offsets. The purpose of this study was to elicit opponent-colour spectral sensitivity functions with isolated step onsets and offsets, and to compare the form and sensitivity of these functions. Spectral sensitivity functions were determined for large, long duration, step onset and step offset stimuli. Four human observers participated in the study. The opponent-colour functions obtained for onsets and offsets are largely similar in both form and sensitivity. Of particular interest is the finding that there is no reduction in sensitivity for blue offsets. These data are consistent with recently published psychological data and apparently at variance with physiological data that suggest a paucity of S-cone OFF-neurones in the primate retina and dorsal lateral geniculate nucleus (dLGN).

Adult↗

[The use of a test model in a stepped form (test steps) for the clarification of different problem situations in X-ray diagnosis. 2. The use of test steps for testing the POLAROID-TPX immediate X-ray picture system].

The stepwedge, described in part 1 and in other publications, was used for the examination of the POLAROID-Instant Radiographic System. The result showed, that this system is a quite acceptable method for the practitioner. POLAROID-radiographs, in comparison with the classic radiographs, show equal contrast and detail-visibility, but demand a higher radiation dose.

Animals↗

An office-based instrument for exercise counseling and prescription in primary care. The Step Test Exercise Prescription (STEP).

BACKGROUND: Available evidence suggests that despite physicians' positive attitudes toward exercise as an important part of promoting a healthy lifestyle, few physicians actually prescribe exercise for their patients. One barrier may be lack of a standard office instrument. OBJECTIVES: To determine the (1) exercise counseling habits among a large group of Canadian family physicians and (2) acceptance and utilization of an exercise counseling instrument geared to primary care practice. DESIGN: Randomized control trial. SETTING: Primary care practice. PARTICIPANTS: Family physicians (N = 400) from 3 regions of Canada, representing both rural and urban practice (ratio of 1:3). Patients (10 per practice) were healthy community dwellers older than 65 years obtained as a convenience sample in their family practice. INTERVENTIONS: In phase 1, 400 physicians listed as being in general or family practice by their provincial registries were randomly selected from a larger group listed by these registries and contacted by telephone. A total of 362 completed a 10-minute questionnaire that detailed practice demographics, preventive practice, and exercise counseling habits. In phase 2, 293 agreed to further participate in the administration of an exercise prescription randomly assigned to them by the study team. Two methods of exercise prescription were compared: counseling using the American College of Sports Medicine guidelines (control) and counseling using guidelines and an office-based step test (Step Test Exercise Prescription [STEP]) to determine fitness level and prescribe an exercise training heart rate. Physicians were asked to deliver their assigned exercise prescription to a convenience sample of the next 10 healthy patients older than 65 years who presented to the office. MAIN OUTCOME MEASURES: Primary outcome measures were physician exercise counseling confidence and knowledge before and after the study. Secondary outcomes included details of the exercise counseling sessions (e.g., time required). RESULTS: In phase 1, more than 90% of the 362 physicians claimed to practice preventive health counseling, and 70% claimed to include exercise counseling. Only 67.4% felt confident regarding their exercise prescribing, and most (93.8%) were interested in improving their exercise prescribing skills. The leading barriers to exercise prescription were described in order as inadequate time, lack of necessary skills and tools, and lack of reimbursement. In phase 2, no difference in physician profile, patient profile, or indications for exercise counseling were observed between control (n = 145) and STEP (n = 148) groups. STEP was significantly longer (16.4 vs 12.9 min; P = .001) to administer; however, improvement in physician confidence (P = .01) and knowledge (P = .009) were significantly greater compared with controls. CONCLUSIONS: Most family physicians practiced preventive exercise counseling but reported lack of time and skills as barriers to this practice. Physicians randomized to the STEP group took longer to deliver exercise advice but felt more confident and knowledgeable compared with controls.

Aged↗

Scale-up of free-flow electrophoresis: II. Purification of alcohol dehydrogenase from a crude yeast extract by field step electrophoresis and combined field step-zone electrophoresis.

Results of the purification of alcohol dehydrogenase (ADH) by field step electrophoresis and combined field step-zone electrophoresis are presented. In field step electrophoresis, optimization of voltage, residence time and pH of the sample solution led to a maximal purification factor of 2.8 and a yield of 89% ADH. The limit of loading capacity was reached at a protein concentration of the sample solution of approximately 4 g/L, allowing a maximal throughput of 1.14 g/h with a yield of 86% and a 2.8-fold purification in the Elphor VaP 22 apparatus. With a production scale apparatus a throughput of 2.07 g/h without any loss of separation quality could be achieved. By introducing the sample solution into the separation chamber through 3 inlets, simultaneously, the throughput was increased to 3.2 g/h with a purification factor of 2.7 and a yield of 82% ADH. For the combined field step-zone electrophoresis method a maximum purification factor of 3.6 and a yield of 80% ADH were achieved. The loading capacity was limited to a 4.13 g/L protein concentration of the sample solution, resulting in a throughput of 440 mg/h. Injecting the sample solution simultaneously into 3 inlets resulted in a maximum throughput of 1.92 g/h with 3.1-fold purification and a yield of 80% ADH. Zone electrophoresis, field step electrophoresis and a combination of both are compared with respect to resolution, throughput and the application potential in a protein purification scheme. A scale-up to 3 g/h is possible in zone electrophoresis and field step electrophoresis.(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol Dehydrogenase↗

Age-related differences in stepping performance during step cycle-related removal of vision.

The aim of the present study was to investigate whether there are age-related changes in the ability of individuals to use vision to plan (feedforward control) and guide (on-line control) foot placement during locomotion. This aim was achieved by constraining the availability of vision and comparing the effects on the stepping performances of older and young adults during a precision stepping task. We experimentally controlled the availability of visual information such that: (1) vision was only available during each stance phase of the targeting limb, (2) vision was only available during each swing phase of the targeting limb or (3) vision was always available. Our visual manipulations had relatively little effect on younger adults' stepping performance as demonstrated by their missing the target on less than 10% of occasions. However, there were clear visual condition-related differences in older adults' stepping performance. When vision was only available during the stance phase of the targeting limb, older adults demonstrated significantly larger foot placement error and associated task failure rate (23%) than trials in which vision was always available (10%). There was an even greater increase in older adults' foot placement error and task failure rate (42%) during trials in which vision was only available in the swing phase than the other visual conditions. These findings suggest that older adults need vision at particular times during the step cycle, to effectively pre-plan future stepping movements. We discuss the evidence that these age-related changes in performance reflect decline in visual and visuomotor CNS pathways.

Adult↗

Effect of pronase treatment on step-down and step-up photophobic responses in Euglena gracilis.

Pronase-treated cells of Euglena gracilis Z show no discernible ultrastructural effects on the photoreceptor apparatus; however, there are physiological effects on swimming speed and on step-up and step-down photophobic responses, especially the latter. Pronase acts differently on the two photophobic responses: the step-down response is completely inhibited after 2 hr., whereas inhibition of the step-up response occurs in only 50% of the cells even after 24 hr. The effects are fully reversible, with step-up recovery quite rapid and step-down recovery considerably slower.

Animals↗

Step-by-step measurements of soft tissue balancing during total knee arthroplasty for patients with varus knees.

Using a step-by-step procedure, we measured joint gap during surgery using a simple device with a torque meter in 45 osteoarthritis knee joints (43 patients) with varus deformity. The effects of specific cuts or releases of the anatomic portion on joint gaps were investigated. Each cut or release resulted in various increases in the medial gap from 1.2 to 3.8 mm on average. The final gap measurements averaged 24.1 mm medially and 27.6 mm laterally in extension, and 24.6 mm medially and 27.2 mm laterally in flexion. The results of the measurements showed that each step-by-step procedure had a tendency of gap increase. The results led us to measure soft tissue balancing in a step-by-step procedure during total knee arthroplasty.

Arthroplasty, Replacement, Knee↗

Test-re-test reliability of walking speed, step length and step width measurement after traumatic brain injury: a pilot study.

PRIMARY OBJECTIVE: Assess the test-re-test reliability of walking speed, step length and step width measurement in people with traumatic brain injury (TBI). RESEARCH DESIGN: Repeated measures (two test occasions). METHODS: Thirteen people with TBI completed four comfortable and four fast-paced walking trials of the 10 m walk test and two trials of the 6-minute walk test (6MWT). Walking speed, step length and step width were measured during the 10 m walk test and walking distance and average speed were measured during the 6MWT. The tests were repeated 1-week later. MAIN RESULTS: Walking speed and distance showed excellent test-re-test reliability, with an intra-class correlation coefficient (ICC) of 0.95-0.96. Reliability was also high for step length and width measurement (ICC 0.91-0.98). CONCLUSIONS: This test-re-test reliability means that walking speed and distance and step length and width can be used by physiotherapists to monitor improvements in walking after TBI.

Adult↗

Student performances on Step 1 and Step 2 of the United States Medical Licensing Examination following implementation of a problem-based learning curriculum.

PURPOSE: To examine students' performances on Step 1 and Step 2 of the United States Medical Licensing Examination (USMLE) following the implementation of a problem-based learning curriculum. METHOD: Performances on Step 1 of the USMLE for four classes at the University of Missouri-Columbia School of Medicine that completed a new problem-based learning curriculum (1997, 1998, 1999, and 2000) were compared with those of the last two classes to learn in the traditional curriculum (1995 and 1996). Performances on Step 2 of the USMLE for the classes of 1997, 1998, and 1999 were also compared with those of the classes of 1995 and 1996. The authors analyzed matriculation data (GPAs and MCAT scores) for all six classes. They compared all data with those of U.S. and Canadian first-time USMLE takers. RESULTS: The mean scores were higher on USMLE Step 1 for classes in the problem-based learning curriculum than for classes in the traditional curriculum. The mean scores for Step 2 were above the national mean for classes in the revised curriculum and below the national mean for classes in the traditional curriculum. The admission profiles of these classes were essentially the same before and after the change in curriculum. CONCLUSIONS: Major PBL revisions of the curriculum did not compromise the performances of medical students on the licensing examinations; in fact, they may have contributed to higher scores.

Canada↗

Kinetic model for step flow growth of [100] steps.

A kinetic model for the step flow growth of [100] steps is derived. This model extends the implicit close-to-equilibrium assumption in the classical Burton-Cabrera-Frank theory to out-of-equilibrium growth regimes common in molecular beam epitaxy. In equilibrium, the kink density coincides with Burton, Cabrera, and Frank [Philos. Trans. R. Soc. London, Ser. A 243, 299 (1951)] but in a planar steady state solution for a periodic sequence of steps the kink density derivates and we analyze its scaling behavior with the step Peclet number. Furthermore, we observe a discontinuity of adatoms on the steps that might give a new explaination for step bunching.

Journal Article↗

Kinetics of faceting driven by attractive step-step interactions on vicinal Si(113).

We have studied the far-from-equilibrium kinetics of faceting caused by short-ranged attractive step-step interactions on vicinal Si(113), using scanning tunneling microscopy. We show that a network of step bunches coarsens via both zipping up of the neighboring step bunches and irreversible binding events which alter the local topological configuration. A step-network model which incorporates the irreversible step-bunch-binding events yields quantitative understanding of the experimental results.

Journal Article↗

Step structures on III-V phosphide (001) surfaces: how do steps and Sb affect CuPt ordering of GaInP2?

The observation of III-V phosphide (001)-(2 x 2) surfaces makes it possible to solve a long standing mystery of step structures. First-principles calculations show that a bulklike type-B step on a hydrogenated 2 x 2 surface is more stable than a rebonded one by 1.1 eV/unit step. In contrast, this energy difference for a H-free beta(2 x 4) surface is only 0.5 eV/unit step. The large difference explains why the CuPt ordering of GaInP is stronger in metal-organic chemical vapor deposition than in molecular beam epitaxy. However, a minute amount of Sb will preferentially attach to the 2 x 2 surface steps and induce additional step structures that cause ordering disruption.

Journal Article↗

2-Step IMAT and 2-Step IMRT: a geometrical approach.

The purpose of this paper is to develop a method that reduces the number of segments for intensity modulated arc therapy (IMAT) and intensity modulated radiotherapy (IMRT) for concave target volumes (TV). The aim was to utilize no more than two intensity levels per organ at risk (OAR) and to derive both optimal segment widths and weights from geometric considerations. Brahme's model of an annular target surrounding a circular OAR was used as test model. Brahme's solution was substituted by a single segment added to a simple field blocking the OAR. Width and weight of the segment were the free parameters to optimize. The objective function to minimize was the root mean square (rms) error of the dose in the target volume. One boundary condition was--neglecting scatter--"zero-dose" to the OAR. The resulting rules for width and weight of the additive segment are referred to as "optimized 2-Step IMAT" and "2-Step IMRT." The recommendations were applied to some simplified plans representing clinical cases using a commercial planning system. Optimized 2-Step IMAT improved the rms by a factor of 4 with respect to techniques simply blocking the OAR. The additional segment reduced the rms below 3% for cases with gaps between OAR and TV larger than 8% of the TV diameter. The results for 2-Step IMAT are applicable to IMRT and aperture modulated arc therapy (AMAT). 2-Step IMAT can be utilized for noncylindrical cases and for more than one OAR. A geometrical and topological approach to IMAT and IMRT can be useful to understand fluence profiles. The results could be applied to ameliorate other topology-based procedures used in some planning systems. Basic mechanisms of 2-Step IMAT can assist with the creation of rules for adaptive IMRT to compensate for patient motion.

Algorithms↗