Total Number Of Rotations Research Articles

Radiology Resident Diagnostic In-Training Exam Scores: Impact of Subspecialty Imaging Volume and Rotation Scheduling

PurposeTo determine the relationship between resident imaging volumes and number of subspecialty rotations with Diagnostic Radiology In-Training (DXIT) subspecialty scores. MethodsDXIT-scaled subspecialty scores from a single large diagnostic radiology training program from 2014 to 2020 were obtained. The cumulative number of imaging studies dictated by each resident and specific rotations were mapped to each subspecialty for each year of training. DXIT subspecialty scores were compared against the total subspecialty imaging volume and the total number of rotations in a subspecialty for each resident year. A total of 52 radiology residents were trained during the study period and included in the dataset. ResultsThere was a positive linear relationship between the number of neuro studies and scaled neuro DXIT scores for R1s (Pearson coefficient: 0.29; p-value: 0.034) and between the number of breast studies and the number of neuro studies with DXIT scores for R2s (Pearson coefficients: 0.50 and 0.45, respectively; p-values: 0.001 and 0.003, respectively). Furthermore, a positive significant linear relationship between the total number of rotations in cardiac, breast, neuro, and thoracic subspecialties and their scaled DXIT scores for R2 residents (Pearson coefficients: 0.34, 0.49, 0.33, and 0.32, respectively; p-value: 0.025, 0.001, 0.03, and 0.036, respectively) and between the total number of nuclear medicine rotations with DXIT scores for R3s (Pearson coefficient: 0.41; p-value: 0.016). ConclusionResident subspecialty imaging volumes and rotations have a variable impact on DXIT scores. Understanding the impact of study volume and the number of subspecialty rotations on resident medical knowledge will help residents and program directors determine how much emphasis to place on these factors during residency.

Pycnogenol ameliorates motor function and gene expressions of NF-ƙB and Nrf2 in a 6-hydroxydopamine-induced experimental model of Parkinson's disease in male NMRI mice.

We investigated the effect of Pycnogenol as an antioxidant on improving motor function, depression, and the expression of NF-ƙB and Nrf2 genes in the experimental model of Parkinson's disease. Forty adult male NMRI mice weighing about 30g were randomly divided into five groups of eight. Saline group: received 3μl of saline, as 6-hydroxydopamine (6-OHDA) solvent, unilaterally in the left striatum, treatment groups: first received 3µl 6-OHDA unilaterally inside the ipsilateral striatum and then divided into subgroup A: received distilled water, Pycnogenol solvent, by gavage for 7days (lesion group), and subgroup B: received Pycnogenol at doses of 10, 20, and 30mg/kg by gavage for 7days. Seven days after Parkinson's model induction, the apomorphine test, the degree of catalepsy by bar test, the duration of immobility (depression) by forced swimming test (FST) were measured. In addition, the expression of NF-ƙB and Nrf2 genes was measured using the real-time PCR technique. The total number of rotations in the apomorphine test decreased significantly in the groups receiving Pycnogenol. Administration of Pycnogenol significantly reduced catalepsy. The study of depression in the group receiving Pycnogenol showed a significant reduction. Also, Pycnogenol increased the expression of the Nrf2 anti-inflammatory gene, but it had no significant difference in the expression of NF-ƙB gene. Pycnogenol, presumably with its antioxidative and genomic effects, improves the expression of the anti-inflammatory gene and found that neuroprotection effect in the brain.

Spheronisation of a basket screen-extruded paste using screens of different hole diameters

In order to gain a better understanding of wiping mode screen extrusion-spheronisation process, a 45wt% MCC/water paste was extruded using a basket screen extruder and the extrudate size and shape evolution during spheronisation tests were investigated in this study. Following the regular formulation tests, 30g of extrudates with random lengths were employed as a starting charge for each spheronisation test. Two screens with 1 and 2mm diameter holes were used to generate extrudates of the two diameters.It was found that the mathematical relationship between time to complete spheronisation (tend) and spheroniser plate rotational speeds (ω) varied with extrudate diameters. For the 1mm diameter extrudates, tend scaled with ω−3.8, which was close to that predicted by a simple collision model, whereas the product of tend and ω was relatively constant for the 2mm extrudates. Projected images and SEM images of the dry pellets showed that the shape of 1mm diameter material during spheronisation went through a dumb-bell stage, and the dumb-bells folded over together to form pellets. In comparison, there were few dumb-bells observed during spheronisation of 2mm extrudates, and agglomeration was the dominant scenario by which fines attached to big segments to form ellipses and to be rounded into spheres. In the case of the 2mm extrudates, the aspect ratio was changed mainly with the total number of rotations, and the trend showed little variation between different spheronisation speeds. Based on the observation, it was able to propose a phenomenological model to illustrate pellet shape evolution as well as a semi-empirical mathematical relationship to demonstrate the correlation between processing parameters at an optimal condition for each case. The former emphasised the differences in the shape change route of extrudate with different diameters. The later provided a quantitative guide for optimisation of a spheronisation process. The results suggested that the strain experienced by the paste during extrusion has played an important role in extrudate breakage at the early stage of spheronisation. The size of extrudate segments, after breakage, then determined their spheronisation behaviour during following processing.

Microfiber cloths reduce the transfer of Clostridium difficile spores to environmental surfaces compared with cotton cloths

Environmental surfaces in health care facilities contaminated with Clostridium difficile spores can be a reservoir that contribute to transmission of hospital-acquired infections. Microfiber cleaning cloths may improve the effectiveness of surface cleaning. The objective of this study was to assess the removal and transfer of C difficile spores on surfaces cleaned by microfiber compared with cotton cloths. C difficile spores (approximately 4.2 log(10)/site) were applied to ceramic surfaces. Microfiber or cotton cloths were used to wipe the surfaces that were sprayed with either buffer or a nonsporicidal cleaning agent. To ensure reproducible pressure and surface contact time, a drill apparatus was used. The pressure was 1.5-1.77N, and the total number of rotations was 10. Viable counts were used to assess the efficiency of microfiber and cotton cloths in removing and transferring spores. Of 4.4 log(10)C difficile spores inoculated on a ceramic surface, microfiber and cotton cloths removed 2.4 and 1.7 log(10), respectively. Microfiber cloths containing 4.2 log(10)C difficile spores transferred 1.7 log(10)C difficile spores when used to wipe a ceramic surface compared with cotton cloths that transferred 2.4 log(10). Similarly microfiber wipes transferred fewer spores on consecutive surfaces wiped compared with cotton cloths (0.8 log(10) vs 1.80 log(10)). The use of microfiber cloths may reduce the risk of C difficile spore transfer during surface cleaning.

TH‐C‐134‐01: Computed Tomography 2: Dose Basics and Getting the Most From Your Dose

TH‐C‐134‐01: Computed Tomography 2: Dose Basics and Getting the Most From Your Dose

L‐dopa‐induced dyskinesias in unilateral 6‐hydroxydopamine‐lesioned rats are not modified by excitotoxic lesion of the entopeduncular nucleus and substantia nigra pars reticulata

l-Dopa-induced dyskinesias (LIDs) are a troublesome complication in Parkinson's disease after long-term therapy and a major reason for surgical treatment. LIDs are effectively eliminated by surgery. We aimed to reproduce such effect in the 6-hydroxydopamine (6-OHDA)-lesioned rat model. Single or combined lesions with quinolinic acid were caused in the entopeduncular nucleus (EP) and substantia nigra pars reticulata (SNr) on 6-hydroxydopamine (6-OHDA)-lesioned rats treated for 3 weeks with l-Dopa (6 mg/kg plus 15 mg/kg benserazide, i.p.). l-Dopa administration was continued for a further week following the lesion and abnormal involuntary movements (AIMs) scored at the end of treatment. Neither the individual lesions of the EP and SNr nor the combined lesions had any antidyskinetic effect nor decreased the total number of rotations. These results suggest that excitotoxic lesions of neurons bodies of the output nuclei of the basal ganglia, which destroy cell bodies and spare fibers of passage, do not induce a beneficial reduction of dyskinesias in contrast to thermolytic lesions in humans (which provokes a complete tissue destruction), thus supporting the possibility that other nuclei or systems might be involved in the antidyskinetic effect of pallidotomy.

TU‐A‐217BCD‐01: Introductory CT Dosimetry (and What We Can Learn from Making Measurements on Cylinders)

A variety of methods are used to describe and control the radiation output of a CT scanner. Different approaches may serve to emphasize one facet of a particular scan over another, favor the lexicon and style of a specific manufacturer or simply reflect history. The multiplicity of terms often adds confusion to what should be a simple task: to characterize the output of a CT machine in terms of the radiation dose to a cylinder. We will begin by examining radiation dose to cylinders with an emphasis on isolating superfluous parameters.We start, as in TG111, with an infinite helical scan of an infinitely long cylindrical phantom. During such a scan the dose at any point in the cylinder will asymptotically build up to its ultimate value Deq. The spatial average of this value, Deq, can serve as an indicator of scanner output and along with the total number of rotations N determine Etot, the total energy absorbed by the cylinder. If a finite cylinder is long enough (≥ Leq), a scan through it from one end to the other will yield these values in its central plane.The approach to Deq can conveniently be described by h(L), a robust function of scan length L which depends only weakly on z axis collimation and tube potential. This function facilitates the simple calculation of the lower dose to the central plane resulting from a finite scan. If the length of the cylinder is finite, as it is for the standard CTDI phantom, the dose is reduced further in a predictable fashion resulting in good correlation between Deq,bar and CTDIvol which in turn has been shown to be a useful tool in equating the radiation output between scanners differing in model and vendor.Though CTDIvol (and Deq,bar) are useful for characterizing CT machine output, we need to include the effect of patient size in assessing patient dose. TG204 has used measurements on phantoms of varying size to determine a size specific dose estimate (SSDE) which serves to accomplish this task. The SSDE has also proven to be very helpful in designing protocols for patients of varying size, especially pediatric patients.Learning Objectives:1. To describe the radiation dose to a cylinder in uncomplicated terms, starting with the particularly simple case of an infinite scan to an infinite cylinder.2. To extend the description to finite scans to infinite cylinders in terms of the h(L) function and then to the standard CTDI phantoms.3. To describe some of the subtleties in making reliable CTDI measurements.4. The demonstrated fact that dose indices (e.g., CTDIvol) provide a reliable indicator of machine output will be used to show, for example, how patient scans from machines of varying model and manufacturer can be compared.5. To describe how characterizing the dose to cylinders of varying size can be used both to provide a reasonable index of patient dose and as a useful tool in the design of pediatric protocols.

TU-A-201B-04: Estimating Dose to Eye Lens and Skin from Radiation Dose from CT Brain Perfusion Examinations: Comparison to CTDIvol Values

Purpose: In brain perfusion studies, the patient's head is scanned repeatedly at one location over a short period of time to monitor contrast wash in and wash out. This may result in high radiation doses to the skin and the eye lens and possibly deterministic effects. The purpose of this study is to estimate the radiation dose to skin and eye lens from brain perfusion studies under a variety of scanning conditions and to compare these to CTDIvol. Method and Materials: Skin dose and eye lens dose were estimated using Monte Carlo simulations with a detailed patient model (GSF Model Irene) and CT source models. Brain perfusion scans were simulated with axial scans using the widest available collimation at various scan locations. For each available kVp, the total mAs (mAs/rotation × number of rotations) to reach 2 Gy for eye lens and for skin was determined. Meanwhile, CTDIvol under each condition was obtained to investigate how well it predicts these doses. Results: For all kVps at four different scanners, the total number of rotations that would cause the dose to eye lens and skin reach 2Gy were calculated. For example, for a 300 mAs/rotation scan at 120kVp for scanner B, 58 rotations would result in an eye lens dose of 2Gy, and 47 rotations would result in a maximum skin dose of 2Gy. Depending on different kVp, CT scanners, and scan location, CTDIvol overestimates the eye lens dose by 46% to 18500% and it overestimates the skin dose by 25% to 82%. Conclusion: This study provides detailed information about the radiation dose to eye lens and skin from CT brain perfusion examinations. CTDIvol reported on the scanner console generally overestimates the dose to eye lens and skin. The results could help to improve the design of CT scan protocols.

Curl Mechanism of a Curling Stone on Ice Pebbles

We present a physical model that accounts for the curl mechanism of a curling stone on ice pebbles. The evaporation-abrasion model is based on the two essential features of curling: pebbles and running band. The ice friction coefficient at the rear half of a running band is larger than that at the front half because of cooling due to evaporation of pebbles. The asymmetry of the friction force is enhanced by mechanical interactions of ice debris produced by the front running band with the rear band, and result in the curl, or lateral deflection of the stone.The asymmetry is larger, that is the curl distance is larger, at smaller velocity, higher temperature, lower humidity, and larger radius of a running band. However, it is independent of the angular velocity, that is the curl distance does not depend on the total number of rotations.

Effect of locus coeruleus denervation on levodopa-induced motor fluctuations in hemiparkinsonian rats

Parkinson's disease (PD) is characterized not only by a progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) but also by a degeneration of locus coeruleus (LC) noradrenergic neurons. It has been suggested that deficient LC noradrenergic mechanisms might play a critical role in symptomatology and in the progression of PD. However, the effect of LC depletion on levodopa-induced motor complications, such as the motor fluctuations, is still unknown. Male Sprague-Dawley rats received 50 mg/kg intraperitoneal (i.p.) of [N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine] (DSP-4) or saline 7 days before the day of 6-hydroxydopamine (6-OHDA, 8 microg) administration in the medial forebrain bundle. Four weeks later, animals were treated with levodopa (25 mg/kg with benserazide, twice at day, i.p.) for 22 days. Rotational behavior was measured on days 1 and 22 of levodopa administration. Tyrosine hydroxylase (TH) immunohistochemistry was performed to evaluate the neurodegeneration in the SNc and LC. Striatal dopamine transporter (DAT) immunohistochemistry was performed to evaluate DA depletion. As expected, levodopa administration decreased the duration of the motor response in the vehicle-pretreated group (P < 0.01). A potentiation of levodopa-induced shortening in the duration of motor response was not achieved after LC depletion since no significant differences were observed in the duration of rotational behavior between these two groups on day 22. In addition, LC depletion did not potentiate either the total number of rotations or the maximal peak of rotation induced by levodopa treatment. These results suggest that LC depletion might not be involved in the pathophysiology of levodopa-induced motor fluctuations.

Training in pediatric critical care medicine: A survey of pediatric residency training programs.

After completing their critical care rotations, pediatric residents are expected to have acquired skills in the resuscitation of critically ill newborns and children. Recent Accreditation Council on Graduate Medical Education (ACGME) guidelines have limited the time devoted to critical care training during pediatric residency. We sought to determine how individual programs have structured their critical care training experience in light of these changes. A questionnaire was mailed to each pediatric residency program listed in the 1996-1997 Graduate Medical Education Directory. Information was obtained regarding the structure of critical care training. Data were analyzed using descriptive techniques, one-way analysis of variance with Scheffé post hoc test, and Fisher exact test as appropriate. Data were received from 149 programs (71% response rate). Most programs were in compliance with ACGME standards regarding the number of months devoted to neonatal intensive care, pediatric intensive care, and emergency medicine. There were no significant differences in the total number of rotations in either the neonatal intensive care unit (NICU) or the pediatric intensive care unit (PICU) when the programs were stratified by size. There were no significant differences in the percentage of programs requiring night call in either the NICU or the PICU during off-service months. However, small programs (< 25 residents) required significantly fewer rotations in emergency medicine (P < 0.001). Most programs complemented the critical care experience by offering additional rotations and advanced life support training. Pediatric residency programs have structured their critical care rotations in a similar fashion in accordance with ACGME guidelines. The success in meeting the stated objectives, as measured by the ability of graduating residents to stabilize critically ill children, is not known and will require further study.

Experimental analysis of the kneading disk region in a co-rotating twin screw extruder: Part 2. glass-fiber degradation during compounding

The fiber degradation in the kneading disk region of a co-rotating twin screw extruder was studied with a closed single-stage co-rotating twin screw extruder as a model for the analysis. In a previous article, we reported that the stress in the kneading zone was proportional to the screw torque. In the present study, we measured the fiber-length distributions and the average fiber lengths under various compounding conditions. It was found that the fiber-length distributions depend upon the shear stress and the total number of rotations and that the fiber-length distributions were identical if the average fiber lengths were the same. © 1997 John Wiley & Sons, Inc. Adv in Polym Techn 16: 25–32, 1997

Sensitization of rotation behavior in rats with unilateral 6-hydroxydopamine or kainic acid-induced striatal lesions

Following unilateral 6-hydroxydopamine (6-OHDA) lesions of the substantia nigra or unilateral kainic acid (KA) lesions of the striatum rats displayed rotation behavior in response to apomorphine (0.25 mg/kg SC or 1 mg/kg SC for the 6-OHDA- and KA-lesioned rats respectively). Three to five days following the initial apomorphine challenge rats were challenged under identical conditions with the same dose of apomorphine received previously. Both 6-OHDA- and KA-lesioned rats demonstrated a significant increase in the total number of rotations. Following a subsequent challenge with apomorphine, rats showed further increases in the total number of rotations. With the second and the subsequent apomorphine challenges there were significant increases in the maximal number of rotations, a significant decrease in the time of onset of rotation behavior and in some cases an increase in the duration of the rotation behavior. These increases in rotation behavior following repeated challenges with apomorphine indicate a supersensitivity to dopamine receptor agonists distinct from that elicited by lesions and chronic antagonist treatments. Furthermore, the utility of the rotation behavior model for testing the efficacy of dopaminergic agonists might be compromised if repeated challenges in individual animals are employed.

円板粉砕機の開発とその湿式粉砕性能

A disk mill with several rings and a rod as grinding media in the chamber was developed. There is much frictional crushing between grinding media and a chamber in the mill. It is generally accepted that frictional crushing is effective for ultrafine grinding. There is the possibility of realizing the disk mill can produce alarge quantity of submicron particles with less energy consumption.Effects of rotating speed of the mill, the feed weight and etc. on grinding performance were tested to obtain the optimum operating conditions for the disk mill. And it was proved the median size of ground product was not related to rotational speed but total number of rotations.

The generating function for coincidence site lattices in the cubic system

The derivation of the generating function given by Bleris & Delavignette [Acta Cryst. (1981), A37, 779- 786] is simplified and made rigorous. It is shown that their main result can also be deduced directly from Grimmer [Acta Cryst. (1974), A30, 685-688]. The following applications of the generating function are described: determining all rotations that generate coincidence site lattices (CSLs) by giving their axis and angle or their matrix, determining the equivalence classes of rotations with respect to cubic symmetry and the 180° and minimum-angle rotations that they contain, determining the number of rotations in each equivalence class and the total number of rotations that generate a CSL with given unit-cell volume Σ. We also discuss how a basis for the CSL can be computed and how a bicrystal with a plane grain boundary can be characterized.

Removal of the nπ ambiguity in observations of total electron content

Two of the main sources of error in converting observations of the Faraday rotation angle of a signal from a geostationary satellite into total electron content ( N T ) are the uncertainty in the baseline—corresponding to the initial polarisation—and the uncertainty in the total number of rotations—the ‘ nπ ambiguity’. A new method of resolving the nπ ambiguity, through the use of critical frequency data, is described. The method has been applied to data obtained at Sydney from Syncom 3. Results suggest that this comparatively simple method is quite reliable. The same method has been used to estimate the zero for absolute measurements of N T . It appears to give consistent results but yields a value which is rather different from that calculated on the basis of data previously published on Syncom 3.

Faraday rotation measurements of electron content near the magnetic equator

At the Electronics Laboratory of the Military Research and Development Center, Bangkok, Thailand (13.7°N latitude, 100.1°E longitude), Faraday rotation observations of the 54-MHz signal from the Transit 4-A (1961 Omicron 1) satellite were made during 10 months of a sunspot minimum period (1964). The satellite has an essentially circular orbit with an inclination of 67° and a spin-stabilized linear-polarized antenna. In this paper, two methods of analysis, involving rotation rate and total number of rotations, are applied to the Bangkok observations. The rotation-rate method is used to determine the electron content when the angle between the ray path and the geomagnetic field is 90° (transverse position). The total-rotations method is used to determine the latitudinal variations of the electron content for five selected satellite passes from a joint analysis of observations at three stations, Singapore, Bangkok, and Hong Kong. A comparison of the calculated critical frequency with observed ionosonde critical frequencies at Singapore, Bangkok, and Macao shows some evidence that the equivalent slab thickness may be considered independent of latitude near the magnetic equator.

Measurement of the Total Electron Content With the Differential Faraday Effect Using the Satellite Explorer 22

The signals of the American satellite Explorer 22 on 20, 40, 41 Mc/s have been received and their amplitudes recorded. The records show the Faraday effect when a fixed linearly polarized antenna is used. Using the Faraday effect, the total electron content can be computed, the total number of rotations being determined by comparing records of 40 and 41 Mc/s.The considerations of this paper are based upon the period January‐April 1965. Total electron content decreasing to the north prevail. In addition, a comparison of the Faraday effect on 20 and 40 Mc/s was performed. At small zenithal distances the Faraday periods on both frequencies (reduced to the same frequency) become equal; at larger distances typical deviations are observed.

Zone refining tungsten sheet bars in an electron beam furnace

In order to gain a better understanding of wiping mode screen extrusion-spheronisation process, a 45 wt% MCC/water paste was extruded using a basket screen extruder and the extrudate size and shape evolution during spheronisation tests were investigated in this study. Following the regular formulation tests, 30 g of extrudates with random lengths were employed as a starting charge for each spheronisation test. Two screens with 1 and 2 mm diameter holes were used to generate extrudates of the two diameters.It was found that the mathematical relationship between time to complete spheronisation (tend) and spheroniser plate rotational speeds (ω) varied with extrudate diameters. For the 1 mm diameter extrudates, tend scaled with ω− 3.8, which was close to that predicted by a simple collision model, whereas the product of tend and ω was relatively constant for the 2 mm extrudates. Projected images and SEM images of the dry pellets showed that the shape of 1 mm diameter material during spheronisation went through a dumb-bell stage, and the dumb-bells folded over together to form pellets. In comparison, there were few dumb-bells observed during spheronisation of 2 mm extrudates, and agglomeration was the dominant scenario by which fines attached to big segments to form ellipses and to be rounded into spheres. In the case of the 2 mm extrudates, the aspect ratio was changed mainly with the total number of rotations, and the trend showed little variation between different spheronisation speeds. Based on the observation, it was able to propose a phenomenological model to illustrate pellet shape evolution as well as a semi-empirical mathematical relationship to demonstrate the correlation between processing parameters at an optimal condition for each case. The former emphasised the differences in the shape change route of extrudate with different diameters. The later provided a quantitative guide for optimisation of a spheronisation process. The results suggested that the strain experienced by the paste during extrusion has played an important role in extrudate breakage at the early stage of spheronisation. The size of extrudate segments, after breakage, then determined their spheronisation behaviour during following processing.

Flocculation, subsidence, and filtration of phosphate slimes: IV. Flocculation by gums, and polyelectrolytes and their influence on filtration rate

The efficiencies of a large number of gums and polyelectrolytes as flocculants for improving flocculation and filtration of phosphate slimes have been investigated. Such factors as the speed of rotation and the total number of rotations in the mixing of flocculants and slimes, and the methods of adding the flocculants are discussed. The method of preparing stock solutions of flocculants and the age of such stock solutions significantly affect the flocculating efficiency in some cases. All the flocculants tested produce an optimum (maximum) in flocculation and, hence, filtration rate within a very narrow increment of flocculant concentration. This behavior was previously observed with starches. The pertinent data for 12 commercial products (out of about !50 tested), found to be the most effective flocculants for phosphate slimes, are summarized.