bluuebunny/crossref_metadata_2025 huggingface dataset:
Real‐time equalization of region‐of‐interest fluoroscopic images using binary masks
Authors: Rudin Stephen , Bednarek Daniel R. , Yang Chang‐Ying J.
Published: July 2002

In region‐of‐interest (ROI) radiologic imaging, the x‐ray beam is attenuated peripherally to the region of interest to reduce patient exposure. This attenuation reduces the peripheral image brightness which may cause contrast in the periphery to also be reduced due to video chain nonlinearity. For optimal viewing, it is necessary that the image brightness and contrast in the periphery be brought back to the levels in the ROI. Previously, digital subtraction angiography roadmapping equipment has been used for this equalization; however, the procedure is not independent of patient and gantry motion. A new motion independent method to achieve this equalization involves dividing the real‐time video signal into two digital streams one of which is brightness and contrast enhanced. A pre‐acquired binary mask image is created by thresholding the image of a uniform object obtained with the ROI filter in place. This binary mask is used to control the recombination of the two image streams in a digital pipeline processor in order to select the ROI from the unprocessed stream and the periphery from the enhanced stream. This system provides image equalization at 30 frame/s for real‐time ROI imaging display. Images from this method demonstrate excellent image quality even for peripheral exposure reduction factors exceeding 10.
Bandpass optical flow for tagged MRI
Authors: Prince Jerry L. , Gupta Sandeep N. , Osman Nael F.
Published: July 2002

MR tagging has shown great promise for detailed noninvasive cardiac motion imaging. Our research uses low‐frequency tags coupled with gradient‐based optical flow estimation to compute cardiac motion. We develop here a novel, fast, fully automated optical flow method for tagged MRI by exploiting the Fourier content of the tagged images. This new method, called bandpass optical flow, works by extracting various subband images from tagged cardiac data, and then formulating multiple optical flow constraints for each subband. The resulting system is solved by least squares pseudo‐inversion. The proposed method is validated on simulated and real tagged data.
Modeling heart and lung complication data in radiation therapy of the breast
Authors: Gagliardi Giovanna
Published: July 2002

In breast cancer, radiotherapy represents the most effective adjunct to surgery to prevent loco‐regional recurrences. Serious side‐effects following breast cancer radiotherapy are both cardiac and pulmonary. In this thesis, complication and dose distribution data were modeled to quantitatively describe the complication probability after a given treatment. The relative seriality model was used for the parameterization. Excess long‐term cardiac mortality data for breast cancer patients treated with various radiotherapy techniques were derived from the randomized trials in Stockholm (1971–1976) and Oslo (1964–1972). Dose distribution data were reconstructed with a three‐dimensional treatment planning system. A dose‐response relationship describing the data was determined. This served as a model to predict the probability of excess cardiac mortality in a group of 100 stage I breast cancer patients planned for radiotherapy using a conventional technique. A subgroup of the patients had a significant risk of excess long‐term cardiac mortality, due to the irradiation of a relatively large volume of the heart; this could be decreased either by an extended blocking of the beams or by applying a treatment method based on intensity modulation. Radiation pneumonitis data were obtained from patients treated at the Radiumhemmet (1993–1994). Individual three‐dimensional dose distributions were available. Model parameters plus uncertainties were determined using the maximum likelihood method. The uncertainty in the dose‐response curve due to the parameter uncertainties was also considered. The resulting parameters were then used to calculate the pneumonitis probability in five groups of breast cancer patients treated with radiotherapy. The predicted values of pneumonitis were not significantly different from the clinical incidence in three of the groups.
Development and construction of a neutron beam line for accelerator‐based boron neutron capture synovectomy
Authors: Gierga D. P. , Yanch J. C. , Shefer R. E.
Published: July 2002

A potential application of the nuclear reaction for the treatment of rheumatoid arthritis, termed Boron Neutron Capture Synovectomy (BNCS), is under investigation. In an arthritic joint, the synovial lining becomes inflamed and is a source of great pain and discomfort for the afflicted patient. The goal of BNCS is to ablate the synovium, thereby eliminating the symptoms of the arthritis. A BNCS treatment would consist of an intra‐articular injection of boron followed by neutron irradiation of the joint. Monte Carlo radiation transport calculations have been used to develop an accelerator‐based epithermal neutron beam line for BNCS treatments. The model includes a moderator/reflector assembly, neutron producing target, target cooling system, and arthritic joint phantom. Single and parallel opposed beam irradiations have been modeled for the human knee, human finger, and rabbit knee joints. Additional reflectors, placed to the side and back of the joint, have been added to the model and have been shown to improve treatment times and skin doses by about a factor of 2. Several neutron‐producing charged particle reactions have been examined for BNCS, including the reaction at proton energies of 4 and 3.7 MeV, the reaction at deuteron energies of 1.5 and 2.6 MeV, and the reaction at a proton energy of 2.5 MeV. For an accelerator beam current of 1 mA and synovial boron uptake of 1000 ppm, the time to deliver a therapy dose of 10 000 RBE cGy ranges from 3 to 48 min, depending on the treated joint and the neutron producing charged particle reaction. The whole‐body effective dose that a human would incur during a knee treatment has been estimated to be 3.6 rem or 0.75 rem, for 1000 ppm or 19 000 ppm synovial boron uptake, respectively, although the shielding configuration has not yet been optimized. The Monte Carlo design process culminated in the construction, installation, and testing of a dedicated BNCS beam line on the high‐current tandem electrostatic accelerator at the Laboratory for Accelerator Beam Applications at the Massachusetts Institute of Technology.
Physics study of microbeam radiation therapy with PSI‐version of Monte Carlo code GEANT as a new computational tool
Authors: Stepanek J. , Blattmann H. , Laissue J. A. , Lyubimova N. , Di Michiel M. , Slatkin D. N.
Published: July 2002

Microbeam radiation therapy (MRT) is a currently experimental method of radiotherapy which is mediated by an array of parallel microbeams of synchrotron‐wiggler‐generated x‐rays. Suitably selected, nominally supralethal doses of x‐rays delivered to parallel microslices of tumor‐bearing tissues in rats can be either palliative or curative while causing little or no serious damage to contiguous normal tissues. Although the pathogenesis of MRT‐mediated tumor regression is not understood, as in all radiotherapy such understanding will be based ultimately on our understanding of the relationships among the following three factors: (1) microdosimetry, (2) damage to normal tissues, and (3) therapeutic efficacy. Although physical microdosimetry is feasible, published information on MRT microdosimetry to date is computational. This report describes Monte Carlo‐based computational MRT microdosimetry using photon and/or electron scattering and photoionization cross‐section data in the 1 eV through 100 GeV range distributed publicly by the U.S. Lawrence Livermore National Laboratory (LLNL) in the 1990s. These are compared with Monte Carlo‐based microdosimetric computations using a code and physical data available in the 1980s. With the aim of using the PSI‐version of GEANT Monte Carlo code for future macro‐ and micro/nano‐dosimetric studies of Microbeam Radiation Therapy (MRT) a comparison of this code is made with the INHOM(EGS4) (version 1990), Dilmanian‐CPE and Persliden‐CPE Monte Carlo photon–electron codes (both version 1990) with which the absorbed dose distributions were calculated in 1990 and 1991 considering, (a) a single cylindrical microbeam, (b) multiple cylindrical microbeams in an orthogonal square bundle, and (c) multiple planar microbeams. It is shown that the PSI‐version of GEANT can potentially deliver more accurate results (a) using presently the most advanced atomic data, and especially (b) employing “Single‐collision” electron transport instead of only the “Condensed‐history” electron transport as in code INHOM(EGS4). In contrast Dilmanian‐CPE and Persliden‐CPE codes deposit the electron energy locally instead of transporting it to the correct position.
Radiation injury from x‐ray exposure during brachytherapy localization
Authors: Thomadsen B. R. , Paliwal B. R. , Petereit D. G. , Ranallo F. N.
Published: July 2002

Two patients developed skin ulcers secondary to high doses of diagnostic‐energy x rays received during localization procedures as part of brachytherapy treatments. Both were morbidly obese and diabetic. The obesity led to the delivery of estimated skin doses of 83 Gy in one case and 29 Gy in the other in attempts to produce readable images on localization radiographs. This report discusses the factors leading to the injuries, the progression of the injuries over time, and the variables involved in the localization procedures with the aim of preventing future mishaps. The greatest contribution to the large skin dose was the need, with the equipment available, to use multiple exposures to produce a single film, because of the effect of the resultant reciprocity failure.
Transforming echoes into pseudo-action potentials for classifying plants
Authors: Kuc Roman
Published: July 2002

Animals perceive their environment by converting sensory stimuli into action potentials, or temporal point processes, that are interpreted by the brain. This paper investigates the information content of point processes extracted from echoes from in situ plants in an effort to understand how bats recognize landmarks in the field. A mobile sonar converts echoes into biologically similar temporal point processes, termed pseudo-action potentials (PAPs), whose inter-PAP interval relates to echo amplitude. The sonar forms a sector scan of an object to produce a spatial-temporal PAP field. Classifier neurons apply delays and coincidence detection to the PAP field to identify three distinct echo types, glints, blobs, and fuzz, which characterize plant features. Glints are large amplitude echoes exhibiting coherence over successive echoes in the sector scan, typically produced by favorably oriented isolated specular reflectors. Blobs are large echoes lacking coherence, typically bordering glints or formed by collections of interfering reflectors. Fuzz represents weak echoes, typically produced by collection of weak scatterers or by reflectors on the beam periphery. A small mirror reflector models a flat leaf surface and motivates the glint criteria. Classifiers are applied to experimental data from two types of tree trunks, a glint-producing sycamore (Platanus occidenatalis) and a glint-absent Norway maple (Acer platanoides) and two plants, a glint-producing rhododendron (Rhododendron maximus) and a glint-absent yew (Taxus media). We speculate that our narrow-band sonar models the activity of a single frequency bin in the frequency-modulated (FM) sweep emitted by bats, and that one function of the frequency bins in the FM sweep is to form a sector scan of the environment.
Effects of ethanol intoxication on speech suprasegmentals
Authors: Hollien Harry , DeJong Gea , Martin Camilo A. , Schwartz Reva , Liljegren Kristen
Published: July 2002

The effects of ingesting ethanol have been shown to be somewhat variable in humans. To date, there appear to be but few universals. Yet, the question often arises: is it possible to determine if a person is intoxicated by observing them in some manner? A closely related question is: can speech be used for this purpose and, if so, can the degree of intoxication be determined? One of the many issues associated with these questions involves the relationships between a person’s paralinguistic characteristics and the presence and level of inebriation. To this end, young, healthy speakers of both sexes were carefully selected and sorted into roughly equal groups of light, moderate, and heavy drinkers. They were asked to produce four types of utterances during a learning phase, when sober and at four strictly controlled levels of intoxication (three ascending and one descending). The primary motor speech measures employed were speaking fundamental frequency, speech intensity, speaking rate and nonfluencies. Several statistically significant changes were found for increasing intoxication; the primary ones included rises in F0, in task duration and for nonfluencies. Minor gender differences were found but they lacked statistical significance. So did the small differences among the drinking category subgroups and the subject groupings related to levels of perceived intoxication. Finally, although it may be concluded that certain changes in speech suprasegmentals will occur as a function of increasing intoxication, these patterns cannot be viewed as universal since a few subjects (about 20%) exhibited no (or negative) changes.
Pitch strength of iterated rippled noise when the pitch is ambiguous
Authors: Yost William A.
Published: July 2002

Two versions of a cascade of delay, gain following delay, and add circuits were used to generate iterated rippled noise (IRN) stimuli. IRN stimuli produce a repetition pitch whose pitch strength relative to the noise percept can be varied by changing the type of circuit, the attenuation, or the number of iterations in the circuit. The repetition pitch of IRN is different when the delayed noise is subtracted (gain <0) rather than added (gain >0) to the undelayed noise. In the case of subtraction, IRN pitch is often ambiguous having two or more pitches. Listeners were asked to use pitch strength to discriminate between various pairs of IRN stimuli generated with different gains, different network circuits, and different number of iterations. For most conditions the gain was less than one. The data were described by a description based on an exponential function of the largest peak of the autocorrelation function of IRN stimuli [W. A. Yost, J. Acoust. Soc. Am. 100, 511–518 (1996)] processed such that the spectral dominance region is emphasized. These results suggest that the strength of the pitch of IRN stimuli can be described by temporal processing mechanisms as might be revealed by autocorrelation.
An investigation of penetration depth control using parallel opposed ultrasound arrays and a scanning reflector
Authors: Moros Eduardo G. , Fan Xiaobing , Straube William L.
Published: July 2002

A theoretical study of penetration depth control in superficial hyperthermia utilizing parallel opposed linear ultrasound arrays and a double-faced (V-shaped) scanning reflector is presented. This is a dual array system (DAS), where one array operates at a low frequency and the other at a high frequency (1 and 5 MHz, respectively in this study). The arrays are positioned facing each other and both are aimed at a double-faced scanning reflector which distributes the energy over the scanned surface. Each reflecting surface is angled at 45° with respect to the sound propagation direction so that both beams are deflected in the same direction toward the treatment volume. The system was designed to be compatible for combined operation with a medical linear accelerator for the delivery of simultaneous thermoradiotherapy. It is demonstrated that by varying the excitation magnitude of one array relative to the other, it is possible to control the magnitude of absorbed energy as a function of depth, and thus improved control of the heating pattern in all three spatial dimensions is obtained. This improvement is demonstrated with bio-heat transfer simulations which show how penetration depth control translates into control of temperature distributions. The simulations also show that the DAS is able to produce more uniform temperature distributions in highly perfused tissue.
Broad beamwidth ultrasonic transducers for tri-aural perception
Authors: Peremans Herbert
Published: July 2002

As airborne, correlation-based, ultrasonic sensors are becoming more widely used for robotic applications, it becomes increasingly important to have a good understanding of how the transducer’s filtering properties affect the performance of the sensor system. Using well-known results from acoustics, a simple, yet accurate, filtermodel for the Polaroid transducer is described. In the course of this derivation the reason for the accuracy of the often used “moving piston” approximation is also clarified. This filtermodel is then used to analyze the characteristic “peak-doubling” from which the correlation based range sensor used in the tri-aural sensor suffers. The predicted errors are compared with actual measurements by the real sensor system and are found to be in good agreement. Finally, the use of broad beamwidth transducers to avoid these errors is proposed, and it is and argued that this approach has some distinct advantages compared to alternative solutions.
Study on the longitudinal–torsional composite vibration of a sectional exponential horn
Authors: Shuyu Lin
Published: July 2002

The longitudinal–torsional composite vibration of a sectional exponential horn was studied theoretically and experimentally. The horn consists of an exponential horn with an untapered rod at its large end. Based on the plane-wave approximation, the resonance frequency equations and other characteristics for the longitudinal and torsional vibrations of the horn were derived and some theoretical curves were given. Since the sound speeds of the longitudinal and torsional vibrations are different in the same material, the longitudinal and torsional vibrations in a horn are generally difficult to resonate at the same resonance frequency. In this paper, to overcome this problem, the cross-sectional radius decay coefficient of the exponential part in the sectional horn, which determines the sound speeds and other performance parameters of the horn, is selected to make the longitudinal and torsional vibrations resonate at the same frequency. By means of this method, the simultaneous resonance of the longitudinal and torsional vibrations in the horn is achieved by choosing the proper value of the radius decay coefficient. Some sectional exponential horns were designed and made, their resonance frequencies were measured, and the vibrational characteristics of the horn under large excitation were observed qualitatively. Experimental results show that the measured resonance frequencies of the horns are in good agreement with the theoretical results, and the measured resonance frequencies of the longitudinal and torsional vibrations are also in good agreement with each other. Therefore the simultaneous resonance of the longitudinal and torsional vibrations in the same horn are achieved both theoretically and experimentally. This kind of sectional exponential horn can be used in ultrasonic machining, ultrasonic drilling, ultrasonic fatigue testing, and other applications which need very large mechanical displacement amplitudes.
Effects of elastic heterogeneities and anisotropy on mode coupling and signals in shallow water
Authors: Park Minkyu , Odom Robert I.
Published: July 2002

Coupled mode theory is applied to acoustic/elastic wave propagation in shallow water to examine the effects of lateral heterogeneities and transverse isotropy on mode coupling and signals. A numerical code is developed by applying the invariant imbedding technique to the coupled mode theory. From the code, the reflection and transmission matrices and the forward/backward-propagating wave fields in the frequency domain are generated for a range-dependent medium. The effect of transverse isotropy of bottom sediment layers is also considered. Time domain signals are synthesized with a 2-Hz bandwidth between 10 Hz and 12 Hz for the excitation by a unit line force and for an incident fundamental mode. The generation of higher overtones and the decay of the fundamental mode propagating in a range-dependent medium are clearly shown.
Benchmark solutions of plane wave bottom reflection loss
Authors: Ainslie Michael A. , Robins Alvin J. , Prior Mark K.
Published: July 2002

Benchmarks of plane wave bottom reflection loss versus grazing angle are presented at three frequencies (1.5, 15, and 150 Hz) for four different bottom types. Each bottom type comprises a layered fluid sediment representing either sand or mud, overlying a uniform solid substrate (mudstone or basalt). The benchmarks are calculated using exact analytical solutions where available (primary benchmarks) or the numerical model SAFARI-FIPR (secondary benchmarks). The accuracy of the secondary benchmarks is demonstrated by comparison with alternative solution methods (diagnostics). The sensitivity to the assumed density profile is examined for one of the bottom types.
Attenuation and dispersion of sound in dilute suspensions of spherical particles
Authors: Temkin S.
Published: July 2002

This paper considers sound propagation in dilute suspensions of constant-mass particles that can translate and pulsate under the effects of a small amplitude sound wave. A new theory for sound attenuation and dispersion is developed on the basis of the changes of the suspension’s compressibility produced by the relative motions between host fluid and particles. The approach, used earlier to treat propagation in rigid-particle suspensions, decouples the propagation problem from the more difficult problem of obtaining accurate descriptions for the fluid-particle interactions. In this work the role of the pulsational motion is included in the theoretical framework. The resulting theory is thus applicable to aerosols, bubbly liquids, emulsions, and hydrosols composed of elastic particles, and includes, as a special limit, rigid-particle suspensions. The results are expressed in terms of three complex quantities that describe, respectively, the particles’ translational velocity, temperature, and pressure, relative to their counterparts in the fluid. Theoretical results for these quantities, applicable in wide frequency ranges, are available from previous studies [Temkin and Leung, J. Sound Vib. 49, 75–92 (1976), Temkin, J. Fluid. Mech. 380, 1–38 (1999)]. Together with the compressibility theory presented here, they provide a more general description of propagation in dilute suspensions than presently available. In the case of aerosols and hydrosols, the theory produces known results for the attenuation and the sound speed. For bubbly liquids and emulsions the new results presented here differ from those available in the literature. The differences are traced to the neglect in the existing theories of the acoustic pressure disturbance produced by the pulsations of the particles.
Steady-State Melt Flow Behavior of Polyethylene Blends
Authors: Nakajima Nobuyuki , Wong Patrick S. L.
Published: July 2002

The steady-state melt flow behavior covering six decades of shear rate was studied for various types of polyethylene and their blends. Two instruments were used. The Kepe's cone and plate consistometer measures viscosities at low shear rate at the range from 10−2 to 1 sec−1. A gas-driven capillary viscometer gives high shear data. The shear stress at the capillary wall was calculated by the method proposed by Bagley and the shear rate at the wall was obtained after Robinowitsch. A special effort was made to observe the change in low shear flow behavior of a resin due to an addition of gels, high ends or low ends of molecular weight distribution. Addition of low ends up to 20% does not alter the “shape” of the viscosity shear rate flow curve appreciably. But with an addition of high ends, the “shape” of the flow curve changes considerably. With an addition of gels, the flow curve at low shear rises rapidly as shear rate decreases. An inflection was observed followed by a “tail-up” at the low shear range.
Analysis of Flow Properties in Relation to Molecular Parameters for Polymer Melts
Authors: Collins E. A. , Bauer W. H.
Published: July 2002

Reported data on polystyrene, polyethylene, and polydimethylsiloxanes are contradictory with respect to the shear rate at which the transition from Newtonian to non-Newtonian flow occurs. Some data implies that the transition occurs at the same lower limiting shear rate and is independent of molecular weight above a critical molecular weight. On the other hand, other data shows that above a critical molecular weight the transition occurs at lower rates of shear as the molecular weight increases. The considerations of Bueche for melt polymer flow confirm the latter type of transition behavior. It is proposed that the discrepancies are due to molecular weight distribution, temperature effects, and methods of obtaining zero shear viscosities. Data are presented to support these views.
Wall slip of a polydimethylsiloxane extruded through a slit die with rough steel surfaces: Micrometric measurement at the wall with fluorescent-labeled chains
Authors: Legrand Frédéric , Piau Jean Michel , Hervet Hubert
Published: July 2002

Upstream instability and wall slip of a high molecular weight polydimethylsiloxane (PDMS) have been studied in a rough stainless-steel slit die. The velocity field at a micrometric scale close to a wall is determined with a fluorescence technique. A film of a mixture of PDMS and small fluorescent-labeled chains (PDMS–NBD) is deposited on the steel surface prior to the high-pressure flow. During the flow, the fluorescence of a small area in the middle of the surface is excited with an argon laser line and measured with a phototube. The signal decays towards an asymptotic low value, due to stray light and thermal current. The slip velocity is inferred from a comparison between the experimental decrease and a theoretical model, which takes diffusion effects into account. It is shown that the upstream instability induces a transverse oscillating velocity in the channel. A precise determination of the residual fluorescence after the wall slip, with a known diffusion coefficient and surface roughness, shows that the wall slip occurs in a plane localized at less than 1 μm from the ridges of the surface roughness.
Knowledge‐based planning for the radiation therapy treatment plan quality assurance for patients with head and neck cancer
Authors: Cao Wenhua , Gronberg Mary , Olanrewaju Adenike , Whitaker Thomas , Hoffman Karen , Cardenas Carlos , Garden Adam , Skinner Heath , Beadle Beth , Court Laurence
Published: April 2022

This study aimed to investigate the feasibility of using a knowledge‐based planning technique to detect poor quality VMAT plans for patients with head and neck cancer. We created two dose–volume histogram (DVH) prediction models using a commercial knowledge‐based planning system (RapidPlan, Varian Medical Systems, Palo Alto, CA) from plans generated by manual planning (MP) and automated planning (AP) approaches. DVHs were predicted for evaluation cohort 1 (EC1) of 25 patients and compared with achieved DVHs of MP and AP plans to evaluate prediction accuracy. Additionally, we predicted DVHs for evaluation cohort 2 (EC2) of 25 patients for which we intentionally generated plans with suboptimal normal tissue sparing while satisfying dose–volume limits of standard practice. Three radiation oncologists reviewed these plans without seeing the DVH predictions. We found that predicted DVH ranges (upper–lower predictions) were consistently wider for the MP model than for the AP model for all normal structures. The average ranges of mean dose predictions among all structures was 9.7 Gy (MP model) and 3.4 Gy (AP model) for EC1 patients. RapidPlan models identified 7 MP plans as outliers according to mean dose or D1% for at least one structure, while none of AP plans were flagged. For EC2 patients, 22 suboptimal plans were identified by prediction. While re‐generated AP plans validated that these suboptimal plans could be improved, 40 out of 45 structures with predicted poor sparing were also identified by oncologist reviews as requiring additional planning to improve sparing in the clinical setting. Our study shows that knowledge‐based DVH prediction models can be sufficiently accurate for plan quality assurance purposes. A prediction model built by a small cohort automatically‐generated plans was effective in detecting suboptimal plans. Such tools have potential to assist the plan quality assurance workflow for individual patients in the clinic.
Design and standard utilization of safety devices for the radiation treatment management of heavy patients
Authors: Kanchaveli David , Hellman Samuel , Lovelock Dale , Archuadze Giorgi , Biancia Cesar Della
Published: April 2022

Purpose

Increasing number of heavy cancer patients has created challenges in diagnostic imaging and radiation oncology. Practical weight limits of the equipment can become an obstacle both for imaging and treatment of these patients. Most magnetic resonance imaging and computed tomography (CT) tables’ static load capacities are between 450 and 500 pounds, and linear accelerator tables can support similar weights depending on the type of the table and manufacturer. One recurring issue we encountered was failure of the treatment couch's longitudinal drive belt due to heavy patients’ sudden movement. In several cases, snapping of the longitudinal drive belt occurred when the patient's weight was under 300 lbs (below the rated weight limit). Additionally, we observed vertical deflection of the couch when extended/cantilevered with heavy patients. The purpose of this work was to implement immobilization methods and safety devices for radiation treatment management of heavy patients in order to increase patient/provider safety, prevent treatment couch damage, and reduce treatment disruptions.

Materials and methods

We created three safety devices for treatment management of heavy patients. Wooden brace and Scissor jack were used to lock the couch longitudinal axis (while the couch longitudinal drive was floated) during the setup of a heavy patient and absorb the mechanical impulse applied to the couch longitudinal drive belt. Wooden brace was built in house and positioned in between the wall and treatment couch to lock the longitudinal axis. Commercially available 10 in × 10 in scissor jack lift with adjustable height 3 ½ in – 13 in was modified to increase effectiveness and safety. An additional stand was created with adjustable height and rolling rubber wheels to support the couch when extended/cantilevered with heavy patients.

Results

Using these devices prevented the longitudinal belt from breaking and improved the patient/therapist safety at eight treatment sites within our network. No farther couch belt failures were observed since devices were introduced for clinical use. All three devices can be used and removed without any modifications done to the treatment couch.
Hyperventilation‐induced focal seizures in adults: think autoimmune encephalitis
Authors: Wennberg Richard A.
Published: April 2022

Case reports have described rare patients with autoimmune encephalitis in whom focal seizures could be reliably provoked by hyperventilation. With the hypothesis that this phenomenon may have diagnostic significance, all cases of hyperventilation‐induced focal seizures identified during ~10,000 consecutive routine electroencephalography (EEG) studies were reviewed, and corresponding diagnoses established. Seven EEG recordings, in six patients, contained focal hyperventilation‐induced seizures, each of temporal lobe onset. All patients were diagnosed with autoimmune encephalitis, in two cases after EEG; five had voltage‐gated potassium channel complex autoantibodies. Although rare, a hyperventilation‐induced focal seizure during EEG in an adult should raise concern for autoimmune encephalitis.
Association of CD90 Expression by CD14+ Dendritic‐Shaped Cells in Rheumatoid Arthritis Synovial Tissue With Chronic Inflammation
Authors: Kurose Rie , Satoh Takashi , Kurose Akira , Satoh Yo‐Ichi , Ishibashi Yasuyuki , Wakai Yuji , Sasaki Tomoyuki , Ishida Kinji , Ogasawara Katsutoshi , Sawai Takashi
Published: April 2022

Objective

CD14+ dendritic‐shaped cells show a dendritic morphology under the electron microscopy and engage in a pseudoemperipolesis phenomenon with lymphocytes. CD90 has been used as a marker of a major subset of fibroblast‐like synoviocytes in rheumatoid arthritis (RA). In this study, we investigated the significance of CD90 expression in CD14+ dendritic‐shaped cells and its correlation with RA chronic inflammation.

Methods

Double immunofluorescence staining for CD14 and CD90 was performed in the collected tissues, including 12 active RA synovial tissues. The localization of CD14+CD90+ cells, the percentages of CD14+CD90+ cells and vascular areas, the degree of synovitis, and clinical data were investigated. Furthermore, CD14+CD90+ cells analyzed by flow cytometry (CD14highCD90intermediate (int) cells) were sorted from RA synovial cells, and we examined their potential to differentiate into dendritic cells.

Results

Double immunofluorescence staining showed that CD14+CD90+ cells were abundant in RA synovial tissues. The percentages of CD14+CD90+ cells and vascular areas correlated with some of the Krenn synovitis scores, but neither showed a strong correlation with RA disease activity parameters. Flow cytometry analysis indicated that CD14highCD90int cells were more abundant in both peripheral blood samples and synovial tissues in patients with active RA. CD14highCD90int cells were more likely to differentiate into dendritic cells in vitro.

Conclusion

CD14+ dendritic‐shaped cells expressed CD90 in the perivascular areas of RA synovial tissues. These findings suggest that CD14+CD90+ dendritic‐shaped cells migrate from the peripheral blood to the synovial tissue, the site of inflammation, and may contribute to the chronic inflammation of RA as dendritic progenitor cells.
Recent Advances in Cryogenic 3D Printing Technologies
Authors: Li Zongan , Xu Mengjia , Wang Jiahang , Zhang Feng
Published: April 2022

Cryogenic 3D printing, or freeze 3D printing, is an additive manufacturing process that prints an object at “low” temperature atmosphere. It uses a temperature lower than the melting point of the printing material (commonly a water‐based suspension or slurry) to solidify the layered part. Cryogenic 3D printing compasses several different processes including ice 3D printing, freeze from extrusion, freeze nano‐printing (FNP), etc. However, no systematic survey of these technologies is present. In the current review, various 3D printing technologies that use low temperature to solidify the layer are reviewed. The technical aspects such as path planning, heat transfer, and diffusion in multi‐material are investigated. The applications of cryogenic 3D printing are presented including the investment casting, ice sculpture, and microfluidic channel from original ice 3D printing, and functional porous materials from the emerging FNP and low‐temperature deposition. Overall, this article gives a summary of cryogenic 3D printing technologies, including a survey on its technical aspects and potential applications for future research and development.
High‐Temperature Compressive Behavior of Refractory Alumina–Niobium Composite Material
Authors: Günay Gökhan , Zienert Tilo , Endler Dirk , Aneziris Christos G. , Biermann Horst , Weidner Anja
Published: April 2022

The development of coarse‐grained refractory composites combining refractory ceramics with refractory metals provides new approaches for high‐temperature applications. In particular, coarse‐grained Nb‐Al2O3 composites are widely interested due to their promising functional properties such as high thermal shock resistance, low shrinkage and good electrical conductivity. In order to identify and release the potential of these materials in advanced applications, their mechanical behavior should be evaluated. This study presents room‐ and high‐temperature compression behavior up to 1500 °C of Nb‐Al2O3 refractory composites manufactured via castable and extrusion technology. The influences of production method, particle size, open porosity as well as temperature and strain rate are discussed. For comparison, pure niobium and alumina specimens are used as reference materials. The results indicate that Nb‐Al2O3 refractory composites show high ductility at high temperatures. This behavior is also verified with microstructural investigations by scanning electron microscope (SEM).
Multifunctional “Janus‐Type” Bilayer Films Combine Broad‐Range Tissue Adhesion with Guided Drug Release
Authors: Kimna Ceren , Bauer Maria G. , Lutz Theresa M. , Mansi Salma , Akyuz Enes , Doganyigit Zuleyha , Karakol Percin , Mela Petra , Lieleg Oliver
Published: April 2022

Tissue healing is a challenging process that requires the successful and simultaneous management of conflicting priorities. While promoting wound closure, a battle must be won against different external factors that may adversely affect the healing process. Here this problem is approached by creating asymmetrically designed double‐layer Janus‐type bilayer films where distinct functions are implemented into the two sides of the film. Once deployed, those Janus‐type films exhibit strong adhesion to a wide variety of wet tissues and canalize the release of integrated therapeutics toward the tissue side. At the same time, the outer surface of the films acts as a shield against tribological stress, pathogens, and cellular immune recognition. Moreover, when compared to untreated wounds, Janus‐treated skin lesions show accelerated wound closure as well as fast formation of new, intact tissue. Having performed their tasks, Janus‐type films degrade without leaving any traces on the tissues, which makes it possible to apply them to sensitive body surfaces. Thus, it is expected that the Janus‐type bilayer films designed here can be used in a variety of medical applications where conflicting demands must be met at the same time.
Field‐Free Magnetization Switching Driven by Spin–Orbit Torque in L10‐FeCrPt Single Layer
Authors: Lyu Haochang , Zhao Yunchi , Qi Jie , Huang He , Zhang Jingyan , Yang Guang , Guo Yaqin , Shen Shipeng , Qin Weidu , Sun Young , Shen Jianxin , Dou Pengwei , Shao Bokai , Zhang Yi , Jin Kui , Long Youwen , Wei Hongxiang , Shen Baogen , Wang Shouguo
Published: April 2022

Electrical switching of magnetization through spin–orbit torque (SOT) induced by a composition gradient in single‐layer L10‐FePt has garnered considerable research interest owing to its inherent superior perpendicular magnetic anisotropy (PMA) that provides ultrahigh capacity to magnetic storage and memory devices. However, a large in‐plane external magnetic field is typically required to assist SOT‐driven switching, which is still a limitation for the practical application of L10‐FePt. This study reports realizable field‐free magnetization switching by SOT via Cr doping to form a single‐layer magnetic structure with an in‐plane magnetization component oriented toward L10‐FeCrPt [110] direction that strongly depends on the magnetocrystalline anisotropy. The Cr doping yields a considerable in‐plane exchange‐coupling effective field that is conducive toward disintegrating the rotational switching symmetry and facilitates field‐free switching in single‐layer films with PMA. Furthermore, this in‐plane effective field exhibits a nonmonotonic evolution with respect to the Cr‐doping concentration, which is validated using first‐principles calculation with a frustration‐based model of magnetic exchange interactions. Thus, this study delivers an attractive method to facilitate the field‐free electrical manipulations of magnetization in single‐layer ferromagnets to motivate innovative designs for advanced spintronics devices.
In Situ Activated NK Cell as Bio‐Orthogonal Targeted Live‐Cell Nanocarrier Augmented Solid Tumor Immunotherapy
Authors: Meng Dandan , Pan Hong , He Wei , Jiang Xing , Liang Zhenguo , Zhang Xu , Xu Xiaoyu , Wang Zixi , Zheng Jinling , Gong Ping , Li Wenjun , Cai Lintao
Published: April 2022

Natural killer (NK) cell‐based immunotherapy holds prominent potential for cancer treatment. However, its application in solid tumors is limited by a rapid decline in viability and function, as well as inadequate homing and infiltration. Herein, a generalized strategy is offered to construct a bio‐orthogonal targeted live‐cell nanocarrier (N3‐NK‐NPs) by coupling with responsive released interleukin‐21 (IL‐21) nanoparticles (ILNPs) on glyco‐engineered NK cell surfaces. Complementary bio‐orthogonal groups (azide (N3)/bicyclo [6.1.0] nonyne (BCN), serving as an artificial ligand receptor are separately implanted into NK cells (N3‐NK) and tumor cells (BCN‐Raji) via nondestructive metabolic glycoengineering. The bio‐orthogonal strategy effectively promotes the specific recognition and migration of NK cells, showing nearly fourfold deeper infiltration in tumor than control groups. Compared with traditional systemic administration, ILNPs hitchhiking on cell vectors selectively in situ releases the IL‐21 adjuvant in the tumor to produce effective and continuous “pseudo‐autocrine” stimulation surrounding NK cells under a low dose (5 µg kg–1), which greatly promotes proliferation and activation of NK cells, resulting in enhanced therapeutic potential while limiting systemic toxicity. Importantly, live‐cell nanocarrier effectively activates innate immune system through IL‐21 triggered recruitment of multiple immunocytes, significantly improving tumor immune microenvironment. This in situ activated NK cell nanocarrier with bio‐orthogonal targeting provides a universal and powerful strategy for immune cells activation and solid tumor immunotherapy.
Bamboo‐Based Biomaterials for Cell Transportation and Bone Integration
Authors: Xue Jianmin , Ma Hongshi , Song Erhong , Han Fei , Li Tian , Zhang Meng , Zhu Yufang , Liu Jianjun , Wu Chengtie
Published: April 2022

The construction of hierarchical porous structure in biomaterials is of great significance for improving nutrient transport and biological performance. However, it is still challenging to design porous bone substitutes with high strength and biological properties, which limits their clinical applications in load‐bearing bone regeneration. Herein, based on hierarchical porous structure of renewable bamboo, the mineralized calcium phosphate/bamboo composite scaffolds with high strength and excellent transport performance are successfully prepared in combination of biotemplated approach and biomimetic mineralization. The mineralized biomaterials have simultaneously achieved high mechanical strength and low modulus, similar to those of cortical bone. Furthermore, the mineralized biomaterials exhibit good liquid transport capacity and can transport cells along anti‐gravity direction. Based on density functional theory (DFT) calculations, the mineralized calcium phosphate reveals the optimal H2O adsorption energy (−0.651 eV) and low diffusion energy barrier (0.743 eV), which is conducive to enhance hydrophilicity and liquid transport performance. Moreover, owing to the synergistic effect of the porous structure of biotemplate and bioactive mineralized components, the mineralized biomaterials possess enhanced bone integration and osteoconduction properties. The present study shed light on deeper understanding of mineralized biosourced materials, offering a strategy of combining green chemistry with tissue engineering to prepare eco‐friendly biomaterials.
A Gapped Phase in Semimetallic Td‐WTe2 Induced by Lithium Intercalation
Authors: Wang Mengjing , Kumar Aakash , Dong Hao , Woods John M. , Pondick Joshua V. , Xu Shiyu , Hynek David J. , Guo Peijun , Qiu Diana Y. , Cha Judy J.
Published: April 2022

The Weyl semimetal WTe2 has shown several correlated electronic behaviors, such as the quantum spin Hall effect, superconductivity, ferroelectricity, and a possible exciton insulator state, all of which can be tuned by various physical and chemical approaches. Here, a new electronic phase in WTe2 induced by lithium intercalation is discovered. The new phase exhibits an increasing resistivity with decreasing temperature and its carrier density is almost two orders of magnitude lower than the carrier density of the semimetallic Td phase, probed by in situ Hall measurements as a function of lithium intercalation. The theoretical calculations predict the new lithiated phase to be a potential charge density wave (CDW) phase with a bandgap of ≈0.14 eV, in good agreement with the in situ transport data. The new phase is structurally distinct from the initial Td phase, characterized by polarization‐angle‐dependent Raman spectroscopy, and large lattice distortions close to 6% are predicted in the new phase. This finding of a new gapped phase in a 2D semimetal demonstrates electrochemical intercalation as a powerful tuning knob for modulating electron density and phase stability in 2D materials.
An Intracellular Self‐Assembly‐Driven Uninterrupted ROS Generator Augments 5‐Aminolevulinic‐Acid‐Based Tumor Therapy
Authors: Shi Jinjin , Nie Weimin , Zhao Xiu , Yang Xinyuan , Cheng Hui , Zhou Tonghai , Zhang Yun , Zhang Kaixiang , Liu Junjie
Published: April 2022

Free radical therapy based on 5‐aminolevulinic acid (ALA, a precursor of the photosensitizer protoporphyrin IX (PpIX)) has been approved by the US Food and Drug Administration for clinical tumor treatment. However, PpIX can be quickly converted into photoinactive heme, leading to unexpectedly paused production of free radicals and severely hindering its therapeutic benefits. Here, inspired by the natural biotransformation of ALA (ALA‐PpIX‐heme), an uninterrupted reactive oxygen species generator (URG) that converts useless heme to peroxidase mimics via intracellular self‐assembly is developed. The URG is prepared by enwrapping ALA‐loaded polyamide‐amine dendrimers in red blood cell membrane vesicles with a further surface modification of G‐quadruplex‐structured AS1411. The URGs realize “1O2−•OH” uninterrupted generation through “recycling waste” in two steps: i) PpIX generates 1O2 under laser irradiation; and ii) the photoinactive metabolite heme self‐assembled with AS1411 to catalyze H2O2 conversion into •OH. Interestingly, the specific generation of 1O2 in mitochondria and •OH in nuclei further augments the free‐radical‐induced damage. It is demonstrated that URG can continuously produce free radicals for 6 h postirradiation, and shows 3.3‐times more than that of the nonassembly group, achieving nearly 80% regression of tumors in vivo.
Electrically Conductive Photoluminescent Porphyrin Phosphonate Metal–Organic Frameworks
Authors: Zorlu Yunus , Wagner Lukas , Tholen Patrik , Ayhan Mehmet Menaf , Bayraktar Ceyda , Hanna Gabriel , Yazaydin A. Ozgur , Yavuzçetin Özgür , Yücesan Gündoğ
Published: April 2022

Herein, the design and synthesis of a highly photoluminescent and electrically conductive metal–organic framework [Zn{Cu‐p‐H6TPPA}]⋅2 [(CH3)2NH] (designated as GTUB3), which is constructed using the 5,10,15,20‐tetrakis [p‐phenylphosphonic acid] porphyrin (p‐H8TPPA) organic linker, is reported. The bandgap of GTUB3 is measured to be 1.45 and 1.48 eV using diffuse reflectance spectroscopy and photoluminescence (PL) spectroscopy, respectively. The PL decay measurement yields a charge carrier lifetime of 40.6 ns. Impedance and DC measurements yield average electrical conductivities of 0.03 and 4 S m−1, respectively, making GTUB3 a rare example of an electrically conductive 3D metal–organic framework. Thermogravimetric analysis reveals that the organic components of GTUB3 are stable up to 400 °C. Finally, its specific surface area and pore volume are calculated to be 622 m2 g−1 and 0.43 cm3 g−1, respectively, using grand canonical Monte Carlo. Owing to its porosity and high electrical conductivity, GTUB3 may be used as a low‐cost electrode material in next generation of supercapacitors, while its low bandgap and high photoluminescence make it a promising material for optoelectronic applications.