bluuebunny/crossref_metadata_2025 huggingface dataset:
Künstliche Intelligenz in der Endoskopie: Neuronale Netze und maschinelles Sehen – Techniken und Perspektiven
Authors: Schmitz Rüdiger , Werner René , Rösch Thomas
Published: June 2019

Künstliche neuronale Netze als Methoden der künstlichen Intelligenz (KI) können der Endoskopie neue Möglichkeiten eröffnen, etwa im Sinne einer automatischen Polypenerkennung oder der präzisen Vorhersage des histopathologischen Befunds einer Läsion anhand ihres endoskopischen Bildes. Während erste Versuche tatsächlich ein weitreichendes Potenzial erahnen lassen, leiten sich öffentliche und medial transportierte Erwartungen häufig mehr von einer abstrakten Faszination als von der detaillierten Funktionsweise der Methoden ab. Dieser Artikel soll anhand einer selektiven Literaturübersicht ein intuitives Verständnis der Methoden vermitteln und helfen, die Lücke zwischen Funktion und Faszination zu schließen, um Potenzial und Grenzen dieser Techniken im Bereich der Endoskopie realistisch abschätzen zu können.

Mit ihrem Erfolg bei der maschinellen Klassifikation von Bildern haben insbesondere „tiefe neuronale Netze“ der KI nach jahrzehntelanger Forschung zu rasant anwachsendem Interesse verholfen. Wir umreißen kurz die diesbezüglichen Entwicklungen und die Gründe für ihre Bedeutung weit über die Informatik hinaus. Durch den Vergleich von maschinellem und menschlichem Sehen wird ein Verständnis der detaillierten Funktionsweise dieser Methoden und ihrer Erfolge bei Seh-Aufgaben vermittelt. Darauf aufbauend analysieren wir die Funktionsweise jüngst demonstrierter Anwendungen in Hinblick auf methodische Perspektiven und Grenzen, die Aussagekraft bisher erbrachter Leistungsnachweise und die Notwendigkeit weiterer Tests. Zudem geben wir einen Eindruck von weiteren, konkret absehbaren Einzelanwendungen und besprechen, welchen Charakter diese dem Einsatz der künstlichen Intelligenz in der Endoskopie insgesamt geben könnten.
First-Line Therapy for Immune Thrombocytopenia
Authors: Mithoowani Siraj , Arnold Donald M.
Published: June 2019

Immune thrombocytopenia (ITP) is an autoimmune disease affecting blood platelets that causes thrombocytopenia and an increased risk of bleeding. First-line therapy is indicated for patients with bleeding complications or who are at increased risk of bleeding, and the decision to initiate therapy depends not only on the platelet count, but also on other endpoints including quality of life. The choice of first-line therapy depends primarily on how quickly a platelet count response is required, with intravenous immune globulin providing the more rapid response, followed by high-dose dexamethasone and prednisone. In this narrative review, we discuss key issues with first-line therapy in ITP including when to initiate therapy, treatment options and special considerations for children. Evidence-based guidelines are lacking for the emergency management of patients with ITP who present with significant bleeding; we provide our approach to this critical situation.
Comparison of Salivary Calcium Level in Dentulous and Edentulous Patients
Authors: Rabiei Maryam , Asli Hamid Neshandar , Mohamadi Mohadeseh Haji
Published: June 2019

Objectives Calcium is an inorganic component of the saliva, which is especially important in oral and dental health. This study sought to compare unstimulated salivary calcium level of dentulous and edentulous patients.

Materials and Methods This case–control study was conducted on 72 participants, including 36 dentulous and 36 edentulous patients. The unstimulated salivary flow rate of patients and the mean salivary calcium concentration were measured and compared. The data were analyzed using the nonparametric Mann–Whitney U-test.

Results The mean age of participants was 56.3 years. The mean number of teeth was 18.9 in the dentulous group. No significant difference was noted in salivary calcium level of dentulous and edentulous patients. The mean salivary calcium concentration was 0.61 ± 0.3875 mmol/L in dentulous and 0.8025 ± 0.5975 mmol/L in edentulous patients. Salivary calcium level had a significant inverse correlation with salivary flow rate (r = –0.370, p = 0.027), and by every 1-unit increase in salivary flow rate, salivary level of calcium significantly decreased by 3.85 units.

Conclusion Edentate had averagely higher salivary calcium level compared to dentulous. The salivary concentration of calcium ion is not correlated to the presence or absence of teeth. Salivary flow rate reduces the calcium concentration.
Effect of Erbium:Yttrium-Aluminum-Garnet Laser Combined with Mineralizing Agents on Microhardness of Demineralized Dentin
Authors: Hajizadeh Hila , Nemati-Karimooy Atefeh , Babaee-Rishkhori Peiman
Published: June 2019

Objective The aim of this study was to assess the combined effect of erbium:yttrium-aluminum-garnet (Er:YAG) laser and mineralizing agents including casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride in improving the resistance of demineralized dentin at new demineralization process.

Materials and Methods One hundred and twenty healthy dentin surfaces were prepared and demineralized using acidic solutions. Primary microhardness was measured (h1), and samples were randomly divided into six groups. Each group received a different protocol as follows: Group A (control group): no additional treatment, Group B: applying a fluoridated gel, Group C: applying a CPP-ACP-containing cream, Group D: irradiation of Er:YAG laser, Group E: irradiation of Er:YAG laser combined with the application of a fluoridated agent, and Group F: irradiation of Er:YAG laser combined with the application of CPP-ACP-containing cream. Microhardness values were measured afterward (h2). Then, all the groups were re-exposed to acidic solution, and microhardness was measured for the third time (h3). The microhardness data were analyzed using analysis of variance and Scheffe's post hoc test.

Results Although application of mineralizing agents increased the microhardness of demineralized dentin in comparison with the control group, no significant difference was observed using two agents. Comparison of laser groups showed an increase in microhardness only after the irradiation of Er:YAG laser combined with the application of a fluoridated agent. Demineralizing process reduced the microhardness values in all the groups, but the application of a CPP-ACP agent caused the least reduction among the laser irradiated groups. Comparison of hardness changes at the beginning and end of the experiment did not show any significant differences between the groups.

Conclusion Comparison of treatment modalities used in this study exhibited that fluoride had the greatest impact on dentin resistance. Laser irradiation on demineralized dentin did not increase the hardness or resistance to acidic attacks.
Histomorphometric Comparative Analysis between Oral Dysplastic Potentially Malignant Disorders and Oral Squamous Cell Carcinoma
Authors: Pereira Natalia Da Silva , Pinheiro Tiago Novaes
Published: June 2019

Objective This study aimed to determine the correlation between the vascular mast cells and inflammatory changes in the potentially malignant disorders, compared to the oral squamous cell carcinoma (OSCC) in varying degrees of dysplasia.

Materials and Methods Thirty samples were selected: 10 of OSCC, 10 of oral leukoplakia, and 10 of actinic keratosis. The toluidine blue technique was used on the mast cells, and hematoxylin and eosin were used for analyzing the lymphocytes, mitosis, and vessels. The quantification was performed using the ImageJ software after obtaining the images by light microscopy with a × 40 objective. Analysis of variance with p < 0.05 was considered for statistical significance.

Results Mast cells (p < 0.0158), vessels (p < 0.9431), lymphocytes (p < 0.0001), and mitoses (p < 0.0009) were found in OSCC. In potentially malignant disorders, a lower density of these structures and a higher concentration of mitosis in the actinic keratosis were observed.

Conclusion The results showed evidence of a positive correlation between mast cells and vascularization in the OSCC, suggesting the aggression of the disease. Intense inflammatory infiltrate indicates that other molecular events are involved in the carcinogenesis process, and further studies are necessary for a better understanding of it.
Aged Translucent Aesthetic Zirconia: Bond Strength Analysis
Authors: Gallina Bernardo Luiz , Busato Mauro Carlos Agner , Sicoli Eliseu Augusto , Camilotti Veridiana , Mendonca Marcio Jose
Published: June 2019

Objective This study evaluates the bond strength of two compositions of aesthetic translucent zirconia (TZ).

Materials and Methods For this evaluation, test specimens were prepared from ICE Zirkon TZ and Prettau Anterior zirconia (PAZ) that were stored in distilled water at 37°C for two time periods: T1 (24 h) and T2 (90 days) to simulate aging. Two factors were evaluated for the samples—ceramic and aging time. The samples were subjected to tests of microshear strength and fracture type and were evaluated using scanning electron microscopy.

Results The results were analyzed using the D'Agostino test, analysis of variance, and Tukey's test (p < 0.01). Statistically significant differences were observed for ceramic type and aging time.

Conclusion The results showed that PAZ provides significantly superior performance to TZ at the two aging times evaluated.
Management of Postoperative Neurosurgical Patients
Authors: Panda Nidhi B. , Mahajan Shalvi , Chauhan Rajeev
Published: June 2019

Neurosurgical patients are a special subset of patients requiring postoperative care. Challenging neurosurgical disease processes, advanced surgical techniques, and unique individual patient requirements advocate the need for meticulous postoperative care to ensure safe transition toward recovery. Timely detection of systemic and neurological changes allows early diagnostic and therapeutic interventions. The mainstay of postoperative care revolves around airway, maintenance of hemodynamics, sedation, analgesia, nutrition, fluid management, and management of disease-specific complications. In addition to standard monitoring, multimodal neuromonitoring should be used in neurosurgical patients. Hence, four key elements in the postoperative management of neurosurgical patients involve profound insight, rapid response, good communication skills, and team collaboration.
Topical Use of Tranexamic Acid in Cardiac Surgery: A Meta-Analysis
Authors: Habbab Louay M. , Semelhago Lloyd , Lamy André
Published: June 2019

Background This meta-analysis was conducted to investigate the evidence for the efficacy and safety of intrapericardial tranexamic acid (TXA) in cardiac surgery.

Methods We searched MEDLINE from 2000 to 2017 for randomized controlled trials that compared intrapericardial TXA to placebo. We performed a meta-analysis for the eligible trials that focused on chest tube drainage measured during the first 24 hours after surgery as a primary outcome. We also examined the secondary outcome measures of these trials such as the incidence of transfusion requirements following surgery and the evidence for any increase in complication rates.

Results A total of seven randomized controlled trials (six on-pump and one off-pump) comparing topical application of TXA to placebo in 692 patients were eligible for the blood loss outcome data. These trials randomized 372 patients to receive TXA and 320 patients as controls. The use of intrapericardial TXA was associated with a considerable reduction in 24-hour blood loss in all seven studies and a weighted mean difference of −343.56 mL (95% confidence interval: −316.41, −370.72) significantly differed from zero (p = 0.005) with a heterogeneity of I
2 = 0%. The incidence of packed RBC transfusion in TXA patients was significantly lower in one study and was not significant but with trend in favor of TXA in five out of the six studies in which it was reported. In one trial, TXA was not detected in any patient and in another the studied groups were similar in postoperative complications, such as graft patency, myocardial infarction, cerebral infarction, atrial fibrillation, seizures, and infections.

Conclusions Findings from this meta-analysis suggest that intrapericardial use of TXA in patients undergoing cardiac surgery can decrease postoperative bleeding without increasing the risk of postoperative seizures. Future large randomized, double-blind, controlled clinical trials are needed to confirm these promising findings.
Reporting Practices on Immunosuppression and Rejection Management in Face Transplantation: A Systematic Review
Authors: Daneshgaran Giulia , Stern Carrie S. , Garfein Evan S.
Published: June 2019

Background Face transplantation is a demanding operation requiring complex planning and expert technical performance. While the documentation of successes of the first transplants is impressive, there are lacunae in reporting of institutional protocols for other critical operation components, namely, immunosuppression, graft surveillance, and management of rejection and graft failure. The purpose of this review is to assess protocol reporting by face transplant teams to determine where we, as a plastic surgery community, can improve.

Methods A systematic review of PubMed was conducted to identify literature on face transplants published from November, 2005, starting with the first successful transplant to December, 2018. English-language articles were reviewed for reporting of protocols on antimicrobial prophylaxis, immunosuppression, graft surveillance, and management of rejection and graft failure.

Results A total of 44 face transplantation patients were identified. Protocols for antimicrobial prophylaxis, immunosuppressive induction, and maintenance immunosuppression were reported for 61%, 75%, and 73% of patients, respectively. Protocols for graft surveillance and medical management of rejection were reported for 70% of patients in both cases. Surgical salvage strategies to manage graft failure were documented for 43% of patients.

Conclusion The current literature on face transplantation does not include consistent reporting on critical aspects of patient care. Medical protocols outlining guidelines for immunosuppression, graft surveillance, and management of rejection and graft failure are the most critical factors determining overall transplant success. However, they are underreported in the literature. Development and communication of standardized protocols is essential to improve patient outcomes and maximize the results of this procedure.
Testosterone is Key to Increase the Muscle Capillary Density of Old and Trained Rats
Authors: Krause Neto Walter , Silva Wellington de Assis , Silva Amanda dos Santos da , Ciena Adriano Polican , Souza Romeu Rodrigues de , Carbone Patricia Oliva , Anaruma Carlos Alberto , Gama Eliane Florencio
Published: June 2019

Introduction It is indicated that aging reduces muscular vascularity. Thus, strategies that aim to reverse or decrease the progression of these changes are suggested. Therefore, the present study aimed to analyze the blood capillary density of the plantaris muscle (PL) of aged rats submitted to strength training and exogenous testosterone use.

Methods A total of 30 rats were divided equally into the following groups: EA: 20 months old; OLD: 24 months old; OLD + S: testosterone; ST: strength training; and ST + S: strength training + testosterone. Strength training was performed 3 times a week for 15 weeks. Testosterone administration was performed by the intraperitoneal method 2 times a week at a dose of 10mg/kg. All of the morphological parameters were analyzed using morphoquantitative techniques.

Results A significant increase in the capillaries numerical density of the OLD + S and ST + S groups. The OLD + S and ST + S groups demonstrated a higher ratio of capillaries per myofiber than the EA, OLD and ST groups. The OLD and ST groups had a higher ratio than the EA group. The OLD + S, ST and ST + S groups presented a statistically significant increase in the cross-sectional area in the type I fibers when compared with the EA and OLD groups. However, the ST group showed a significant increase compared with the OLD group. In type II fibers, the ST and ST + S groups showed a greater cross-sectional area than the EA group. As for the mean cross-sectional area, the ST and ST + S groups presented significantly larger areas than the other groups.

Conclusion Anabolic steroid administration is crucial to increase the blood capillary density of the plantaris muscle of old rats, independently of the effects of strength training.
Phase Contrast MRI Suggests an Internal Carotid Vascular Tone Alteration in Migraines
Authors: Deverdun Jeremy , Leboucq Nicolas , Pfeuffer Josef , Rivier François , Bousquet Elisa , Benali Amel , Le Bars Emmanuelle
Published: June 2019

Introduction Migraine is the most common neurological disorder and the third most common disease worldwide. However, the underlying mechanisms contributing to its development are not completely understood. Symptoms may arise from a combination of dilation-independent vascular events and neurogenic mechanisms interacting throughout the brain and within the trigeminovascular system in the meninges

Materials and method We report here a case of a patient with a suspected familial hemiplegic migraine who presented an increased recurrence of events from one per month to one every other day. Three magnetic resonance imaging (MRI) acquisitions were performed after the appearance of a strong crisis which included a paresthesia and aphasia along with headaches. Two MRIs were performed close to the crisis, while the last one was done 1 month later.

Results During the crisis, cerebral perfusion exhibits incoherent results. Blood velocity measurements highlight a strong phase lag between left internal carotid artery (ICA) and basilar artery and more importantly right ICA. After a month, parameters came back to standard values.

Conclusion The transitory nature of the observed modifications suggests a reversible alteration of the vascular tone of the ICA in patients with migraine. This alteration seems to follow recovery pattern of the patient.
Outcome and Feasibility after 7 Years of Therapeutic Hypothermia in Southern Brazil
Authors: Procianoy Renato S. , Corso Andrea L. , Schoenardie Bruna O. , de Oliveira Georgia P.F. , Longo Maria G. , Silveira Rita C.
Published: June 2019

Objective This study aimed to describe the experience with a protocol of therapeutic hypothermia (TH) in southern Brazil.

Study Design Newborns with gestational age > 35 weeks with evidence of perinatal asphyxia plus moderate or severe encephalopathy were recruited between March 2011 and November 2017. Whole-body hypothermia for 72 hours, starting within the first 6 hours of life was used. Survivors underwent magnetic resonance imaging (MRI) and electroencephalogram (EEG). The primary outcome was death during hospitalization and neurodevelopment assessed using the Bayley Scales of Infant Development III (BSID III) at 12 months of age.

Results A total of 72 newborns were treated (41 with moderate encephalopathy and 31 with severe encephalopathy), of whom 16 died. MRI was performed in 56 patients, and 24 presented some alterations. Fifty-three patients had an EEG: 11 normal, 20 mildly altered, 12 moderately altered, and 10 severely altered. Forty patients were evaluated through BSID III: 45% presented with some delay in neurodevelopment, 8 (20%) had motor retardation, 15 (37.5%) had language delay, and 13 (32.5%) had a delay in cognitive development.

Conclusion Mortality and adverse events were similar to those described in large randomized controlled trials. TH is a safe and an effective method of neurologic protection in asphyxiated newborns in a developing country when performed adequately.
Evaluating Relationships between Visceral Fat Measures and Adipokines Concentrations among Women with a History of Preeclampsia
Authors: Chandrasekaran Suchitra , Barry Darcy , Melhorn Susan , Easterling Thomas , Gammill Hilary , Schur Ellen
Published: June 2019

Objective We sought to evaluate associations between postpartum plasma adipokine concentrations among women with a history of preeclampsia (PE) without severe features (MPE), PE with severe features (SPE), and no PE (NPE). We also investigated relationships between adipokines and computed tomography (CT)-quantified measures of visceral fat (VF) area (VFA) and subcutaneous fat area (SCFA).

Study Design We performed a secondary analysis of data collected as part of a previously performed cross-sectional study at our institution. Women with and without a history of PE were recruited in 10 years after delivery. VFA and SCFA measures were performed by CT scan. Anthropometric data and peripheral blood samples from subjects were collected concurrently.

Results Plasma adiponectin concentrations (µg/mL) were significantly lower among MPE (18.5 ± 7.1) compared with NPE (27.3 ± 13.8) and SPE (25.7 ± 9.6). Leptin (p = 0.32) and resistin (p = 0.93) concentrations were similar among the groups. Adiponectin concentrations more closely aligned with VFA (β = −0.001, p = 0.03), while resistin concentrations trended toward correlating with SCFA (β = 0.02, p = 0.05). Leptin was not preferential to VFA or SCFA.

Conclusion VF distribution may contribute to the variation in PE phenotype. Adiponectin specifically may be a promising marker representing VFA.
Trail-mediated self-interaction
Authors: Kranz W. Till , Golestanian Ramin
Published: June 2019

A number of microorganisms leave persistent trails while moving along surfaces. For single-cell organisms, the trail-mediated self-interaction will influence the dynamics. It has been discussed recently [Kranz et al., Phys. Rev. Lett. 117, 038101 (2016)] that the self-interaction may localize the organism above a critical coupling χc to the trail. Here, we will derive a generalized active particle model capturing the key features of the self-interaction and analyze its behavior for smaller couplings χ < χc. We find that fluctuations in propulsion speed shift the localization transition to stronger couplings.
A fuzzy artificial neural network-based method for Cerenkov luminescence tomography
Authors: Wei Xiao , Lu Di , Cao Xin , Su Linzhi , Wang Lin , Guo Hongbo , Hou Yuqing , He Xiaowei
Published: June 2019

Cerenkov Luminescence Tomography (CLT) is a non-invasive three-dimensional in vivo detection technology. However, due to the ill-posedness of CLT, the reconstructed result has many artifacts, which will mislead the researchers to make a wrong diagnostic decision. Enlightened by the development of artificial neural networks, we proposed a Fuzzy Autoencoder Clustering method to eliminate these artifacts and improve the reconstruction quality. To assess the performance of our method, several numerical simulation experiments and real physical phantom experiments are conducted. Compared with the raw reconstruction results and the commonly used manual threshold processed ones, it is demonstrated that our method is capable of filtering the artifact areas effectively, making reconstruction results clearer. It is anticipated that the method presented in this paper will help advance the CLT technology and promote the clinic translation of CLT technology.
Dynamics of quantized vortex filaments under a local induction approximation with second-order correction
Authors: Horner Christopher L. , Van Gorder Robert A.
Published: June 2019

We study a second-order local induction approximation (LIA) for the dynamics of a single open quantized vortex filament (such as those filaments arising in superfluid helium). While for a classical vortex filament, this second-order correction can be interpreted as a correction due to the inclusion of axial flow within a filament core, in the quantized filament case, this second order correction can be viewed as a correction due to variable condensate healing length. We compare the evolution of the decay rate, transverse velocity, and rotational velocity of Kelvin waves along vortex filaments under this model to that of the first order LIA of Schwarz for quantized vortex filaments, as well as to a corresponding nonlocal model involving Biot-Savart integrals for the self-induced motion of the vortex filament. For intermediate wavenumbers, the second-order model solutions show improved agreement with the nonlocal Biot-Savart model, due to an additional control parameter. We also consider the stability of Kelvin waves under the second-order corrections; these results allow us to understand the Donnelly-Glaberson instability in the context of the second-order model. The second-order corrections tend to stabilize the resulting solutions, in agreement with what was previously found from the nonlocal Biot-Savart formulation, yet still permit a local description of the vortex filament in terms of a partial differential equation (akin to the first-order LIA) rather than an integro-differential equation.
Growth and fabrication of GaN/Er:GaN/GaN core-cladding planar waveguides
Authors: Sun Z. Y. , Yan Y. Q. , Smith T. B. , Zhao W. P. , Li J. , Lin J. Y. , Jiang H. X.
Published: June 2019

Erbium doped gallium nitride (Er:GaN) bulk crystals have emerged as a promising optical gain material for high energy lasers (HELs) operating at the 1.5 μm “retina-safe” spectral region. Among the many designs of HEL gain medium, the core-cladding planar waveguide (PWG) structure is highly desired due to its abilities to provide excellent optical confinement and heat dissipation. We report the realization of a GaN/Er:GaN/GaN core-cladding PWG structure synthesized by hydride vapor phase epitaxy and processed by mechanical and chemical-mechanical polishing. An Er doping concentration of [Er] = 3 × 1019 atoms/cm3 has been attained in the core layer, as confirmed by secondary ion mass spectrometry measurements. A strong 1.54 μm emission line was detected from the structure under 980 nm resonant excitation. It was shown that these PWGs can achieve a 96% optical confinement in the Er:GaN core layer having a thickness of 50 μm and [Er] = 3 × 1019 atoms/cm3. This work represents an important step toward the realization of practical Er:GaN gain medium for retina-safe HEL applications.
Drag enhancement and turbulence attenuation by small solid particles in an unstably stratified turbulent boundary layer
Authors: Li Dong , Luo Kun , Wang Zhuo , Xiao Wei , Fan Jianren
Published: June 2019

Point-particle direct numerical simulations of particle-laden flows have been conducted to investigate the complex coupling between inertial particles, buoyancy force, and strong shear flows in an unstably stratified turbulent boundary layer over a flat plate. Two-way coupling and particle-particle collisions, i.e., four-way coupling, are considered in the dilute gas-solid flows. The simulation results indicate that the presence of inertial particles with diameter smaller than the Kolmogorov length scale tends to reduce the thermal displacement thickness and enthalpy thickness, while increasing the mean skin-friction coefficient and Nusselt number. The feedback force exerted by the particles on the fluid is found to contribute largely to the drag enhancement. The turbulence intensities and temperature fluctuations are significantly attenuated in the particle-laden flows with respect to the unladen flow. The budgets of the turbulent kinetic energy show that the particles have direct and indirect effects on the modulation of turbulence. On the one hand, the production and the viscous dissipation rate are suppressed by the particles in most regions of the boundary layer. On the other hand, the particle-turbulence interactions produce an extra energy source in the inner layer, while causing an additional energy sink in the outer layer of the boundary layer. These combined effects lead to the pronounced turbulence attenuation observed in this study.
Flow pattern of double-cavity flow at high Reynolds number
Authors: Goltsman Anna , Saushin Ilya
Published: June 2019

The flow structure in a turbulent double-cavity flow has been studied experimentally and numerically. The dynamics of the two-component instantaneous velocity vector fields measured by an optical smoke image velocimetry method and calculated using the ANSYS Fluent 19.2 software has been derived. For a wide range of dynamic similarity numbers of shape factor and ReL, the flow resistance coefficients for the cavity and relative flow mass transfer with the cavities have been estimated; three characteristic flow regimes of double-cavity flow have been distinguished and described; the flow pattern map via the ReL number and shape factor has been obtained.
On the focusing enhancement of Soret zone plates with ultrasound directional transducers
Authors: Pérez-López Sergio , Fuster José Miguel , Candelas Pilar , Rubio Constanza
Published: June 2019

This work analyzes the influence of the distribution of transparent Fresnel regions over the focusing profile of Soret Zone Plates. It is shown that this effect becomes very significant in those fields where directional transducers are employed, such as microwaves or acoustics. A thorough analysis on both the lens transmission efficiency and the focusing enhancement factor is presented. Moreover, experimental measurements are also carried out, validating the theoretical model and demonstrating that the distribution of transparent Fresnel regions becomes a critical parameter in applications requiring directional emitters.
Modeling of surface gap state passivation and Fermi level de-pinning in solar cells
Authors: Lu Haichang , Guo Yuzheng , Li Hongfei , Robertson John
Published: June 2019

The behavior of gap states due to coordination defects (e.g., dangling bonds) and metal induced gap states (MIGS) is compared using density functional supercell calculations. While both types of gap states cause carrier recombination, they are passivated in different ways. Defects can be passivated by shifting their states out of the gap, whereas MIGS lie on normally coordinated atoms and their states cannot be shifted. Their “passivation” requires the insertion of an insulating layer to attenuate them sufficiently before they enter the semiconductor. We show that MIGS also cause Fermi level pinning, inhibiting the control of the work function by the contacts, and so they must also be attenuated to enable certain solar cell designs.
The critical role of honeyeaters in the pollination of the catspaw Anigozanthos humilis (Haemodoraceae)
Authors: van der Kroft Tayla , Roberts David G. , Krauss Siegfried L.
Published: June 2019

The pollination biology of Anigozanthos humilis (Haemodoraceae) was studied within a Banksia woodland reserve using a combination of field techniques and genetic analysis. Motion-triggered cameras were deployed on 25 flowering plants to identify visitors to flowers, quantify visitation rates and assess visitor behaviour. Entire A. humilis plants were caged to exclude potential floral visitors with six treatments: (i) bird and honey possum exclusion, allowing access by insects; (ii) bird and insect exclusion, allowing access by honey possums; (iii) total animal exclusion; (iv) open, allowing access by birds, insects and honey possums; (v) hand-pollination with cross-pollen; and (vi) hand-pollination with self-pollen. Open pollinated seed were genotyped to assess mating system parameters including outcrossing rate. From 23424 h of surveillance with camera traps, 109 visits were recorded, 106 (97%) of which were western spinebills (Acanthorhynchus superciliosus), with three visits by brown honeyeaters (Lichmera indistincta). We recorded an average of 8 (±4) visits per plant, equivalent to one visit every eleven days over the 2016 flowering season (mean = 63 days). Mean seed set per fruit was negligible (0.2–0.3 seed per fruit) for all pollination treatments except open- and hand-pollination with cross pollen. Mean seed set per fruit for hand cross-pollinated flowers (37.1 seed per fruit) was 37 times that of open pollinated flowers (1.0 seed per fruit). Outcrossing rate estimates were not significantly different to one. Our results indicate that at least for the study population and season, A. humilis was largely dependent on western spinebills for delivery of outcross pollen and resulting seed set, but visitation rates were low and pollen limitation was severe. Given the known sensitivity of western spinebills to habitat fragmentation, our results suggest flow on effects that may negatively impact on reproduction, and means that A. humilis may be particularly vulnerable to environmental changes that impact on bird pollinators.
Segmentation into intonational periods
Authors: Lacheret-Dujour Anne , Victorri Bernard
Published: June 2019

This chapter focuses on the processing of the major prosodic unit, called intonational period, in Rhapsodie. We explain why the grammatical concept of sentence cannot be taken as a reference for the segmentation of unelicited speech into major prosodic units. Rather we show that in order to segment an utterance into major prosodic units in the context of an emergent data-driven approach, it is necessary to highlight accurate acoustic cues that produce perceptual effects of demarcation between two units. First, we present the Analor model developed to segment discourse into intonational periods, in particular the different parameters selected for segmentation, and how they interact. Second, we illustrate the choices made to process fillers, disfluencies, and also to resolve problems of segmentation derived from overlaps and backchannels in dialogic samples.
From pitch stylization to automatic tonal annotation of speech corpora
Authors: Mertens Piet
Published: June 2019

This chapter proposes a labeling scheme for pitch-related aspects of speech prosody and describes an automatic annotation system using this scheme.

In the labelling scheme, the fine-grained transcription provides labels indicating the pitch level and pitch movement of individual syllables. The pitch levels “bottom” and “top” indicate the boundaries of the speaker’s pitch range. Three additional levels – “low”, “mid”, “high” – are defined on the basis of pitch changes in the local context. For pitch movements, both simple and compound, the transcription indicates direction (rise, fall, level) and size (large and small melodic intervals), using size categories adjusted to the speaker’s pitch range.

The automatic tonal annotation system combines several processing steps: segmentation into syllabic nuclei, pause detection, pitch stylization, pitch range estimation, pitch movement classification, and pitch level assignment. It uses a rule-based procedure, which unlike commonly used supervized learning techniques does not require a labelled corpus to train the model.
Exploration of the Rhapsodie corpus
Authors: Lacheret-Dujour Anne , Kahane Sylvain , Bawden Rachel , Fleury Serge , Wang Ilaine
Published: June 2019

This chapter describes the data structure of the Rhapsodie Treebank and discusses methodological issues stemming from the complexity of this structure, articulated around three independent, non-aligned, hierarchies: Microsyntactic, macrosyntactic and prosodic, and the challenging questions to be resolved in this context. It discusses the specific problems posed by the simultaneous processing of the phonological stream (prosodic level) and the orthographic stream (syntactic level), which are often far from being isomorphic in French, and the related problem of the processing of disfluent and/or overlapped strings, which have not the same representation in the syntactic and the prosodic hierarchy. Then, it presents the formats adopted to encode prosodic and syntactic annotations and query them simultaneously, given that the prosodic architecture is a non-recursive time-aligned representation while the syntactic one is a recursive tree-based representation.
Validation of the tail replacement method in MTF calculations using the homogeneous and non-homogeneous edges of a phantom
Authors: Anam C , Budi WS , Fujibuchi T , Haryanto F , Dougherty G
Published: June 2019

We validated the tail replacement technique in the modulation transfer function (MTF) calculation of CT images using edges of homogeneous and non-homogeneous phantom using an automated method. The algorithm for the automated MTF calculation consists of several steps. The upper edge of the phantom was detected from its axial image and pixel values was taken to create an edge spread function (ESF). The left tail of the ESF was flipped horizontally to replace the right tail. Differentiating the ESF produced a line spread function (LSF) which was Fourier transformed to produce the MTF. To validate the result for the non-homogeneous phantom was compared with that for a homogeneous phantom. Results showed that in the homogeneous module, the MTF curve generated without tail replacement corresponded to its shape in use. However for the non-homogeneous module, the MTF obtained without tail replacement differed considerably from its shape in use. The 50% value of MTF (MTF-50) without tail replacement was 0.44 cycles/mm compared to 0.33 cycles/mm in use. Using the tail replacement, the MTFs in the homogeneous and non-homogeneous modules were comparable, with MTF-50 values of 0.33 cycles/mm for both. In summary, the MTF cannot be conventionally measured from the edge of the non-homogeneous module, but it can be resolved using the tail replacement technique on the ESF curve.
Resting-state fMRI: comparing default mode network connectivity between normal and low auditory working memory groups
Authors: Othman E A , Yusoff A N , Mohamad M , Abdul Manan H , Abd Hamid A I , Dzulkifli M A , Osman S S , Wan Burhanuddin W I D
Published: June 2019

The relationship between resting effective connectivity (EC) among default mode network (DMN) regions and auditory working memory (AWM) performance is still poorly understood. In this work, resting-state functional magnetic resonance imaging (rsfMRI) was used to determine the optimum connectivity model between posterior cingulate cortex (PCC) and medial prefrontal cortex (mPFC) in 40 healthy male volunteers. in low and normal working memory groups of subjects. Correlation between EC with AWM performance and AWM-capacity was also studied. The participants were divided into two groups which are normal and low AWM-capacity groups based on Malay Version Auditory Verbal Learning Test. The AWM performance was assessed using a word-based backward recall task. Both assessments were conducted outside the MRI scanner. The participants were scanned using a 3-T MRI system and the data were analyzed using statistical parametric mapping (SPM12) and spectral Dynamic Causal Modelling (spDCM). Results revealed that PCC and mPFC were significantly interconnected in both groups. Group analyses showed that the connection between PCC and mPFC exhibits an anti-correlated network. The results also indicated that the AWM performance and AWM-capacity were not associated with EC. These findings suggest that EC at rest between the two regions may not significantly influence cognitive abilities important for this AWM task.
Optimization of digital radiography system using in-house phantom: preliminary study
Authors: Hariyati I , Hani A D F , Craig L A , Lestariningsih I , Lubis L E , Soejoko D S
Published: June 2019

The purpose of this study was to obtain information on optimum exposure parameter combination on simulated thorax and abdomen examinations using Direct-Digital Radiography (DR) and Computed Radiography (CR) systems. An in-house phantom dedicated for quick QC was utilized as an image quality quantification tool in term of contrast. The optimization was performed on Philips Essenta DR, CR Fuji Profect CS, and CR Agfa 10-X. Exposures were performed using corresponding clinical setting with combinations of kVp, mAs, filters, and a variation of simulated patient thicknesses. The Figure of Merit (FOM) was employed as optimization parameter, calculated as ratio of squared Signal Difference to Noise Ratio (SDNR) and surface dose for every measurement. The image quality was evaluated using Modulation Transfer Function (MTF) and Contrast Consistency (CV). Based on FOM, MTF, and CV calculations, acquisitions optimization for thorax examination using DR was obtained on 55-63 kVp, 5-8 mAs, with additional filter 1 mm Al + 0.1 mm Cu. For abdomen examination, the optimized results were 81-102 kVp, 8-12.5 mAs, with additional filters 1 mm Al+0.1 mm Cu and 1 mm Al+0.2 mm Cu. On the other hand, the optimized results using CR on thorax examination were on the range of 55-63 kV, 4-8 mAs, also with the same additional filters with DR. The results of optimization of abdomen examination were on the range of 85-102 kV, 8-20 mAs, and again with the same additional filters. This gave information that different receptors used on the same x-ray unit produced almost similar optimization conditions.
Using in-house quick-QC phantom to characterize computed and direct digital radiography: a preliminary study
Authors: Rahman I N F , Fajar M I , Aini N , Febrianti R H , Lestariningsih I , Gani M R A , Lubis L E , Soejoko D S
Published: June 2019

In this study, two CR receptors (Agfa CR-85X and Agfa CR-10X) and two DDR receptors (Brivo DR-F and Essenta) were characterized in terms of detector sensitivity and image quality. An in-house phantom was specially designed to accommodate image quality assessment for quick QC and is tested as a purpose of this study. The reference quantitative aspect that were used to characterize the imaging units are the correlation between Pixel Value and image receptor dose, whereas evaluation of image quality based on the modules on the in-house phantom uses new proposed metrics (coefficient of linearity, CL, and coefficient of variance, CV). Each system’s unique Pixel Value-dose characteristics are also expressed in the results of the in-house phantom’s metrics (i.e. CL and CV). In addition, the constancy of measured modulation transfer function suggests potential use for system quality judgment. As all characterizations (Pixel Value-dose characteristics, MTF, and new metrics) indicated on unique result for each systems, the study implies that the designed in-house phantom as well as its proposed metric can be promising to be used to characterize digital radiography systems during quick QC.
Factors affecting standardized uptake value of 99mTc-MDP bone SPECT/CT: A phantom study
Authors: Myint TT , Ekjeen T , Chaichana A , Tipparoj R , Wiyaporn K
Published: June 2019

Currently, state-of-the-art SPECT/CT with 3D reconstruction allows for quantitative data that can be represented as standardized uptake value (SUV). However, there are a number of factors that affect the value. The goal of this study was to investigate the factors affecting SUV of 99mTc-MDP bone SPECT/CT. A NEMA phantom with 99mTc-MDP background activity concentration of 18 kBq/ml and tumor to background ratio of 4:1 were studied. The data were acquired based on clinical bone SPECT/CT imaging protocol and OS-EM algorithm with compensation for attenuation, scatter and resolution recovery was applied using 10 subsets and varying iterative numbers from 1 to 5. SUVs (SUVmean and SUVmax) were measured for each sphere using Q.Metrix software. Moreover, three cut-off frequencies of Butterworth filter including 0.35, 0.48 and 0.65 cycle/cm with order of 10 were investigated at 20 iterative updates. The percentage of difference of both SUVs for each sphere was calculated. Both SUVs tended to increase when the iterative update of the OS-EM and cut-off frequency of Butterworth filter were increased. Measurement of SUVs from SPECT/CT is feasible. However, the iterative update, cut-off frequency and sphere size can affect both SUVs.
Preliminary study of ring artifact detection in SPECT imaging using Jaszczak phantom
Authors: Oktaviana A T , Pawiro S A , Siswatining T , Soejoko D S
Published: June 2019

Inspection of imaging SPECT system performance was controlled by Quality Control (QC) regularly. Tomographic imaging parameters in QC, i.e. homogeneity, contrast, and spatial resolution should be tested. These results make it reliable whether the SPECT system will be used. The modular Jaszczak phantom was used for that purpose, as it offers the investigation to all three parameters with a single measurement. Compared to the contrast and spatial resolution, an objective identification of possible ring artifact in the homogeneity is challenging. Artifact simulation of SPECT images which have been generated by disturbance of 4 × 4 cm2 copper sheet located on surface LEHR collimator have been conducted to study the detectability of ring artifact. Uniformity section of Jaszczak phantom which filled with 99mTc was used for acquisition. The confirmed ring artifact was analyzed by Edge Detection and Circle Hough Transform provided by imageJ, and students t-test statistically. From the evaluation by edge detection and circle Hough transform, the present of ring artifact only detected in artifact SPECT images using 1.00, 0.75, and 0.50 mm copper sheet thickness, while in t-test method all copper sheet thickness (including 0.25 mm) detect ring artifact in images.
Performance evaluation of line scanning method in proton therapy
Authors: Azuma Y , Tateoka K
Published: June 2019

Proton therapy system (Sumitomo Heavy Industries, Ltd.) in Sapporo Teishinkai Hospital consists of a cyclotron, a rotating gantry and a multi-purpose nozzle. This nozzle can irradiate both wobbler beam and line scanning beam. Performance of line scanning was evaluated in this study. The authors investigated for items related to the beam delivery. Dose linearity was investigated with a water phantom and a large parallel plate chamber with several dose rates. For evaluation of irradiation time precision, a solid water phantom and the large parallel plate chamber were used. Furthermore, several spot patterns were measured by Scintillator/CCD camera system for the estimation of beam position. Dose linearity is found with less than 1.8 % error with varying conditions. Regarding irradiation time, error is also confirmed with less than about 1.4 % in this measurement. Beam position accuracy and beam size constancy is also precise enough to be used in clinical use. In conclusion, it is found that results in this study are good enough for treatment.
Monte Carlo MCNP-based simulation and radiation measurement of Yttrium-90 bremsstrahlung produced from radiation shielding apparatus
Authors: Onnomdee C , Jumpee C , Channuie J , Sinkaew P , Chuamsaamarkkee K , Charoenphun P
Published: June 2019

Yttrium-90 (90Y) has been widely used in therapeutic nuclear medicine including in the selective internal radiation therapy with 90Y-microsphere. In the procedure 90Y source is protected within the radiation shielding apparatus made of perspex. However, bremsstrahlung radiation may be generated when 90Y interacts with matter. The aim of this study was to evaluate bremsstrahlung radiation produced from radiation shielding apparatus using a scintillation detector and Monte Carlo simulation. The 90Y source in glass vial was placed in the radiation shielding apparatus. Bremsstrahlung measurement and spectrum were performed and recorded using thallium-doped sodium iodide (NaI(Tl)) scintillation detector. Counting time and distance between the detector and apparatus were varied to obtain the optimal condition for bremsstrahlung measurement. Monte Carlo N-Particle (MCNP) 5 was used to simulate bremsstrahlung radiation with the same geometry used in the measurement. For experimental measurement results, the optimal distance and counting time were 10 cm and 120 s, respectively. Although the result of bremsstrahlung spectrum from the detector and simulation exhibited similar trend, markedly greater count rate was observed in simulations than in detector measurements. In conclusion, 90Y bremsstrahlung can be produced from radiation protection apparatus and this can be evaluated by either measurement or simulation.