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To compare capabilities of compressed sensing (CS) with and without deep learning reconstruction (DLR) with those of conventional parallel imaging (PI) with and without DLR for improving examination time and image quality of shoulder MRI for patients with various shoulder diseases.Thirty consecutive patients with suspected shoulder diseases underwent MRI at a 3 T MR system using PI and CS. All MR data was reconstructed with and without DLR. For quantitative image quality evaluation, ROI measurements were used to determine signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). For qualitative image quality assessment, two radiologists evaluated overall image quality, artifacts and diagnostic confidence level using a 5-point scoring system, and consensus of the two readers determined each final value. Tukey's HSD test was used to compare examination times to establish the capability of the two techniques for reducing examination time. All indexes for all methods were then compared by means of Tukey's HSD test or Wilcoxon's signed rank test.CS with and without DLR showed significantly shorter examination times than PI with and without DLR (p 0.05). SNR and CNR of CS or PI with DLR were significantly higher than of those without DLR (p 0.05). Use of DLR significantly improved overall image quality and artifact incidence of CS and PI (p 0.05).Examination time with CS is shorter than with PI without deterioration of image quality of shoulder MRI. Moreover, DLR is useful for both CS and PI for improvement of image quality on shoulder MRI.

Purpose Using CT findings from a prospective, randomized, open-label multicenter trial of favipiravir treatment of COVID-19 patients, the purpose of this study was to compare the utility of machine learning (ML)-based algorithm with that of CT-determined disease severity score and time from disease onset to CT (i.e., time until CT) in this setting. Materials and methods From March to May 2020, 32 COVID-19 patients underwent initial chest CT before enrollment were evaluated in this study. Eighteen patients were randomized to start favipiravir on day 1 (early treatment group), and 14 patients on day 6 of study participation (late treatment group). In this study, percentages of ground-glass opacity (GGO), reticulation, consolidation, emphysema, honeycomb, and nodular lesion volumes were calculated as quantitative indexes by means of the software, while CT-determined disease severity was also visually scored. Next, univariate and stepwise regression analyses were performed to determine relationships between quantitative indexes and time until CT. Moreover, patient outcomes determined as viral clearance in the first 6 days and duration of fever were compared for those who started therapy within 4, 5, or 6 days as time until CT and those who started later by means of the Kaplan–Meier method followed by Wilcoxon’s signed-rank test. Results % GGO and % consolidation showed significant correlations with time until CT (p p p = 0.008). Conclusion ML-based CT texture analysis is equally or more useful for predicting time until CT for favipiravir treatment on COVID-19 patients than CT disease severity score.

Background Pulmonary MRI with ultrashort echo time (UTE) has been compared with chest CT for nodule detection and classification. However, direct comparisons of these methods' capabilities for Lung CT Screening Reporting and Data System (Lung-RADS) evaluation remain lacking. Purpose To compare the capabilities of pulmonary MRI with UTE with those of standard- or low-dose thin-section CT for Lung-RADS classification. Materials and Methods In this prospective study, standard- and low-dose chest CT (270 mA and 60 mA, respectively) and MRI with UTE were used to examine consecutive participants enrolled between January 2017 and December 2020 who met American College of Radiology Appropriateness Criteria for lung cancer screening with low-dose CT. Probability of nodule presence was assessed for all methods with a five-point visual scoring system by two board-certified radiologists. All nodules were then evaluated in terms of their Lung-RADS classification using each method. To compare nodule detection capability of the three methods, consensus for performances was rated by using jackknife free-response receiver operating characteristic analysis, and sensitivity was compared by means of the McNemar test. In addition, weighted κ statistics were used to determine the agreement between Lung-RADS classification obtained with each method and the reference standard generated from standard-dose CT evaluated by two radiologists who were not included in the image analysis session. Results A total of 205 participants (mean age: 64 years ± 7 [standard deviation], 106 men) with 1073 nodules were enrolled. Figure of merit (FOM) (

Since thoracic MR imaging was first used in a clinical setting, it has been suggested that MR imaging has limited clinical utility for thoracic diseases, especially lung diseases, in comparison with x-ray CT and positron emission tomography (PET)/CT. However, in many countries and states and for specific indications, MR imaging has recently become practicable. In addition, recently developed pulmonary MR imaging with ultra-short TE (UTE) and zero TE (ZTE) has enhanced the utility of MR imaging for thoracic diseases in routine clinical practice. Furthermore, MR imaging has been introduced as being capable of assessing pulmonary function. It should be borne in mind, however, that these applications have so far been academically and clinically used only for healthy volunteers, but not for patients with various pulmonary diseases in Japan or other countries. In 2020, the Fleischner Society published a new report, which provides consensus expert opinions regarding appropriate clinical indications of pulmonary MR imaging for not only oncologic but also pulmonary diseases. This review article presents a brief history of MR imaging for thoracic diseases regarding its technical aspects and major clinical indications in Japan 1) in terms of what is currently available, 2) promising but requiring further validation or evaluation, and 3) developments warranting research investigations in preclinical or patient studies. State-of-the-art MR imaging can non-invasively visualize lung structural and functional abnormalities without ionizing radiation and thus provide an alternative to CT. MR imaging is considered as a tool for providing unique information. Moreover, prospective, randomized, and multi-center trials should be conducted to directly compare MR imaging with conventional methods to determine whether the former has equal or superior clinical relevance. The results of these trials together with continued improvements are expected to update or modify recommendations for the use of MRI in near future.

We studied the Z/E preference of N-phenylthioacetamide (thioacetanilide) derivatives in various solvents by means of 1H NMR spectroscopy, as well as molecular dynamics (MD) and other computational analyses. Our experimental results indicate that the Z/E isomer preference of secondary (NH)thioamides of N-phenylthioacetamides shows substantial solvent dependency, whereas the corresponding amides do not show solvent dependency of the Z/E isomer ratios. Detailed study of the solvent effects based on molecular dynamics simulations revealed that there are two main modes of hydrogen (H)-bond formation between solvent and (NH)thioacetamide, which influence the Z/E isomer preference of (NH)thioamides. DFT calculations of NH-thioamide in the presence of one or two explicit solvent molecules in the continuum solvent model can effectively mimic the solvation by multiple solvent molecules surrounding the thioamide in MD simulations and shed light on the precise nature of the interactions between thioamide and solvent. Orbital interaction analysis showed that, counterintuitively, the Z/E preference of NH-thioacetamides is mainly determined by steric repulsion, while that of sterically congested N-methylthioacetamides is mainly determined by thioamide conjugation.

Computed diffusion-weighted imaging (cDWI) is a mathematical computation technique that generates DWIs for any b-value by using actual DWI (aDWI) data with at least two different b-values and may improve differentiation of metastatic from nonmetastatic lymph nodes.To determine the appropriate b-value for cDWI to achieve a better diagnostic capability for lymph node staging (N-staging) in non-small cell lung cancer (NSCLC) patients compared to aDWI, short inversion time (TI) inversion recovery (STIR) imaging, or positron emission tomography with 2-[fluorine-18] fluoro-2-deoxy-d-glucose combined with computed tomography (FDG-PET/CT).Prospective.A total of 245 (127 males and 118 females; mean age 72 years) consecutive histopathologically confirmed NSCLC patients.A 3 T, half-Fourier single-shot turbo spin-echo sequence, electrocardiogram (ECG)-triggered STIR fast advanced spin-echo (FASE) sequence with black blood and STIR acquisition and DWI obtained by FASE with b-values of 0 and 1000 sec/mmFrom aDWIs with b-values of 0 and 1000 (aDWIReceiver operating characteristic curve (ROC) analysis, Youden index, and McNemar's test.Area under the curve (AUC) of CRcDWI with b-value at 600 sec/mm2 TECHNICAL EFFICACY: Stage 2.

Morphological evaluation of the lung is important in the clinical evaluation of pulmonary diseases. However, the disease process, especially in its early phases, may primarily result in changes in pulmonary function without changing the pulmonary structure. In such cases, the traditional imaging approaches to pulmonary morphology may not provide sufficient insight into the underlying pathophysiology. Pulmonary imaging community has therefore tried to assess pulmonary diseases and functions utilizing not only nuclear medicine, but also CT and MR imaging with various technical approaches. In this review, we overview state-of-the art MR methods and the future direction of: (1) ventilation imaging, (2) perfusion imaging and (3) biomechanical evaluation for pulmonary functional imaging.

Temporal bone trauma is frequently encountered in the emergency department. Technologic advances have enabled timely acquisition of thin-section images and multiplanar reconstructions such that temporal bone anatomy can be evaluated in great detail, with excellent delineation of fractures. The temporal bone is composed of a myriad of tiny structures, including many fissures and canals, that must be distinguished from true fractures. In addition, injury to important structures may result in serious complications such as hearing loss, dizziness, imbalance, perilymphatic fistula, cerebrospinal fluid leakage, facial nerve paralysis, and vascular injury. Structures that should be examined include the tympanic cavity and tegmen, the ossicular chain, the bony labyrinth, the facial canal, the internal carotid artery, the jugular foramen and venous sinuses, and the intracranial contents. Radiologists should be familiar with the anatomy of the temporal bone and be able to describe any pathologic findings and make suggestions to referring clinicians to guide management and determine the prognosis. The authors describe the typical CT and MRI appearances of temporal bone trauma, entities that mimic this injury and thus must be differentiated, and compulsory points for evaluating clinically relevant associated complications. Instruction is provided for acquiring the diagnostic skills necessary to report suggested injury status, complications, and likely sequelae to clinicians.©RSNA, 2020.

Background Deep learning reconstruction (DLR) may improve image quality. However, its impact on diffusion-weighted imaging (DWI) of the prostate has yet to be assessed. Purpose To determine whether DLR can improve image quality of diffusion-weighted MRI at

Since the Radiology Diagnostic Oncology Group (RDOG) report had been published in 1991, magnetic resonance (MR) imaging had limited clinical availability for thoracic malignancy, as well as pulmonary diseases. However, technical advancements in MR systems, such as sequence and reconstruction methods, and adjustments in the clinical protocol for gadolinium contrast media administration have provided fruitful results and validated the utility of MR imaging (MRI) for lung cancer evaluations. These techniques include: (1) contrast-enhanced MR angiography for T-factor evaluation, (2) short-time inversion recovery turbo spin-echo sequences as well as diffusion-weighted imaging (DWI) for N-factor assessment, and (3) whole-body MRI with and without DWI and with positron emission tomography fused with MRI for M-factor or TNM stage evaluation as well as for postoperative recurrence assessment of lung cancer or other thoracic tumors using 1.5 tesla (T) or 3T systems. According to these fruitful results, the Fleischner Society has changed its position to approve of MRI for lung or thoracic diseases. The purpose of this review is to analyze recent advances in lung MRI with a particular focus on lung cancer evaluation, clinical staging, and recurrence assessment evaluation.

Ultra-high-resolution CT (UHR-CT), which can be applied normal resolution (NR), high-resolution (HR), and super-high-resolution (SHR) modes, has become available as in conjunction with multi-detector CT (MDCT). Moreover, deep learning reconstruction (DLR) method, as well as filtered back projection (FBP), hybrid-type iterative reconstruction (IR), and model-based IR methods, has been clinically used. The purpose of this study was to directly compare lung CT number and airway dimension evaluation capabilities of UHR-CT using different scan modes with those of MDCT with different reconstruction methods as investigated in a lung density and airway phantom design recommended by QIBA.Lung CT number, inner diameter (ID), inner area (IA), and wall thickness (WT) were measured, and mean differences between measured CT number, ID, IA, WT, and standard reference were compared by means of Tukey's HSD test between all UHR-CT data and MDCT reconstructed with FBP as 1.0-mm section thickness.For each reconstruction method, mean differences in lung CT numbers and all airway parameters on 0.5-mm and 1-mm section thickness CTs obtained with SHR and HR modes showed significant differences with those obtained with the NR mode on UHR-CT and MDCT (p0.05). Moreover, the mean differences on all UHR-CTs obtained with SHR, HR, or NR modes were significantly different from those of 1.0-mm section thickness MDCTs reconstructed with FBP (p0.05).Scan modes and reconstruction methods used for UHR-CT were found to significantly affect lung CT number and airway dimension evaluations as did reconstruction methods used for MDCT.• Scan and reconstruction methods used for UHR-CT showed significantly higher CT numbers and smaller airway dimension evaluations as did those for MDCT in a QIBA phantom study (p0.05). • Mean differences in lung CT number for 0.25-mm, 0.5-mm, and 1.0-mm section thickness CT images obtained with SHR and HR modes were significantly larger than those for CT images at 1.0-mm section thickness obtained with MDCT and reconstructed with FBP (p0.05). • Mean differences in inner diameter (ID), inner area (IA), and wall thickness (WT) measured with SHR and HR modes on 0.5- and 1.0-mm section thickness CT images were significantly smaller than those obtained with NR mode on UHR-CT and MDCT (p0.05).

We studied the

Quantitative analyses of gamma-ray accumulation in single-photon emission computed tomography (SPECT), and the evaluation of antiresorptive agent-related osteonecrosis of the jaw (ARONJ) have been reported recently. However, the relationship between the quantitative parameters calculated from SPECT and the detailed morphological changes observed in computed tomography (CT) remains unclear. This study aimed to investigate patients’ characteristics and morphological changes observed on CT, and their effects on the quantitative values in SPECT. From April 2017 to March 2019, patients diagnosed with ARONJ at our hospital were enrolled. The data obtained before September 2017 were reviewed retrospectively, and other data were collected prospectively. CT scans were evaluated for internal texture, sequestrum formation, periosteal reaction, cortical perforation, bone expansion, and pathological fracture. For quantitative assessment, the ratio of the maximum standardized uptake value (SUV) to the mean SUV in the temporal bone (rSUVmax) was calculated from SPECT images. The factors affecting rSUVmax were investigated by multiple regression analysis. The statistical significance level was set at α = 0.05. Overall, 55 lesions of 42 patients (median age and interquartile range, 75 [67–80 years], 27 female) were evaluated. Male sex (p = 0.007) and bilateral location (p

The coronavirus disease (COVID-19) pandemic has complicated the work of general physicians due to the vagueness of fever standards. Because of the high virulence of the causative virus, the disease is rapidly spreading worldwide, even reaching the rural areas in Japan. During the first wave of the pandemic, the Japanese government set the standard as a temperature of 37.5°C lasting for more than four days. However, after the government deleted this standard from its website, there was confusion in the medical institutions, as they struggled to set their fever standards. As a result, social fear might force healthcare professionals to bring down the standard for fever to increase the sensitivity and identify patients with COVID-19 more accurately. During the second wave, the fever standard was set at 37°C to enable high sensitivity. Subsequently, general physicians had to approach many people with temperatures higher than 37°C who came to the hospital seeking treatment for their symptoms or to visit their families. People seek to avoid contracting the COVID-19 infection for health-related and social reasons. When there is a possibility of healthcare professionals testing positive, hospitals may have to shut down and face criticism from society, as the mass media generally accuses these hospitals of mismanagement.

To demonstrate the utility of compressed sensing with parallel imaging (Compressed SPEEDER) and AiCE compared with that of conventional parallel imaging (SPEEDER) for shortening examination time and improving image quality of women's pelvic MRI.Thirty consecutive patients with women's pelvic diseases (mean age 50 years) underwent T2-weighted imaging using Compressed SPEEDER as well as conventional SPEEDER reconstructed with and without AiCE. The examination times were recorded, and signal-to-noise ratio (SNR) was calculated for every patient. Moreover, overall image quality was assessed using a 5-point scoring system, and final scores for all patients were determined by consensus of two readers. Mean examination time, SNR and overall image quality were compared among the four data sets by Wilcoxon signed-rank test.Examination times for Compressed SPEEDER with and without AiCE were significantly shorter than those for conventional SPEEDER with and without AiCE (with AiCE: p 0.0001, without AiCE: p 0.0001). SNR of Compressed SPEEDER and of SPEEDER with AiCE was significantly superior to that of Compressed SPEEDER without AiCE (vs. Compressed SPEEDER, p = 0.01; vs. SPEEDER, p = 0.009). Overall image quality of Compressed SPEEDER with AiCE and of SPEEDER with and without AiCE was significantly higher than that of Compressed SPEEDER without AiCE (vs. Compressed SPEEDER with AiCE, p 0.0001; vs. SPEEDER with AiCE, p 0.0001; SPEEDER without AiCE, p = 0.0003).Image quality and shorten examination time for T2-weighted imaging in women's pelvic MRI can be significantly improved by using Compressed SPEEDER with AiCE in comparison with conventional SPEEDER, although other sequences were not tested.

Large size and low dislocation density bulk gallium nitride (GaN) crystals were successfully grown by original acidic ammonothermal method SCAAT™ (Super Critical Acidic Ammonia Technology). It enabled us to obtain extremely high crystallinity true bulk GaN. In this article, 2-inch size non-polar m-plane GaN and nearly 4-inch size polar c-plane GaN were demonstrated. The dislocation and stacking fault density of m-plane GaN were in the range of 102 to 103 cm-2 and 0 to 5 cm-1, respectively. The full width at half maximum (FWHM) of X-ray rocking curve (XRC) on (10-12) plane was 6.4 arcsec. The dislocation density of c-plane GaN was in the range of 103 to 104 cm-2. The off-angle distribution of nearly 4-inch size c-plane GaN was ±0.006° in the span of 80 mm. The types of dislocations in the c-plane GaN were identified by transmission electron microscope (TEM) observation. Hydride vapor phase epitaxy (HVPE) growth on the SCAA™ c-plane seed was carried out and obtained 2-inch wafer. The crystallinity was comparable to SCAAT™ seed; FWHM of XRC was less than 10 arcsec and off-angle distribution was ±0.017°.

It is not easy to explain the conformational stability of flavan-3-ols. Factors governing it were investigated based on bond orbital interactions. The interactions between the substituent groups on the C2 and C3 positions play a critical role in the conformational stabilities. In the benzoyloxy types, the destabilization effects due to the interaction between the bonding orbital of the aromatic ring on C2 and the lone pair orbital of the oxygen atom on C3 are responsible for the relative stability of the conformations. In contrast, the conformational stabilities of the hydroxy types are determined by the stabilization effects arising from the electron delocalization from the bonding orbital to the vacant orbitals of the atoms. These results show that the stabilization effects due to the electron delocalization between the vicinal substituent groups is an important factor in the conformational stability of molecules in addition to the destabilization effects due to steric repulsion.

Frontier orbital theory is demonstrated by investigating the appropriately divided parts of transition states, useful for understanding an essential aspect of transition-metal- and lanthanide-mediated reactions. Atomic orbitals are in phase with each other in the outer space of the antibonding orbitals of the bonds between transition-metal and main-group atoms.

Neighboring group participation is defined as the action of a substituent to stabilize a transition state or an intermediate by forming a bond or a partial bond with the reaction center. In addition to the primary interaction with the nearest neighboring group, secondary interactions involving another neighboring group(s) could also occur in principle. Here, we revisit this issue by examining the influence of secondary interactions on the stability and reactivity of the putative iminylium cation intermediates, formed by N-O bond cleavage of 1-tetralone oxime systems. A direct observation of a peri-bromo-iminylium intermediate in solution supported the involvement of iminylium cations and the stabilizing effect of secondary interactions arising from a distal tandem substituent. Both experimental and computational findings support the idea that secondary interactions of a tandem-neighboring group on the primary peri-heteroatom (Br, Cl, and O(Me))-iminylium bonding interaction, i.e., a weak halogen bonding interaction (ester (nitro) oxygen-halogen bonding) and an unprecedented hydrogen bonding interaction between a nitro oxygen atom and a CH3O hydrogen atom, are crucial determinants of the reaction pathway, leading to either overwhelmingly selective syn-migration of the oxime functionality or covalent bond formation under acid-catalyzed Beckmann rearrangement conditions.

To directly compare the capability of compressed sensing (CS) and parallel imaging (PI) accelerated T2 FSE (Fast Spin Echo) sequence with PI for head and neck MR imaging.Thirty consecutive patients with various head and neck diseases (15 men and 15 women, mean age 53 ± 22 years) underwent MR imaging by PI with CS and by PI. Reduction factors were as follows: PI with CS, 3 and PI, 1.5. Examination times for PI with CS and PI were all recorded. For quantitative image quality assessment, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. For qualitative assessment, two investigators assessed overall image quality, artifacts and diagnostic confidence level using a 5-point scoring system, and final scores were determined by consensus of two readers. Mean examination time and all indexes were compared by means of paired t-test and Wilcoxon signed-rank test. Inter-observer agreement for each qualitative index was assessed in terms of kappa statistics.Mean examination time for PI with CS (83.5 ± 11.0 s) was significantly shorter than that for PI (173.0 ± 54.4 s, p 0.0001). SNR and CNR of PI with CS were significantly better than those with PI (mean SNR; 11.2 ± 3.6 vs 8.9 ± 2.6, median of CNR; 7.4 vs. 6.1, p 0.0001). All inter-observer agreements were assessed as significant and substantial (0.62 κ 0.81).PI with CS accelerated T2 weighted sequence performs equally well or even slightly better than its PI accelerated, conventional counterpart at reduced scan times in the context of head and neck MR imaging.

Defects in ammonothermal GaN have been studied using a monoenergetic positron beam. Through measurements of Doppler broadening spectra of the annihilation radiation, the major defect species was identified as a Ga vacancy coupled with impurities such as oxygen and/or hydrogen. Those defects were found to be stable even after annealing at 1000 °C. The shape parameter S for the Doppler broadening spectrum corresponding to positron annihilation at the surface was found to be decreased by illumination within energy ranges of 1.5–2.6 eV and 3.2–3.6 eV. This phenomenon is attributed to the suppression of recombinations between holes and electrons due to trapping centers, which can hold electrons for a long time, and a resultant accumulation of holes at the surface. Recovery of the S value required almost one day, but it was shortened by the annealing at 1000 °C.

Fluid collections in the retropharyngeal space (RPS) result from a wide spectrum of diseases, including retropharyngeal abscess, cervical osteomyelitis, and calcific tendinitis of the longus colli muscle. These conditions should be managed by different specialties; beginning with care in the emergency room, physicians from orthopedics, pediatrics, otolaryngology, and oncology are in charge of the treatment. Since these diseases demonstrate similar fluid collections in the RPS on computed tomography (CT) and magnetic resonance imaging (MRI), the radiologist's diagnosis based on the characteristic imaging findings is very important to identify the primary disease. Also, since some of the diseases require immediate surgical intervention to avoid life-threatening mediastinitis or airway obstruction, radiologists must distinguish these diseases correctly and provide recommendations for their management to physicians. Understanding clinical features and imaging findings of these fluid collections in the RPS is crucial for the best care.

Recently, exchange repulsion and electron delocalization have been a focus of attention as the origin of the anomeric effect. However, the details of these interactions remain unclear. In this study, to elucidate what exchange repulsion and electron delocalization contribute to anomer stabilities of 2-hydroxytetrahydropyran (2-hydroxy-THP), the electronic structures of the anomers were investigated using bond model analysis. The vicinal bond interactions around the anomeric carbon make the equatorial configuration of the hydroxy group more stable than the axial configuration. Exchange repulsions contribute much to this relative stability of the equatorial configuration. However, exchange repulsion and electron delocalization due to 1,3-diaxial interactions and other interactions involving lone pair electrons of oxygen make the axial configuration more stable overall than the equatorial configuration. The anomeric effect in glucose can also be explained in a manner similar to that in 2-hydroxy-THP. Additionally, interactions between the vicinal hydroxy groups contribute to the stabilization of the axial configuration.

The frontier orbital theory is applied to investigate an organolanthanide-catalyzed reaction at the electronic level, using hydroamination/cyclization reactions of primary aminoalkynes. The insertion of the alkyne functionality into the Ln–N bond in Cp 2 LnNH(CH 2 ) 3 C CH involved in the turnover-limiting cyclization step is found to be favored by the phases of HOMO of HC C(CH 2 ) 3 NH − and LUMO of closed-shell Cp 2 Ln + (Ln = La, Lu) or the LUMO+2 of excessive spins of open-shell Cp 2 Sm + . The LUMO and LUMO+1 of Cp 2 Sm + are 4f orbitals contracted too much to effectively overlap with HOMO of the counterpart. The HOMO–LUMO/LUMO+2 overlaps are visually shown and numerically confirmed to increase in the order of Ln = La

The conformational properties of N-acyl azoles (imidazole, pyrazole, and triazole) were examined. The N-2′,4′,6′-trichlorobenzoyl azoles were stable in methanol at room temperature, and no hydrolyzed products were observed over 7 days in the presence of 5% trifluoroacetic acid or 5% triethylamine in CDCl3. The high stability may be explained by the double-bond amide character caused by the steric hindrance due to the ortho-substituents in the benzoyl group. While specific E-amide preferences were observed in N-acyl pyrazoles/triazoles, the amides of the imidazoles gave a mixture of E and Z. One of the conceivable ideas to rationalize this conformational preference may be repulsive interaction between two sets of lone-pair electrons on the pyrazole 2-nitrogen (nN) and the carbonyl oxygen atoms (nO) in the Z-conformation of N-acyl pyrazoles/triazoles. However, analysis of orbital interactions suggested that in the case of the E-conformation of N-acyl pyrazoles, such electron repulsion is small because of di...

Single-center, single-arm, prospective time-series study.To assess the cost-effectiveness and improvement in quality of life (QOL) of percutaneous vertebroplasty (PVP).PVP is known to relieve back pain and increase QOL for osteoporotic compression fractures. However, the economic value of PVP has never been evaluated in Japan where universal health care system is adopted.We prospectively followed up 163 patients with acute vertebral osteoporotic compression fractures, 44 males aged 76.4±6.0 years and 119 females aged 76.8±7.1 years, who underwent PVP. To measure health-related QOL and pain during 52 weeks observation, we used the European Quality of Life-5 Dimensions (EQ-5D), the Rolland-Morris Disability Questionnaire (RMD), the 8-item Short-Form health survey (SF-8), and visual analogue scale (VAS). Quality-adjusted life years (QALY) were calculated using the change of health utility of EQ-5D. The direct medical cost was calculated by accounting system of the hospital and Japanese health insurance system. Cost-effectiveness was analyzed using incremental cost-effectiveness ratio (ICER): Δ medical cost/Δ QALY.After PVP, improvement in EQ-5D, RMD, SF-8, and VAS scores were observed. The gain of QALY until 52 weeks was 0.162. The estimated lifetime gain of QALY reached 1.421. The direct medical cost for PVP was ¥286,740 (about 3061 US dollars). Cost-effectiveness analysis using ICER showed that lifetime medical cost for a gain of 1 QALY was ¥201,748 (about 2154 US dollars). Correlations between changes in EQ-5D scores and other parameters such as RMD, SF-8, and VAS were observed during most of the study period, which might support the reliability and applicability to measure health utilities by EQ-5D for osteoporotic compression fractures in Japan as well.PVP may improve QOL and ameliorate pain for acute osteoporotic compression fractures and be cost-effective in Japan.

The effect of the thermal annealing on an acidic ammonothermal gallium nitride (GaN) crystal grown toward the c- and m-directions was investigated. The specific annihilation of hydrogenated Ga vacancies was confirmed for the GaN crystal grown toward the m-direction but not for that grown toward the c-direction. A transparent and yellow luminescence-free ammonothermal GaN substrate was realized. The annihilation of the hydrogenated Ga vacancies was explained by the difference in the diffusion of F incorporated as a mineralizer between the c- and m-directions.

An evident issue in performing GaN growth along the c-direction is the generation of V-shaped pits on its surface. Here, we investigated the transition of the angle of facets forming a V-shaped pit via three-photon excitation photoluminescence (3PPL). The intermittent doping of Ge was introduced to GaN growth to observe the growth front. The size of the V-shaped pit composed of { 10 1 ¯ 2 } facets decreased along the growth direction, whereas that composed of { 10 1 ¯ 1 } facets, increased. Furthermore, planar growths of c-GaN and semipolar GaN having various surface orientations revealed that the V-shaped pit composed of { 10 1 ¯ 2 } was likely to annihilate rather than that of { 10 1 ¯ 1 } under the growth condition of N2 carrier gas, which coincides with the result of 3PPL.

We report a case of ileal internal hernia through the foramen of Winslow into the lesser sac. Preoperative computed tomography (CT) demonstrated that the herniated ileum, which showed a closed-loop obstruction, was located behind the portal vein, and the vein was subsequently compressed and narrowed by the herniated ileum. We found that similar cases in the literature of Winslow's foramen hernias that caused portal vein compression; however, portal vein narrowing has not been described as a characteristic CT finding. The narrowed portal vein sign could be useful in diagnosing the hernia through the foramen of Winslow.

We propose a method to compute the restoring force characteristics and dissipated energy to detect damage level of viaducts for railways and highways, using only acceleration. The acceleration data were measured by accelerometers which were installed on the top and the bottom of the structures. Wireless sensor network is used to compute and collect the data. Using this system, the information of restoring force characteristic and dissipated energy can be created.

The frontier orbital theory is applied to ruthenium olefin metathesis. The formal [2+2] cycloaddition step, that is, the key step involved in the catalytic cycle of the reaction, is found to be favored by the phases of the HOMO and LUMO, in sharp contrast to [2+2] cycloaddition reactions between olefins. In the LUMO of transition metal part, a d-orbital overlaps out of phase with the vacant p-orbital of the carbene in the inner space of the metal–carbon π bond as is expected, but the remote lobe of the d orbital overlaps in phase in the outer space of the bond. This is a characteristic feature of the antibonding orbitals of transition metal bonds. The outer orbital phase plays more important role in the interaction. The significantly enhanced activity of the ‘second-generation’ catalysts or N -heterocyclic carbenes (NHC’s) comes from the high HOMO energy.

We investigated the electronic structures of the transition states of the oxidative addition, transmetalation, and reductive elimination steps in the catalytic cycle of the title reaction. The frontier orbital theory was surprisingly found to be applicable whereas any d orbitals of transition metals can be a main component of frontier orbitals because of their close energies. Visualizing the actually calculated HOMO and LUMO of the two parts of the transition structure of each step clearly demonstrated their orbital phase matching in favor of overlapping. The HOMO for the transmetalation step suggests that electron-donating ability of the carbon–metal bond of organometallic compounds (RMX) could control the reactivities of related cross-coupling reactions. The energies of the molecular orbitals having large amplitudes of the C–M bonding orbitals of RMX explain why the Suzuki–Miyaura cross-coupling reaction needs a base while the Kumada–Tamao and Negishi reactions take place without any bases.

The nonradiative lifetime (τNR) of the near-band-edge emission in various quality GaN samples is compared with the results of positron annihilation measurement, in order to identify the origin and to determine the capture-cross-section of the major intrinsic nonradiative recombination centers (NRCs). The room-temperature τNR of various n-type GaN samples increased with decreasing the concentration of divacancies composed of a Ga vacancy (VGa) and a N vacancy (VN), namely, VGaVN. The τNR value also increased with increasing the diffusion length of positrons, which is almost proportional to the inverse third root of the gross concentration of all point defects. The results indicate that major intrinsic NRC in n-type GaN is VGaVN. From the relationship between its concentration and τNR, its hole capture-cross-section is estimated to be about 7 × 10−14 cm2. Different from the case of 4H-SiC, the major NRCs in p-type and n-type GaN are different: the major NRCs in Mg-doped p-type GaN epilayers are assigned to ...

The phase transitions in (CH 3 ) 3 NCH 2 COOH·H 2 PO 3 at T C1 =355 K and at T C2 =216 K were studied by nuclear magnetic resonance. Spin–lattice relaxation time T 1 of the 13 C nucleus in the CH 3 group shows two-mode behavior without showing anomaly in the both phase transitions. Activation energies are determined to be 23.1(9) and 1.3(2) kJmol -1 for two modes. T 1 of the 13 C nucleus in the CH 2 group exhibits a shallow dip around T C1 , suggesting that the motion of the CH 2 group slows down more or less at T C1 . T 1 of the 31 P nucleus takes a minimum at 253 K and activation energy is obtained as 12.6(2) kJmol -1 . In addition to the T 1 minimum, this shows a sharp dip at T C1 due to the critical slowing-down of the HPO 3 2- motion. The incomplete slow-down of the CH 2 motion is considered to be induced by the coupling with the disorder of the HPO 3 2- anion. The critical relaxation rate of the 31 P nucleus is well reproduced by the quasi-one-dimensional Ising model. Interaction parameters for intr...

For rating unambiguous performance of a light-emitting semiconductor material, determination of the absolute quantum efficiency (AQE) of radiation, which is basically a product of internal quantum efficiency (IQE) and light-extraction efficiency, is the most delightful way. Here, we propose the use of omnidirectional photoluminescence (ODPL) spectroscopy for quantifying AQE of the near-band-edge (NBE) emission, in order to evaluate bulk GaN crystals and wafers. When the measurement was carried out in the air, the AQE showed a continuous decrease most likely due to the formation of extrinsic nonradiative recombination channels at the surface by photo-pumping. However, such an influence was suppressed by measuring ODPL in an inert ambient such as nitrogen or in vacuum. Consequently, AQE was revealed to depend on the photo-pumping density. The increase in AQE of the NBE emission caused by the increase in the excess carrier concentration was significant, indicating gradual saturation of nonradiative recombina...

We investigated the structures and the stabilities of the three-membered rings (X = Si, P, S; Y = CH2, NH, O; n = 2 or 3) containing a hypervalent atom (X) and disclosed their origins by developing and applying an electron-pair bond model for hypervalent molecules. For the rings containing a pentacoordinated Si or P atom, the (ap, eq) isomers with the ring bonds in the apical and equatorial positions are local minima, while the (eq, eq) isomers with both ring bonds in the equatorial positions are the transition states of pseudorotation reactions due to the high ring strains. In contrast, the (ap, eq) and (eq, eq) isomers for the rings containing a tetracoordinated P or S atom are both local minima. The tetracoordinated species are less strained than the pentacoordinated ones because of the effect of the lone pair on X giving rise to less antibonding properties of the electron delocalization between the geminal ring bonds on X. Moreover, the more strained (eq, eq) isomers are surprisingly more stable than ...

N-Nitrosamines can be considered as potential nitric oxide (NO)/nitrosonium ion (NO(+)) donors. However, the relation of the structures of N-nitrosamines, in particular of aliphatic N-nitrosamines, to the characteristics of release of NO or NO(+) remains unclear. Here we show that aliphatic N-nitrosoamines of 7-azabicyclo[2.2.1]heptanes can undergo heterolytic N-NO bond cleavage. On the basis of the observation of reduced rotational barriers of the N-NO bonds in solution and nitrogen-pyramidal structures of the N-nitroso group in the solid state, we postulate that N-NO bond cleavage of N-nitrosamines is enhanced by a reduction of the resonance in the N-NO group. Computational studies suggest that these structural features of the N-nitrosamines of 7-azabicyclo[2.2.1]heptane are derived from angle strain imposed on the CNC angles.

Structures and reactions of CH3OCH2M (M = Li, Na, K) were investigated in a theoretical manner. CH3OCH2M has the acute bond angle of ∠M-C-O due to a strong coordination of the oxygen to the alkali metals. The nucleophilic substitution reaction of the substrate CH3OCH2Li by the nucleophile CH3OCH2Li is more preferred than the carbene generation by α-elimination and a nucleophilic substitution of CH3OCH2Li by CH3Li. The resulting 2-methoxyethyllithium readily liberated lithium methoxide to afford ethylene, which added to the anion species to give an ethylated product. Among the CH3OCH2M (M = Li, Na, K), CH3OCH2K is the most nucleophilic, due to the high σC–K level, while CH3OCH2Li is the most nucleophilic because of the lowest σ*C–O level. This supports a previously proposed mechanism for the ethylation of indole derivatives by methyl ethers in the presence of BuLi - t-BuOK.