Relapsing bronchopneumonia due to community-associated methicillin-resistant Staphylococcus aureus: a case report.

BACKGROUND: The emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has increased the incidence of community-onset MRSA infection. Respiratory tract infections caused by MRSA has been noted for their severity; however, repeated relapses that require extended antibiotic therapy are rare. CASE PRESENTATION: We report a case of relapsing bronchopneumonia caused by CA-MRSA in a 56-year-old man. The patient responded to antibiotics, but repeatedly relapsed after stopping treatment. MRSA was consistently isolated from airway specimens during each relapse. Extended oral antibiotic treatment with trimethoprim/sulfamethoxazole (TMP/SMX) for 6 months achieved infection control. Whole-genome sequencing of the isolated strain revealed that the causative agent was sequence type (ST)1/staphylococcal cassette chromosome mec (SCCmec) type IVa, a clone that is rapidly increasing in Japan. DISCUSSION AND CONCLUSIONS: This patient had an unusual course of MRSA bronchopneumonia with repeated relapses. Although the choice of antibiotics for long-term use in MRSA respiratory tract infections has not been well established, TMP/SMX was effective and well tolerated for long-term therapy in this case. The clinical course of infections related to the rapid emerging clone, ST1/SCCmec type IVa warrants further attention.

Assessment of clinical relevance of antigen improves diagnostic accuracy of hypersensitivity pneumonitis.

BACKGROUND: Exposure assessment is integral to the diagnosis of hypersensitivity pneumonitis (HP). Although the clinical relevance of exposed antigens is essential for the assessment, many of the previous guidelines or reports have only evaluated simple exposure histories or immunological tests. To overcome this problem, the Exposure Assessment Form (EAF) was developed as an assessment tool for classifying the exposure grade from G0 to G4. The EAF was modified from the description in the Japanese clinical practice guide 2022 for HP published by the Japanese Respiratory Society. METHODS: One hundred and seventy-two consecutive patients with interstitial lung disease who underwent multidisciplinary discussion (MDD) at our hospital were retrospectively examined. We assessed whether the use of the EAF improved the diagnostic performance of the international guideline of HP. We also evaluated whether the exposure grade affected the prognosis of HP. RESULTS: Even when a HP diagnosis was made with a confidence of 70% or higher according to the international guideline, less than half of these cases resulted in a final diagnosis of HP when the exposure grades were lower than G3. When the result of the EAF was integrated into the exposure definition of the international guideline, the specificity of the diagnostic performance improved, while sensitivity was maintained. Furthermore, HP patients with an exposure grade of G3 or higher showed a tendency to take a longer time to initiate medication. CONCLUSIONS: This is the first study to evaluate the clinical relevance of possible antigens using the EAF. Assessing the exposure grade prevents overdiagnosis and improves the diagnostic performance of the international guideline.

Efficacy of fracture stem in reverse shoulder arthroplasty for 3- or 4-part proximal humerus fractures.

BACKGROUND: This study compared the clinical results of fracture stems and conventional stems using the same glenoid component in reverse shoulder arthroplasty for proximal humerus fractures in the elderly. METHODS: This retrospective study included 35 patients who underwent Grammont-type reverse shoulder arthroplasty for proximal humerus fractures from 2014 to 2020. The average age at surgery was 79.2 (range, 65-92) years, with 33 female shoulders. Fracture types per Neer classification were 3-part fracture, 4-part fracture, in 13 and 22 shoulders, respectively. The final follow-up period was 35 (range, 24-81) months. The Constant score, American Shoulder and Elbow Surgeons score, shoulder range of motion, and healing of greater tuberosities at the final follow-up of AEQUALIS™ REVERSED (Conventional stem group: n = 15) and AEQUALIS™ REVERSED FX (Fractured stem group: n = 20) were retrospectively investigated. RESULTS: There were no statistically significant differences in age at surgery, sex, body mass index, fracture type, waiting time from injury to surgery, or preoperative general condition between the groups. The Constant and American Shoulder and Elbow Surgeons scores of the fractured stem group were significantly higher than those of the conventional stem group (P = 0.038 and P = 0.023, respectively). The anterior elevation and external rotation at the side of the fractured stem group also showed significantly higher values than those of the conventional stem group (fractured stem group vs. conventional stem group: anterior elevation 127° ± 25° vs. 105° ± 35°, P = 0.041; external rotation 28° ± 13° vs. 13° ± 12°, P = 0.015). The greater tuberosity healing rate was 46.7% (7/15) in the conventional stem group and 85.0% (17/20) in the fractured stem group (P＝0.027). CONCLUSIONS: The findings suggest that use of a fracture-specific stem rather than a conventional stem in Grammont-type reverse shoulder arthroplasty for proximal humerus fractures improves tuberosity healing, postoperative range of motion, and clinical scores.

Morphological and histological evaluation of the tendon-bone junction in porcine shoulders to create a rotator cuff tear and repair model.

BACKGROUND: This study aimed to morphologically and histologically examine whether pig is useful as models for rotator cuff tear (RCT). METHODS: The morphology of the scapula and humerus bones was evaluated by taking X-ray and three-dimensional computed tomography (3D CT) scans of the right shoulders of five female pigs (age: 4 months). The rotator cuff (RC) footprint at the humeral insertion of these was observed and its shape was measured. Next, they underwent general anesthesia and an acute rotator cuff tear/rotator cuff repair (RCT/RCR) model was created using a deltoid split approach. Four weeks after surgery, the animals were euthanized, the shoulder joints were harvested, and the repaired RC was evaluated by hematoxylin and eosin staining and toluidine blue staining. RESULTS: The scapula of the pig had a vestigial acromion, in contrast to that in humans. The supraspinatus and infraspinatus tendons were connected so as to overlap each other and attached to the postero-superior part of the greater tuberosity. These tendons were located extra-articularly, separate from the joint capsule. The average antero-posterior length of the foot print was 17.4 ± 0.7 mm on the medial margin and 19.1 ± 2.2 mm on the lateral margin. The maximum medial-to-lateral width of it was 5.1 ± 0.5 mm. In all RCT/RCR models at 4 weeks after surgery, the repaired RC compound tendon was visually confirmed to be continuous with the footprint. Histologically, it was confirmed that regeneration of the four-layer structure of the bone-tendon junction had occurred. CONCLUSION: Porcine supraspinatus and infraspinatus attachment to the greater tuberosity have a structure similar to that of sheep and dogs, which is advantageous for creating the RCT/RCR model. It might be used for future in vivo studies of shoulder joint diseases. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: Pigs could potentially serve as a viable model for rotator cuff tears.

The influence of COVID-19 epidemic on the number of orthopaedic surgeries in Japan.

BACKGROUND: There is limited data on the impact of COVID-19 epidemic on the number of orthopaedic surgeries in Japan. METHODS: We conducted a nationwide hospital survey asking for the monthly number of orthopaedic surgeries performed at each facility from January 2019 to June 2021. Those facilities that had performed at least 100 surgeries in 2019 were included for analyses. The facilities were further grouped by prefecture and by hospital characteristics. A brief health economic evaluation was also performed. Risk ratios were compared using univariate analyses with P < 0.05 considered statistically significant. RESULTS: Questionnaire was sent to 1988 hospitals with 1671 hospitals (84%) responding. The survey data indicated a total number of orthopaedic surgeries decreased in 2020 compared to 2019 (1,061,541 vs 1,119,955 P < 0.01), and also for the first six months of 2021 compared to the same period in 2019 (530,388 vs 550,378 P < 0.01). In 2020, over 50% of all facilities in nearly all of the prefectures saw a decline in surgical procedures. The risk of incurring more than a 25% decease in the number of surgeries was significantly higher in 2020 for class I designated medical institutions compared to those that were not designated for any types of infectious diseases among the institutions with a tertiary emergency medical center in 2020 (crude risk ratio 2.9: 95% CI 1.2-7.4, p = 0.02) and in 2021 (crude risk ratio 4.7: 95% CI 1 0.9-12.1, p < 0.01). The estimated total nationwide decrease of revenue were in the range of approximately ¥29.2 to ¥116.8 billion per year for orthopaedic surgeries alone. CONCLUSION: There was a statistically significant decrease in the number of orthopaedic surgeries in Japan. The magnitude of the decline varied by prefectures and hospital characteristics, with the greater impact imposed on medical institutions with higher classification functions. The estimated immediate health economic impact was sizable.

MuLBSTA score is a useful tool for predicting COVID-19 disease behavior.

BACKGROUND: The prediction of COVID-19 disease behavior in the early phase of infection is challenging but urgently needed. MuLBSTA score is a scoring system that predicts the mortality of viral pneumonia induced by a variety of viruses, including coronavirus, but the scoring system has not been verified in novel coronavirus pneumonia. The aim of this study was to validate this scoring system for estimating the risk of disease worsening in patients with COVID-19. METHODS: This study included the patients who were treated between April 1 st and March 13 th , 2020. The patients were classified into mild, moderate, and severe groups according to the extent of respiratory failure. MuLBSTA score was applied to estimate the risk of disease worsening in each severity group and we validated the utility of the scoring system. RESULTS: A total of 72 patients were analyzed. Among the 46 patients with mild disease, 17 showed disease progression to moderate or severe disease after admission. The model showed a sensitivity of 100% and a specificity of only 34.5% with a cut-off value of 5 points. Among the 55 patients with mild or moderate disease, 6 deteriorated to severe disease, and the model showed a sensitivity of 83.3% and a specificity of 71.4% with a cut-off value of 11 points. CONCLUSIONS: This study showed that MuLBSTA score is a potentially useful tool for predicting COVID-19 disease behavior. This scoring system may be used as one of the criteria to identify high-risk patients worsening to life-threatening status.

Predictors associated with clinical improvement of SARS-CoV-2 pneumonia.

BACKGROUND: There are few agents that have been proven effective for COVID-19. Predicting clinical improvement as well as mortality or severity is very important. OBJECTIVES: This study aimed to investigate the factors associated with the clinical improvement of COVID-19. METHODS: Overall, 74 patients receiving treatment for COVID-19 at Tokyo Medical and Dental University Hospital from April 6th to May 15th, 2020 were included in this study. Clinical improvement was evaluated, which defined as the decline of two levels on a six-point ordinal scale of clinical status or discharge alive from the hospital within 28 days after admission. The clinical courses were particularly investigated and the factors related to time to clinical improvement were analyzed with the log-rank test and the Cox proportional hazard model. RESULTS: Forty-nine patients required oxygen support during hospitalization, 22 patients required invasive mechanical ventilation, and 5 patients required extracorporeal membrane oxygenation. A total of 83% of cases reached clinical improvement. Longer period of time from onset to admission (≥10 days) (HR, 1.057; 95% CI, 1.002-1.114), no hypertension (HR, 2.077; 95% CI, 1.006-4.287), and low D-dimer levels (<1 µg/ml) (HR, 2.372; 95% CI, 1.229-4.576) were confirmed to be significant predictive factors for time to clinical improvement. Furthermore, a lower SARS-CoV-2 RNA copy number was also a predictive factor for clinical improvement. CONCLUSIONS: Several predictors for the clinical improvement of COVID-19 pneumonia were identified. These results may be important for the management of COVID-19 pneumonia.

Propionibacterium acnes-associated sarcoidosis complicated by acute bird-related hypersensitivity pneumonitis.

BACKGROUND: The number of reports on sarcoidosis complicated by hypersensitivity pneumonitis (HP) is limited, and most describe cases complicated by chronic bird-related HP. Here, we present for the first time a case with Propionibacterium acnes-associated sarcoidosis complicated by acute bird-related HP. CASE PRESENTATION: A 62-year-old man with a past medical history of sarcoidosis was admitted to our department, and chest computed tomography showed diffuse ground-glass opacities, which appeared as he rapidly increased the number of pigeons he kept for a competition. Random transbronchial lung biopsy revealed well-formed non-caseating epithelioid granulomas, which contained positively stained substances on immunohistochemistry using the PAB antibody, a specific monoclonal antibody against P. acnes lipoteichoic acid. Poorly formed non-caseating granulomas without positively stained substances were also detected. CONCLUSION: We describe the successful identification of this exceptionally rare case of sarcoidosis complicated by acute bird-related HP in which two morphologically and immunohistologically different types of granulomas were present in the same lung.

Relationship between postoperative retear and preoperative fatty degeneration in large and massive rotator cuff tears: quantitative analysis using T2 mapping.

BACKGROUND: Fatty degeneration of the rotator cuff muscles is reported to be associated with retear after rotator cuff repair. The purpose of this study was to assess the relationship between retear and preoperative fatty degeneration, as quantified by T2 mapping. METHODS: This prospective cohort study included 83 large and 24 massive rotator cuff tears (average age, 67 years; range, 46-82 years). All patients preoperatively underwent T2 mapping magnetic resonance imaging, and T2 values of the supraspinatus and infraspinatus muscles were quantified. Cuff integrity was evaluated with magnetic resonance imaging 1 year postoperatively. Preoperative T2 values were compared between the retear and intact groups. The preoperative Goutallier stage, Constant score, and the shoulder score of the University of California at Los Angeles were also compared between the 2 groups. RESULTS: Retear was found in 32 shoulders (30%). Postoperative Constant and University of California at Los Angeles scores were significantly higher in intact shoulders than in retear shoulders (P < .001 for both). Mean preoperative T2 values of supraspinatus and infraspinatus were 77.4 ± 13.2 ms and 73.2 ± 15.3 ms in retear shoulders and 66.5 ± 11.1 ms and 58.6 ± 11.7 ms in intact shoulders, respectively; the differences were significant in both muscles (P < .001). Cutoff values for prediction of retear were 71.8 ms in supraspinatus and 63.1 ms in infraspinatus. There were no significant differences in the preoperative Goutallier stages of supraspinatus and infraspinatus between the 2 groups. CONCLUSIONS: Retear shoulders demonstrated significantly higher preoperative T2 values than intact shoulders. T2 mapping can be a useful tool for predicting postoperative retears.

Blood flow evaluation by dynamic magnetic resonance imaging of symptomatic rotator cuff tears and frozen shoulders.

BACKGROUND: This study compared imaging findings of blood flow changes between symptomatic rotator cuff tear (RCT) and frozen shoulder (FS) by using 3-dimensional dynamic magnetic resonance imaging (MRI) to determine the clinical characteristics of symptomatic RCT. METHODS: The 2 study groups comprised 31 symptomatic RCT patients who underwent arthroscopic rotator cuff repair and 30 patients with FS. We denoted abnormal blood flow detected around the glenohumeral joint as the burning sign (BS). We evaluated the characteristics of dynamic MRI and compared them between BS-positive and BS-negative patients in the RCT group. RESULTS: All members of the FS group showed the BS. Conversely, the incidence of the BS in RCT patients was 53% (16 of 31). The BS in RCT and FS patients was observed in the rotator interval in 16 shoulders, in the axillary pouch in 3 shoulders (P < .01), and in the intertubercular groove in 10 RCT and 12 FS patients. In the RCT group, 16 patients with BS had a statistically significantly higher Numeric Rating Score at rest (P = .0005) and in motion (P = .04) than the 15 patients without BS and exhibited a higher rate of small and medium tears and a higher rate of shoulder contracture. CONCLUSION: Dynamic MRI of symptomatic RCT (53.3%) highlighted abnormal vascularization around the glenohumeral joint, which may be associated with pain and contracture in RCT as in FS.

Characteristics of dynamic magnetic resonance imaging of idiopathic severe frozen shoulder.

BACKGROUND: The purpose of this study was to evaluate the effectiveness of current techniques for dynamic 3-dimensional magnetic resonance imaging (MRI) in the diagnosis of idiopathic severe frozen shoulder (FS). MATERIALS AND METHODS: Subjects consisted of 5 healthy volunteers and 16 patients with idiopathic severe FS. We defined severe idiopathic FS as follows: range of motion ≤100° in forward flexion, ≤10° in external rotation, and ≤L5 in internal rotation. All patients suffered from continued global range of motion loss for at least 6 months. We evaluated the diagnostic characteristics of 3-dimensional dynamic MRI in FS patients compared with those in healthy volunteers. RESULTS: MRI of all FS patients displayed an abnormal intake of blood flow from the acromial arterial network and the branches of circumflex humeral arteries into the axillary pouch and the rotator interval. We named this finding "burning sign." The burning sign was present at all phases of the condition. In the FS group, the patients with enhanced deposition of contrast medium in the axillary pouch in the delayed phase (n = 11) had a statistically significant score for pain during exercise, higher than that of patients with reduced deposition of contrast medium at the same site (n = 5; P = .027). CONCLUSION: Burning sign is an abnormal finding that appears in dynamic MRI of severe FS. Hence, the burning sign may be associated with pain and inflammation in idiopathic FS.

Short-term clinical results of frozen shoulder treated with shoulder manipulation under ultrasound-guided cervical nerve root block at outpatient setting: A case series.

BACKGROUND: We evaluated the short-term clinical outcomes of frozen shoulder treatment via shoulder manipulation under ultrasound-guided cervical nerve root block (MUC). METHODS: This study included frozen shoulder patients who were unresponsive to conservative therapy for at least 6 months and were then treated with MUC. Patients with a rotator cuff tear, calcifying tendinitis, osteoarthritis, or any other shoulder disorder were excluded following X-ray, ultrasound, and magnetic resonance imaging evaluation. Although 25 patients were initially included, three patients were not followed-up for at least 1 year. We investigated a final total of 22 patients; the average age was 58 years and 59% were female. We measured shoulder pain, shoulder range of motion, and American Shoulder and Elbow Surgeons shoulder scores immediately prior to MUC, 1 week after MUC, and 1 year after MUC. A Short-Form 36-Item Health Survey was administered before MUC and 1 year after MUC. We used the Friedman and Wilcoxon signed-rank tests to identify statistical differences. Significance was defined as p < 0.05. RESULTS: MUC significantly improved shoulder pain during motion, range of motion, and American Shoulder and Elbow Surgeons scores 1 week after MUC. This improvement persisted at the 1-year follow-up. Seven of the eight Short-Form 36-Item Health Survey measures were significantly improved 1 year after MUC. One patient (4.5%) developed Horner's syndrome, although symptoms resolved within several hours without treatment. CONCLUSION: MUC for frozen shoulder was safe and resulted in a significant improvement in shoulder pain and range of motion 1 week after the procedure. This improvement persisted at the 1-year follow-up.

Differences in fatty degeneration of rotator cuff muscles at different sites, as quantified by T2 mapping.

BACKGROUND: Fatty degeneration of the cuff muscles is usually evaluated at the Y-view in oblique sagittal images. It was recently proposed that muscle shift after repair may influence the fatty degeneration values, and the evaluation of the muscles at a more medial site was recommended. However, the differences in muscle quality in accord with measurement sites have been unclear. Here we evaluated differences in fatty degeneration of the rotator cuff muscles measured quantitatively at different sites, using T2 mapping. METHODS: We assessed 702 shoulders of 675 patients (335 males, 340 females; mean age, 62 years) who underwent MRI including T2 mapping. There were 345 shoulders without rotator cuff tears and 357 shoulders with tears: partial tear = 103 shoulders; small = 63; medium = 94; large = 71; massive = 26. T2 values of the supraspinatus and infraspinatus muscles were measured on the Y-view and on the image that was 15 mm medial to the Y-view. RESULTS: The T2 values at the medial site increased with the tear extent, as did those on the Y-view. There were no significant differences in supraspinatus T2 values between those on the Y-view and at the medial site in all tear size groups except medium and large tears (p = 0.008 and p < 0.001, respectively). There were also no significant differences in infraspinatus T2 values between the two sites in all tear size groups except large tears (p = 0.002). However, the differences were relatively small (2.4-5.6 ms), which were within the standard deviations of the measurements. CONCLUSIONS: The T2 values of the supraspinatus and infraspinatus muscles on the Y-view and at 15 mm medial to it were almost identical, with the exception of small differences in the case of larger tears.

Magnetic resonance imaging and short-term clinical results of severe frozen shoulder treated with manipulation under ultrasound-guided cervical nerve root block.

BACKGROUND: We evaluated the magnetic resonance (MR) imaging findings and short-term clinical outcomes of severe idiopathic frozen shoulder treated with manipulation under ultrasound-guided cervical nerve root block (MUC). METHODS: The subjects were 30 patients (average age, 55.2 years; 12 men, 18 women) with severe frozen shoulder. Severe idiopathic frozen shoulder was defined as follows: a range of motion (ROM) of ≤ 100° in forward flexion, ≤ 10° in external rotation, and at or below the fifth lumbar vertebral level in internal rotation. Before the manipulation, all patients had continued global ROM loss for at least 6 months. Before and after manipulation, they underwent MR imaging. MR images and clinical results were evaluated 1 month after the procedure. RESULTS: In terms of the capsule tear pattern, MR imaging showed 14 midsubstance tears and 15 humeral avulsions of glenohumeral ligament-like lesions. An anterior labrum tear occurred in 4 shoulders, whereas 15 shoulders showed a bone bruise in the posterosuperior and anteromedial portions of the humeral head despite no humeral shaft fracture. There were significant improvements in the ROM, Constant-Murley score, American Shoulder and Elbow Surgeons score, and Numeric Rating Scale score from before treatment to 1 month after the procedure. CONCLUSION: MR imaging of patients with severe frozen shoulder after MUC showed 29 capsule tears, 4 labrum tears, and 15 bone bruises of the humeral head. Approximately 50% of patients are likely to experience bone bruising after MUC. Long-term follow-up of these patients should be performed carefully.

True boundary for the formation of homoleptic transition-metal hydride complexes.

Despite many exploratory studies over the past several decades, the presently known transition metals that form homoleptic transition-metal hydride complexes are limited to the Groups 7-12. Here we present evidence for the formation of Mg3 CrH8 , containing the first Group 6 hydride complex [CrH7 ](5-) . Our theoretical calculations reveal that pentagonal-bipyramidal H coordination allows the formation of σ-bonds between H and Cr. The results are strongly supported by neutron diffraction and IR spectroscopic measurements. Given that the Group 3-5 elements favor ionic/metallic bonding with H, along with the current results, the true boundary for the formation of homoleptic transition-metal hydride complexes should be between Group 5 and 6. As the H coordination number generally tends to increase with decreasing atomic number of transition metals, the revised boundary suggests high potential for further discovery of hydrogen-rich materials that are of both technological and fundamental interest.

Effect of orthodontic treatment on occlusal condition and masticatory function.

Change in occlusion and masticatory function after orthodontic treatment was investigated by a follow-up study in a group of 14 patients with malocclusion (3 men, 11 women, aged 12-46 years). All completed a food questionnaire and underwent occlusal force evaluation using a pressure-sensitive sheet at pre-treatment, post-treatment, and during the retention phase. The number of foods identified as difficult to eat decreased at post-treatment in all patients. The mean occlusal force was 646.6±223.5 N at pretreatment, 401.1±109.1 N at post-treatment, and 530.6±183.6 N during the retention phase. The mean occlusal contact area was 14.1±5.9 mm(2) at pre-treatment, 6.5±1.7 mm(2) at post-treatment, and 9.8±3.8 mm(2) during the retention phase. The mean average occlusal pressure was 47.6±6.6 MPa at pre-treatment, 62.2±5.7 MPa at post-treatment, and 55.4±6.7 MPa during the retention phase. A Dental Prescale film evaluation revealed that occlusal force and occlusal contact area increased over the 1-year retention phase. An improvement in level of satisfaction with mastication ability was reported at post-treatment and during the retention phase. Average occlusal pressure at post-treatment increased significantly (p <0.01), which may account for the observed increase in the ability of the patients to bite through food. These results suggest that an increase in average occlusal pressure improves level of satisfaction with mastication ability.

Pulmonary Artery Aneurysm in a Patient with Nontuberculous Mycobacteria Infection.

Nontuberculous mycobacterial (NTM) infection sometimes leads to the development of pulmonary artery aneurysm (PAA), a rare but life-threatening complication. We herein report a 64-year-old woman with a history of NTM infection who presented with severe hemoptysis. Computed tomography revealed a ruptured PAA, which was treated successfully with pulmonary artery embolization. Subsequent right total pneumonectomy was performed to control infection. This case emphasizes the need to consider PAA in patients with NTM infection who present with hemoptysis. Early detection and appropriate management are critical for preventing this fatal complication.

Pseudo-Wet Plasma Mechanism Enabling High-Throughput Dry Etching of SiO2 by Cryogenic-Assisted Surface Reactions.

Manufacturing semiconductor devices requires advanced patterning technologies, including reactive ion etching (RIE) based on the synergistic interactions between ions and etch gas. However, these interactions weaken as devices continuously scale down to sub-nanoscale, primarily attributed to the diminished transport of radicals and ions into the small features. This leads to a significant decrease in etch rate (ER). Here, a novel synergistic interaction involving ions, surface-adsorbed chemistries, and materials at cryogenic temperatures is found to exhibit a significant increase in the ER of SiO2 using CF4/H2 plasmas. The ER increases twofold when plasma with H2/(CF4 + H2) = 33% is used and the substrate temperature is lowered from 20 to -60 °C. The adsorption of HF and H2O on the SiO2 surface at cryogenic temperatures is confirmed using in situ Fourier transform infrared spectroscopy. The synergistic interactions of the surface-adsorbed HF/H2O as etching catalysts and plasma species result in the ER enhancement. Therefore, a mechanism called "pseudo-wet plasma etching" is proposed to explain the cryogenic etching process. This synergy demonstrates that the enhanced etch process is determined by the surface interactions between ions, surface-adsorbed chemistry, and the material being etched, rather than interactions between ion and gas phase, as observed in the conventional RIE.

A Case of Solitary Pure Ground-glass Opacity Suspected of Being the Initial Presentation of Nonfibrotic Hypersensitivity Pneumonitis.

We herein report a rare case of hypersensitivity pneumonitis (HP) that was initially demonstrated as solitary pure ground-glass opacity (GGO) on chest computed tomography (CT). A 51-year-old woman with a history of breast cancer underwent follow-up CT, which revealed solitary pure GGO. The patient developed exertional dyspnea after two years, and CT revealed diffuse centrilobular nodules in addition to GGO, which had increased in size. An antigen avoidance test was performed to diagnose HP, leading to the resolution of CT abnormalities, including the GGO. Our findings suggested that nonfibrotic HP can present as solitary pure GGO.