Inorganic PM2.5 reduction in Kanto, Japan: The role of ammonia and its emission sources control strategies.

Ammonia (NH3) is attracting attention as a carbon-free energy source and a significant precursor to inorganic PM2.5 (hereafter PM2.5), aside from NOx and SOx. Since the emission of NH3 has often been overlooked compared to NOx and SOx, this study aims to reveal the role of NH3 and its emission control on PM2.5 in Kanto, Japan. With the aid of gas ratio (GR) quantitatively defining the stoichiometry between the three precursors to PM2.5, and the aid of atmospheric modeling software ADMER-PRO, coupled with thermodynamics calculations, the spatiotemporal distribution along with PM2.5 reduction under different NH3 emission cutoff strategies in Kanto had been revealed for the first time. The cutoff of NH3 emission could effectively reduce the PM2.5 concentration, with sources originated from agriculture, human/pet activities, and vehicle sources, overall giving a 93.32% PM2.5 reduction. Different cutoff strategies lead to distinct reduction efficiencies of the overall and local PM2.5 concentrations, with GR as a crucial factor. The regions with GR ∼1, are sensitive to the NH3 concentration for forming PM2.5, at which the NH3 reduction strategies should be applied with high priority. On the other hand, installing a new NH3 emission source should be avoided in the region with GR < 1, suppressing the so-yielded PM2.5 pollution. The future PM2.5 pollution control related to the NH3 emission control strategies based on GR, which is stoichiometry-based and applicable to regions other than Kanto, has been discussed.

Ozone responses to reduced precursor emissions: A modeling analysis on how attainable goals can improve air quality in the Mexico City Metropolitan Area.

High tropospheric ozone (O3) concentrations prevent the improvement of the air quality in the Mexico City Metropolitan Area (MCMA). Although the problem has improved considerably since the 1990s, a rebound in O3 levels in recent years has raised concerns about the deteriorating air quality. The nonlinear relationship between O3 formation and the emissions of its main precursors, i.e., volatile organic compounds (VOCs) and nitrogen oxides (NOx), is a challenge when measures are enacted for effective mitigation of the O3 problem. This study evaluated the reduction in precursors, VOCs and NOx, using an up-to-date regional air quality model (HERMES-Mex-WRF-CMAQ). For evaluating realizable scenarios, the decline in VOC achieved in Japan after policy implementation was the targeted VOC reduction (40 % from area sources), and the NOx reduction observed in the MCMA during the COVID-19 pandemic was the targeted NOx reduction (40 % from mobile sources). The analysis evaluated the O3 responses to changes in a single precursor and a combination of both during a period of high O3 concentrations (April 2019). The results showed that 40 % reduction in VOC emissions would decrease the O3 8-h maximum concentrations by 16 %. However, 40 % reduction in NOx emissions would increase O3 by >15 %. The simultaneous reduction of both precursors did not significantly affect O3 levels. The diagnosis of ozone sensitivity using the H2O2/HNO3 ratios reinforced the simulation findings, indicating that VOC emissions limited ozone formation in most MCMA areas. As the simulated scenarios were based on factual case studies, our research offers insights into the realistic aims of MCMA policies to reduce O3 levels.

Enhancement of in vitro antibacterial activity and bioactivity of iodine-loaded titanium by micro-scale regulation using mixed-acid treatment.

Postoperative infection and subsequent device loss are serious complications in the use of titanium dental implants and plates for jawbone reconstruction. We have previously reported that NaOH-CaCl2 -thermal-ICl3 -treated titanium (NaCaThIo) has a nano-scale surface and exhibits antibacterial activity against Staphylococcus aureus. The present study examined the surface properties of mixed-acid treated and then iodine-treated titanium (MA-NaCaThIo), and evaluated oral antibacterial activity and cytotoxicity compared with the results obtained with NaCaThIo. MA-NaCaThIo formed a surface layer with a nano-scale network structure having microscale irregularities, and both the thickness of the surface layer (1.49 ± 0.16 µm) and the average surface roughness (0.35 ± 0.03 µm) were significantly higher than those of NaCaThIo. Furthermore, MA-NaCaThIo maintained high hydrophilicity with a contact angle of 7.5 ± 1.7° even after 4 weeks, as well as improved apatite formation, iodine ion release, and antibacterial activity against Prevotella intermedia compared to NaCaThIo. Cell culture test revealed that MA-NaCaThIo exhibited no cytotoxicity against MG-63 and Vero cells, while increased cell proliferation, ALP activity and mineralization of MG-63 compared to NaCaThIo. This treated titanium is expected to be useful for the development of next-generation titanium devices having both bone-bonding and antibacterial properties.

Clinical Study of 14 Cases of Bone Augmentation with Selective Laser Melting Titanium Mesh Plates.

Additive manufacturing techniques are being used in the medical field. Orthopedic hip prostheses and denture bases are designed and fabricated based on the patient's computer-aided design (CAD) data. We attempted to incorporate this technique into dental implant bone augmentation. Surgical simulation was performed using patient data. Fourteen patients underwent bone augmentation using a selective laser melting (SLM) titanium mesh plate. The results showed no evidence of infection in any of the 14 patients. In 12 patients, only one fixation screw was used, and good results were obtained. The SLM titanium mesh plate was good adaptation in all cases, with bone occupancy greater than 90%. The average bone resorption of the marginal alveolar bone from the time of dental implant placement to the time of the superstructure placement was 0.69 ± 0.25 mm. Implant superstructures were placed in all cases, and bone augmentation with SLM titanium mesh plates was considered a useful technique.

The Differences of Gambling-Related Harms Among Low-Investment and Normal-Investment Pachinko/Pachislot Players in Japan: A Cross Sectional Study.

Pachinko and pachislot are popular types of gambling activities in Japan. Prior studies in Japan have reported a concerning prevalence of problem gambling among adult players. While these studies have identified various gambling-related harms, Japanese research on harm-minimization strategies is scarce. Therefore, the present study aimed to compare differences of gambling-related harms among normal-, half-, and quarter-pachi players to the usefulness of low-investment pachinko and pachislot as a harm-reduction strategy. We considered gamblers who played games that cost the typical amount of money to be "normal-pachi players." Those who played low-investment games were categorized as "half-pachi players" and "quarter-pachi players," reflecting those who played games at half or one quarter the cost of a typical machine, respectively. To assess the harm-reduction effect, a one-way ANCOVA was conducted to compare the impact of the groups (normal-pachi players [n = 101], half-pachi players [n = 104], and quarter-pachi players [n = 100]) on dependent variables, namely the number of days players had gambled during the prior month; total time and amount of money spent on gambling; debts caused by gambling; gambling severity; cognitive distortion; depressive symptoms; and problems in work, family, and social life. We demonstrated that the amount of money spent by quarter-pachi players on gambling during the past month was lower than that of normal-pachi players. However, we did not find significant differences with respect to any other gambling-related harms among normal-, half-, and quarter-pachi players. Low-investment pachinko and pachislot players spends less the amount of money spent on gambling. Low-investment pachinko and pachislot would thus partly act as a harm-minimization strategy. Moreover, the results of the present study indicate that the problems at work affect various outcomes for gamblers. Given that 90% of the participants in this study were employed, the results of this study may have important implications for employed gamblers.

Impact of introducing net-zero carbon strategies on tropospheric ozone (O3) and fine particulate matter (PM2.5) concentrations in Japanese region in 2050.

In this study, we estimated the future emission inventory of primary air pollutants in Japan in 2050 after introducing low-carbon technology based on the results of the socio-economic model provided by the Japanese government. The results suggested that introducing net-zero carbon technology would contribute to a 50-60 % decrease in primary NOx, SO2, and CO emissions and a ~30 % decrease in primary emissions of volatile organic compounds (VOCs) and PM2.5. The estimated emission inventory and future meteorological conditions in 2050 were applied as inputs to a chemical transport model. A scenario involving the application of future reduction strategies with relatively moderate global warming (RCP4.5) was evaluated. The results showed that the concentration of tropospheric ozone (O3) was highly reduced compared with that in 2015 after applying net-zero carbon reduction strategies. On the other hand, the fine particulate matter (PM2.5) concentration under the 2050 scenario was expected to be equal or higher because of the growth in secondary aerosol formation caused by the increase in short-wave radiation. Finally, the premature mortality change from 2015 to 2050 was analyzed, and the change in air quality contributed by net-zero carbon technology will contribute to a ~4000 decrease in premature deaths in Japan.

Characterization of Oral Microbiota Following Chemotherapy in Patients With Hematopoietic Malignancies.

Oral microbiota may be associated with serious local or systemic medical conditions resulting from chemotherapy. This study was conducted to evaluate the changes in the oral microbiota following the initiation of chemotherapy in patients with hematopoietic malignancies and to identify the characteristics of the oral microbiota associated with oral mucositis. Oral samples were collected from 57 patients with hematopoietic malignancies at 2 time points: before the start of chemotherapy and 8 to 20 days after the start of chemotherapy, when chemotherapy-induced oral mucositis often occurs, and 16S rRNA metagenomic analyses were performed. Comparative and linear discriminant analysis effect size (LEfSe) analyses were used to determine the characteristic bacterial groups before and after the initiation of chemotherapy and in those who developed oral mucositis. The alpha and beta diversities of oral microbiota before and after the initiation of chemotherapy differed significantly (operational taxonomic unit index, P < .001; Shannon's index, P < .001; unweighted UniFrac distances, P = .001; and weighted UniFrac distances, P = .001). The LEfSe analysis revealed a group of bacteria whose abundance differed significantly before and after the initiation of chemotherapy. In the group of patients who developed oral mucositis, a characteristic group of bacteria was identified before the start of chemotherapy. In conclusion, we characterized the oral microbiota associated with the initiation of chemotherapy in patients with hematopoietic malignancies. In addition, our findings suggest that oral microbiota composition before the start of chemotherapy may be associated with oral mucositis. The results of this study emphasize the importance of oral management focusing on the oral microbiota during chemotherapy in patients with hematologic malignancies.

Application of the Homologous Modeling Technique for Precision Medicine in the Field of Oral and Maxillofacial Surgery.

In the field of oral and maxillofacial surgery, establishment of a new method for predicting morphology is desirable. Therefore, the purpose of the present study was to establish a new method for predicting the original shape of a mandibular defect site using the homologous modeling technique. This study used data from 44 patients who underwent computed tomography in the Department of Oral Surgery at Osaka Medical College. Two types of homologous models were constructed: total mandible (TM) and half mandible (HM). Principal component analysis (PCA) was performed using point cloud data of the homologous model M and homologous model HM, and a multiple regression equation was created using the PC value of TM as the object variable and PC value of HM as the explanatory variable. The predicted PC (M) was created from PC (HM) using a regression formula, back-calculated from point cloud data from PC (M), to create the predicted mandible model. Finally, the original image (TC-M) and estimated mandible were superposed and examined. The mean absolute error between the predicted mandible and actual mandible was 1.04 ± 1.35 mm. We believe that this method will be applicable in actual clinical practice.

A stepwise route to domesticate rice by controlling seed shattering and panicle shape.

Asian rice (Oryza sativa L.) is consumed by more than half of the world's population. Despite its global importance, the process of early rice domestication remains unclear. During domestication, wild rice (Oryza rufipogon Griff.) acquired non-seed-shattering behavior, allowing humans to increase grain yield. Previous studies argued that a reduction in seed shattering triggered by the sh4 mutation led to increased yield during rice domestication, but our experiments using wild introgression lines show that the domesticated sh4 allele alone is insufficient for shattering loss in O. rufipogon. The interruption of abscission layer formation requires both sh4 and qSH3 mutations, demonstrating that the selection of shattering loss in wild rice was not as simple as previously suggested. Here we identified a causal single-nucleotide polymorphism at qSH3 within the seed-shattering gene OsSh1, which is conserved in indica and japonica subspecies but absent in the circum-aus group of rice. Through harvest experiments, we further demonstrated that seed shattering alone did not significantly impact yield; rather, yield increases were observed with closed panicle formation controlled by SPR3 and further augmented by nonshattering, conferred by integration of sh4 and qSH3 alleles. Complementary manipulation of panicle shape and seed shattering results in a mechanically stable panicle structure. We propose a stepwise route for the earliest phase of rice domestication, wherein selection of visible SPR3-controlled closed panicle morphology was instrumental in the sequential recruitment of sh4 and qSH3, which together led to the loss of shattering.

Usefulness of ultrasound in diagnosing long head of the biceps tendon malposition in patients with rotator cuff tears.

PURPOSE: This study aimed to determine the role of preoperative shoulder ultrasonography (SUS) in detecting positional abnormalities of the long head of the biceps tendon (LHBT) and predicting subscapularis (SSC) tears in patients with rotator cuff injuries. METHODS: A total of 331 patients (365 shoulders) who had undergone arthroscopic shoulder surgery for the treatment of rotator cuff tears were included in the study. Their preoperative SUS and magnetic resonance imaging (MRI) findings were examined retrospectively to assess the presence of LHBT abnormalities at the bicipital groove. Using arthroscopic findings as the standard of reference, the sensitivity, specificity, and diagnostic accuracy of SUS and MRI were calculated for detection of LHBT malposition. Furthermore, the correlation between SSC rupture and preoperative LHBT condition was evaluated by MRI and SUS. RESULTS: LHBT malposition was preoperatively diagnosed with a sensitivity of 92%, specificity of 90%, and accuracy of 91% with SUS, and a sensitivity of 74%, specificity of 84%, and accuracy of 80% with MRI. Preoperative SUS was significantly superior to MRI in terms of sensitivity, specificity, and accuracy (p < 0.001 each). Further, the preoperative SUS LHBT findings could predict well the presence or absence of intraoperative SSC rupture (odds ratio: 1.73, p < 0.001). CONCLUSION: SUS is a useful diagnostic modality for preoperative detection of LHBT malposition and prediction of SSC tears in patients with rotator cuff tears.

Acromioclavicular joint instability on cross-body adduction view: the biomechanical effect of acromioclavicular and coracoclavicular ligaments sectioning.

BACKGROUND: The acromioclavicular (AC) and coracoclavicular (CC) ligaments are important stabilizers of the AC joint. We hypothesized that AC and trapezoid ligament injuries induce AC joint instability and that the clavicle can override the acromion on cross-body adduction view even in the absence of conoid ligament injury. Accordingly, we investigated how sectioning the AC and CC ligaments contribute to AC joint instability in the cross-body adduction position. METHODS: Six fresh-frozen cadaveric shoulders were used in this study, comprising five male and one female specimen, with a mean age of 68.7 (range, 51-87) years. The left side of the trunk and upper limb, and the cervical and thoracic vertebrae and sternum were firmly fixed with an external fixator. The displacement of the distal end of the clavicle relative to the acromion was measured using an electromagnetic tracking device. We simulated AC joint dislocation by the sequential resection of the AC ligament, AC joint capsule, and CC ligaments in the following order of stages. Stage 0: Intact AC and CC ligaments and acromioclavicular joint capsule; stage 1: Completely sectioned AC ligament, capsule and joint disc; stage 2: Sectioned trapezoid ligament; and stage 3: Sectioned conoid ligament. The superior clavicle displacement related to the acromion was measured in the horizontal adduction position, and clavicle overriding on the acromion was assessed radiologically at each stage. Data were analyzed using a one-way analysis of variance and post-hoc tests. RESULTS: Superior displacement was 0.3 mm at stage 1, 6.5 mm at stage 2, and 10.7 mm at stage 3. On the cross-body adduction view, there was no distal clavicle overriding at stages 0 and 1, and distal clavicle overriding was observed in five cases (5/6: 83%) at stage 2 and in six cases (6/6: 100%) at stage 3. CONCLUSION: We found that AC and trapezoid ligament sectioning induced AC joint instability and that the clavicle could override the acromion on cross-body adduction view regardless of conoid ligament sectioning. The traumatic sections of the AC and trapezoid ligament may lead to high grade AC joint instability, and the distal clavicle may subsequently override the acromion.

The effect of simple heat treatment on apatite formation on grit-blasted/acid-etched dental Ti implants already in clinical use.

Grit-blasted/acid-etched titanium dental implants have a moderately roughened surface that is suitable for cell adhesion and exhibits faster osseointegration. However, the roughened surface does not always maintain stable fixation over a long period. In this study, a simple heat treatment at 600°C was performed on a commercially available dental Ti implant with grit-blasting/acid-etching, and its effect on mineralization capacity was assessed by examining apatite formation in a simulated body fluid (SBF). The as-purchased implant displayed a moderately roughened surface at the micrometer scale. Its surface was composed of titanium hydride accompanied by a small amount of alumina particles derived from the grit-blasting. Heat treatment transformed the titanium hydride into rutile without evidently changing the surface morphology. The immersion in SBF revealed that apatite formed on the heated implant at 7 days. Furthermore, apatite formed on the Ti rod surface within 1 day when the metal was subjected to acid and heat treatment without blasting. These indicate that apatite formation was conferred on the commercially available dental implant by simple heat treatment, although its induction period was slightly affected by alumina particles remaining on the implant surface. The heat-treated implant should achieve stronger and more stable bone bonding due to its apatite formation.

The validation and reliability of a Japanese version of the Problematic Online Gaming Questionnaire (POGQ-J).

BACKGROUND: The Problematic Online Gaming Questionnaire (POGQ) is an 18-item self-rated measure designed to assess the degree of problematic online gaming. This study translated the POGQ into Japanese (POGQ-J) and examined the POGQ-J's factor structure, validity, and reliability for a Japanese population. METHOD: A total of 285 undergraduate students (128 males, 157 females, Mage = 19.66, SD = 1.36) participated in this study. RESULTS: A confirmatory factor analysis indicated the appropriateness of the POGQ-J's six-factor structure, χ2(129) = 106.027, p < .931; CFI = .957; RMSEA = .040; SRMR = .054. Regarding convergent validity, the POGQ-J was found to be related to the time spent on online gaming (r = .309), the Game Addiction Scale for Adolescents (r = .824), and Young's Internet Addiction Test (r = .581). Finally, the POGQ-J was found to have a high test-retest reliability. CONCLUSIONS: The POGQ-J is valid and reliable for assessing problematic online gaming in a Japanese population.

Exploring the size of reference population for expected accuracy of genomic prediction using simulated and real data in Japanese Black cattle.

BACKGROUND: Size of reference population is a crucial factor affecting the accuracy of prediction of the genomic estimated breeding value (GEBV). There are few studies in beef cattle that have compared accuracies achieved using real data to that achieved with simulated data and deterministic predictions. Thus, extent to which traits of interest affect accuracy of genomic prediction in Japanese Black cattle remains obscure. This study aimed to explore the size of reference population for expected accuracy of genomic prediction for simulated and carcass traits in Japanese Black cattle using a large amount of samples. RESULTS: A simulation analysis showed that heritability and size of reference population substantially impacted the accuracy of GEBV, whereas the number of quantitative trait loci did not. The estimated numbers of independent chromosome segments (Me) and the related weighting factor (w) derived from simulation results and a maximum likelihood (ML) approach were 1900-3900 and 1, respectively. The expected accuracy for trait with heritability of 0.1-0.5 fitted well with empirical values when the reference population comprised > 5000 animals. The heritability for carcass traits was estimated to be 0.29-0.41 and the accuracy of GEBVs was relatively consistent with simulation results. When the reference population comprised 7000-11,000 animals, the accuracy of GEBV for carcass traits can range 0.73-0.79, which is comparable to estimated breeding value obtained in the progeny test. CONCLUSION: Our simulation analysis demonstrated that the expected accuracy of GEBV for a polygenic trait with low-to-moderate heritability could be practical in Japanese Black cattle population. For carcass traits, a total of 7000-11,000 animals can be a sufficient size of reference population for genomic prediction.

Histological Evaluation of Porous Additive-Manufacturing Titanium Artificial Bone in Rat Calvarial Bone Defects.

Jaw reconstruction using an additive-manufacturing titanium artificial bone (AMTAB) has recently attracted considerable attention. The synthesis of a titanium artificial bone is based on three-dimensional computed tomography images acquired before surgery. A histological evaluation of porous AMTAB (pAMTAB) embedded in rat calvarial bone defects was conducted. This study examined three groups: rats implanted with mixed-acid and heat-treated pAMTAB, rats implanted with untreated pAMTAB, and rats with no implant. In both pAMTAB groups, bone defects were created in rat calvarial bones using a 5-mm trephine bar, followed by pAMTAB implantation. The pAMTAB was fixed to the defect using the fitting force of the surrounding bones. The rats were sacrificed at 4, 8, and 16 weeks after implantation, and the skull was dissected. Undecalcified ground slides were prepared and stained with Villanueva Goldner. Compared with the no implant control group, both pAMTAB groups exhibited new bone formation inside the defect, with greater bone formation in the mixed-acid and heat-treated pAMTAB group than in the untreated pAMTAB group, but the difference was not significant. These data suggest that pAMTAB induces bone formation after implantation in bone defects. Bone formation appears to be enhanced by prior mixed-acid and heat-treated pAMTAB.

Increased nitrogen deposition contributes to plant biodiversity loss in Japan: Insights from long-term historical monitoring data.

Atmospheric deposition of reactive nitrogen compounds (Nrs) has been recognized as a threat to plant diversity in terrestrial ecosystems. As a first attempt to investigate the relationship between Nrs deposition and plant diversity loss in Japan, we collected and analyzed the available long-term nationwide monitoring data on annual Nrs deposition and plant (tree) species, and evaluated the relationship between Nrs deposition and plant species loss at corresponding sites. Analyses of the available data showed that the amount of Nrs deposited annually tended to decrease at two monitoring sites (Yusuhara, Hedomisaki) and increase at six monitoring sites across Japan (Rishiri, Sadoseki, Tokyo, Aichi, Oki, and Ogasawara) during the late 1980s to 2011, especially at Aichi (11.8-21.6 kgN·ha-1·yr-1), Tokyo (10.0-23.5 kgN·ha-1·yr-1), Oki (6.63-14.1 kgN·ha-1·yr-1), and Rishiri (4.52-7.82 kgN·ha-1·yr-1). Another long-term study, the Monitoring Sites 1000 Project, investigated the growth of tree species at 20 core sites across Japan during 2004-2012. The sites with higher potential plant diversity loss were close to those sites where Nrs deposition had markedly increased over the 20 years, such as Tokyo, Aichi, and Oki. Analyses of long-term monitoring data for tree species in the Tokyo University Forest in Aichi revealed that 22 of the 273 tree species (8.05%) disappeared during the period of 1990-2010, and twelve out of the 22 lost species were shrub species less than 5 m tall. Although our study obviously has some limitations in quantitatively presenting the relationship between the loss of plant diversity and increased atmospheric Nrs deposition in Japan, our findings provide evidence for this relationship based on analyses of historical nationwide monitoring data. These findings will be useful for establishing N critical loads for Japanese forests.

Bioactivation Treatment with Mixed Acid and Heat on Titanium Implants Fabricated by Selective Laser Melting Enhances Preosteoblast Cell Differentiation.

Selective laser melting (SLM) is a promising technology capable of producing individual characteristics with a high degree of surface roughness for implants. These surfaces can be modified so as to increase their osseointegration, bone generation and biocompatibility, features which are critical to their clinical success. In this study, we evaluated the effects on preosteoblast proliferation and differentiation of titanium metal (Ti) with a high degree of roughness (Ra = 5.4266 ± 1.282 µm) prepared by SLM (SLM-Ti) that was also subjected to surface bioactive treatment by mixed acid and heat (MAH). The results showed that the MAH treatment further increased the surface roughness, wettability and apatite formation capacity of SLM-Ti, features which are useful for cell attachment and bone bonding. Quantitative measurement of osteogenic-related gene expression by RT-PCR indicated that the MC3T3-E1 cells on the SLM-Ti MAH surface presented a stronger tendency towards osteogenic differentiation at the genetic level through significantly increased expression of Alp, Ocn, Runx2 and Opn. We conclude that bio-activated SLM-Ti enhanced preosteoblast differentiation. These findings suggest that the mixed acid and heat treatment on SLM-Ti is promising method for preparing the next generation of orthopedic and dental implants because of its apatite formation and cell differentiation capability.

The Role of the Acromioclavicular Ligament in Acromioclavicular Joint Stability: A Cadaveric Biomechanical Study.

BACKGROUND: Acromioclavicular (AC) joint dislocation is evaluated using the radiologically based Rockwood classification. The relationship between ligamentous injury and radiological assessment is still controversial. PURPOSE/HYPOTHESIS: To investigate how the AC ligament and trapezoid ligament biomechanically contribute to the stability of the AC joint using cadaveric specimens. The hypothesis was that isolated sectioning of the AC ligament would result in increased instability in the superior direction and that displacement >50% of the AC joint would occur. STUDY DESIGN: Controlled laboratory study. METHODS: Six shoulders from 6 fresh-frozen cadavers were used in this study. Both the scapula and sternum were solidly fixed on a customized wooden jig with an external fixator. We simulated distal clavicular dislocation with sequential sectioning of the AC and coracoclavicular (CC) ligaments. Sectioning stages were defined as follows: stage 0, the AC ligament, CC ligament, and AC joint capsule were left intact; stage 1, the anteroinferior bundle of the AC ligament, joint capsule, and disk were sectioned; stage 2, the superoposterior bundle of the AC ligament was sectioned; and stage 3, the trapezoid ligament was sectioned. The distal clavicle was loaded with 70 N in the superior and posterior directions, and the magnitudes of displacement were measured. RESULTS: The amounts of superior displacement averaged 3.7 mm (stage 0), 3.8 mm (stage 1), 8.3 mm (stage 2), and 9.5 mm (stage 3). Superior displacement >50% of the AC joint was observed in stage 2 (4/6; 67%) and stage 3 (6/6; 100%). The magnitudes of posterior displacement were 3.7 mm (stage 0), 3.7 mm (stage 1), 5.6 mm (stage 2), and 9.8 mm (stage 3). Posterior displacement >50% of the AC joint was observed in stage 3 (1/6; 17%). CONCLUSION: We found that the AC ligaments contribute significantly to AC joint stability, and superior displacement >50% of the AC joint can occur with AC ligament tears alone. CLINICAL RELEVANCE: The AC ligament plays an important role not only in horizontal stability but also in vertical stability of the AC joint.

Comparative evaluation of microbial profiles of oral samples obtained at different collection time points and using different methods.

OBJECTIVES: Recently, the oral microbiome has been found to be associated with oral and general health status. Although various oral sample collection protocols are available, the potential differences between the results yielded by these protocols remain unclear. In this study, we aimed to determine the effects of different time points and methods of oral sample collection on the outcomes of microbiome analysis. MATERIALS AND METHODS: Oral samples were collected from eight healthy individuals at four different time points: 2 h after eating, immediately after teeth brushing, immediately after waking up, and 2 h after eating on the subsequent day. Four methods of saliva collection were evaluated: spitting, gum chewing, cotton swab, and oral rinse. Oral microbiomes of these samples were compared by analyzing the bacterial 16S rRNA gene sequence data. RESULTS: The oral microbial composition at the genus level was similar among all sample collection time points and methods. Alpha diversity was not significantly different among the groups, whereas beta diversity was different between the spitting and cotton swab methods. Compared with the between-subject variations, the weighted UniFrac distances between the groups were not minor. CONCLUSIONS: Although the oral microbiome profiles obtained at different collection time points and using different methods were similar, some differences were detected. CLINICAL RELEVANCE: The results of the present study suggest that although all the described protocols are useful, comparisons among microbiomes of samples collected by different methods are not appropriate. Researchers must be aware of the issues regarding the impact of saliva collection methods.