Formate-producing capacity provided by reducing ability of Streptococcus thermophilus nicotinamide adenine dinucleotide oxidase determines yogurt acidification rate.

Yogurt is made by fermenting milk with 2 lactic acid bacteria, Lactobacillus delbrueckii ssp. bulgaricus and Streptococcus thermophilus. To comprehensively understand the protocooperation mechanism between S. thermophilus and L. bulgaricus in yogurt fermentation, we examined 24 combinations of cocultures comprising 7 fast- or slow-acidifying S. thermophilus strains with 6 fast- or slow-acidifying L. bulgaricus strains. Furthermore, 3 NADH oxidase (Nox)-deficient mutants (Δnox) and one pyruvate formate-lyase deficient mutant (ΔpflB) of S. thermophilus were used to evaluate the factor that determines the acidification rate of S. thermophilus. The results revealed that the acidification rate of S. thermophilus monoculture determined the yogurt fermentation rates, despite the coexistence of L. bulgaricus, whose acidification rate was either fast or slow. Significant correlation was found between the acidification rate of S. thermophilus monoculture and the amount of formate production. Result using ΔpflB showed that the formate was indispensable for the acidification of S. thermophilus. Moreover, results of the Δnox experiments revealed that formate production required Nox activity, which not only regulated dissolved oxygen, but also the redox potential. The Nox provided the large decrease in redox potential required by pyruvate formate-lyase to produce formate. A highly significant correlation was found between formate accumulation and Nox activity in S. thermophilus. In conclusion, the formate production ability provided by the action of Nox activity determines the acidification rate of S. thermophilus, and consequently, regulates yogurt coculture fermentation.

Evaluation of flexible ureteroscope with an omni-directional bending tip, using a JOYSTICK unit (URF-Y0016): an ex-vivo study.

PURPOSE: To compare the range of reach of our newly designed omni-directional ureteroscope (URF-Y0016), compared to the commonly used URF-P6, FlexX2s, and LithoVue™ scopes, in the upper, middle, and lower calyces in an ex-vivo pyelocaliceal model. METHODS: We fabricated a three-dimensional pyelocaliceal model of the upper, middle, and lower pole calyces using urethane and acrylic resin. The inner surface of the dome of each calyx was engraved with reference lines along eight directions, set at 10° of latitude from the top to the base of the dome, and at angles of 0-90°, to precisely determine the range of reach of each scope. The main feature of the URF-Y0016 scope is the omni-directional bending of the tip of the flexible ureteroscope, with the control of these four directions integrated into a handgun-type control unit with a joystick. The range of reach within each calyx was measured by four expert surgeons. RESULTS: The URF-Y0016 scope provided a greater range of reach along all directions in the lower pole calyx compared to URF-P6, FlexX2s, and LithoVue™ scopes (p < 0.001), particularly along the anterior-posterior direction in the lower lobe calyx. However, the URF-Y0016 scope did not influence the improvement of reach range in the upper and middle pole calyx compared to URF-P6, FlexX2s, and LithoVue™ scopes (p = 0.08, p = 0.296). CONCLUSION: The novel design of the URF-Y0016 could improve treatment outcomes for calyceal stones in the lower pole in practice.

The association between dentition status and sarcopenia in Japanese adults aged ≥75 years.

Sarcopenia is an age-related loss of muscle mass and muscle strength or physical performance. There are limited data on the association between oral health and sarcopenia. To test the hypothesis that impaired dentition status was associated with sarcopenia, we conducted a cross-sectional study. A total of 272 community-dwelling Japanese adults aged ≥75 years for whom data were available from comprehensive health examinations conducted in 2015 were included in this study. During dental examination, the number of natural teeth and occluding pairs of natural teeth was counted. In denture wearers, the fit of the removable dentures was also evaluated. The criteria proposed by the Asian Working Group for Sarcopenia were used to define sarcopenia. A multivariable logistic regression model was used to evaluate the association between dentition status and the presence of sarcopenia. The prevalence of sarcopenia was 25·7% (70/272). Compared to individuals with ≥10 occluding pairs of natural teeth, those with no occluding pairs of natural teeth had significantly higher risk of having sarcopenia (adjusted odds ratio, 3·37; 95% confidence interval, 1·07-10·61), after adjusting for possible confounders. In addition, compared to individuals with well-fitting dentures, those with ill-fitting dentures had significantly higher risk of having sarcopenia (adjusted odds ratio, 5·07; 95% confidence interval, 1·59-16·19). Our findings suggest that impaired dentition status is significantly associated with sarcopenia among community-dwelling Japanese adults aged ≥75 years. Future longitudinal studies with larger, more diverse populations are necessary to validate our findings.

Longitudinal relationship of severe periodontitis with cognitive decline in older Japanese.

BACKGROUND AND OBJECTIVE: Epidemiologic data examining the longitudinal relationship between periodontitis and cognitive status are very limited, especially in Asian populations. The present study examined the longitudinal relationship of periodontitis with cognitive decline in 85 Japanese community-dwelling individuals (average age: 79.3 years) for whom data were available from comprehensive health examinations conducted in 2010 and 2013. MATERIAL AND METHODS: Based on a baseline full-mouth periodontal examination, severe periodontitis was defined using a Centers for Disease Control and Prevention/American Academy of Periodontology definition. Cognitive decline during the 3-year study period was defined using the results of the Mini-Mental State Examination (MMSE). Information on age, gender, education, depression, body mass index, smoking status, alcohol use, exercise, hypertension, diabetes, history of cardiovascular disease and stroke, and baseline MMSE scores were obtained and tested as potential confounders in the statistical models. RESULTS: Among 85 study participants, 21 (24.7%) were defined as having severe periodontitis. Multivariable Poisson regression analyses revealed that severe periodontitis was significantly associated with an increased risk of cognitive decline [adjusted relative risk = 2.2; 95% confidence interval (95% CI): 1.1-4.5]. Furthermore, multivariable linear regression analyses revealed that participants with severe periodontitis had a 1.8-point greater decrease (95% CI: -3.3 to -0.2) in MMSE score than those without severe periodontitis. CONCLUSION: Within the limitations related to its small sample size, the findings of the present study suggest that severe periodontitis is significantly associated with future decline in cognitive function among community-dwelling older Japanese subjects.

Retrospective study for risk factors for febrile UTI in spinal cord injury patients with routine concomitant intermittent catheterization in outpatient settings.

STUDY DESIGN: Retrospective study. OBJECTIVES: The objective of this study was to investigate the clinical risk factors for febrile urinary tract infection (UTI) in spinal cord injury-associated neurogenic bladder (NB) patients who perform routine clean intermittent catheterization (CIC). SETTING: Rehabilitation Hospital, Kobe, Japan. METHODS: Over a 3-year period, we retrospectively assessed the clinical risk factors for febrile UTI in 259 spinal cord injury patients diagnosed as NB and performing routine CIC with regard to the factors such as gender, the presence of pyuria and bacteriuria, and the categories of the American Spinal Injury Association (ASIA) impairment scale. RESULTS: A total of 67 patients had febrile UTI in the follow-up period, with 57 cases of pyelonephritis, 11 cases of epididymitis and 2 cases of prostatitis, including the patients with plural infectious diseases. The causative bacteria were ranked as follows: Escherichia coli (74 cases), Pseudomonas aeruginosa (17 cases), Enterococcus faecalis (14 cases) and Klebsiella pneumoniae (12 cases). Antibiotic-resistant E. coli were seen, with 10.5% instances of extended-spectrum ß-lactamase (ESBL) production and 23.8% of fluoroquinolone resistance. Multivariate analyses of clinical risk factors for febrile UTI showed that gender (male, P=0.0431), and ASIA impairment scale C or more severe (P=0.0266) were significantly associated with febrile UTI occurrence in NB patients with routine CIC. CONCLUSION: Our data demonstrated gender (male) and ASIA impairment scale C or more severe were significantly associated with febrile UTI occurrence in NB patients using routine CIC. Further prospective studies are necessary to define the full spectrum of possible risk factors for febrile UTI in these patients.

Effects of dutasteride on serum free-testosterone and clinical significance of testosterone changes.

Sixty-two patients with benign prostate hyperplasia (BPH) who were being treated with dutasteride participated in this study. Prostate volume, uroflowmetry, blood tests, the International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF-5) were determined before and 1, 3 and 12 months after the treatment with dutasteride. Patients were divided into two groups based on changes in serum testosterone after 1 month: Group A (>20% increase; n = 33) or Group B (<20% increase; n = 29). Serum free-testosterone levels were 20.4% higher after 1 month and remained constant thereafter. When Groups A and B were compared, baseline free-testosterone levels were significantly lower in Group A, IPSS QOL was significantly better in Group A at 3 and 12 months, and no significant differences were observed in uroflowmetry, prostate volume, IPSS or IIEF-5. A univariate analysis identified serum free-testosterone levels and the IPSS storage symptom subscore as significant factors influencing IPSS QOL at 12 months, and only the IPSS storage symptom subscore appeared to be independently related to IPSS QOL. These results indicate that dutasteride increases serum free-testosterone levels in BPH patients, particularly with low baseline free-testosterone levels, and the increase in free-testosterone may have further add-on impacts on their urinary tract symptoms.

Seminal level of clusterin in infertile men as a significant biomarker reflecting spermatogenesis.

The objective of this study was to assess the impact of seminal clusterin level on spermatogenesis in infertile men. This study included 89 men who visited our clinic due to infertility, consisting of 28, 33, and 28 diagnosed with normospermia, oligozoospermia and nonobstructive azoospermia (NOA) respectively. The seminal clusterin concentrations measured by enzyme-linked immunosorbent assay were 47.9, 28.2 and 18.4 ng ml-1 in men with normospermia, oligozoospermia and NOA, respectively, with significant differences among these three groups (P < 0.01). Microdissection testicular sperm extraction (MD-TESE) was performed in the 28 men with NOA, and spermatozoon was successfully retrieved from 9. There was a significant correlation between seminal clusterin level and testicular clusterin protein expression evaluated by immunohistochemical staining in these men with NOA (P = 0.026). Of several parameters available before MD-TESE, the univariate analysis identified serum follicle-stimulating hormone (FSH) level <10 IU ml-1 and seminal clusterin level ≥18 ng ml-1 as significant predictors of sperm retrieval, and of these, only serum FSH level <10 IU ml-1 was shown to be independently associated with sperm retrieval in the multivariate analysis. Accordingly, it might be worthy to further evaluate the significance of seminal clusterin level as a biomarker for the assessment of spermatogenic status in infertile men.

Clusterin produced by Sertoli cells inhibits heat stress-induced apoptosis in the rat testis.

The objectives of this study were to determine whether the inhibition of clusterin expression in rat Sertoli cells enhances heat stress-induced apoptosis. The scrotums of rats were immersed in a water bath of 43 °C for 15 min. Testicular weight and germ cell number markedly decreased after the heat treatment in a time-dependent manner. In contrast, clusterin mRNA and protein expression levels were significantly up-regulated and peaked on day 21. The apoptotic index was markedly increased 1 day after the heat treatment. We then purified Sertoli cells from the rat testes, and an expression vector containing siRNA targeting the clusterin gene was transiently transfected into Sertoli cells. Following exposure to heat stress at 41 °C for 12 h, clusterin mRNA was markedly up-regulated after transfection with the control vector; however, the transfection of siRNA targeting the clusterin resulted in >70% reduction in the expression of clusterin mRNA. Furthermore, the apoptotic index in these Sertoli cells was significantly higher after the treatment with siRNA targeting the clusterin than control, and the most prominent difference was observed within 24 h after the heat treatment. These results suggest that an increase in the secretion of clusterin by Sertoli cells protects the testes from heat stress-induced injury.

Prospective assessment of health-related quality of life in men with late-onset hypogonadism who received testosterone replacement therapy.

The objective of this study was to characterise the status of health-related quality of life (HRQOL) in Japanese men with late-onset hypogonadism (LOH) treated with testosterone replacement therapy (TRT). HRQOL in 69 consecutive Japanese men with LOH undergoing TRT for at least 6 months was prospectively evaluated before and 6 months after the initiation of TRT using the Medical Outcomes Study 8-Item Short-Form Health Survey (SF-8). All eight-scale scores except for bodily pain (BP) in the 69 patients at 6 months after the introduction of TRT significantly improved compared with those before TRT; however, all scale scores except for BP in the 69 patients were significantly inferior to those in age-matched Japanese controls irrespective of the timing of SF-8. Multivariate analyses of several parameters revealed that both age and Aging Male Symptom (AMS) score had an independent impact on mental health (MH), despite the lack of an independent association between any score and the remaining factors examined. TRT appeared to significantly improve the status of HRQOL in men with LOH; however, even after the introduction of TRT, HRQOL associated with MH remained significantly impaired in elderly men and/or those with a high AMS score.

Phase I/II study of S-1 in combination with sorafenib for metastatic renal cell carcinoma.

BACKGROUND: The potential of S-1 for the treatment of metastatic renal cell carcinoma (mRCC) has been shown in two phase II studies. We aimed to assess the safety, tolerance, pharmacokinetics and clinical activity of S-1 combined with sorafenib in patients with mRCC. PATIENTS AND METHODS: In this multicenter, single-arm, open-label, phase I/II study of S-1 plus sorafenib, we recruited patients with clear-cell or papillary renal cell carcinoma who had received a maximum of one prior cytokine-based regimen. The phase I primary end points were the maximum tolerated dose (MTD) and recommended dose (RD). S-1 was administered orally at 60, 80, 100 or 120 mg/day on days 1-28 of a 42-day cycle in combination with sorafenib (400 or 800 mg/day), given daily with dose adjustment. In phase II, the primary end point was to assess the overall response rate (ORR) at the RD. RESULTS: Nine patients were enrolled into phase I and 21 (including 6 patients who received the RD in the phase I portion) were enrolled into phase II. In the phase I portion, the MTD could not be determined, and the RD was defined as S-1 80 mg/m(2)/day on days 1-28 + sorafenib 800 mg/day on days 1-42. In the phase II portion, 21 patients were fully assessable for efficacy and safety. The confirmed ORR was 52% [95% confidence interval (CI) 29.8-74.3], including one complete response (5%) and 10 partial responses (48%). The median progression-free survival was 9.9 (95% CI 6.5-17.1) months. The most frequently reported treatment-related adverse event for all grades was hand-foot skin reaction (100%). The major reasons for dose reduction were hand-foot skin reaction (38%) and rash (14%). CONCLUSION: Combination therapy with S-1 plus sorafenib is effective and tolerable for patients with mRCC. However, skin events management is important in S-1 plus sorafenib combination therapy.

Involvement of TRPV1 and AQP2 in hypertonic stress by xylitol in odontoblast cells.

AIM: To examine the responses of mouse odontoblast-lineage cell line (OLC) cultures to xylitol-induced hypertonic stress. METHODOLOGY: OLCs were treated with xylitol, sucrose, sorbitol, mannitol, arabinose and lyxose. Cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay. The expression of transient receptor potential vanilloids (TRPV) 1, 3 and 4 was detected using a reverse transcriptase-polymerase chain reaction (RT-PCR) assay. The expression of aquaporin (AQP) 2 was detected using immunofluorescence and Western blotting analysis. The expression of interleukin-6 (IL-6) under xylitol-induced hypertonic stress was assessed using an enzyme-linked immunosorbent assay (ELISA). Small interfering ribonucleic acid (siRNA) for AQP-2 was used to inhibition assay. RESULTS: Xylitol-induced hypertonic stress did not decrease OLC viability, unlike the other sugars tested. OLCs expressed TRPV1, 3 and 4 as well as AQP2. Xylitol inhibited lipopolysaccharide (LPS)-induced IL-6 expression after 3 h of hypertonic stress. TRPV1 mRNA expression was upregulated by xylitol. Costimulation with HgCl2 (AQP inhibitor) and Ruthenium red (TRPV1 inhibitor) decreased cell viability with xylitol stimulation. OLCs treated with siRNA against TRPV1 exhibited decreased cell viability with xylitol stimulation. CONCLUSION: OLCs have high-cell viability under xylitol-induced hypertonic stress, which may be associated with TRPV1 and AQP2 expressions.

Emergence and prevention measures for multidrug resistant Pseudomonas aeruginosa in catheter-associated urinary tract infection in spinal cord injury patients.

OBJECTIVE: To evaluate measures for preventing multidrug resistant Pseudomonas aeruginosa (MDRP) in catheter-associated urinary tract infection (CAUTI) in spinal cord injury patients. SETTING: Spinal Cord Injury Unit of Hyogo Prefectural Hyogo Prefectural Rehabilitation Center, Kobe, Japan. METHODS: We defined MDRP as resistance to amikacin, imipenem and levofloxacin. We had eight cases of MDRP-causing CAUTI in hospitalized neurogenic bladder patients caused by spinal cord injury in 2 months. Pulse-field gel electrophoresis (PFGE) was performed for epidemiological studies. We assessed prevention measures against MDRP emergence from the 2nd month, such as surveillance of CAUTI and infection control, and evaluated the outcomes of these measures over a total of 8 months. RESULTS: Our PFGE results showed that these eight MDRP isolates could be considered as closely related strains. We concluded that this was an MDRP outbreak that was causing CAUTI. The isolated ratio of MDRP began to decrease over 4 months of surveillance and significantly decreased in the 4th quarter (7th and 8th months) compared with the 1st quarter (1st and 2nd months) (P=0.021) even though urinary tract device usage significantly increased over the same period (P<0.001). CONCLUSION: We experienced an outbreak of emergent MDRP causing CAUTI in neurogenic bladder patients with spinal cord injury. Our preventive measures for isolating the outbreak, including surveillance, may have led to the decrease we observed in the ratio of MDRP isolated.

Robot-assisted surgical approach to bladder cancer: a decade of progress!

Robot-assisted radical cystectomy (RARC) has gained popularity and proven its efficacy, safety and reproducibility in the last decade. RARC has resulted in less blood loss, enhanced recovery, and shorter hospital stay. RARC has proven to have similar or better postoperative morbidity, mortality and equal oncologic, outcomes. Limiting factors to the acceptance of this surgical approach have included its steep learning curve and the lack of both long-term outcome data. This article systematically reviews the literature comparing the outcomes for RARC (comparisons with open radical cystectomy when performed at the same institution) with a focus on operative, complications, oncologic, functional and survival outcomes.

Association between dental status and food diversity among older Japanese.

OBJECTIVE: To investigate the relationship of dental status to food diversity among older Japanese. DESIGN AND SETTING: A community-based cross-sectional study conducted in the town of Tosa, Kochi Prefecture, Japan. METHODS: The study participants were 252 Japanese (84 men and 168 women, average age 81.2 years) and dentate participants were classified into three groups: 1-9 teeth, 10-19 teeth and 20 or more teeth. Food diversity was assessed as a validated measure of dietary quality using the 11-item Food Diversity Score Kyoto (FDSK-11), which evaluates frequency of consumption of 11 main food groups. Multivariable analysis of the differences in FDSK-11 score ranging from 0 to 11, with a higher score indicating greater food diversity, among the three dental status groups was conducted using general linear models. All the performed analyses were stratified by gender. RESULTS: There was no association between dental status and food diversity score in models for men. In contrast, women with ≤ 9 teeth and with 10-19 teeth had significantly lower FDSK-11 scores than women with ≥ 20 teeth after adjusting for confounders (p < 0.001 and p = 0.009, respectively). Additionally, there was a trend toward lower scores for FDSK-11 with fewer teeth (p = 0.001). CONCLUSION: A less varied diet, as indicated by low FDSK-11 score, was observed in female participants with fewer teeth. Tooth loss was associated with poor diet quality among older Japanese women.

Electromyogram biofeedback training for daytime clenching and its effect on sleep bruxism.

Bruxism contributes to the development of temporomandibular disorders as well as causes dental problems. Although it is an important issue in clinical dentistry, no treatment approaches have been proven effective. This study aimed to use electromyogram (EMG) biofeedback (BF) training to improve awake bruxism (AB) and examine its effect on sleep bruxism (SB). Twelve male participants (mean age, 26·8 ± 2·5 years) with subjective symptoms of AB or a diagnosis of SB were randomly divided into BF (n = 7) and control (CO, n = 5) groups to undergo 5-h daytime and night-time EMG measurements for three consecutive weeks. EMG electrodes were placed over the temporalis muscle on the habitual masticatory side. Those in the BF group underwent BF training to remind them of the occurrence of undesirable clenching activity when excessive EMG activity of certain burst duration was generated in week 2. Then, EMGs were recorded at week 3 as the post-BF test. Those in the CO group underwent EMG measurement without any EMG BF training throughout the study period. Although the number of tonic EMG events did not show statistically significant differences among weeks 1-3 in the CO group, events in weeks 2 and 3 decreased significantly compared with those in week 1, both daytime and night-time, in the BF group (P < 0·05, Scheffé's test). This study results suggest that EMG BF to improve AB tonic EMG events can also provide an effective approach to regulate SB tonic EMG events.

A case of maxillary sarcoma in a chimpanzee (Pan troglodytes).

Oral malignancy is rare in chimpanzees. A 34-year-old female chimpanzee (Pan troglodytes) at Kumamoto Sanctuary, Japan, had developed it. Treatment is technically difficult for chimpanzees while malignant neoplasm is seemingly rising in captive populations. Widespread expert discussion, guidelines for treatment, especially for great apes in terminal stages is urgently needed.

Achieved pregnancy with the delivery of a healthy child by TESE-ICSI 7 years after bilateral adult orchidopexy: a case report.

We report pregnancy with the delivery of a healthy child by TESE-ICSI 7 years after bilateral adult orchidopexy. A 29-year-old patient presented with infertility and previous bilateral cryptorchidism, but no surgical treatment had ever been performed. His partner had been assessed by a gynaecologist, and no contributing female factors were detected. Orchidopexy and conventional testicular sperm extraction (TESE) were performed and microdissection TESE 10 months after orchidopexy. The second microdissection TESE with intracytoplasmic sperm injection (ICSI) was performed 7 years after orchidopexy. The couple achieved pregnancy with the delivery of a healthy child by TESE-ICSI. It is concluded that bilateral orchidopexy in adulthood progresses spermatogenesis gradually, and microdissection TESE may succeed after a certain period of time following treatment.

Acquired resistance to temsirolimus in human renal cell carcinoma cells is mediated by the constitutive activation of signal transduction pathways through mTORC2.

BACKGROUND: The objective of this study was to characterise the mechanism underlying acquired resistance to temsirolimus, an inhibitor of mammalian target of rapamycin (mTOR), in renal cell carcinoma (RCC). METHODS: A parental human RCC cell line, ACHN (ACHN/P), was continuously exposed to increasing doses of up to 20 µM of temsirolimus, and a cell line resistant to temsirolimus (ACHN/R), showing a sixfold higher IC50 than that of ACHN/P, was developed. RESULTS: Following treatment with temsirolimus, phosphorylation of S6 kinase in ACHN/P was markedly inhibited, whereas there was no detectable expression of phosphorylated S6 in ACHN/R before and after temsirolimus treatment. However, AKT and p44/42 mitogen-activated protein kinase (MAPK) were constitutively phosphorylated even after temsirolimus treatment in ACHN/R, but not in ACHN/P. There was no significant difference between the sensitivities of ACHN/P and ACHN/R to KU0063794, a dual inhibitor of mTOR complex 1 (mTORC1) and mTORC2. Similar sensitivities to temsirolimus in ACHN/P and ACHN/R could be achieved by additional treatment with specific inhibitors of AKT- and MAPK-signaling pathways. CONCLUSION: The activation of signal transduction pathways via mTORC2, but not via mTORC1, may have an important role in the acquisition of a resistant phenotype to temsirolimus in RCC.

Determination of daytime clenching events in subjects with and without self-reported clenching.

To confirm the validity of self-awareness of daytime clenching, specific electromyogram (EMG) characteristics of clenching behaviour were determined using surface EMG recordings. Temporal muscle EMGs were recorded for 5 h in 13 subjects with self-reported clenching (clenching group: 27·5 ± 3·8 years old) and 12 subjects without self-reported clenching (control group: 28·6 ± 7·1 years old). All EMG data were recorded and stored on a portable EMG apparatus. The device was similar in size to a hearing aid, and suitable to record daytime EMG without restriction of daily activities. A clenching event was defined as muscle activity exceeding 10% of the maximum voluntary contraction. Furthermore, simultaneous voice recording was also performed to identify the corresponding EMG event as functional or parafunctional. The mean number of clenching events was 192·8 ± 228·8 and 24·8 ± 26·5 in the clenching and the control groups, respectively (P < 0·05, Mann-Whitney U-test); the number of functional events was not significantly different between the groups. Because there was a significant difference in the number of clenching events between the groups, self-reported daytime clenching is considered to be a reliable screening parameter for awake bruxism.

Time-, spin-, and angle-resolved photoemission spectroscopy with a 1-MHz 10.7-eV pulse laser.

We describe a setup of time-, spin-, and angle-resolved photoemission spectroscopy (tr-SARPES) employing a 10.7 eV (λ = 115.6 nm) pulse laser at a 1 MHz repetition rate as a probe photon source. This equipment effectively combines the technologies of a high-power Yb:fiber laser, ultraviolet-driven harmonic generation in Xe gas, and a SARPES apparatus equipped with very-low-energy-electron-diffraction spin detectors. A high repetition rate (1 MHz) of the probe laser allows experiments with the photoemission space-charge effects significantly reduced, despite a high flux of 1013 photons/s on the sample. The relatively high photon energy (10.7 eV) also brings the capability of observing a wide momentum range that covers the entire Brillouin zone of many materials while ensuring high momentum resolution. The experimental setup overcomes the low efficiency of spin-resolved measurements, which gets even more severe for the pump-probed unoccupied states, and affords the opportunity to investigate ultrafast electron and spin dynamics of modern quantum materials with energy and time resolutions of 25 meV and 360 fs, respectively.