Study of the mandibular canal and its surrounding canals by multi-view cone-beam computed tomography.

OBJECTIVES: To determine the mandibular anatomical structures by observing cone-beam computed tomography (CBCT) from multiple angles. MATERIALS AND METHODS: This retrospective study analyzed 1593 consecutive CBCT images. Ultimately, 95 CBCTs met the inclusion criteria. The mandibular, inferior lingual, and bony canals at the tooth apex were studied by multi-angle observation CBCT. Descriptive statistics were used for statistical analysis. RESULTS: It is beneficial to further observe the anastomosis of the mandibular, lingual, and mandibular canals when the course of the mandibular lingual canal is observed on CBCT cross-section. The frequency of the inferior lingual canal anastomosis with the mandibular canal was 43.2% (95% confidence interval (CI) 33, 53.3) in the sample. The mental foramen was located below the long axis of the tooth in a few samples, with an occurrence rate of 29.5% (95% CI 20.1, 38.8). The occurrence rate of various types of the bony canal at the apex of the tooth in canines, first premolars, second premolars, first molars, and second molars under the root apex was recorded through the multi-angle observation of the dental volume reformat (DVR) and three-dimensional (3D) levels in CBCT. CONCLUSION: This study demonstrates the utility of CBCT imaging in examining mandibular anatomy from multiple angles, providing valuable insights into anatomical variations, and enhancing our understanding of mandibular structures. This research emphasizes the crucial role of meticulous CBCT examination in precisely identifying and understanding key anatomical structures, ultimately reducing the risk of surgical complications. CRITICAL RELEVANCE STATEMENT: By examining cone-beam computed tomography scans from various perspectives, it is possible to determine the precise position of anatomical structures within the jaw. This allows for a more accurate assessment, reducing the risk of harm to these structures during treatment. KEY POINTS: • It is crucial to utilize image data effectively to enhance the comprehension of human anatomy. • We captured detailed images of the mandible from different angles and orientations utilizing cone-beam computed tomography (CBCT). • This study provides essential anatomical information for procedural planning to ensure optimal outcomes and patient safety.

Analysis of etiology and clinical features of spontaneous downbeat nystagmus: a retrospective study.

Objective: To investigate the topical diagnosis, possible etiology and mechanism of spontaneous downbeat nystagmus (sDBN) patients with dizziness/vertigo. Methods: The clinical features of dizziness/vertigo patients accompanied with DBN were retrospectively reviewed in the Vertigo Center of our hospital from January 2018 to March 2021. The clinical features of dizziness/vertigo patients accompanied with DBN were reviewed. Comprehensive VNG, bithermal caloric testing, video-head-impulse test (vHIT), vestibular-evoked myogenic potentials (VEMP), head magnetic resonance imaging (MRI), three-dimensional fluid-attenuated incersion recovery magnetic resonance imaging (3D-FLAIR MRI) in the inner ear, serum immunology and other examinations were to determine the lesion site, and analyze its possible etiology and mechanism. Results: A total of 54 patients were included. Among them, 70.4% (n = 38) of DBN patients were diagnosed with episodic vestibular syndrome (EVS), 22.2% (n = 12) with chronic vestibular syndrome (CVS), and 7.4% (n = 4) with acute vestibular syndrome (AVS). Among all the patients, 51.9% of DBN patients had clear etiology, with central lesions of 29.6% and peripheral diseases of 22.2%. The most common diseases in DBN patients were cerebellar lesions (13.0%, n = 7) and vestibular migraine (13.0%, n = 7), followed by benign positional paroxysmal vertigo (7.4%, n = 4) and drug-related dizziness/vertigo (5.6%, n = 3). The other 48.1% of the patients had unknown etiology. 53.8% (14/26) of patients with idiopathic DBN had decreased semicircular canal function, with 42.9% (6/14) decreased posterior semicircular canal function. The posterior semicircular canal gain in DBN patients decreased compared to the anterior semicircular canal in the same conjugate plane. Patients with peripheral DBN were more prone to horizontal/torsional nystagmus during positional testing. Conclusion: In our study, DBN patients have a relative decrease in posterior semicircular canal gain, which is possibly a particular result found in a subset of downbeat nystagmus patients. The changes in nystagmus during positional testing may be helpful in distinguishing between peripheral and central causes.

Spatio-temporal patterns and drivers of CH4 and CO2 fluxes from rivers and lakes in highly urbanized areas.

Gaseous carbon exchange at the water-air interface of rivers and lakes is an essential process for regional and global carbon cycle assessments. Many studies have shown that rivers surrounding urban landscapes can be hotspots for greenhouse gas (GHG) emissions. Here we investigated the variability of diffusive GHG (methane [CH4] and carbon dioxide [CO2]) emissions from rivers in different landscapes (i.e., urban, agricultural and mixed) and from lakes in Suzhou, a highly urbanized region in eastern China. GHG emissions in the Suzhou metropolitan water network followed a typical seasonal pattern, with the highest fluxes in summer, and were primarily influenced by temperature and dissolved oxygen concentration. Surprisingly, lakes were emission hotspots, with mean CH4 and CO2 fluxes of 2.80 and 128.89 mg m-2 h-1, respectively, translating to a total CO2-equivalent flux of 0.21 g CO2-eq m-2 d-1. The global warming potential of urban and mixed rivers (0.19 g CO2-eq m-2 d-1) was comparable to that for lakes, but about twice the value for agricultural rivers (0.10 g CO2-eq m-2 d-1). Factors related to the high GHG emissions in lakes included hypoxic water conditions and an adequate nutrient supply. Riverine CH4 emissions were primarily associated with the concentrations of total dissolved solids (TDS), ammonia­nitrogen and chlorophyll a. CO2 emissions in rivers were mainly closely related to TDS, with suitable conditions allowing rapid organic matter decomposition. Compared with other types of rivers, urban rivers had more available organic matter and therefore higher CO2 emissions. Overall, this study emphasizes the need for a deeper understanding of the impact of GHG emissions from different water types on global warming in rapidly urbanizing regions. Flexible management measures are urgently needed to mitigate CO2 and CH4 emissions more effectively in the context of the shrinking gap between urban and rural areas with growing socio-economic development.

Characteristics and Possible Mechanisms of Direction-Reversing Nystagmus During Positional Testing in Patients With Benign Paroxysmal Positional Vertigo.

OBJECTIVES: The occurrence of direction-reversing nystagmus during positional testing in patients with benign paroxysmal positional vertigo (BPPV) is not uncommon. Further in-depth analysis of the characteristics and possible mechanisms of direction-reversing nystagmus will help us to diagnose and treat BPPV more precisely. The study aimed to analyze the incidence and characteristics of direction-reversing nystagmus during positional testing in BPPV patients, evaluate the outcomes of canalith repositioning procedure for these patients, and further explore the possible mechanism of reversal nystagmus in BPPV patients. STUDY DESIGN: Retrospective study. SETTING: Single-center study. PATIENTS: A total of 575 patients with BPPV who visited the Vertigo Clinic of our hospital between April 2017 and June 2021 were enrolled. MAIN OUTCOME MEASURES: Dix-Hallpike and supine roll tests were performed. The nystagmus was recorded using videonystagmography. The characteristics of direction-reversing nystagmus and the possible underlying mechanism were analyzed. RESULTS: Patients with BPPV who showed reversal nystagmus accounted for 9.39% (54 of 575) of all BPPV patients visiting our hospital during the same period, of which 5.57% (32 of 575) had horizontal semicircular canal BPPV (HC-BPPV), and 3.83% (22 of 575) had posterior semicircular canal BPPV (PC-BPPV). The maximum slow-phase velocities (mSPVs) of the first-phase nystagmus were greater in HC-BPPV and PC-BPPV patients with reversal nystagmus than those without ( p = 0.04 and p = 0.01, respectively). In all HC-BPPV and PC-BPPV patients with reversal nystagmus, the mSPV of the first-phase nystagmus was greater than that of the second-phase nystagmus ( p < 0.01). The duration of the second-phase nystagmus was longer than 60 seconds in 93.75% (30 of 32) of the HC-BPPV patients and 77.27% (17 of 22) of the PC-BPPV patients ( p = 0.107, Fisher exact test). HC-BPPV and PC-BPPV patients with reversal nystagmus both required more than one canalith repositioning procedure compared with those without (HC-BPPV: 75 versus 28.13%, p < 0.001; PC-BPPV: 59.09 versus 13.64%, p = 0.002). CONCLUSIONS: The cause of second-phase nystagmus in BPPV patients with direction-reversing nystagmus may be related to the involvement of central adaptation mechanisms secondary to the overpowering mSPV of the first-phase nystagmus.

Comparison of clinical characteristics and vestibular function test results in patients with vestibular migraine and Menière's disease.

OBJECTIVES: The differentiation between Vestibular Migraine (VM) and Meniere's Disease (MD) is difficult because of overlapping symptoms. The study aimed to compare the clinical characteristics and vestibular function test results between VM and MD patients. METHODS: Seventy-one patients with definite VM and 31 patients with definite unilateral MD were included. All patients received Caloric Test (CT), Video Head Impulse Test (vHIT) and Vestibular Evoked Myogenic Potential (VEMP) test within 7 days after visiting the hospital. Results of these tests were compared between groups. RESULTS: Most VM patients (64.0%) experienced spontaneous internal vertigo, while most MD patients (66.7%) experienced spontaneous external vertigo. MD patients had more severe vestibular symptoms and autonomic responses compared to VM patients during attacks (p =  0.03, p = 0.00, respectively). The nystagmus intensity of CT-induced was greater in VM patients than in MD patients (p = 0.003). More VM patients had CT intolerance and Central Positional Nystagmus (CPN) compared to MD patients (p = 0.002, p = 0.006, respectively). More MD patients had CT(+) and vHIT saccades wave compared to VM patients (p < 0.001, p = 0.002, respectively). The non-elicitation rate of cervical VEMP was higher, and the ocular VEMP amplitudes were lower in MD patients than in VM patients (p = 0.002, p = 0.018). CONCLUSIONS: Vestibular symptoms during attacks combined with the results of vestibular function tests may be used to differentiate between VM and MD. The diverse nature of vestibular symptoms (especially internal vertigo), history of motion sickness and CT intolerance may provide clues to the diagnosis of VM, whereas spontaneous external vertigo, CT(+) with vHIT(-), and the presence of saccades may provide clues to the diagnosis of MD.

Geriatric benign paroxysmal positional vertigo: a single-center study.

OBJECTIVE: To compare the clinical features, risk factors, distribution of Benign Paroxysmal Positional Vertigo (BPPV) subtypes, and effectiveness of canalith repositioning between geriatric and non-geriatric patients with BPPV. METHODS: A total of 400 patients with BPPV were enrolled. Canalith repositioning was performed according to the semicircular canals involved. Patients were divided by age into a geriatric group (≥60 years) and a non-geriatric group (20-59 years). Clinical characteristics, potential age-related risk factors, distribution of subtypes, and effectiveness of canalith repositioning were compared between the groups. RESULTS: Female sex was significantly more common in all age groups, with a peak female-to-male ratio of 5.1:1 in the group aged 50-59 years. There was a higher proportion of men in the geriatric group. A history of disease associated with atherosclerosis was significantly more common in the geriatric group (p < 0.05). Migraine was significantly more common in the non-geriatric group (p = 0.018), as was posterior canal BPPV. The horizontal canal BPPV (especially horizontal canal BPPV-cupulolithiasis), and multicanal BPPV subtypes were more common in the geriatric group, whereas anterior canal BPPV was more common in the non-geriatric group. Two canalith repositioning sessions were effective in 58.0% of the geriatric cases and in 72.6% of the non-geriatric cases (p = 0.002). There was a tendency for the effectiveness of canalith repositioning to decrease with increasing age. CONCLUSION: BPPV was more common in women. However, the proportion of men with BPPV increased with age. Elderly patients often had a history of diseases associated with atherosclerosis (i.e., hypertension, diabetes, and hyperlipidemia). The horizontal canal BPPV (particularly horizontal canal BPPV-cupulolithiasis) and multicanal BPPV subtypes were more common and the anterior canal BPPV subtype was less common in elderly patients. The effectiveness of canalith repositioning may decrease with age. Therefore, older patients should receive more comprehensive medical treatment.

Spontaneous nystagmus with an upbeat component: Central or peripheral vestibular disorders?

Objective: To determine the topical diagnosis and etiologies of spontaneous nystagmus (SN) with an upbeat component. Methods: We retrospectively recruited 43 patients with SN with an upbeat component at a university hospital in China from 2020 to 2022. SN with an upbeat component was divided into pure upbeat nystagmus (UBN), SN with a predominant upbeat component, and SN with a non-predominant upbeat component. We analyzed their clinical and neurotologic findings and the final diagnosis. Results: Fourteen (32.6%) of them showed pure UBN, while 29 (67.4%) exhibited SN mixed with an upbeat component, mixed upbeat-horizontal in 15, mixed upbeat-horizontal-torsional in 13, and upbeat-torsional in the remaining one. Pure UBN and SN with a predominant upbeat component were more common in central than in peripheral vestibular disorders [16 (80.0%) vs. 0 (0%), Chi-Square test, p < 0.001]. Central vestibular disorders were diagnosed in 20 (46.5%) patients, peripheral in 14 (32.6%), and undetermined in nine (20.9%) patients. The underlying causes mainly included acute unilateral peripheral vestibulopathy (n = 11), posterior circulation infarction (n = 9), benign recurrent vertigo (n = 4), vestibular migraine (VM, n = 3), and VM of childhood (n = 2). Conclusion: SN with an upbeat component can be seen in both central and peripheral vestibular disorders. Pure UBN was a characteristic sign of central vestibular dysfunction. Central vestibular disorders should be highly suspected when patients show pure UBN or SN with a predominant upbeat component.

Risk factors for early neurologic deterioration in single small subcortical infarction without carrier artery stenosis: predictors at the early stage.

OBJECTIVES: This study aimed to assess the epidemiological features and explore the potential risk factors for early neurological deterioration (END) in patients with acute single small subcortical infarction (SSSI) who underwent antiplatelet therapy without carotid artery stenosis. MATERIALS & METHODS: Patients with SSSI, as confirmed by cranial magnetic resonance imaging (MRI), who were hospitalized within 48 h after the onset of symptoms were enrolled. END was mainly defined as increment in the National Institutes of Health Stroke Scale (NIHSS) score of ≥ 2 points or any new neurological deficit. Poor functional outcome was defined as modified Rankin Scale (mRS) score of > 2 points at 3-month after the onset. The association of END with multiple indicators was assessed at the early stage of admission using multivariate logistic regression analysis, and adjusted odds ratios (aORs) were calculated. RESULTS: A total of 280 patients were enrolled from June 2020 to May 2021, of whom, END occurred in 44 (15.7%) patients (median age, 64 years; 70.5% male), while END occurred during sleep in 28 (63.6%) patients. History of hypertension (aOR: 4.82, p = 0.001), infarction in internal capsule (aOR: 3.35, p = 0.001), and elevated level of low-density lipoprotein cholesterol (LDL-C; aOR: 0.036, p = 0.0016) were significantly associated with the risk of END. Patients with END (aOR: 5.74, p = 0.002), history of diabetes (aOR: 2.61, p = 0.020), and higher NIHSS scores at discharge (per 1-score increase, aOR: 1.29, p = 0.026) were associated with the poor functional outcome at 3-month after the onset. CONCLUSION: Patients with a history of hypertension, infarction in internal capsule or a higher level of LDL-C were found to be at a higher risk of END.

Geriatric benign paroxysmal positional vertigo: a single-center study

Abstract Objective To compare the clinical features, risk factors, distribution of Benign Paroxysmal Positional Vertigo (BPPV) subtypes, and effectiveness of canalith repositioning between geriatric and non-geriatric patients with BPPV. Methods A total of 400 patients with BPPV were enrolled. Canalith repositioning was performed according to the semicircular canals involved. Patients were divided by age into a geriatric group (≥60 years) and a non-geriatric group (20-59 years). Clinical characteristics, potential age-related risk factors, distribution of subtypes, and effectiveness of canalith repositioning were compared between the groups. Results Female sex was significantly more common in all age groups, with a peak female-to-male ratio of 5.1:1 in the group aged 50-59 years. There was a higher proportion of men in the geriatric group. A history of disease associated with atherosclerosis was significantly more common in the geriatric group (p< 0.05). Migraine was significantly more common in the non-geriatric group (p= 0.018), as was posterior canal BPPV. The horizontal canal BPPV (especially horizontal canal BPPV-cupulolithiasis), and multicanal BPPV subtypes were more common in the geriatric group, whereas anterior canal BPPV was more common in the non-geriatric group. Two canalith repositioning sessions were effective in 58.0% of the geriatric cases and in 72.6% of the non-geriatric cases (p= 0.002). There was a tendency for the effectiveness of canalith repositioning to decrease with increasing age. Conclusion BPPV was more common in women. However, the proportion of men with BPPV increased with age. Elderly patients often had a history of diseases associated with atherosclerosis (i.e., hypertension, diabetes, and hyperlipidemia). The horizontal canal BPPV (particularly horizontal canal BPPV-cupulolithiasis) and multicanal BPPV subtypes were more common and the anterior canal BPPV subtype was less common in elderly patients. The effectiveness of canalith repositioning may decrease with age. Therefore, older patients should receive more comprehensive medical treatment. Level of evidence: 4.

Comparison of clinical characteristics and vestibular function test results in patients with vestibular migraine and Menière's disease

Abstract Objectives The differentiation between Vestibular Migraine (VM) and Meniere's Disease (MD) is difficult because of overlapping symptoms. The study aimed to compare the clinical characteristics and vestibular function test results between VM and MD patients. Methods Seventy-one patients with definite VM and 31 patients with definite unilateral MD were included. All patients received Caloric Test (CT), Video Head Impulse Test (vHIT) and Vestibular Evoked Myogenic Potential (VEMP) test within 7 days after visiting the hospital. Results of these tests were compared between groups. Results Most VM patients (64.0%) experienced spontaneous internal vertigo, while most MD patients (66.7%) experienced spontaneous external vertigo. MD patients had more severe vestibular symptoms and autonomic responses compared to VM patients during attacks (p= 0.03, p= 0.00, respectively). The nystagmus intensity of CT-induced was greater in VM patients than in MD patients (p= 0.003). More VM patients had CT intolerance and Central Positional Nystagmus (CPN) compared to MD patients (p= 0.002, p = 0.006, respectively). More MD patients had CT(+) and vHIT saccades wave compared to VM patients (p< 0.001, p= 0.002, respectively). The non-elicitation rate of cervical VEMP was higher, and the ocular VEMP amplitudes were lower in MD patients than in VM patients (p = 0.002, p= 0.018). Conclusions Vestibular symptoms during attacks combined with the results of vestibular function tests may be used to differentiate between VM and MD. The diverse nature of vestibular symptoms (especially internal vertigo), history of motion sickness and CT intolerance may provide clues to the diagnosis of VM, whereas spontaneous external vertigo, CT(+) with vHIT(-), and the presence of saccades may provide clues to the diagnosis of MD. Level of evidence: 4.

The diagnostic value of the ocular tilt reaction plus head tilt subjective visual vertical (±45°) in patients with acute central vascular vertigo.

Objectives: To investigate the localization diagnostic value of the ocular tilt reaction (OTR) plus head tilt subjective visual vertical (SVV) in patients with acute central vascular vertigo (ACVV). Methods: We enrolled 40 patients with acute infarction, 20 with unilateral brainstem infarction (BI) and 20 with unilateral cerebellar infarction (CI). We also included 20 patients with unilateral peripheral vestibular disorders (UPVD) as the control group. The participants completed the OTR and SVV during head tilt (±45°) within 1 week of symptom onset. Results: In patients with ACVV, including that caused by lateral medullary infarction (100%, 2/2), partial pontine infarction (21%, 3/14), and cerebellum infarction (35%, 7/20), we observed ipsiversive OTR, similar to that seen in UPVD patients (80.0%, 16/20). Some of the patients with medial medullary infarction (50%, 1/2), partial pons infarction (42%, 6/14), midbrain infarction (100%, 2/2), and partial cerebellum infarction (30.0%, 6/20) showed contraversive OTR. The skew deviation (SD) of the BI group with ACVV was significantly greater than that of the UPVD group (6.60 ± 2.70° vs. 1.80 ± 1.30°, Z = -2.50, P = 0.012), such that the mean SD of the patients with a pons infarction was 9.50° and that of patients with medulla infarction was 5.00°. In ACVV patients with no cerebellar damage, the area under the curve of the receiver operating characteristic curve corresponding to the use of SD to predict brainstem damage was 0.92 (95%CI: 0.73-1.00), with a sensitivity of 100% and a specificity of 80% when SD ≥ 3°. We found no statistical difference in SD between the UPVD and CI groups (1.33 ± 0.58° vs. 1.80 ± 1.30°, Z = -0.344, P = 0.73). Compared with the UPVD patients, the ACVV patients with a partial pons infarction (43%, 6/14, χ2 = 13.68, P = 0.002) or medulla infarction (25%, 1/4, χ2 = 4.94, P = 0.103) exhibited signs of the ipsiversive E-effect with the contraversive A-effect, while those with a partial medulla infarction (50%, 2/4), pons infarction (43%, 6/14), or cerebellar infarction (60%, 12/20) exhibited a pathological symmetrical increase in the E-effect. Conclusions: The evaluation of OTR plus head tilt SVV (±45°) in vertigo patients is helpful for identifying and diagnosing ACVV, especially when SD is ≥ 3° or the E-effect is symmetrically increased.

Canal switch in benign paroxysmal positional vertigo: Clinical characteristics and possible mechanisms.

Background: Canal switch-benign paroxysmal positional vertigo (CS-BPPV) refers to the phenomenon in which otolith particles move from one canal to another (on the ipsilateral side) during or after canalith repositioning procedure (CRP). However, the clinical characteristics of CS-BPPV and the underlying pathological mechanisms remain unclear. In this study, we investigated the incidence of canal switch (CS) for the different semicircular canals in benign paroxysmal positional vertigo (BPPV), examined nystagmus characteristics, and explored the underlying mechanisms. Methods: Clinical data for 1,099 patients with single-canal BPPV were collected and retrospectively analyzed. The incidences of CS in the different types of BPPV were analyzed. Patients were divided into CS-BPPV and non-CS (NCS)-BPPV groups according to whether they exhibited CS after CRP. The baseline characteristics and nystagmus characteristics of patients were compared between the two groups. Results: Patients with BPPV who developed or did not develop CS accounted for 4.6% (51/1,099) and 95.4% (1,048/1,099), respectively, of the patients included in the study. There were no statistically significant differences between the two groups in terms of sex, age, side of the canals involved, hypertension, or diabetes. CS was observed in 3.7% (25/677) of patients with PC-BPPV, including conversion between posterior canal (PC) and horizontal canal (HC) (1.6%, 11/677), and between PC and anterior canal (AC) (2.1%, 14/677). CS was observed in 5.2% (17/327) of patients with HC-BPPV, including from HC to PC (4.3%, 14/327), and from HC to AC (0.9%, 3/327). CS was found in 9.5% (9/95) of patients with AC-BPPV, including from AC to PC (8.4%, 8/95), and from AC to HC (1.1%, 1/95). The intensity of nystagmus was significantly greater in the CS-BPPV group compared with that in the NCS-BPPV group [24.00 (11-39) vs. 12.00 (7-24), P < 0.001]. Furthermore, the incidence of direction-reversing nystagmus was significantly higher in the CS-BPPV group than in the NCS-BPPV group [31.4% (16/51) vs. 4.3% (45/1,048), P < 0.001]. Conclusions: CS in BPPV is uncommon. Patients with AC-BPPV are more likely to develop CS, followed by patients with HC-BPPV and PC-BPPV. The occurrence of CS-BPPV may be related to the anatomical structure of the semicircular canals. When the canals contain large/heavy accumulations of otolith particles, CS may be more common during re-examination after CRP.

Microbially mediated Fe-N coupled cycling at different hydrological regimes in riparian wetland.

Although the significance of the coupled Fe- and N- cycling processes on biogeochemical transformation in riparian wetlands is well-known, the regulation associated with the changes on the microbiotas during different hydrological regimes remains unclear. This study performed field investigations on the bacterial community compositions (BCC) and specific genera associated to Fe- and N- cycling in the rhizosphere soil and sediments in a riparian wetland in Poyang lake, China. The predominant phyla Proteobacteria, Acidobacteria, and Nitrospirae from all the samples remarkably decreased after long-term continuous flooding, while Actinobacteria, Firmicutes and Bacteroidetes were enriched. For the family level, the relative abundances of iron-oxidizing bacteria (FeOB) Gallionellaceae, and N fixing bacteria Nitrospiraceae and Bradyrhizobiaceae significantly declined upon the long-term flooding and then increased with dewatering, which were consistent with the functional genes sequencing analysis. In which, the Bradyrhizobiaceae (RA 2.0 %-34.6 %) was the dominant nirS denitrifier and potential iron-reducing bacteria (FeRB), Sideroxydans lithotrophicus was one of the dominant FeOB (RA 1.7 %-23 %), which was also identified to be the nirS dentrifier (RA 0.2 %-4.3 %). The absolute quantification of the functional genes levels including nirS, nirK, FeRB (Geobacter spp.) showed their significant increases by 3-7 times upon desiccation compared to that under post-CF. The PCA and RDA results indicated the linkage between redox changes of N and Fe during inundation mediated by FeRB, NOB, and FeOB, which were closely related to hydrochemical indices NO3-, Fe2+ and SO42-. These evidences all implied the likely occurrence of nitrate reduction coupled to Fe(II) oxidation (NRFeOx) under oligotrophic conditions, which was potentially facilitated by metabolizers consisting of highly correlated Bradyrhizobiaceae and Sideroxydans (rho = 0.86, p < 0.01). These findings provide an interpretation of the biological reactions in the microbially mediated NRFeOx processes driven by hydrological change, which could assist the mechanistic understanding of the global biogeochemical cycles of iron and nitrogen in riparian wetlands.

Clinical Application of Different Vertical Position Tests for Posterior Canal-Benign Paroxysmal Positional Vertigo-Cupulolithiasis.

Background: Posterior canal-benign paroxysmal positional vertigo-cupulolithiasis (PC-BPPV-cu) is a new and controversial type of benign paroxysmal positional vertigo (BPPV). At present, there are few relevant clinical studies as to whether the Half Dix-Hallpike test (Half D-HT) induces more obvious nystagmus than the Dix Hallpike test (D-HT) and straight head hanging test (SHH) in patients with PC-BPPV-cu. Objectives: To investigate the clinical characteristics of PC-BPPV-cu, and analyze the diagnostic significance of the Dix-Hallpike test (D-HT), Half D-HT, and straight head hanging (SHH) test in these patients. Methods: A total of 46 patients with PC-BPPV-cu were enrolled, and divided into two groups (N = 23): a group A (induction order: D-HT, Half D-HT, SHH) and a group B (induction order: Half D-HT, D-HT, SHH). Results: Among 46 patients with PC-BPPV-cu, the bilateral and unilateral abnormality rates of the disease side were 5 cases and 41 cases, respectively. There were significant differences in the proportion of torsional-upbeating nystagmus and upbeating nystagmus among the three headhanging positions in 46 patients with PC-BPPV-cu (P < 0.001). The slow phase velocity (SPV) of induced nystagmus at half D-HT supine position was slower than D-HT supine position (P < 0.05) and SHH supine position (P < 0.05). The nystagmus latency of D-HT supine position was significantly shorter than half D-HT (P < 0.05) and SHH (P < 0.05). PC-BPPV-cu patients were accompanied by 53.5% semicircular canal paresis, 69.6% audiological abnormalities, 76% cervical vestibular evoked myogenic potential (cVEMP), and 75% video head impulse test (vHIT) abnormalities, the concordance rates of the four detection methods were similar (χ2 = 0.243, P = 0.970). Conclusions: The Half D-HT is simple and feasible, but might have a risk of false-negative diagnoses of the torsional-upbeating nystagmus and upbeating nystagmus. The D-HT is still a classic induction method for PC-BPPV-cu. The two complement each other and may aid in the diagnosis of PC-BPPV-cu patients. Future clinical applications of Half D-HT require extensive research to determine its diagnostic efficacy.

An Efficient Strategy for Reinforcing Flexible Ceramic Membranes.

Herein, we present a facile reinforcement method for the large-scale fabrication of highly flexible, mechanically stable, temperature-resistant ceramic lightweight membranes based on the cross-linked assembly of zirconia-silica (ZrO2-SiO2) nanofibrous and montmorillonite (MMT) nanosheets through electrospinning and a subsequent calcination process. The resulting MMT@ZrO2-SiO2 membranes exhibit high flexibility with a bending rigidity of 0.2 cN mm-1, robust mechanical performance with a tensile strength of up to 1.83 MPa, robust fire resistance, and temperature-invariant mechanical stability from -196 to 1000 °C. The thermal superinsulation with a thermal conductivity as low as 0.026 W m-1 K-1 and the improved mechanical strength can be attributed to the cross-linked interfacial interaction between the ZrO2-SiO2 nanofibers and the MMT nanosheets. Additionally, a firefighter uniform with MMT@ZrO2-SiO2 membranes inside features a superior thermal protective property up to the A2 level (combined flame and radiant exposure) and an excellent fire resistance of up to 1000 °C, which is ideal for next-generation firefighter uniform manufacturing.

Temporal responses of hydrochemical variables and dissolved Fe(II) to flooding at a lake riparian wetland under different vegetation revealing by high resolution DGT.

The interplay between hydrological and biogeochemical processes in riparian wetland was recognized to lead directly to the temporal variations of surface water quality. However, the effects of flooding and vegetation on the release and entrapment of heavy metals and nutrients in riparian wetland remain poorly understood. The study aimed at investigating the influences of flooding and vegetation on the hydrochemical and Fe-redox change in the soil porewater and shallow groundwater, in Poyang lake riparian wetland through hydrochemical monitoring and diffusive gradient technology (DGT). The hydrochemical profiles and results of PCA analysis on the temporal datasets both demonstrated that vegetation had significant influences on the hydrochemistry of rhizosphere depth zone (RDZ) and shallow groundwater depth zone (SGZ). The Ca, K, Na, Mg, Mn and DOC at RDZ of both plants showed significant increasing trends from pre-to post-flooding while were observed minor change at the SGZ. The extracted PC1-PC3 from PCA analysis suggested that mineral dissolution and fermentation were dominating processes that explained 64.1% of the hydrochemical variability under the wetting-drying cycle. The synchronous changes of Fe(II), SO42-, DOC and ORP were found to occur at the SGZ of Carex, implying the likely occurrence of Fe- and S- redox reactions. The Fe(II) DGT profiles evidenced the temporal iron reduction and oxidation occurring at the rhizosphere following the wetting-drying cycle, as also reflected by the high opposite Fe2+ and DO association through PCA analysis. The high resolution temporal-spatial Fe(II) distribution suggested also the interface between lake water and groundwater was relatively stable under flooding. These results highlight that the release of dissolved Fe(II) from the wetland rhizosphere driven by flood may result in the release of Fe-associated heavy metals from riparian wetland to surface water, and hence pose potential threats to the surface water quality. Thereby, the flow and flood should be properly controlled and vegetation effects need to be carefully considered in the water resources management of lake-floodplain system.

Tracking Ultrafast Structural Dynamics in a Dual-Emission Anti-Kasha-Active Fluorophore Using Femtosecond Stimulated Raman Spectroscopy.

The anti-Kasha process provides the possibility of using high-energy excited states to develop novel applications. Our previous research (Nature communications, 2020, 11, 793) has demonstrated a dual-emission anti-Kasha-active fluorophore for bioimaging application, which exhibits near-infrared emissions from the S1 state and visible anti-Kasha emissions from the S2 state. Here, we applied tunable blue-side femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption spectroscopy, assisted by quantum calculations, to reveal the anti-Kasha dual emission mechanism, in which the emergence of two fluorescing states is due to the retardation of internal conversion from the S2 state to the S1 state. It has been demonstrated that the facts of anti-Kasha high-energy emission are commonly attributed to a large energy gap between the two excited states, leading to a decrease in the internal conversion rate due to a poor Franck-Condon factor. In this study, analysis of the calculation and FSRS experimental results provide us further insight into the dual-emission anti-Kasha mechanism, where the observation of hydrogen out-of-plane Raman modes from FSRS suggested that, in addition to the energy-gap law, the initial photoinduced molecular conformational change plays a key role in influencing the rate of internal conversion.

The decomposition of macrozoobenthos induces large releases of phosphorus from sediments.

Lake eutrophication and algal blooms may result in the mortality of macrozoobenthos. However, it is still not clear how macrozoobenthos decomposition affect phosphorus (P) mobility in sediments. High-resolution dialysis (HR-Peeper) and the diffusive gradients in thin films (DGT) technique were used in this study to assess the dissolved organic matter (DOM), dissolved/DGT-labile iron (Fe), P, and sulfur (S(-II)) profiles at a millimeter resolution. The decomposition of Bellamya aeruginosa significantly increased the internal loading of sediments P. The Fe(III) and sulfate were reduced under anaerobic conditions and promoted P desorption from sediments. This was supported by the significant increase in DGT-labile S(-II) and dissolved/DGT-labile P, Fe(II) and the significant positive correlation between Fe and P on day 8. The simultaneous increase in DOM and soluble reactive phosphorus (SRP) and the significant positive relationship between these factors were observed during the decomposition of B. aeruginosa. This suggested that complexation of DOM with metals may promotes the release of P from sediments.

[Effect and mechanism of testosterone level on inflammatory bone resorption in periodontitis with mice].

PURPOSE: To investigate the effect of testosterone level on inflammatory bone resorption in periodontitis with mice. METHODS: Forty-eight SD mice were randomly divided into unligated group, sham operation group, castration group, castration + testosterone group, 12 mice in each group. At 6 weeks after ligation, serum testosterone levels were measured, and alveolar bone loss (ABL) and alveolar bone absorption area were compared by hematoxylin - eosin staining and methylene blue staining. The expression of inflammatory cytokine messenger RNA(mRNA) in gingival tissue was measured by real-time fluorescence quantitative PCR. SPSS 20.0 software package was used to analyze the data. RESULTS: Serum testosterone level among four groups was the highest in the unligated group, followed by castration + testosterone group, sham operation group and castration group, with significant difference(P<0.05). The ABL of the castration + testosterone group was significantly larger than that of the unligated group, the sham operation group and the castration group(P<0.05). The ABL of the castration group was significantly smaller than that of the sham operation group (P<0.05). The alveolar bone resorption area of the castration + testosterone group was significantly larger than that of the unligated group, the sham operation group and the castration group(P<0.05). The alveolar bone resorption area of the castration group was significantly smaller than that of the sham operation group (P<0.05). Interleukin-1ß (IL-1ß) mRNA, interleukin-6(IL-6) mRNA and tumor necrosis factor-α(TNF-α) mRNA levels in gingival tissues of sham operation group, castration group and castration + testosterone group were significantly higher than the unligated group. The levels of interleukin-10(IL-10) mRNA in gingival tissues of sham operation group, castration group and castration + testosterone group were significantly lower than those in unligated group(P<0.05). The level of IL-1ß mRNA in gingival tissues among four groups was the the highest in the unligated group, followed by castration + testosterone group, sham operation group and castration group, with significant difference (P<0.05). Serum testosterone levels were positively correlated with ABL, alveolar bone resorption area, and IL-1ß (P<0.05). CONCLUSIONS: Periodontitis with mice have decreased testosterone levels, and long-term testosterone depletion can reduce inflammatory bone resorption in alveolar bone, which may be achieved by reducing the level of IL-1ß, indicating that reduction of the level of testosterone in periodontitis patients may be a new treatment target for alveolar bone resorption.

LncRNA LEF1-AS1 promotes osteogenic differentiation of dental pulp stem cells via sponging miR-24-3p.

The role of lncRNA LEF1-AS1 in the regulation of osteogenic differentiation of dental pulp stem cells (DPSCs) is still obscure. Here, we demonstrated that LncRNA LEF1-AS1 expression was associated with osteogenic differentiation of DPSCs and overexpression of LEF1-AS1 promoted osteogenic differentiation. Moreover, lncRNA LEF1-AS1 and miR-24-3p could directly regulate each other and LEF1-AS1 acted as sponge partner of miR-24-3p. Furthermore, LEF1-AS1 and miR-24-3p synergized to regulate osteogenic differentiation of DPSCs. Finally, we verified TGFBR1 was the direct target of miR-24-3p in osteogenic differentiation of DPSCs and miR-24-3p/LEF1-AS1 sponged to regulate TGFBR1 expression. Our study revealed a novel mechanism about how did lncRNA LEF1-AS1 execute function in osteogenesis of DPSCs and thus might serve as potential therapeutic target for the bone regeneration in the dental pulp.