Antarctic ice shelf potentially stabilized by export of meltwater in surface river.

Meltwater stored in ponds and crevasses can weaken and fracture ice shelves, triggering their rapid disintegration. This ice-shelf collapse results in an increased flux of ice from adjacent glaciers and ice streams, thereby raising sea level globally. However, surface rivers forming on ice shelves could potentially export stored meltwater and prevent its destructive effects. Here we present evidence for persistent active drainage networks-interconnected streams, ponds and rivers-on the Nansen Ice Shelf in Antarctica that export a large fraction of the ice shelf's meltwater into the ocean. We find that active drainage has exported water off the ice surface through waterfalls and dolines for more than a century. The surface river terminates in a 130-metre-wide waterfall that can export the entire annual surface melt over the course of seven days. During warmer melt seasons, these drainage networks adapt to changing environmental conditions by remaining active for longer and exporting more water. Similar networks are present on the ice shelf in front of Petermann Glacier, Greenland, but other systems, such as on the Larsen C and Amery Ice Shelves, retain surface water at present. The underlying reasons for export versus retention remain unclear. Nonetheless our results suggest that, in a future warming climate, surface rivers could export melt off the large ice shelves surrounding Antarctica-contrary to present Antarctic ice-sheet models, which assume that meltwater is stored on the ice surface where it triggers ice-shelf disintegration.

Pseudomonas neustonica sp. nov., isolated from the sea surface microlayer of the Ross Sea (Antarctica).

Gram-stain-negative, aerobic and rod-shaped bacterial strains, designated SSM26T and SSM44, were isolated from a sea surface microlayer sample from the Ross Sea, Antarctica. Analysis of the 16S rRNA gene sequences of strains SSM26T and SSM44 revealed a clear affiliation with the genus Pseudomonas. Based on the results of phylogenetic analysis, strains SSM26T and SSM44 showed the closest phylogenetic relationship with the species Pseudomonas sabulinigri KCTC 22137T with the 16S rRNA gene sequence similarity level of 98.5 %. Strains SSM26T and SSM44 grew optimally at 30 °C, pH 7.0-7.5 and 0.5-10.0 % NaCl (w/v). The major cellular fatty acids were C18 : 1 ω7c (31.3-34.9 %), C16 : 0 (15.5-20.2 %), summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c; 19.5-25.4 %) and C12 : 0 (6.0-9.3 %). The genomic DNA G+C content of each strain was 56.2 mol%. Genomic relatedness analyses based on the average nucleotide identity and the genome-to-genome distance showed that strains SSM26T and SSM44 constituted a single species that was clearly distinguishable from its phylogenetically close relatives. The combined phenotypic, chemotaxonomic, genomic and phylogenetic data also showed that strains SSM26T and SSM44 could be distinguished from validly published members of the genus Pseudomonas. Thus, these strains should be classified as representing a novel species in the genus Pseudomonas, for which the name Pseudomonas neustonica sp. nov. is proposed with the type strain SSM26T (=KCCM 43193T=JCM 31284T=PAMC 28426T) and a sister strain SSM44 (=KCCM 43194=JCM 31285=PAMC 28427).

Pseudoalteromonas neustonica sp. nov., isolated from the sea surface microlayer of the Ross Sea (Antarctica), and emended description of the genus Pseudoalteromonas.

A Gram-stain-negative, facultatively anaerobic, rod-shaped and motile strain, designated PAMC 28425T, was isolated from a sea surface microlayer sample from the Ross Sea, Antarctica. Analysis of the 16S rRNA gene sequence of strain PAMC 28425T showed an affiliation with the genus Pseudoalteromonas. Phylogenetic analyses revealed that strain PAMC 28425T formed a clade with Pseudoalteromonas prydzensis MB8-11T and Pseudoalteromonas mariniglutinosaKMM 3635T with 16S rRNA gene sequence similarities of 98.3-98.6 %. Genomic relatedness analyses based on the average nucleotide identity and the genome-to-genome distance showed that strain PAMC 28425T is clearly distinguished from the phylogenetically close relatives. Cells of strain PAMC 28425T grew optimally at 25 °C and pH 7.5-8.5 in the presence of 1.0-3.0 % (w/v) sea salts. The major cellular fatty acids (>10 %) were C16 : 1ω6c and/or C16 : 1ω7c, C16 : 0, and C18 : 1ω6c and/or C18 : 1ω7c. The genomic DNA G+C content was 39.7 mol%. On the basis of the phylogenetic, genomic, chemotaxonomic and phenotypic data presented, we propose the name Pseudoalteromonas neustonica sp. nov. with the type strain PAMC 28425T (=KCCM 43187T=JCM 31286T).

Reclassification of Halomonas caseinilytica Wu et al. 2008 as a later synonym of Halomonas sinaiensis Romano et al. 2007, and emendation of the species description.

The taxonomic relationship between Halomonas sinaiensis DSM 18067(T) and Halomonas caseinilytica JCM 14802(T) has not been established, despite the high similarity (99.6 %) of their 16S rRNA gene sequences. To clarify their taxonomic positions, a polyphasic approach was applied to both type strains. Genomic relatedness analyses between H. sinaiensis DSM 18067(T) and H. caseinilytica JCM 14802(T) resulted in an average nucleotide identity of 99.5 % and an estimated DNA-DNA hybridization of 96.1 % by the genome-to-genome distance calculator, indicating that they belong to a single species. Phenotypic and chemotaxonomic characteristics showed no pronounced differences between the two type strains. Based on the results of this polyphasic study, it is proposed that H. caseinilytica JCM 14802(T) is a later heterotypic synonym of H. sinaiensis DSM 18067(T). An emended description for the species H. sinaiensis is given.

Association between vestibular schwannomas and mobile phone use.

Vestibular schwannomas (VSs) grow in the region where the energy from mobile phone use is absorbed. We examined the associations of VSs with mobile phone use. This study included 119 patients who had undergone surgical tumor removal. We used two approaches in this investigation. First, a case-control study for the association of mobile phone use and incidence of VSs was conducted. Both cases and controls were investigated with questions based on INTERPHONE guidelines. Amount of mobile phone use according to duration, daily amount, and cumulative hours were compared between two groups. We also conducted a case-case study. The location and volume of the tumors were investigated by MRI. Associations between the estimated amount of mobile phone use and tumor volume and between the laterality of phone use and tumor location were analyzed. In a case-control study, the odds ratio (OR) of tumor incidence according to mobile phone use was 0.956. In the case-case study, tumor volume and estimated cumulative hours showed a strong correlation (r(2) = 0.144, p = 0.002), and regular mobile phone users showed tumors of a markedly larger volume than those of non-regular users (p < 0.001). When the analysis was limited to regular users who had serviceable hearing, laterality showed a strong correlation with tumor side (OR = 4.5). We found that tumors may coincide with the more frequently used ear of mobile phones and tumor volume that showed strong correlation with amount of mobile phone use, thus there is a possibility that mobile phone use may affect tumor growth.

High Salinity Shelf Water production rates in Terra Nova Bay, Ross Sea from high-resolution salinity observations.

High Salinity Shelf Water (HSSW) formed in the Ross Sea of Antarctica is a precursor to Antarctic Bottom Water (AABW), a water mass that constitutes the bottom limb of the global overturning circulation. HSSW production rates are poorly constrained, as in-situ observations are scarce. Here, we present high-vertical-and-temporal-resolution salinity time series collected in austral winter 2017 from a mooring in Terra Nova Bay (TNB), one of two major sites of HSSW production in the Ross Sea. We calculate an annual-average HSSW production rate of ~0.4 Sv (106 m3 s-1), which we use to ground truth additional estimates across 2012-2021 made from parametrized net surface heat fluxes. We find sub-seasonal and interannual variability on the order of [Formula: see text] [Formula: see text], with a strong dependence on variability in open-water area that suggests a sensitivity of TNB HSSW production rates to changes in the local wind regime and offshore sea ice pack.

Ice front retreat reconfigures meltwater-driven gyres modulating ocean heat delivery to an Antarctic ice shelf.

Pine Island Ice Shelf (PIIS) buttresses the Pine Island Glacier, the key contributor to sea-level rise. PIIS has thinned owing to ocean-driven melting, and its calving front has retreated, leading to buttressing loss. PIIS melting depends primarily on the thermocline variability in its front. Furthermore, local ocean circulation shifts adjust heat transport within Pine Island Bay (PIB), yet oceanic processes underlying the ice front retreat remain unclear. Here, we report a PIB double-gyre that moves with the PIIS calving front and hypothesise that it controls ocean heat input towards PIIS. Glacial melt generates cyclonic and anticyclonic gyres near and off PIIS, and meltwater outflows converge into the anticyclonic gyre with a deep-convex-downward thermocline. The double-gyre migrated eastward as the calving front retreated, placing the anticyclonic gyre over a shallow seafloor ridge, reducing the ocean heat input towards PIIS. Reconfigurations of meltwater-driven gyres associated with moving ice boundaries might be crucial in modulating ocean heat delivery to glacial ice.

Subthreshold continuous electrical stimulation facilitates functional recovery of facial nerve after crush injury in rabbit.

We sought to determine whether electrical stimulation (ES) with subthreshold, continuous, low-frequency impulses is a viable clinical method for improving functional recovery after facial nerve crush injury. In 10 rabbits, bilateral crush injuries were made on the facial nerve by compression for 30 s with mosquito forceps, causing complete facial paralysis. Subthreshold continuous direct current ES with 20-Hz square-wave pulses was applied to the proximal stump on one side for 4 weeks. Vibrissae movement returned significantly earlier on the ES side, with a less variable recovery time. Electrophysiologically, the stimulated side had a significantly shorter latency, longer duration, and faster conduction velocity. Light and transmission electron microscopy revealed that the electrical stimulation also markedly decreased Wallerian degeneration. The average numbers of fluorescent, double-labeled nerve cells were significantly different between the ES and non-ES sides. This study shows that subthreshold, continuous, low-frequency ES immediately after a crush injury of the facial nerve results in earlier recovery of facial function and shorter overall recovery time.

Clinical characteristics of acoustic trauma caused by gunshot noise in mass rifle drills without ear protection.

One of the major occupational hazards of working in military service is being subjected to intense impulse noise. We analyzed the clinical presentation of acoustic traumas, induced by mass rifle gunshot noise during military training, in unprotected patients. We evaluated 189 soldiers who had otologic symptoms after rifle shooting exercises without using any hearing protection. All soldiers had been training on the K2 rifle. We took medical histories; conducted physical examinations and hearing evaluations (pure-tone audiometry, speech audiometry, and impedence audiometry); and distributed the Newmann's Tinnitus Handicap Inventory (THI) survey. In addition, we evaluated a normal control group of 64 subjects of similar age who had never fired a rifle. In the patient group, the most common and irritating reported symptom was tinnitus (94.2%), and the average THI score in the patient group was 39.51 ± 14.87, which was significantly higher than the control group score (0.56 ± 3.94) (p < 0.001). Average outcomes of post-exposure air conduction thresholds were 21.33 ± 13.25 dB HL in the affected ears. These levels also were significantly higher than those of the control group (9.16 ± 4.07dB HL) (p < 0.001). Hearing loss was most prominent at high frequencies. An asymmetry of hearing loss related to head position during shooting was not observed. Acoustic trauma induced by gunshot noise can cause permanent tinnitus and hearing loss. Hearing protection (bilateral earplugs) and environmental reform are necessary.

An open access dataset for developing automated detectors of Antarctic baleen whale sounds and performance evaluation of two commonly used detectors.

Since 2001, hundreds of thousands of hours of underwater acoustic recordings have been made throughout the Southern Ocean south of 60° S. Detailed analysis of the occurrence of marine mammal sounds in these circumpolar recordings could provide novel insights into their ecology, but manual inspection of the entirety of all recordings would be prohibitively time consuming and expensive. Automated signal processing methods have now developed to the point that they can be applied to these data in a cost-effective manner. However training and evaluating the efficacy of these automated signal processing methods still requires a representative annotated library of sounds to identify the true presence and absence of different sound types. This work presents such a library of annotated recordings for the purpose of training and evaluating automated detectors of Antarctic blue and fin whale calls. Creation of the library has focused on the annotation of a representative sample of recordings to ensure that automated algorithms can be developed and tested across a broad range of instruments, locations, environmental conditions, and years. To demonstrate the utility of the library, we characterise the performance of two automated detection algorithms that have been commonly used to detect stereotyped calls of blue and fin whales. The availability of this library will facilitate development of improved detectors for the acoustic presence of Southern Ocean blue and fin whales. It can also be expanded upon to facilitate standardization of subsequent analysis of spatiotemporal trends in call-density of these circumpolar species.

The effect of surgical timing on functional outcomes of traumatic facial nerve paralysis.

BACKGROUND: The optimal timing for surgical exploration of traumatic facial paralysis to best preserve facial function is currently controversial. This article reviews the final outcomes of facial function in patients with traumatic intratemporal facial nerve injury according to the timing of surgical exploration. METHODS: We performed a retrospective review of 58 patients with complete facial nerve paralysis caused by temporal bone fractures as a result of head trauma between 1998 and 2007. Patients were divided into three groups according to the type of trauma. The only difference between patients in each group was the timing of the surgical exploration. Characteristics assessed in the study included type of trauma, location of facial nerve injury, timing of surgical intervention, audiometric findings, surgical approach, and long-term follow-up of recovery of facial nerve function, as assessed by two facial nerve grading systems. RESULTS: The final functional gains in early-operated patients were 3.7 +/- 0.59 on the House-Brackmann (HB) scale and 75.6 +/- 10.88 on the Sunnybrook scale. The outcome in late-operated patients was 2.17 +/- 0.52 on the HB scale and 34.7 +/- 16.95 on the Sunnybrook scale, and that of nonoperated patients was 2.0 +/- 0.63 on the HB scale and 26.8 +/- 6.27 on the Sunnybrook scale. CONCLUSION: This study demonstrated that some patients with traumatic facial nerve paralysis who had nerve conduction studies consistent with a poor prognosis regained considerable facial function after early surgical intervention. However, late exploration after facial nerve paralysis did not result in positive outcomes, regardless of the type of temporal bone fracture or the site of injury, and no difference was observed compared with conservative treatment.

Neural maturation enhanced by exercise-induced extracellular derivatives.

Physical activity has profound effects on neuronal progenitor cell growth, differentiation, and integration, but the mechanism for these effects is still ambiguous. Using a mouse model, we investigated the effects of two weeks of treadmill running on the dynamics of the size distribution and miRNA profiles of serum extracellular derivatives (EDs) using particle-sizing analysis and small RNA sequencing. We found that an increased average diameter of EDs in the running group compared with the sedentary group (p < 0.05), and 16 miRNAs were significantly altered (p < 0.05) in the running group. Furthermore, functional annotation analysis of differentially expressed miRNA-predicted target genes showed that many of these target genes are involved in the PI3K-Akt pathway. Exercise-induced serum EDs increased Neuro2A cell viability and Akt phosphorylation. We also found that expression levels of neuronal maturation markers such as Microtubule-Associated Protein 2 (MAP2ab) and Neuronal nuclei (NeuN) were increased (p < 0.05, respectively), and that inhibition of the PI3K-Akt pathway by LY294002 pre-treatment ameliorated their expression in Neuro2A cells. Finally, the administration of exercise-induced EDs for 3 days increased the Histone 3 phosphorylation and ß-III tubulin expression in Ink/Arf null neural stem cells and progenitors (NSPCs) under each proliferation and differentiation condition. These results suggest that exercise-induced circulating EDs may mediate neuronal maturation during exercise.

Lactate consumption mediates repeated high-intensity interval exercise-enhanced executive function in adult males.

PURPOSE: Lactate is a principal energy substrate for the brain during exercise. A single bout of high-intensity interval exercise (HIIE) can increase the blood lactate level, brain lactate uptake, and executive function (EF). However, repeated HIIE can attenuate exercise-induced increases in lactate level and EF. The lactate levels in the brain and blood are reported to be correlated with exercise-enhanced EF. However, research is yet to explain the cause-and-effect relationship between lactate and EF. This study examined whether lactate consumption improves the attenuated exerciseenhanced EF caused by repeated HIIE. METHODS: Eleven healthy men performed two sets of HIIE, and after each set, 30 min were given for rest and examination. In the 2nd set, the subjects consumed experimental beverages containing (n = 6) and not containing (n = 5) lactate. Blood, cardiovascular, and psychological variables were measured, and EF was evaluated by the computerized color-word Stroop test. RESULTS: The lactate group had a higher EF (P < 0.05) and tended to have a higher blood lactate level (P = 0.082) than the control group in the 2nd set of HIIE. Moreover, blood lactate concentration was correlated with the interference score (i.e., reverse score of EF) (r = -0.394; P < 0.05). CONCLUSION: Our results suggest that the attenuated exercise-enhanced EF after repeated HIIE can be improved through lactate consumption. However, the role of lactate needs to be elucidated in future studies, as it can be used for improving athletes' performance and also in cognitive decline-related clinical studies.

Clinical and molecular characterizations of novel POU3F4 mutations reveal that DFN3 is due to null function of POU3F4 protein.

X-linked deafness type 3 (DFN3), the most prevalent X-linked form of hereditary deafness, is caused by mutations in the POU3F4 locus, which encodes a member of the POU family of transcription factors. Despite numerous reports on clinical evaluations and genetic analyses describing novel POU3F4 mutations, little is known about how such mutations affect normal functions of the POU3F4 protein and cause inner ear malformations and deafness. Here we describe three novel mutations of the POU3F4 gene and their clinical characterizations in three Korean families carrying deafness segregating at the DFN3 locus. The three mutations cause a substitution (p.Arg329Pro) or a deletion (p.Ser310del) of highly conserved amino acid residues in the POU homeodomain or a truncation that eliminates both DNA-binding domains (p.Ala116fs). In an attempt to better understand the molecular mechanisms underlying their inner ear defects, we examined the behavior of the normal and mutant forms of the POU3F4 protein in C3H/10T1/2 mesodermal cells. Protein modeling as well as in vitro assays demonstrated that these mutations are detrimental to the tertiary structure of the POU3F4 protein and severely affect its ability to bind DNA. All three mutated POU3F4 proteins failed to transactivate expression of a reporter gene. In addition, all three failed to inhibit the transcriptional activity of wild-type proteins when both wild-type and mutant proteins were coexpressed. Since most of the mutations reported for DFN3 thus far are associated with regions that encode the DNA binding domains of POU3F4, our results strongly suggest that the deafness in DFN3 patients is largely due to the null function of POU3F4.

How long should the sudden hearing loss patients be followed after early steroid combination therapy?

To evaluate the beginning time and the completion time of hearing improvement in patients with sudden hearing loss who were treated with combination therapy including oral steroid. From September 2006 to December 2007, 102 idiopathic sudden hearing loss patients who showed any 'recovery' in hearing according to the Siegel's criteria after treatment were analyzed. Pure tone audiometries were performed on the pretreatment day and on the third, seventh, fourteenth post-treatment day, and on the first, second, third, sixth post-treatment month. The time of initial hearing improvement and the completion time of hearing improvement were analyzed. Of 102 patients who showed any improvement, cumulatively, 93.1% showed beginning of hearing improvement within 14 days after treatment. Complete recovery or an end of change was achieved in cumulatively 80.4% of the patients within 1 month after treatment and in 92.2% of the patients within 2 months after treatment. Prognosis can be predicted approximately 2 weeks after start of treatment because time of commencement shows plateau after 2 weeks in improved cases. Hearing should be followed-up for at least 2 months after treatment in patients who show incomplete or delayed hearing improvement.

Transoral robotic surgery (TORS) in laryngeal and hypopharyngeal cancer.

OBJECTIVES: The current trend in managing laryngeal and hypopharyngeal cancer is to perform organ preservation therapy, which improves quality of life and decreases treatment-related morbidity. Transoral robotic surgery (TORS) can overcome the limit of "line of sight" often met in classic transoral procedure. We utilized a robotic surgical system to evaluate the feasibility and oncologic safety of transoral partial pharyngectomy and laryngectomy. MATERIALS AND METHODS: TORS was performed by using a "da Vinci surgical robot" (Intuitive Surgical, Inc., Sunnyvale, CA). An FK retractor (Gyrus Medical Inc., Maple Grove, MN) was used to expose the cancerous lesion transorally, and an endoscopic arm was introduced through the oral cavity with two instrument arms placed 30 degrees apart from the endoscopic arm. We performed TORS on 1 patient with pyriform sinus carcinoma and 4 patients with glottic carcinoma as a prospective human trial. RESULTS: Average surgical time measured was 39 minutes, including an average of 25 minutes used for locating the robotic surgical system in place and exposing the lesion. TORS can provide a magnified three-dimensional view and overcome the limitation resulting from the "line of sight" that hinders the classic transoral procedure. All surgical resection margins were free of carcinoma. There were no perioperative complications, and also, no mortality due to the surgical procedure. CONCLUSIONS: This study demonstrates that the application of TORS for partial pharyngectomy and partial laryngectomy is technically feasible and safe.

Jugular foramen schwannoma: analysis on its origin and location.

OBJECTIVE: To examine the microsurgical anatomy of the jugular foramen and correlate anatomical findings to clinical manifestations of jugular foramen schwannomas concerning tumor origin and location. STUDY DESIGN: Anatomical analysis of jugular foramen was performed by dissection of 25 cadavers (50 sides). By retrospective review of 9 cases of jugular foramen schwannomas surgically treated, the origin and location of tumor were studied. SETTING: Tertiary referral center. MAIN OUTCOME MEASURES: The anatomical characteristics of jugular foramen, lower cranial nerves, and inferior petrosal sinus were correlated with the origin and growth pattern of jugular foramen schwannomas. RESULTS: The superior and inferior ganglions of the glossopharyngeal nerve and the superior ganglion of the vagus nerve were located within the jugular foramen. The superior ganglions of the glossopharyngeal and vagus nerves were located superiorly, whereas the inferior ganglion of the glossopharyngeal nerve was found inferiorly in relation to the inferior petrosal sinus orifice. In our series of 9 cases of jugular foramen schwannoma, the most common nerve of origin was the vagus nerve, followed by the glossopharyngeal nerve. CONCLUSION: The reason for the predilection of the jugular foramen schwannoma for the glossopharyngeal and vagus nerves may be associated with the presence of their ganglions within the jugular foramen. Also, the inferior petrosal sinus may act as a barrier to tumor growth, and the location of the ganglion of tumor origination within the jugular foramen in relation to the inferior petrosal sinus may be correlated to the predominant direction of tumor extension.

Surgical treatment and outcomes of temporal bone chondroblastoma.

Chondroblastoma is an uncommon primary benign bone tumor that usually arises in the epiphyses of the long bones. Temporal bone chondroblastoma is a rare primary bone tumor that affects the floor of the middle cranial fossa and temporomandibular joint (TMJ). The biological nature of temporal bone chondroblastoma is occasionally aggressive because of local invasion and is known to have a high recurrence after curettage. Therefore, complete resection is recommended. However, the literature provides little information regarding long-term surgical outcomes and complications after surgical resection. The authors have retrospectively analyzed four cases of temporal bone chondroblastoma that had been completely excised by a single surgeon with an eventual long-term follow-up. A single surgeon operated on four patients, two males and two females, with a mean age of 34 years, at the Department of Otorhinolaryngology, Severance Hospital. In all cases, the tumor involved the middle cranial fossa dura and the mandibular fossa with variable degree of infiltration. All patients have had no tumor recurrence to date (mean follow-up period of 5 years). Complete surgical resection of the temporal bone chondroblastoma is the gold standard for treatment. Precise preoperative image evaluation of tumor extension and proper management of the dura mater and temporomandibular joint (TMJ) are the major important features in complete surgical removal that minimize complications in temporal bone chondroblastoma treatment.