A numerical modeling study on barotropic and baroclinic responses of the Chesapeake Bay to hurricane events

The barotropic and baroclinic responses of the Chesapeake Bay to forcings from two hurricanes were investigated by using unstructured-grid three-dimensional hydrodynamic models. The model domain includes Chesapeake Bay proper, the tributaries, and its extended continental shelf in the mid-Atlantic Bight. Two hurricanes were studied: Hurricane Floyd of September, 1999 and Hurricane Isabel of September, 2003, both of which made landfall within 100 km of the Chesapeake Bay mouth. Hurricane Floyd in 1999 passed through the entrance of the Bay from southwest to northeast along the coastlines of Virginia as a Category 1 storm, whereas Hurricane Isabel in 2003 made landfall on the east coast of North Carolina and moved inland toward the northwest as a Category 2 storm. For the barotropic simulation of the Bay responding to the hurricanes, the model results were compared with Bay-wide water level observations and the model showed reasonable prediction skill. It was found that the storm surge has two phases: a primary surge induced by the remote winds and a secondary surge induced by the local winds. For both hurricanes, the primary surge induced by remote winds propagated into the Bay initially, but the subsequent phase, influenced by the local wind, was notably different. Hurricane Floyd was followed by northerly (down-Bay) winds, that reduced the primary surge effect and caused a localized set-down; Hurricane Isabel was followed by southerly (up-Bay) winds, which superimposed on the primary surge effect and caused a localized set-up. The volume and salt fluxes were estimated at selected cross-sectional transects throughout the Bay, and it was found consistently for each transect that the net influx dominated during Hurricane Isabel while the net outflux dominated during Hurricane Floyd. For the Bay\u27s tributaries, the large inland river discharge at the headwater can couple with the storm surge event to increase sea surface elevation on the second phase of sea surface elevation rise, which has a significant impact on inundation in the local low-lying areas. For the baroclinic response of the Bay to the hurricanes, the model results agreed reasonably well with additional observed data: sea surface elevation, velocity, and salinity profiles. From the perspective of salt flux, oceanic saltwater influx was evidently pushed into the Bay from the continental shelf at the initial phase of Hurricanes Floyd and Isabel associated with storm surge and salt intrusion. In the second phase, follow up with, down-bay local winds of eastern-type storms tend to enhance the stratification whereas up-Bay local winds of western-type storms tend to reduce the stratification. The hurricane surface wind stress is the primary agent for destratifying water column by transferring generated turbulent kinetic energy to the lower layer. The wind-induced straining during Hurricane Floyd was verified using non-dimensional parameters that incorporated the wind direction and the horizontal salinity gradient. Direct precipitation of hurricane rainfall acted more like a point source onto the Bay surface water, which created a layer of low surface salinity on the sea surface. It has an implication dynamically on generating a sea surface horizontal pressure gradient and re-distributing salinity field after the storm. Extra efforts have been made to conduct idealized experiments for comparing long-term recovery of the Bay to the disturbance created by the two hurricanes. Realistic hurricane wind forcing was applied in a 4-day window with the same initial condition applied in the beginning, and the quasi-steady state condition achieved in the end. Through this exercise, it was found that it took Bay 5-7 days to return to normal condition from the sea surface elevation disturbances for both Hurricanes Floyd and Isabel. For the salinity fields, it took within a range of 20-30 days to recover to the pre-storm condition for the middle and southern portions of the Bay. For the northern portion of the Bay, however, due to the landward barotropic pressure gradient generated a strong salinity rebound and the associated oscillation subsequently after Hurricane Floyd passed, it required twice as long to recover. Sensitivity testing of the effect of river discharge (immediately after the storm) on the recovery time has also been performed. Lastly, the influences of continental shelf dynamics on the Bay\u27s response to the hurricane were examined. It was found that the along shelf wind contributed to the inflow and ouflow at the Bay mouth in the form of Ekman transport, which complemented the contribution generated by the Bay\u27s local wind. The onshore and offshore shelf wind also played a significant role. Because the cyclonic pattern of the hurricane wind field, when the hurricane made the landfall in the US East coast, an along-the-shelf pressure gradient from the north to the south was generated. This pressure gradient, coupled with the Coriolis and friction forces, can generate a quasi-geostrophic balance flow serving to prevent or enhance the inflow across the Bay mouth. The effect is particularly noticeable in the relaxation period during the hurricane passage

The association of serum irisin with anthropometric, metabolic, and bone parameters in obese children and adolescents

BackgroundIrisin is an adipomyokine secreted by muscle and adipose cells, and it plays a role in glucose, fat, and bone metabolism. This study aimed to determine the correlation of serum irisin levels with anthropometric, metabolic, and bone parameters in obese children and adolescents.MethodsThis single-center study included 103 Korean children and adolescents: 54 (52.4%) obese participants with a body mass index (BMI) ≥95th percentile and 49 (47.6%) healthy controls with BMI within the 15th to 85th percentile. Various parameters were measured, including fasting blood glucose, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), triglyceride and glucose (TyG) index, lipid profile, alkaline phosphatase (ALP), osteocalcin, and 25(OH)-Vitamin D levels. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DEXA) in 33 healthy subjects.ResultsSerum irisin was significantly higher in the obese group than in the control group (mean 18.1 ± 3.5 vs. 16.2 ± 2.0 ng/mL; p = 0.001). Serum irisin level was positively correlated with chronological age (r = 0.28; p = 0.004), height SDS (r = 0.24; p = 0.02), BMI SDS (r = 0.37; p < 0. 001), fasting glucose (r = 0.27; p = 0.007), fasting insulin (r = 0.23; p = 0.03), HOMA-IR (r = 0.21; p = 0.04), osteocalcin (r = 0.27; p = 0.006) and negatively correlated with HDL cholesterol (r = -0.29; p = 0.005). All these correlations were evident in obese subjects but not in healthy subjects. ALP and 25(OH)-Vitamin D were unrelated to irisin levels. Among 33 healthy subjects, total body-less head (TBLH) BMD Z-score was positively correlated with serum irisin (r = 0.39; p = 0.03), osteocalcin (r = 0.40; p = 0.02), fasting insulin (r = 0.39; p = 0.04), and HOMA-IR (r = 0.38; p = 0.047).ConclusionThis study demonstrated an association between irisin levels and glucose, lipid, and bone parameters in children and adolescents. Our findings suggest that irisin has a potential role in metabolic disorders and bone health in obese children and adolescents

The Effect of Ca-P Coated Bovine Bone Mineral on Bone Regeneration around Dental Implant in Dogs

There are many obstacles to overcome in implant dentistry. The bony defect around implant can be seen in immediate installation procedures. Following tooth extraction, however, a socket often presents dimensions that may be considerably greater than the dimensions of a conventional implant

Factors affecting height velocity in normal prepubertal children

Purpose To analyze the effects of clinical and laboratory factors, including insulin-like growth factor (IGF) levels, on the height velocity of normal prepubertal children. Methods Ninety-five healthy prepubertal children (33 boys, 62 girls) were enrolled. The mean chronological age was 6.3±1.4 years, with a height standard deviation score (SDS) of -0.88±0.70. IGF-1, IGF binding protein-3 (IGFBP-3), SDS for anthropometric measurements, and changes in SDS for anthropometric measurements were analyzed for 1 year, and their associations with 1-year height velocity were investigated. Results The group of children with a 1-year height velocity of ≥6 cm were chronologically younger than the group with a 1-year height velocity of <6 cm (5.9±1.3 years vs. 6.7±1.3 years, P=0.004), with a lesser increase of SDS for body mass index (BMI) over 1 year (-0.18±0.68 vs. 0.13±0.53, P=0.014). There were no differences between the 2 groups in IGF-1 SDS and IGFBP-3 SDS. Multiple linear regression showed that baseline chronological age (r=0.243, P=0.026) and height SDS (r=0.236, P=0.030) were positively associated with IGF-1 SDS. Binomial logistic regression showed that an older chronologic age at referral (odds ratio [OR], 0.68; 95% confidence interval [CI], 0.47–0.99) and an increase of BMI SDS over 1 year (OR, 0.41; 95% CI, 0.18–0.89) were associated with a decreased growth possibility of an above-average height velocity (≥6 cm/yr). Conclusions Height velocity of normal prepubertal children is affected by an increase of BMI SDS and chronological age. Prepubertal IGF-1 SDS reflects height SDS at the time of measurement but is not associated with subsequent height velocity

Characteristics of Hearing Loss Among Older Adults in the Korean Genome and Epidemiology Study: A Community-Based Longitudinal Cohort Study With an 8-Year Follow-up

Objectives. This study investigated the 8-year incidence and progression of hearing loss (HL) and its types and examined the risk factors for changes in HL. Methods. This longitudinal cohort study analyzed data from the Korean Genome and Epidemiology Study (KoGES), an ongoing, prospective, community-based cohort study that has been conducted since 2001. Altogether, 1,890 residents of urban areas in Korea aged 45–75 years at time 1 (baseline) were included in the study. Pure-tone audiometry (PTA) testing was performed twice, at time 1 (2008–2009) and time 2 (2015–2018, follow-up), 8 years apart. HL grades were defined as seven mutually exclusive categories following the revised World Health Organization classification. Incidence was defined as PTA >20 dB HL in the better ear at time 2 among those without HL at time 1. Progression was defined as the progressive deterioration of HL among those with HL at time 1. The three types of HL constituted sensorineural (SNHL), conductive, and mixed HL. Results. At time 1, 36.40% of patients were diagnosed with HL, which increased to 51.64% at time 2. The 8-year incidence of HL was 27.20%, and progressive deterioration of HL occurred in 23.11% of those with HL. SNHL was the most common type of HL, and its prevalence markedly increased at time 2. Multivariate analysis demonstrated that the incidence of HL was significantly associated with increasing age, male sex (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.07–2.81), and diabetes mellitus (OR, 1.43; 95% CI, 1.04–1.96). Alcohol consumption was a risk factor for HL deterioration among those with HL at time 1. Conclusion. The prevalence and deterioration of HL were extremely high among older adults, and age was the strongest risk factor for these changes. Therefore, timely screening and intervention are necessary to prevent HL and delay its deterioration among older adults

Hepatic glycogenosis in type 1 diabetes mellitus mimicking Mauriac syndrome

Hepatic glycogenosis in type 1 diabetes mellitus (DM) can be caused by poor glycemic control due to insulin deficiency, excessive insulin treatment for diabetic ketoacidosis, or excessive glucose administration to control hypoglycemia. Mauriac syndrome, which is characterized by hepatomegaly due to hepatic glycogenosis, growth retardation, delayed puberty, and Cushingoid features, is a rare diabetic complication. We report a case of hepatic glycogenosis mimicking Mauriac syndrome. A 14-year-old girl with poorly controlled type 1 DM was admitted to The Catholic University of Korea, Seoul St. Mary's Hospital for abdominal pain and distension. Physical examination revealed hepatomegaly and a Cushingoid face. The growth rate of the patient had decreased, and she had not yet experienced menarche. Laboratory findings revealed elevated liver enzyme levels. A liver biopsy confirmed hepatic glycogenosis. Continuous glucose monitoring showed hyperglycemia after meals and frequent hypoglycemia before meals. To control hyperglycemia, we increased insulin dosage by using an insulin pump. In addition, we prescribed uncooked cornstarch to prevent hypoglycemia. After strict blood glucose control, the patient's liver functions and size normalized. The patient subsequently underwent menarche. Hepatic glycogenosis is a complication of type 1 DM that is reversible with appropriate glycemic control

The Role of Sphingosine Kinase 1/Sphingosine-1-Phosphate Pathway in the Myogenic Tone of Posterior Cerebral Arteries

AIMS: The goal of the current study was to determine whether the sphingosine kinase 1 (SK1)/sphingosine-1-phosphate (S1P) pathway is involved in myogenic vasoconstriction under normal physiological conditions. In the present study, we assessed whether endogenous S1P generated by pressure participates in myogenic vasoconstriction and which signaling pathways are involved in SK1/S1P-induced myogenic response under normal physiological conditions. METHODS AND RESULTS: We measured pressure-induced myogenic response, Ca(2+) concentration, and 20 kDa myosin light chain phosphorylation (MLC(20)) in rabbit posterior cerebral arteries (PCAs). SK1 was expressed and activated by elevated transmural pressure in rabbit PCAs. Translocation of SK1 by pressure elevation was blocked in the absence of external Ca(2+) and in the presence of mechanosensitive ion channel and voltage-sensitive Ca(2+) channel blockers. Pressure-induced myogenic tone was inhibited in rabbit PCAs treated with sphingosine kinase inhibitor (SKI), but was augmented by treatment with NaF, which is an inhibitor of sphingosine-1-phosphate phosphohydrolase. Exogenous S1P further augmented pressure-induced myogenic responses. Pressure induced an increase in Ca(2+) concentration leading to the development of myogenic tone, which was inhibited by SKI. Exogenous S1P further increased the pressure-induced increased Ca(2+) concentration and myogenic tone, but SKI had no effect. Pressure- and exogenous S1P-induced myogenic tone was inhibited by pre-treatment with the Rho kinase inhibitor and NADPH oxidase inhibitors. Pressure- and exogenous S1P-induced myogenic tone were inhibited by pre-treatment with S1P receptor blockers, W146 (S1P1), JTE013 (S1P2), and CAY10444 (S1P3). MLC(20) phosphorylation was increased when the transmural pressure was raised from 40 to 80 mmHg and exogenous S1P further increased MLC(20) phosphorylation. The pressure-induced increase of MLC(20) phosphorylation was inhibited by pre-treatment of arteries with SKI. CONCLUSIONS: Our results suggest that the SK1/S1P pathway may play an important role in pressure-induced myogenic responses in rabbit PCAs under normal physiological conditions