Modeling Kelvin-Helmholtz Instability at the High-Latitude Boundary Layer in a Global Magnetosphere Simulation.

The Kelvin-Helmholtz instability at the magnetospheric boundary plays a crucial role in solar wind-magnetosphere-ionosphere coupling, particle entry, and energization. The full extent of its impact has remained an open question due, in part, to global models without sufficient resolution to capture waves at higher latitudes. Using global magnetohydrodynamic simulations, we investigate an event when the Magnetospheric Multiscale (MMS) mission observed periodic low-frequency waves at the dawn-flank, high-latitude boundary layer. We show the layer to be unstable, even though the slow solar wind with the draped interplanetary magnetic field is seemingly unfavorable for wave generation. The simulated velocity shear at the boundary is thin ( ∼ 0.65 R E ) and requires commensurately high spatial resolution. These results, together with MMS observations, confirm for the first time in fully three-dimensional global geometry that KH waves can grow in this region and thus can be an important process for energetic particle acceleration, dynamics, and transport.

Early prediction of response to chemoradiotherapy for head and neck cancer: reliability of restaging with combined positron emission tomography and computed tomography.

OBJECTIVE: To assess the role of combined positron emission tomography and computed tomography (PET-CT) in predicting early treatment response at the primary site and in the neck after chemoradiotherapy (CRT) for advanced squamous cell carcinoma of the head and neck (SCCHN). DESIGN: Retrospective analysis with a median follow-up of 24 months. SETTING: Academic, tertiary referral center. PATIENTS AND INTERVENTIONS: Thirty-one patients who were treated with concomitant intra-arterial CRT underwent PET-CT 6 to 8 weeks after the completion of treatment. Patients with findings on the physical examination, CT, or PET-CT indicative of persistent disease underwent appropriate surgical intervention for pathological assessment. Patients with a complete clinical response were observed with routine follow-up physical examination for disease recurrence. No evidence of disease at least 6 months after the completion of PET-CT was considered confirmation of complete clinical response. MAIN OUTCOME MEASURES: Presence or absence of residual or recurrent disease during the follow-up period was used to calculate the sensitivity, specificity, and positive and negative predictive values of PET-CT for the primary site and the neck. RESULTS: Assessment of tumor response at the primary site with PET-CT had a sensitivity, specificity, and positive and negative predictive values of 83%, 54%, 31%, and 92%, respectively. In patients with pretreatment N1 to N3 disease, the sensitivity, specificity, and positive and negative predictive values of posttreatment PET-CT were 75%, more than 94%, more than 75%, and 94%, respectively, and the specificity and negative predictive value for patients with pretreatment N0 disease in the neck were 92% and more than 92%, respectively. CONCLUSIONS: Negative PET-CT findings accurately determine early disease response at the primary site and in the neck. False-positive findings are common at the primary site. Patients with a negative PET-CT finding after the completion of intra-arterial CRT do not require surgical intervention.

Novel cyclic sugar imines: carbohydrate mimics and easily elaborated scaffolds for aza-sugars.

[reaction: see text] Representative simple or polyhydroxylated, pyrrolidine (e.g, DRAM) or piperidine (e.g., DNJ) imines not only are potential carbohydrate-processing enzyme inhibitors that may be formed as regioisomeric variants but also are scaffolds that may be rapidly elaborated to diversely functionalized aza-sugars through highly diastereoselective organometallic additions.

Variations in serum OKT3 concentration based upon age, sex, transplanted organ, treatment regimen, and anti-OKT3 antibody status.

An essential parameter of the efficacy of OKT3 therapy is serial determinations of serum OKT3 levels. We hypothesized that precise monitoring of these levels would optimize treatment protocols. Therefore, enzyme-linked immunosorbent assay (ELISA) technology was utilized to measure OKT3 serum concentrations daily during 263 OKT3 treatment courses in recipients of solid organ grafts. Patient characteristics were: mean age 33 years (0.1-71), 147 male/116 female, 134 kidney/82 liver/47 heart, 122 prophylaxis/141 rejection, and 213 conventional dosing/50 increased dosing. Mean OKT3 levels were higher in women than in men at all time points from day 1 to day 14, reaching the greatest difference between groups on day 7 (849 versus 598 ng/ml, p = 0.004). Patients receiving OKT3 as a component of a prophylactic protocol had higher levels than those receiving the drug for treatment of rejection from day 1 to day 6, with the greatest difference between groups occurring on day 1 (678 versus 333 ng/ml, p < 0.00001). However, from day 7 to day 14 patients receiving OKT3 prophylactically had lower mean OKT3 levels than did those receiving OKT3 for rejection, with the greatest difference between groups occurring on day 11 (555 versus 784 ng/ml, p < 0.05). Liver transplant recipients had significantly higher OKT3 levels than did kidney or heart transplants at all time points. However, more liver patients required increased OKT3 doses to modulate peripheral blood CD3+ cells to < 25/mm3. Kidney recipients had higher levels than did heart recipients. Children < 10 years of age had higher OKT3 levels than did older patients at all time points.(ABSTRACT TRUNCATED AT 250 WORDS)