Ultra-high-resolution observations of persistent null-point reconnection in the solar corona.

Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km s-1 and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona.

Fast plasmoid-mediated reconnection in a solar flare.

Magnetic reconnection is a multi-faceted process of energy conversion in astrophysical, space and laboratory plasmas that operates at microscopic scales but has macroscopic drivers and consequences. Solar flares present a key laboratory for its study, leaving imprints of the microscopic physics in radiation spectra and allowing the macroscopic evolution to be imaged, yet a full observational characterization remains elusive. Here we combine high resolution imaging and spectral observations of a confined solar flare at multiple wavelengths with data-constrained magnetohydrodynamic modeling to study the dynamics of the flare plasma from the current sheet to the plasmoid scale. The analysis suggests that the flare resulted from the interaction of a twisted magnetic flux rope surrounding a filament with nearby magnetic loops whose feet are anchored in chromospheric fibrils. Bright cusp-shaped structures represent the region around a reconnecting separator or quasi-separator (hyperbolic flux tube). The fast reconnection, which is relevant for other astrophysical environments, revealed plasmoids in the current sheet and separatrices and associated unresolved turbulent motions.

Flux Rope Formation Due to Shearing and Zipper Reconnection.

Zipper reconnection has been proposed as a mechanism for creating most of the twist in the flux tubes that are present prior to eruptive flares and coronal mass ejections. We have conducted a first numerical experiment on this new regime of reconnection, where two initially untwisted parallel flux tubes are sheared and reconnected to form a large flux rope. We describe the properties of this experiment, including the linkage of magnetic flux between concentrated flux sources at the base of the simulation, the twist of the newly formed flux rope, and the conversion of mutual magnetic helicity in the sheared pre-reconnection state into the self-helicity of the newly formed flux rope.

Flux-Rope Twist in Eruptive Flares and CMEs: Due to Zipper and Main-Phase Reconnection.

The nature of three-dimensional reconnection when a twisted flux tube erupts during an eruptive flare or coronal mass ejection is considered. The reconnection has two phases: first of all, 3D "zipper reconnection" propagates along the initial coronal arcade, parallel to the polarity inversion line (PIL); then subsequent quasi-2D "main-phase reconnection" in the low corona around a flux rope during its eruption produces coronal loops and chromospheric ribbons that propagate away from the PIL in a direction normal to it. One scenario starts with a sheared arcade: the zipper reconnection creates a twisted flux rope of roughly one turn ( 2 π radians of twist), and then main-phase reconnection builds up the bulk of the erupting flux rope with a relatively uniform twist of a few turns. A second scenario starts with a pre-existing flux rope under the arcade. Here the zipper phase can create a core with many turns that depend on the ratio of the magnetic fluxes in the newly formed flare ribbons and the new flux rope. Main phase reconnection then adds a layer of roughly uniform twist to the twisted central core. Both phases and scenarios are modeled in a simple way that assumes the initial magnetic flux is fragmented along the PIL. The model uses conservation of magnetic helicity and flux, together with equipartition of magnetic helicity, to deduce the twist of the erupting flux rope in terms the geometry of the initial configuration. Interplanetary observations show some flux ropes have a fairly uniform twist, which could be produced when the zipper phase and any pre-existing flux rope possess small or moderate twist (up to one or two turns). Other interplanetary flux ropes have highly twisted cores (up to five turns), which could be produced when there is a pre-existing flux rope and an active zipper phase that creates substantial extra twist.

Extreme ultraviolet imaging of three-dimensional magnetic reconnection in a solar eruption.

Magnetic reconnection, a change of magnetic field connectivity, is a fundamental physical process in which magnetic energy is released explosively, and it is responsible for various eruptive phenomena in the universe. However, this process is difficult to observe directly. Here, the magnetic topology associated with a solar reconnection event is studied in three dimensions using the combined perspectives of two spacecraft. The sequence of extreme ultraviolet images clearly shows that two groups of oppositely directed and non-coplanar magnetic loops gradually approach each other, forming a separator or quasi-separator and then reconnecting. The plasma near the reconnection site is subsequently heated from ∼1 to ≥5 MK. Shortly afterwards, warm flare loops (∼3 MK) appear underneath the hot plasma. Other observational signatures of reconnection, including plasma inflows and downflows, are unambiguously revealed and quantitatively measured. These observations provide direct evidence of magnetic reconnection in a three-dimensional configuration and reveal its origin.

Association of white blood cell subfraction concentration with fitness and fatness.

OBJECTIVE: To examine the association between fitness, BMI, and neutrophil, lymphocyte, monocyte, basophil, and eosinophil concentrations in apparently healthy, non-smoking men. DESIGN: Cross-sectional study of 452 men from the Aerobics Center Longitudinal Study examining the resting concentration of white blood cell subfractions across fitness (maximal METs during a treadmill exercise test) and fatness (BMI) categories after adjusting for age. RESULTS: Fitness was inversely associated with all WBC subfraction concentrations. After further adjustment for BMI, only total WBC, neutrophil, and basophil concentrations remained significantly associated with fitness. BMI was directly associated with total WBC, neutrophil, lymphocyte, monocyte, and basophil concentrations and, when fitness was added to the model, only monocytes lost significance. CONCLUSION: Fitness (inversely) and fatness (directly) are associated with WBC subfraction populations.

Obesity, macrophage migration inhibitory factor, and weight loss.

OBJECTIVE: Elevated macrophage migration inhibitory factor (MIF) has been implicated as a causal mechanism in a number of disease conditions including cardiovascular disease (CVD), diabetes, and cancer. Excess body fat is associated with an increased risk of numerous health conditions including CVD, diabetes, and cancer. To our knowledge, the association between MIF and obesity status and the effect of weight loss on serum MIF concentrations have not been reported. In this study, we examined the effects of participation in a behavior-based weight loss program on MIF concentrations in obese individuals. SUBJECTS: Study participants were 71 men and women enrolled in The Cooper Institute Weight Management Program. Participants were predominantly female (68%, n=48), middle-aged (46.5+/-9.8 y), and severely obese (BMI=43.0+/-8.6). METHOD: Plasma MIF concentrations and other standard risk factors were measured before and after participation in a diet and physical activity based weight management program. RESULTS: The mean follow-up was 8.5+/-3.0 months with an average weight loss of 14.4 kg (P<0.001). The majority of clinical risk factors significantly improved at follow-up. Median levels of plasma MIF concentration were significantly lower at follow-up (median [IQR]; 5.1[3.6-10.3]) compared to baseline (8.4 [4.3-48.8]; P=0.0005). The percentage of participants with plasma MIF concentration > or =19.5 mg/nl (highest tertile at baseline) decreased from 33.8 to 5.6% (P<0.001). Further, elevated baseline plasma MIF concentration was associated with markers of beta-cell dysfunction and reductions in MIF were associated with improvements in beta-cell function. CONCLUSIONS: Circulating MIF concentrations are elevated in obese but otherwise healthy individuals; however, this elevation in MIF is not uniform across individuals. In obese individuals with elevated circulating MIF concentrations, participation in physical activity and a dietary-focused weight management program resulted in substantial reduction in MIF.

Associations between cardiorespiratory fitness and C-reactive protein in men.

OBJECTIVE: This study examined the association between cardiorespiratory fitness and C-reactive protein (CRP), with adjustment for weight and within weight categories. METHODS AND RESULTS: We calculated median and adjusted geometric mean CRP levels, percentages of individuals with an elevated CRP (> or =2.00 mg/L), and odds ratios of elevated CRP across 5 levels of cardiorespiratory fitness for 722 men. CRP values were adjusted for age, body mass index, vitamin use, statin medication use, aspirin use, the presence of inflammatory disease, cardiovascular disease, and diabetes, and smoking habit. We found an inverse association of CRP across fitness levels (P for trend<0.001), with the highest adjusted CRP value in the lowest fitness quintile (1.64 [1.27 to 2.11] mg/L) and the lowest adjusted CRP value in the highest fitness quintile (0.70 [0.60 to 0.80] mg/L). Similar results were found for the prevalence of elevated CRP across fitness quintiles. We used logistic regression to model the adjusted odds for elevated CRP and found that compared with the referent first quintile, the second (odds ratio [OR] 0.43, 95% CI 0.22 to 0.85), third (OR 0.33, 95% CI 0.17 to 0.65), fourth (OR 0.23, 95% CI 0.12 to 0.47), and fifth (OR 0.17, 95% CI 0.08 to 0.37) quintiles of fitness had significantly lower odds of elevated CRP. Similar results were found when examining the CRP-fitness relation within categories of body fatness (normal weight, overweight, and obese) and waist girth (<102 or > or =102 cm). CONCLUSIONS: Cardiorespiratory fitness levels were inversely associated with CRP values and the prevalence of elevated CRP values in this sample of men from the Aerobics Center Longitudinal Study.

Antiorthostatic suspension for 14 days does not diminish the oxidative response of neutrophils in mice.

The effects of long-term spaceflight on inflammatory responses have not been well-studied in either humans or animals. It is thus important to determine if the functions of immune and inflammatory cells are altered in models of spaceflight. One such animal model is antiorthostatic suspension (AOS), in which the experimental animal is subjected to a head-down tilt that mimics both the stress and the cephalad fluid shift experienced in spaceflight. A previous study reported that the peritoneal neutrophils from mice experiencing AOS generated less superoxide than unsuspended controls. We expanded on this study using several different stimuli and measuring the oxidative response of murine neutrophils in a variety of ways. These responses included the rate, lag period, and dose/response characteristics for superoxide generation, FACS analysis with dihydrodichlorofluorescein as a substrate, and a chemiluminescence response with luminol as a substrate. We also examined phagocytosis of three different microorganisms. While some effects of orthostatic suspension (attributable to the stress of the apparatus) were observed, no clear effects of AOS on oxidative function of the peritoneal neutrophils were seen.

A phase I study of subcutaneous recombinant interleukin-2 and interferon alfa-2a.

BACKGROUND: Both recombinant interferon alfa and interleukin-2 (IL-2) have been shown to have some activity as single agents in metastatic renal cell cancer (RCC), although their activity is minimal in more common solid tumors. Recent preclinical studies have suggested that the combination of these two agents is especially promising. METHODS: Subcutaneous recombinant interferon alfa-2a and IL-2 were administered at one of five dose levels to 33 patients with refractory solid tumors, including 21 patients with RCC. A constant ratio of 5:1 of interferon alfa-2a to IL-2 was used. Interferon alfa-2a and IL-2 were administered three and five times weekly, respectively, for a total of 4 weeks, followed by a rest of 1-3 weeks between cycles. RESULTS: The dose-limiting toxic effects included hypotension, nephrotoxicity, and fatigue. At the recommended Phase II dose of 7.5 million units (MU)/m2 of interferon alfa-2a and 1.5 MU/m2 of IL-2, 12 patients were treated. Ten of 12 completed the 4-week cycle without modification. Four patients at that dose level had Grade 3-4 toxic effects. Partial responses were observed in 4 of 16 assessable patients with RCC. CONCLUSIONS: Subcutaneous interferon alfa-2a and IL-2 can be self-administered safely on an outpatient basis. At tolerable doses, responses can be achieved in metastatic RCC.

Spontaneous regression of histologically proved pulmonary metastases from renal cell carcinoma: a case with 5-year followup.

Spontaneous regression of biopsy proved metastatic renal cell carcinoma is rare. We describe a 39-year-old man who had histologically proved metastatic disease to the lungs after nephrectomy. The lesions had spontaneously regressed 3 months later. The patient remained without evidence of recurrence 5 years after diagnosis.

Hearing results from endolymphatic sac surgery.

This report examines the effect of the endolymphatic shunt on hearing. The study group was drawn from 101 shunt operations for intractable vertigo between 1983 and 1987. Thirty ears met criteria for diagnosis, level of preoperative hearing impairment, and length of follow-up. The control group consisted of 30 ears with symptoms severe enough to prompt recommendations for shunt surgery, but the patients either opted against surgery or improved. The results were analyzed using the 1985 AAO-HNS reporting criteria. When looking at worst postoperative (or worst scores after 2 years of follow-up in controls) compared to worst preoperative (or worst scores in the first 6 months of presentation in controls), we found no significant difference between the study group (average loss of 9 dB pure-tone average [PTA] and 16% speech discrimination [SD]) as compared to the control group (average loss of 3 dB PTA and 10% SD). However, when using the first and last audiograms for the control group, there was a statistically significant difference as compared to the worst preoperative and postoperative scores in the shunt group. Using the first and last scores, the control group had a better outcome (PTA improved 2 dB, SD score dropped 5%). There was no significant difference between groups for percentage of patients whose hearing improved, remained the same, or worsened. In conclusion, the endolymphatic shunt operation did not significantly effect the long-term hearing results.

Medical staff privileges for ethics consultants: an institutional model.

On January 1, 1991, the Joint Commission required hospitals to be equipped for resolving moral dilemmas that arise in the care of a patient. Regulation of those professing expertise in clinical ethics is new and untested yet must be evaluated and further developed to protect patients from practitioners who lack expertise in clinical ethics but may promote themselves as qualified. The authors report the development of standard criteria for clinical ethics consultation privileges as one model to protect patients. An institutional medical staff model utilizing approved credentialing mechanisms is a generous umbrella under which patients may be protected, qualified clinical ethicists may practice, and continuous quality improvement may be sought.

Optimal drug therapy in the treatment of testicular cancer.

Although testes cancer is the most common malignancy affecting young men, dramatic survival rates are now possible with the development of optimal individualised drug therapy. Human chorionic gonadotropin and alpha-fetoprotein are important tumour markers associated with testes cancer, and can provide essential information about prognosis and treatment efficacy. For treatment purposes, testicular germ-cell malignancies are broadly classified as seminomatous or non-seminomatous. Early stage seminomas are treated with radiotherapy, while more advanced disease requires systemic chemotherapy. Stage I nonseminoma patients can now be offered the option of retroperitoneal lymph node dissection (RPLND) or close clinical observation, while patients with stage II or III nonseminoma should generally be treated with chemotherapy. The dramatic survival rates now apparent with chemotherapy are due in large part to the introduction of cisplatin (cisplatinum II)-based chemotherapy and to the optimisation of therapy based on pretreatment risk analysis. The most common chemotherapeutic regimen for standard risk patients includes cisplatin and etoposide (VP 16213) and long term disease-free survival rates exceed 80%. A subset of poor risk patients with significantly reduced survival can be defined. These patients, and patients with relapsed or refractory disease, should receive more aggressive regimens, and ifosfamide (isophosphamide) is proving to be a particularly promising new agent in this regard. High-dose carboplatin with autologous bone marrow rescue is another encouraging alternative currently being investigated for these patients. Chemotherapy, despite substantial effectiveness, is not without toxicity, which consists primarily of myelosuppression, nausea and emesis, and renal toxicity. With careful monitoring and prophylaxis, however, these toxicities can generally be ameliorated or avoided.