Direct observation of ion cyclotron damping of turbulence in Earth's magnetosheath plasma.

Plasma turbulence plays a key role in space and astrophysical plasma systems, enabling the energy of magnetic fields and plasma flows to be transported to particle kinetic scales at which the turbulence dissipates and heats the plasma. Identifying the physical mechanisms responsible for the dissipation of the turbulent energy is a critical step in developing the predictive capability for the turbulent heating needed by global models. In this work, spacecraft measurements of the electromagnetic fields and ion velocity distributions by the Magnetospheric Multiscale (MMS) mission are used to generate velocity-space signatures that identify ion cyclotron damping in Earth's turbulent magnetosheath, in agreement with analytical modeling. Furthermore, the rate of ion energization is directly quantified and combined with a previous analysis of the electron energization to identify the dominant channels of turbulent dissipation and determine the partitioning of energy among species in this interval.

Alfvénic velocity spikes and rotational flows in the near-Sun solar wind.

The prediction of a supersonic solar wind1 was first confirmed by spacecraft near Earth2,3 and later by spacecraft at heliocentric distances as small as 62 solar radii4. These missions showed that plasma accelerates as it emerges from the corona, aided by unidentified processes that transport energy outwards from the Sun before depositing it in the wind. Alfvénic fluctuations are a promising candidate for such a process because they are seen in the corona and solar wind and contain considerable energy5-7. Magnetic tension forces the corona to co-rotate with the Sun, but any residual rotation far from the Sun reported until now has been much smaller than the amplitude of waves and deflections from interacting wind streams8. Here we report observations of solar-wind plasma at heliocentric distances of about 35 solar radii9-11, well within the distance at which stream interactions become important. We find that Alfvén waves organize into structured velocity spikes with duration of up to minutes, which are associated with propagating S-like bends in the magnetic-field lines. We detect an increasing rotational component to the flow velocity of the solar wind around the Sun, peaking at 35 to 50 kilometres per second-considerably above the amplitude of the waves. These flows exceed classical velocity predictions of a few kilometres per second, challenging models of circulation in the corona and calling into question our understanding of how stars lose angular momentum and spin down as they age12-14.

Methane hydrate emergence from Lake Baikal: direct observations, modelling, and hydrate footprints in seasonal ice cover.

This paper provides a novel report of methane hydrates rising from bottom sediments to the surface of Lake Baikal, validated by photo and video records. The ascent of hydrates in the water column was confirmed by hydroacoustic data showing rising objects with velocities significantly exceeding the typical speeds (18-25 cm s-1) of gas bubbles. Mathematical modelling along with velocity and depth estimates of the presumed methane hydrates coincided with values observed from echograms. Modelling results also showed that a methane hydrate fragment with initial radius of 2.5 cm or greater could reach the surface of Lake Baikal given summer water column temperature conditions. Results further show that while methane bubbles released from the deep sedimentary reservoir would dissolve in the Lake Baikal water column, transport in hydrate form is not only viable but may represent a previously overlooked source of surface methane with subsequent emissions to the atmosphere. Methane hydrates captured within the ice cover may also cause the formation of unique ice structures and morphologies observed around Lake Baikal. Sampling of these ice structures detected methane content that exceeded concentrations measured in surrounding ice and from the atmosphere demonstrating a link with the methane transport processes described here.

Full-scale evaluation of methane production under oxic conditions in a mesotrophic lake.

Oxic lake surface waters are frequently oversaturated with methane (CH4). The contribution to the global CH4 cycle is significant, thus leading to an increasing number of studies and stimulating debates. Here we show, using a mass balance, on a temperate, mesotrophic lake, that ~90% of CH4 emissions to the atmosphere is due to CH4 produced within the oxic surface mixed layer (SML) during the stratified period, while the often observed CH4 maximum at the thermocline represents only a physically driven accumulation. Negligible surface CH4 oxidation suggests that the produced 110 ± 60 nmol CH4 L-1 d-1 efficiently escapes to the atmosphere. Stable carbon isotope ratios indicate that CH4 in the SML is distinct from sedimentary CH4 production, suggesting alternative pathways and precursors. Our approach reveals CH4 production in the epilimnion that is currently overlooked, and that research on possible mechanisms behind the methane paradox should additionally focus on the lake surface layer.

Size does matter: importance of large bubbles and small-scale hot spots for methane transport.

Ebullition (bubbling) is an important mechanism for the transfer of methane (CH4) from shallow waters to the atmosphere. Because of their stochastic nature, however, ebullition fluxes are difficult to accurately resolve. Hydroacoustic surveys have the potential to significantly improve the spatiotemporal observation of emission fluxes, but knowledge of bubble size distribution is also necessary to accurately assess local, regional, and global water body CH4 emission estimates. Therefore, we explore the importance of bubble size and small-scale flux variability on CH4 transport in and emissions from a reservoir with a bubble-size-calibrated echosounder that can efficiently and economically survey greater areas while still resolving individual bubbles. Using a postprocessing method that resolves bubble density, we found that the largest 10% of the >6700 observed bubbles were responsible for more than 65% of the total CH4 transport. Furthermore, the asymmetry of CH4 ebullition flux distribution and the high spatial heterogeneity of those fluxes suggests that inadvertently omitting emission hot spots (i.e., areas of high flux) could lead to significant underestimations of CH4 emissions from localized areas and potentially from entire water bodies. While the bubble sizes resolved by the hydroacoustic method may provide insight into the factors controlling ebullition (e.g., sediment type, carbon sedimentation), the better resolution of small-scale CH4 emission hot spots afforded by hydroacoustics will bring us closer to the true CH4 emission estimates from all shallow waters, be them lakes, reservoirs, or coastal oceans and seas.

Minimizing minimally invasive surgery: the 5-mm trocar laparoscopic pyeloplasty.

BACKGROUND AND PURPOSE: Laparoscopic pyeloplasty has evolved into the procedure of choice when definitive repair of the obstructed ureteropelvic junction is contemplated. Its main advantage over the gold standard of open pyeloplasty is decreased morbidity. We have utilized only three 5-mm ports in our last 15 pyeloplasties in an effort to further reduce morbidity and improve acceptance by an often-younger patient population. PATIENTS AND METHODS: Fifteen consecutive patients underwent laparoscopic transperitoneal pyeloplasty by the 5-mm port technique. Three trocars were utilized, two for the working instruments and one for a 5-mm telescope mounted on a voice-activated robotic arm (AESOP; Intuitive Surgical, Sunnyvale, CA). Three patients required an additional trocar for liver retraction. All patients underwent dismembered pyeloplasty and had indwelling double-pigtail stents placed for 4 to 6 weeks. RESULTS: The mean operative time was 195 minutes (range 120-240 minutes). The average blood loss was 30 mL. None of our patients required open conversion. With a median follow-up of 10 months (range 3-15 months), all 15 patients have shown both subjective (freedom from symptoms) and objective (renal scan) improvement. CONCLUSION: We believe our technique has further minimized the morbidity of laparoscopic pyeloplasty without compromising the outcome. The 5-mm trocars obviate fascial closure, decrease patient discomfort, and improve cosmesis. Furthermore, the use of the robotic arm eliminates the need for a surgical assistant and makes this an essentially "one-person" procedure.

Does hormonal therapy influence sexual function in men receiving 3D conformal radiation therapy for prostate cancer?

PURPOSE: We evaluated the effect of three-dimensional conformal radiation therapy (3D-CRT) with or without hormonal therapy (HT) on sexual function (SF) in prostate cancer patients whose SF was known before all treatment. METHODS AND MATERIALS: Between March 1996 and March 1999, 144 patients received 3D-CRT (median dose = 70.2 Gy, range 66.6-79.2 Gy) for prostate cancer and had pre- and post-therapy SF data. All SF data were obtained with the O'Leary Brief SF Inventory, a self-administered, multidimensional, validated instrument. We defined total sexual potency as erections firm enough for penetration during intercourse. Mean follow-up time was 21 months (SD +/- 11 months). The Wilcoxon signed-rank test was used to test for significance of the change from baseline. RESULTS: Before 3D-CRT, 87 (60%) of 144 men were totally potent as compared to only 47 (47%) of 101 at 1-year follow-up. Of the 60 men totally potent at baseline and followed for at least 1 year, 35 (58%) remained totally potent. These changes corresponded to a significant reduction in SF (p < 0.05). Patients who had 3D-CRT alone were more likely to be totally potent at 1 year than those receiving 3D-CRT with HT (56% vs. 31%, p = 0.012); however, they were also more likely to be potent at baseline (71% vs. 44%, p = 0.001). Although these two groups had a significant reduction in SF from baseline, their change was not significantly different from each other. CONCLUSION: These data indicate that 3D-CRT causes a significant reduction in total sexual potency as compared to pretreatment baseline. The addition of HT does not appear to increase the risk of sexual dysfunction.

Comparison and clinical evaluation of hand-assist devices for hand-assisted laparoscopy.

Hand-assisted laparoscopic surgery (HALS) is being used increasingly in urologic laparoscopy, particularly for laparoscopic nephrectomy. Hand-assist devices (HADs) facilitate the intra-abdominal placement of the hand during laparoscopy. There are currently three HADs available in the United States: the Pneumo Sleeve, the Handport, and the Intromit. The performance of each HAD is assessed regarding usage options, maintenance of pneumoperitoneum, device failure, exchange of intra-abdominal hands, adaptation to obese patients, and specimen removal. The use of these devices is reviewed based on our experience in more than 100 cases of HALS.

Hand-assisted laparoscopic nephroureterectomy: description of technique.

PURPOSE: Traditional treatment of transitional cell carcinoma of the upper urinary tract (UTTCC) has been nephroureterectomy by open surgical techniques, often requiring two incisions. Our experience and technique for hand-assisted laparoscopic nephroureterectomy (HALNU) is reviewed. MATERIALS AND METHODS: Thirty-two patients had HALNU performed by one of three surgeons from August 1998 to October 2000. The distal ureter and bladder cuff was resected laparoscopically and sutured closed in 15 patients and resected by combined cystoscopic and laparoscopic approach in 17 patients. RESULTS: The indication for surgery was UTTCC for 29 patients and benign conditions in 2 patients. The mean operating time (including initial cystoscopy) was 372 minutes (281-530), and the mean blood loss was 541 cc (50-3500). The mean hospital stay was 5.5 days (3-12). There were no positive surgical margins, local recurrences, trocar site seeding, or wound seeding. CONCLUSIONS: HALNU is an effective minimally invasive approach for the treatment of UTTCC.

Transurethral microwave thermotherapy of the prostate without intravenous sedation: results of a single United States center using both low- and high-energy protocols. TJUH TUMT Study Group.

PURPOSE: Previous studies have indicated that high-energy transurethral microwave thermotherapy (TUMT) requires intravenous (IV) sedation and/or narcotics for patient tolerance. This study was performed to determine tolerability, patient acceptance, and efficacy of TUMT using both low- and high-energy protocols in a single United States university setting. MATERIALS AND METHODS: Between August 11, 1997 and October 28, 1999, 210 men (mean age 64.9 +/- 9.1 years) presenting with symptomatic benign prostatic hyperplasia (BPH) received treatment with a Prostatron TUMT using either the low-energy Prostasoft 2.O or high-energy Prostasoft 2.5 software. Each patient had digital rectal examination and prostate-specific antigen level consistent with BPH, American Urological Association symptom score > or = 15, and Qmax <15 mL/s. Each patient received TUMT with only ibuprofen 400 mg by mouth (PO), lorazepam 1.0 mg PO, and ketorolac 30 mg intramuscularly (IM) prior to TUMT. A few patients who were concerned about limited pain threshold received oxycodone 5 mg/acetaminophen 325 mg PO. Of 210 patients treated, 12-month efficacy data were available for analysis in 80 patients. RESULTS: Forty-eight men (mean age 65 +/- 9.2 years) received low-energy 2.0 software TUMT, and 32 men (mean age 65.1 +/- 9.2 years) were treated with high-energy 2.5 software. Mean prostatic volume was 44.3 +/- 23.9 mL and 60.7 +/- 26.4 mL for the 2.0 and 2.5 groups, respectively. Mean energy delivered was 108.8 +/- 50.4 kJ and 173.1 +/- 41.1 kJ for the 2.0 and 2.5 treatment groups, respectively. International Prostate Symptom Score decreased from 23 pre-TUMT to 8 post-TUMT and 21 pre-TUMT to 10 post-TUMT at 12 months in the 2.0 and 2.5 groups, respectively. Mean peak flow rate improved 31.9% from 9.1 mL/s pre-TUMT to 12.0 mL/s post-TUMT and 45.8% from 9.6 mL/s pre-TUMT to 14.0 mL/s post-TUMT at 12 months in the 2.0 and 2.5 groups, respectively. All but two patients tolerated treatment without IV sedation. One patient experienced intolerable rectal spasm, and treatment was terminated in another patient because of poorly controlled hypertension. CONCLUSIONS: Patients can be treated safely with TUMT using either low or high energy, with almost universal patient tolerance and without the need for IV sedation or narcotics, if they premedicated effectively using a PO/IM regimen. Patients experience significant relief of symptoms whether low- or high-energy TUMT is used; however, high-energy TUMT improves flow rate to a greater extent than does low-energy therapy.

The multidisciplinary clinic approach to prostate cancer counseling and treatment.

The optimum management for an individual patient with prostate cancer is not well defined. Patients with localized disease may be offered options ranging from observation, hormonal therapy, cryotherapy, radiation therapy, or surgery. Each option may have unique aspects to consider when counseling a patient often leading to multiple physician visits over an extended period of time. Since 1996, the Kimmel Cancer Center of Thomas Jefferson University has offered newly diagnosed urologic cancer patients the opportunity to be evaluated in a multidisciplinary clinic. Here, multiple physician consultative visits, including pathologic and radiologic evaluation and protocol evaluation, are provided during the session. Herein we report on our experience with this multidisciplinary approach for patients with prostate cancer.

Understanding unfamiliar words: the influence of processing resources, vocabulary knowledge, and age.

In a 2-experiment design, the authors assessed the role of age and ability in defining unfamiliar words from context. In Experiment 1, 60 adults aged 18-33 and 60 adults aged 61-96 read passages with cues to the meaning of rare words, then defined them. Older adults produced fewer components of the words' meanings and were more likely to produce generalized interpretations of the precise meaning. In Experiment 2, 726 adults aged 30-97 selected definitions from 4 choices: the exact definition, a generalized interpretation of the exact definition, a generalized interpretation of the story, and definition-irrelevant information from the story. Adults over age 75 selected fewer precise definitions and more generalized interpretations of the story than younger ones. Findings suggest that older adults may have special difficulties in deriving the meaning of unfamiliar words from context.

Management of hemorrhage during laparoscopy.

Bleeding can be a complication of laparoscopic procedures commonly performed by urologists, such as pelvic node dissection and nephrectomy, and is often difficult to manage. Hemorrhage also can occur as a result of Veress needle or trocar placement, and there are specific strategies for the management of these injuries. Laparoscopic clip appliers, laparoscopic staplers, laparoscopic suturing, various energy sources (monopolar and bipolar electrocautery, laser, ultrasonic dissectors, and argon beam coagulators), and topical agents (gelatin foam, cellulose, collagen, and fibrin sealant) can be used to obtain hemostasis. Converting to laparotomy to obtain hemostasis may be necessary in some cases. Proper patient selection is important for lowering the risk of hemorrhage.

Open trials as a method of prioritizing medications for inclusion in controlled trials for cocaine dependence.

This paper describes a rapid and systematic method of using open trials to identify medications that may be useful for the treatment of cocaine dependence. Results of these open trials can be used to prioritize medications for inclusion in subsequent double-blind, placebo-controlled trials. Preliminary results are presented from the evaluation of propranolol, nefazodone, and the combination of phentermine and fenfluramine (phen/fen). Each medication was evaluated in an open trial, and results were compared to results obtained from a group that received a multivitamin. Outcome measures included treatment retention, urine toxicology screens, self-reported cocaine use, and changes on the Addiction Severity Index (ASI). Treatment retention was significantly better in the propranolol group than in the multivitamin group. Concurrent alcohol abuse was associated with increased rates of attrition in the multivitamin group, and the phen/fen group, but not in the propranolol group. Neither the nefazodone nor the phen/fen groups showed any outcome advantages over the multivitamin group. We conclude that propranolol may enhance retention among cocaine-dependent patients, especially among those who also abuse alcohol. These results encourage a double-blind, placebo-controlled trial of propranolol.

Rapid eye movement sleep changes during the adaptation night in combat veterans with posttraumatic stress disorder.

BACKGROUND: Hyperarousal in posttraumatic stress disorder (PTSD) is manifested during sleep as well as waking. Elevated rapid eye movement sleep (REMS) phasic activity, likely signifying central nervous system alerting, has been identified in PTSD. The authors reasoned that PTSD compared to control subjects would show particularly increased REMS phasic activity on the first night of polysomnography, with adaptation to a novel environment. METHODS: First-night polysomnograms of 17 veterans with PTSD were compared with those of 11 control subjects. Sleep was also studied in subsets of both groups over two nights. RESULTS: On the first night, the PTSD subjects had a higher density of rapid eye movements in the first REMS period. This measure was increased on the first compared to the second night, but there was no interaction effect between night and group. CONCLUSIONS: REMS changes are again demonstrated in veterans with PTSD. Introduction to a novel environment activated a REMS phasic process, but not differentially in PTSD compared to control subjects.

Reliability and validity of the Cocaine Selective Severity Assessment.

This article assesses the reliability and validity of the Cocaine Selective Severity Assessment (CSSA), a measure of cocaine abstinence signs and symptoms. Interrater reliability and scale internal consistency were high. Initial CSSA scores were significantly higher in cocaine-dependent subjects than in alcohol-dependent subjects. Initial CSSA scores were highly correlated with recent cocaine use and with severity measures from the Addiction Severity Index (ASI) including the interviewer severity rating and composite score in the drug section. Among cocaine-dependent subjects, initial CSSA scores were higher for those who failed to achieve abstinence or who subsequently dropped out of treatment. Further, CSSA scores showed consistent and marked declines over time for subjects who continued in treatment and remained abstinent. The CSSA appears to be a reliable and valid measure of cocaine abstinence symptoms and a useful predictor of negative outcomes in cocaine dependence treatment.

Urinary dysfunction in Lyme disease.

Lyme disease, which is caused by the spirochete Borrelia burgdorferi, is associated with a variety of neurological sequelae. We describe 7 patients with neuro-borreliosis who also had lower urinary tract dysfunction. Urodynamic evaluation revealed detrusor hyperreflexia in 5 patients and detrusor areflexia in 2. Detrusor external sphincter dyssynergia was not noted on electromyography in any patient. We observed that the urinary tract may be involved in 2 respects in the course of Lyme disease: 1) voiding dysfunction may be part of neuro-borreliosis and 2) the spirochete may directly invade the urinary tract. In 1 patient bladder infection by the Lyme spirochete was documented on biopsy. Neurological and urological symptoms in all patients were slow to resolve and convalescence was protracted. Relapses of active Lyme disease and residual neurological deficits were common. Urologists practicing in areas endemic for Lyme disease need to be aware of B. burgdorferi infection in the differential diagnosis of neurogenic bladder dysfunction. Conservative bladder management including clean intermittent catheterization guided by urodynamic evaluation is recommended.