A nearby long gamma-ray burst from a merger of compact objects.

Gamma-ray bursts (GRBs) are flashes of high-energy radiation arising from energetic cosmic explosions. Bursts of long (greater than two seconds) duration are produced by the core-collapse of massive stars1, and those of short (less than two seconds) duration by the merger of compact objects, such as two neutron stars2. A third class of events with hybrid high-energy properties was identified3, but never conclusively linked to a stellar progenitor. The lack of bright supernovae rules out typical core-collapse explosions4-6, but their distance scales prevent sensitive searches for direct signatures of a progenitor system. Only tentative evidence for a kilonova has been presented7,8. Here we report observations of the exceptionally bright GRB 211211A, which classify it as a hybrid event and constrain its distance scale to only 346 megaparsecs. Our measurements indicate that its lower-energy (from ultraviolet to near-infrared) counterpart is powered by a luminous (approximately 1042 erg per second) kilonova possibly formed in the ejecta of a compact object merger.

A new gamma-ray burst classification scheme from GRB 060614.

Gamma-ray bursts (GRBs) are known to come in two duration classes, separated at approximately 2 s. Long-duration bursts originate from star-forming regions in galaxies, have accompanying supernovae when these are near enough to observe and are probably caused by massive-star collapsars. Recent observations show that short-duration bursts originate in regions within their host galaxies that have lower star-formation rates, consistent with binary neutron star or neutron star-black hole mergers. Moreover, although their hosts are predominantly nearby galaxies, no supernovae have been so far associated with short-duration GRBs. Here we report that the bright, nearby GRB 060614 does not fit into either class. Its approximately 102-s duration groups it with long-duration GRBs, while its temporal lag and peak luminosity fall entirely within the short-duration GRB subclass. Moreover, very deep optical observations exclude an accompanying supernova, similar to short-duration GRBs. This combination of a long-duration event without an accompanying supernova poses a challenge to both the collapsar and the merging-neutron-star interpretations and opens the door to a new GRB classification scheme that straddles both long- and short-duration bursts.

Limits on the cosmological abundance of supermassive compact objects from a millilensing search in gamma-ray burst data.

A new search for the gravitational lens effects of a significant cosmological density of supermassive compact objects (SCOs) on gamma-ray bursts (GRBs) has yielded a null result. We inspected the timing data of 774 BATSE-triggered GRBs for evidence of millilensing: repeated peaks similar in light-curve shape and spectra. Our null detection leads us to conclude that, in all candidate universes simulated, Omega(SCO)<0.1 is favored for SCO masses in the range 10(5)

Modified alpha wrap techniques for dynamic urethral graciloplasty in an animal model.

Urethral sphincter reconstruction with a stimulated skeletal muscle flap has been used for treatment of severe intrinsic sphincter deficiency. Urethral strictures and failures were reported in some of the initial experiences. The etiology of these problems is not known, but elevated resting urethral pressures and excessive urethral displacement with stimulation are possible causes. We modified two operative techniques in forming dynamic urinary graciloplasty (DUG) in an attempt to minimize resting urethral pressure without stimulation and urethral mobility during stimulation. Two types of DUG were used. In the first group, a small flap (partial muscle wrap) from the gracilis muscle with an attachment site on the muscle was constructed in four dogs. In the second group, three dogs with a modified alpha wrap and proximal attachments were used. All of the gracilis muscle wraps were stimulated using an implanted programmable pulse stimulator with electrodes attached over the motor nerve. Following a 2-week, postrecovery period, urethral pressure measurements were obtained with and without stimulation. Five weeks were used for stimulation to condition the muscle. This was followed by 4 weeks of continuous stimulation. Thus, devices were implanted for 11 weeks. Before conditioning of the muscles was initiated, the partial muscle wrap pressure at rest was 42 +/- 27 cm H2O, which was higher than the incomplete alpha wrap resting pressure of 20 +/- 4 cm H2O. Stimulated partial flap pressure was 161 +/- 50 cm H2O, and stimulated modified alpha wrap pressures was 71 +/- 27 cm H2O. After conditioning with the modified alpha wrap, the resting and stimulated pressures were unchanged from before conditioning. Technical problems precluded collection of data during the conditioning period in dogs with partial flaps. During stimulation, the partial muscle wrap demonstrated marked deviation, whereas the modified alpha wrap had minimal urethral movement. Postmortem evaluation indicated no urethral stricture or fistula formation with either of the two types of wraps. The modified alpha wrap had several positive features. Advantages over the partial wrap were minimal resting pressures, reduced urethral mobility, and adequate sustained pressures during stimulation. Therefore, in contrast to the partial gracilis muscle wrap, aspects of the incomplete alpha wrap should be considered further for DUG.

History, physical examination, and classification of neurogenic voiding dysfunction.

Although exceptions exist, clinical and urodynamic findings can be predicted on the basis of the location of the neurologic lesions. Conversely, these findings can be used to predict the location of the lesion. Recognition of similar patterns allows for classification, and classification allows the physician more readily to devise a diagnostic and therapeutic plan. Furthermore, a simple and practical classification system facilitates communication between physicians.

Use of synthetic material in sling surgery: a minimally invasive approach.

Traditionally, autologous material has been favored over synthetic material in the construction of pubovaginal slings for the treatment of female stress urinary incontinence (SUI). This preference arose largely because of concern about an increased incidence of infection or sling erosion when synthetic materials are used. However, when care is taken to minimize the amount of synthetic material, reduce total operative time, and limit exposure of the material to the operative field, female SUI can be treated effectively with synthetic material with an acceptably low complication rate. Furthermore, utilization of slings constructed with artificial graft material can be minimally invasive, cost effective, and well tolerated.

Parapubic hernia following radical retropubic prostatectomy.

We report a parapubic hernia in a 54-year-old patient following radical retropubic prostatectomy. This complication can occur when the musculotendinous insertions of the rectus abdominis muscle are divided from the pubis. Bowel contents herniate over the pubic crest and can be misdiagnosed as an incisional or inguinal hernia. Successful repair depends on closure of the entire defect. Elective repair necessitates the use of prosthetic mesh.

Visual laser ablation of the prostate: clinical experience in 108 patients.

Visual laser ablation of the prostate was performed on 108 patients (ages 44 to 84 years) as an outpatient procedure from May 1992 to October 1992. Preoperatively, the patients underwent digital rectal examinations, determination of prostate specific antigen levels and transrectal ultrasound guided biopsies when necessary to rule out the presence of prostate cancer. The Urolase laser fiber delivery system was used to transmit laser energy from a neodymium: YAG generator. For the 97 patients with preoperative and postoperative American Urological Association symptom index testing, scores decreased by an average of 12.59 (p < 0.001). For the 75 patients with preoperative and postoperative uroflow rates an average increase of 4.92 ml. per second (p < 0.001) was noted following the procedure. Only 3 patients required hospitalization for an average of 1.33 days. No patient required a blood transfusion. There have been no fluid or electrolyte abnormalities following visual laser ablation of the prostate. There have been no recognizable urethral strictures, deaths or postoperative sepsis. Only 3 patients experienced retrograde ejaculation. We found visual laser ablation of the prostate to be a cost-effective and less morbid alternative to traditional transurethral resection of the prostate.

A quantitative comparison of the ability of diamond and K-type files to remove dentin.

Diamond endodontic files and K-type files were compared for their ability to remove dentin when powered both by hand and by ultrasound. The diamond files were significantly superior dentin-removing instruments, especially when energized by ultrasound.

Ultrasonic versus hand filing of dentin: a quantitative study.

Ultrasonic versus hand-powered K type files were compared for their ability to remove dentin from a standardized canal. The ultrasonic energized file removed a significantly greater amount of dentin in a fixed time period.