Tripled yield in direct-drive laser fusion through statistical modelling.

Focusing laser light onto a very small target can produce the conditions for laboratory-scale nuclear fusion of hydrogen isotopes. The lack of accurate predictive models, which are essential for the design of high-performance laser-fusion experiments, is a major obstacle to achieving thermonuclear ignition. Here we report a statistical approach that was used to design and quantitatively predict the results of implosions of solid deuterium-tritium targets carried out with the 30-kilojoule OMEGA laser system, leading to tripling of the fusion yield to its highest value so far for direct-drive laser fusion. When scaled to the laser energies of the National Ignition Facility (1.9 megajoules), these targets are predicted to produce a fusion energy output of about 500 kilojoules-several times larger than the fusion yields currently achieved at that facility. This approach could guide the exploration of the vast parameter space of thermonuclear ignition conditions and enhance our understanding of laser-fusion physics.

DNA Origami Fiducial for Accurate 3D Atomic Force Microscopy Imaging.

Atomic force microscopy (AFM) is a powerful technique for imaging molecules, macromolecular complexes, and nanoparticles with nanometer resolution. However, AFM images are distorted by the shape of the tip used. These distortions can be corrected if the tip shape can be determined by scanning a sample with features sharper than the tip and higher than the object of interest. Here we present a 3D DNA origami structure as fiducial for tip reconstruction and image correction. Our fiducial is stable under a broad range of conditions and has sharp steps at different heights that enable reliable tip reconstruction from as few as ten fiducials. The DNA origami is readily codeposited with biological and nonbiological samples, achieves higher precision for the tip apex than polycrystalline samples, and dramatically improves the accuracy of the lateral dimensions determined from the images. Our fiducial thus enables accurate and precise AFM imaging for a broad range of applications.

Optical characterization of the on-target OMEGA focal spot at high energy using the full-beam in-tank diagnostic.

The full-beam in-tank (FBIT) diagnostic has been deployed to directly measure the target-plane beam fluence profile, when operated at high energy, of the OMEGA Laser System at the University of Rochester's Laboratory for Laser Energetics. This paper presents the results of early measurements taken with this diagnostic and discusses an improvement that has overcome performance limitations discovered during the initial testing. The diagnostic gives new insight into the ability of the OMEGA Laser System to provide uniform fluence profiles that are consistent across all 60 beams in the laser. The ultimate goal of the FBIT diagnostic is to allow accurate assessment of the fluence uniformity on a spherical target in 60-beam implosion experiments.

Power balancing the multibeam OMEGA laser.

Multibeam lasers often require an output beam balance that specifies the degree of simultaneity of the laser output energy, instantaneous power, or instantaneous irradiance (power per unit area). This work describes the general problem of balancing a multibeam laser. Specific techniques used to balance the output power of the 60-beam pulsed OMEGA Laser System are discussed along with a measured reduction of beam-to-beam imbalance. In particular, the square-pulse distortion induced by a simple saturating amplifier operating with its output at some fraction of its saturation fluence is derived, and a method to exchange gain between saturated amplifiers in a single beam that have different saturation fluences to adjust balance is described.

Publisher's Note: Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA [Phys. Rev. Lett. 117, 025001 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.117.025001.

Demonstration of Fuel Hot-Spot Pressure in Excess of 50 Gbar for Direct-Drive, Layered Deuterium-Tritium Implosions on OMEGA.

A record fuel hot-spot pressure P_{hs}=56±7 Gbar was inferred from x-ray and nuclear diagnostics for direct-drive inertial confinement fusion cryogenic, layered deuterium-tritium implosions on the 60-beam, 30-kJ, 351-nm OMEGA Laser System. When hydrodynamically scaled to the energy of the National Ignition Facility, these implosions achieved a Lawson parameter ∼60% of the value required for ignition [A. Bose et al., Phys. Rev. E 93, 011201(R) (2016)], similar to indirect-drive implosions [R. Betti et al., Phys. Rev. Lett. 114, 255003 (2015)], and nearly half of the direct-drive ignition-threshold pressure. Relative to symmetric, one-dimensional simulations, the inferred hot-spot pressure is approximately 40% lower. Three-dimensional simulations suggest that low-mode distortion of the hot spot seeded by laser-drive nonuniformity and target-positioning error reduces target performance.

Scaling hot-electron generation to high-power, kilojoule-class laser-solid interactions.

Thin-foil targets were irradiated with high-power (1 ≤ P(L) ≤ 210 TW), 10-ps pulses focused to intensities of I>10(18) W/cm(2) and studied with K-photon spectroscopy. Comparing the energy emitted in K photons to target-heating calculations shows a laser-energy-coupling efficiency to hot electrons of η(L-e) = 20 ± 10%. Time-resolved x-ray emission measurements suggest that laser energy is coupled to hot electrons over the entire duration of the incident laser drive. Comparison of the K-photon emission data to previous data at similar laser intensities shows that η(L-e) is independent of laser-pulse duration from 1 ≤ τ(p) ≤ 10 ps.

Quantification of the Structure of Colloidal Gas-Liquid Interfaces.

We have quantified the structure of the colloidal gas-liquid interface using synchrotron X-ray reflectivity measurements on a model colloid-polymer mixture. The interfacial width shows mean-field scaling with the colloid density difference, and the density profiles appear to be monotonic. Furthermore, our measurements allow us to distinguish between different theoretical polymer descriptions commonly used to model colloid-polymer mixtures. Our results highlight the importance of capturing the correct polymer physics in obtaining a quantitative theoretical description of the colloidal gas-liquid interface.

One-stage combined delayed bladder closure with Kelly radical soft-tissue mobilization in bladder exstrophy: preliminary results.

BACKGROUND: The radical soft-tissue mobilization (RSTM, or Kelly repair) is an anatomical reconstruction of bladder exstrophy generally performed as a second part of a two-step strategy, following successful neonatal bladder closure. OBJECTIVE: The objective of this study is to determine the feasibility of a combined procedure of delayed bladder closure and RSTM in one stage without pelvic osteotomy, in both primary and failed initial closure. DESIGN, SETTING, AND PARTICIPANTS: From 11/2015 to 01/2018, 27 bladder exstrophy patients underwent combined bladder closure with RSTM by the same surgical team at four cooperating tertiary referral centers for bladder exstrophy, including 20 primary repairs (delayed bladder closure, median age 3.0m [0.5-37m]) and seven secondary repairs after failed attempt at neonatal closure, median age 10m [8-33m]. INTERVENTION: RSTM included full mobilization of the bladder plate, urogenital diaphragm, and corpora cavernosa from the medial pelvic walls, followed by anatomical reconstruction with antireflux procedure, bladder closure, urethrocervicoplasty, muscle sphincter approximation, and penile/clitoral reconstruction. OUTCOME MEASUREMENTS: The main criteria were bladder dehiscence or prolapse. Secondary outcomes included bladder neck fistula or urethral fistula, urethral stenosis, and parietal hernia. Continence and voiding have not been addressed at this stage. RESULTS AND LIMITATIONS: All bladder exstrophy cases were successfully closed without osteotomy, with no case of bladder dehiscence after 12 m [3-30] follow-up. COMPLICATIONS: Urethral fistula or stenosis occurred in eight patients: 4/5 fistulae closed spontaneously in less than 3 months; four urethral stenoses were successfully treated with 1-3 sessions of endoscopic high-pressure balloon dilatation or meatoplasty; one patient with persistent bladder neck fistula is currently awaiting repair. Although the follow-up is short, it does allow examination of the main outcome criterion, namely bladder dehiscence, which is usually expected to happen very early after surgery. CONCLUSION: The Kelly RSTM can be safely combined with delayed bladder closure without osteotomy in both primary and redo cases in classic bladder exstrophy.

Large-aperture grating tiling by interferometry for petawatt chirped-pulse-amplification systems.

A tiled-grating assembly with three large-scale gratings is developed with real-time interferometric tiling control for the OMEGA EP Laser Facility. An automatic tiling method is achieved and used to tile a three-tile grating assembly with the overall wavefront reconstructed. Tiling-parameters sensitivity and focal-spot degradation from all combined tiling errors are analyzed for a pulse compressor composed of four such assemblies.

A picosecond beam-timing system for the OMEGA laser.

A timing system is demonstrated for the OMEGA Laser System that guarantees all 60 beams will arrive on target simultaneously with a root mean square variability of 4 ps. The system relies on placing a scattering sphere at the target position to couple the ultraviolet light from each beam into a single photodetector.

Management of upper esophageal sphincter disorders: indications and complications of myotomy.

Since 1951, when it was first used as a treatment for post-poliomyelitis dysphagia, cricopharyngeal myotomy (CPM) has been used in the treatment of various neurogenic, myogenic, structural, and idiopathic disorders. Yet, the efficacy of CPM in treating patients with upper esophageal sphincter (UES) disorders remains controversial. Despite favorable reports regarding its success, too few studies about indications, complications, and outcomes of CPM have been conducted to quell the controversy. Swallowing is accomplished when three primary conditions exist: (1) the cricopharyngeus muscle (CP) relaxes--that is, it is not tonically contracted, (2) the laryngo-hyoid complex elevates in an anterior-superior direction to open the sphincter, and (3) pharyngeal pressure is sufficient to propel a bolus through the open sphincter. CPM is indicated when the second and third conditions are "adequate" but the first is inadequate, thus resulting in pharyngeal dysphagia associated with a defective opening of the UES. UES dysfunction is determined most often through patient history, physical examination, and testing. Patients with Zenker's (pharyngoesophageal) diverticulum, oculopharyngeal dystrophy, or inclusion body myositis are among those reported to have the most positive responses to CPM. Modified barium swallow is the most common measurement of UES dysfunction; manometry also is used, but to a lesser degree because of catheter motion during swallowing. There are four approaches to CPM, including: (1) the external technique, which is indicated when a muscle biopsy or neck exploration is needed; (2) the endoscopic approach, which is reported to work best with patients with Zenker's diverticulum and offers the choice of electrocautery, laser, or the surgical stapler--the last option being the best choice for high-risk patients; (3) balloon dilatation of the UES, a low-risk option that reportedly works best in patients with fibrosis of the CP; and (4) botulinum toxin injection of the CP transcervically or endoscopically, which offers low risk and minimal or no anesthesia. This approach best serves cases of failed relaxation of the CP. Each approach has potential complications, but reports of such are few and rarely severe. In all cases, massive reflux should be controlled before CPM and the patient should be medically stable. Patient selection for CPM remains inadequate. To assess the efficacy of CPM, more multi-institutional outcome studies need to be conducted. In the meanwhile, clinical judgment and selective testing via modified barium swallow are the best methods for identifying patients who may derive the most benefit from CPM.

A fluorescent cell-based assay for cytochrome P-450 isozyme 1A2 induction and inhibition.

High throughput lead optimization requires simple, homogeneous cell-based assays capable of defining the druglike properties of first-round screening hits. Induction and inhibition of the Phase I drug-metabolizing enzymes are central to this process. We report here an assay for induction and inhibition of cytochrome P-450 (CYP) isozyme 1A2 that meets these requirements. It utilizes HepG2/C3A, a human liver cell line, and ethoxyresorufin. Using methylcholanthrene, CYP1A2 can be induced dramatically, and it is inhibited by furafylline, a mechanism-based inhibitor of this enzyme.

Lumbar ureteral shunt--an unusual cause of ureteral obstruction.

In a neurosurgical patient with a lumbar ureteral shunt in place for many years ureteral obstruction and hydronephrosis developed. The shunt tubing was removed surgically from the ureter leaving a portion of the shunt in the subarachnoid space without sequelae. Historically, most patients undergoing this type procedure had an ipsilateral nephrectomy performed at the time of shunt placement; however, this patient did not. It is important to be aware of this "antique" procedure as it may cause urologic complications.

The importance of the pedicle for the survival of a vascularized free flap: an experimental study on rats.

It has been assumed, but never shown experimentally, that the survival of a free vascularized full-thickness island flap is based on the vascular pedicle. A study using the rat was designed to assess the three parameters of flap survival: the vascular pedicle, the recipient bed, and the perimeter of the recipient area. Isolation of the pedicle by ligation caused flap necrosis in 18 out of the 20 groin flaps. An intact pedicle, with the other two parameters excluded, led to flap survival in 75% (9 of 12 flaps). Our results indicate that the critical factor to island flap survival in the immediate postoperative period is the vasculature supplying the pedicle. The two other factors are of limited importance.

Myology of the pharyngoesophageal segment: gross anatomic and histologic characteristics.

Although numerous studies have been performed on the function and dysfunction of the pharyngoesophageal segment, few studies have investigated features of the musculature in this area. Thus, the purpose of this study was to systematically exam. ine the structure (gross anatomy and histology) in this area and to relate these findings to the functions of the pharyngoesophageal segment. Twenty-one autopsy and surgery patients underwent careful measurement and observation of 1. the vertical (cephalad-caudad) height of the cricopharyngeus muscle (CP); 2. the presence or absence of Kilfian's dehiscence; and 3. the separation or blending of the CP with the upper esophageal circular muscles. Of the 21 subjects, muscle specimens were removed from 8 (4 autopsy, 4 surgical) to include a muscle strip from the upper esophageal circular muscles, CP, and inferior pharyngeal constrictor and submitted to a battery of histological and histochemical tests. Gross anatomic measurements of the vertical height of the CP were substantially longer than those reported elsewhere. Killian's dehiscence was shown to be present in fewer than one third of the specimens. Histology of these muscles also showed significant differences from the muscles discussed in other published reports, particularly when fresh and autopsy material were compared. These specialized muscles, therefore, require further detailed study.

Pseudomonas rhinosinusitis.

Although rare in the otherwise healthy patient, pseudomonas rhinosinusitis is encountered most frequently in the immunocompromised host or severely traumatized patient. Intravenous antibiotic therapy in conjunction with aggressive surgical drainage is required. Two cases are documented that are typical of this philosophy. A third patient with isolated nasal involvement, because of multiple medical disabilities, was treated with local debridement and topical therapy alone and responded.

Ludwig's angina: an update.

Despite a reduction in preantibiotic mortality rates that exceeded 50%, Ludwig's angina remains a potentially lethal entity primarily because of rapidly progressive airway obstruction. Since the reports of several large series in the 1940's, there have been put sporadic case reports because of widespread use of antibiotics in orodental infection, improved dental care, as well as adherence to strict diagnostic criteria. Since this entity is now uncommon, unnecessary delay in diagnosis and management may occur and may result in serious complications. This presentation will consist of an historical review, discussion of pathogenesis followed by clinical presentation, bacteriology and treatment, as well as a detailed analysis of our most recent 20 cases. There were no complications and no deaths. The infection resolved with medical therapy in 11 patients, while 9 patients required surgical procedures. Penicillin, clindamycin or chloramphenicol were started initially in all cases. Four of these 9 patients developed a localized abscess, while on antibiotics, which required drainage. Tracheotomy or intubation was necessary in 7 patients. Early and aggressive use of appropriate antibiotics and protection of the airway are the mainstays of a successful treatment regimen. Judicious surgical intervention is indicated in those patients who develop localized abscesses while on antibiotics or are unresponsive to medical management.

Laryngopyocele as a cause of airway obstruction.

Symptomatic laryngoceles are unusual lesions. Laryngopyoceles are even more unusual, with a total of 32 cases reported in the world literature. Two cases of laryngopyocele presenting as airway obstruction are described along with a review of the anatomy, etiology, clinical course, and management of this lesion. An argument is made supporting the resection of the symptomatic laryngocele to prevent the rapid respiratory obstruction that may occur in the presence of a laryngopyocele.

An unusual foreign body of the tongue masquerading as malignancy.

Foreign bodies within the tongue are a rare finding. The history is often not helpful as it is usually remote. Presented is a case of an unusual foreign body in the tongue which masqueraded as a malignancy. The differential diagnosis of an asymptomatic tongue swelling or tongue pain should include foreign body.