Energy Principles of Scientific Breakeven in an Inertial Fusion Experiment

Fusion "scientific breakeven" (i.e., unity target gain G_{target}, total fusion energy out > laser energy input) has been achieved for the first time (here, G_{target}∼1.5). This Letter reports on the physics principles of the design changes that led to the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce target gain greater than unity and exceeded the previously obtained conditions needed for ignition by the Lawson criterion. Key elements of the success came from reducing "coast time" (the time duration between the end of the laser pulse and implosion peak compression) and maximizing the internal energy delivered to the "hot spot" (the yield producing part of the fusion fuel). The link between coast time and maximally efficient conversion of kinetic energy into internal energy is explained. The energetics consequences of asymmetry and hydrodynamic-induced mixing were part of high-yield big radius implosion design experimental and design strategy. Herein, it is shown how asymmetry and mixing consolidate into one key relationship. It is shown that mixing distills into a kinetic energy cost similar to the impact of implosion asymmetry, shifting the threshold for ignition to higher implosion kinetic energy-a factor not normally included in most statements of the generalized Lawson criterion, but the key needed modifications clearly emerge.

Diagnosing the origin and impact of low-mode asymmetries in ignition experiments at the National Ignition Facility

Inertial confinement fusion ignition requires high inflight shell velocity, good energy coupling between the hotspot and shell, and high areal density at peak compression. Three-dimensional asymmetries caused by imperfections in the drive symmetry or target can grow and damage the coupling and confinement. Recent high-yield experiments have shown that low-mode asymmetries are a key degradation mechanism and contribute to variability. We show the experimental signatures and impacts of asymmetry change with increasing implosion yield given the same initial cause. This letter has implications for improving robustness to a key degradation in ignition experiments.

Measurement of Dark Ice-Ablator Mix in Inertial Confinement Fusion

We present measurements of ice-ablator mix at stagnation of inertially confined, cryogenically layered capsule implosions. An ice layer thickness scan with layers significantly thinner than used in ignition experiments enables us to investigate mix near the inner ablator interface. Our experiments reveal for the first time that the majority of atomically mixed ablator material is "dark" mix. It is seeded by the ice-ablator interface instability and located in the relatively cooler, denser region of the fuel assembly surrounding the fusion hot spot. The amount of dark mix is an important quantity as it is thought to affect both fusion fuel compression and burn propagation when it turns into hot mix as the burn wave propagates through the initially colder fuel region surrounding an igniting hot spot. We demonstrate a significant reduction in ice-ablator mix in the hot-spot boundary region when we increase the initial ice layer thickness.

Design of multi neutron-to-gamma converter array for measuring time resolved ion temperature of inertial confinement fusion implosions

The ion temperature varying during inertial confinement fusion implosions changes the amount of Doppler broadening of the fusion products, creating subtle changes in the fusion neutron pulse as it moves away from the implosion. A diagnostic design to try to measure these subtle effects is introduced-leveraging the fast time resolution of gas Cherenkov detectors along with a multi-puck array that converts a small amount of the neutron pulse into gamma-rays, one can measure multiple snapshots of the neutron pulse at intermediate distances. Precise measurements of the propagating neutron pulse, specifically the variation in the peak location and the skew, could be used to infer time-evolved ion temperature evolved during peak compression.

Thermal decoupling of deuterium and tritium during the inertial confinement fusion shock-convergence phase

A series of thin glass-shell shock-driven DT gas-filled capsule implosions was conducted at the OMEGA laser facility. These experiments generate conditions relevant to the central plasma during the shock-convergence phase of ablatively driven inertial confinement fusion (ICF) implosions. The spectral temperatures inferred from the DTn and DDn spectra are most consistent with a two-ion-temperature plasma, where the initial apparent temperature ratio, T_{T}/T_{D}, is 1.5. This is an experimental confirmation of the long-standing conjecture that plasma shocks couple energy directly proportional to the species mass in multi-ion plasmas. The apparent temperature ratio trend with equilibration time matches expected thermal equilibration described by hydrodynamic theory. This indicates that deuterium and tritium ions have different energy distributions for the time period surrounding shock convergence in ignition-relevant ICF implosions.

The five line-of-sight neutron time-of-flight (nToF) suite on the National Ignition Facility (NIF)

Measurement of the neutron spectrum from inertial confinement fusion implosions is one of the primary diagnostics of implosion performance. Analysis of the spectrum gives access to quantities such as neutron yield, hot-spot velocity, apparent ion temperature, and compressed fuel ρr through measurement of the down-scatter ratio. On the National Ignition Facility, the neutron time-of-flight suite has been upgraded to include five independent, collimated lines of sight, each comprising a high dynamic range bibenzyl/diphenylacetylene-stilbene scintillator [R. Hatarik et al., Plasma Fusion Res. 9, 4404104 (2014)] and high-speed fused silica Cherenkov detectors [A. S. Moore et al., Rev. Sci. Instrum. 89, 10I120 (2018)].

Evidence of Three-Dimensional Asymmetries Seeded by High-Density Carbon-Ablator Nonuniformity in Experiments at the National Ignition Facility

Inertial confinement fusion implosions must achieve high in-flight shell velocity, sufficient energy coupling between the hot spot and imploding shell, and high areal density (ρR=∫ρdr) at stagnation. Asymmetries in ρR degrade the coupling of shell kinetic energy to the hot spot and reduce the confinement of that energy. We present the first evidence that nonuniformity in the ablator shell thickness (∼0.5% of the total thickness) in high-density carbon experiments is a significant cause for observed 3D ρR asymmetries at the National Ignition Facility. These shell-thickness nonuniformities have significantly impacted some recent experiments leading to ρR asymmetries on the order of ∼25% of the average ρR and hot spot velocities of ∼100  km/s. This work reveals the origin of a significant implosion performance degradation in ignition experiments and places stringent new requirements on capsule thickness metrology and symmetry.

Velocity correction for neutron activation diagnostics at the NIF

The velocity distribution of the hotspot in an inertial confinement fusion implosion changes the energy spectra of fusion neutrons emitted from the experiment as a function of viewing angle. These velocity-induced spectral changes affect the response of neutron activation diagnostics (NADs) positioned around the experiment and must be accounted for to correctly extract information about areal density (ρR) asymmetry from the data. Three mechanisms through which average hotspot velocity affects NAD activation are addressed: change in activation cross section due to the Doppler shift of the mean neutron energy, kinematic focusing of neutron fluence, and change in the scattering cross section due to the Doppler shift. Using the hotspot velocity inferred from neutron time-of-flight measurements of D-T and D-D fusion neutrons, the hotspot velocity is shown to account for the observed NAD activation asymmetry in a calibration shot with negligible fuel ρR. A robust method to evaluate uncertainties in spherical-harmonic fits to the NAD data due to the velocity correction and detector uncertainty is discussed.

Tokyo Guidelines 2018: antimicrobial therapy for acute cholangitis and cholecystitis

Antimicrobial therapy is a mainstay of the management for patients with acute cholangitis and/or cholecystitis. The Tokyo Guidelines 2018 (TG18) provides recommendations for the appropriate use of antimicrobials for community-acquired and healthcare-associated infections. The listed agents are for empirical therapy provided before the infecting isolates are identified. Antimicrobial agents are listed by class-definitions and TG18 severity grade I, II, and III subcategorized by clinical settings. In the era of emerging and increasing antimicrobial resistance, monitoring and updating local antibiograms is underscored. Prudent antimicrobial usage and early de-escalation or termination of antimicrobial therapy are now important parts of decision-making. What is new in TG18 is that the duration of antimicrobial therapy for both acute cholangitis and cholecystitis is systematically reviewed. Prophylactic antimicrobial usage for elective endoscopic retrograde cholangiopancreatography is no longer recommended and the section was deleted in TG18. Free full articles and mobile app of TG18 are available at: http://www.jshbps.jp/modules/en/index.php?content_id=47. Related clinical questions and references are also included.

Tokyo Guidelines 2018: management bundles for acute cholangitis and cholecystitis

Management bundles that define items or procedures strongly recommended in clinical practice have been used in many guidelines in recent years. Application of these bundles facilitates the adaptation of guidelines and helps improve the prognosis of target diseases. In Tokyo Guidelines 2013 (TG13), we proposed management bundles for acute cholangitis and cholecystitis. Here, in Tokyo Guidelines 2018 (TG18), we redefine the management bundles for acute cholangitis and cholecystitis. Critical parts of the bundles in TG18 include the diagnostic process, severity assessment, transfer of patients if necessary, and therapeutic approach at each time point. Observance of these items and procedures should improve the prognosis of acute cholangitis and cholecystitis. Studies are now needed to evaluate the dissemination of these TG18 bundles and their effectiveness. Free full articles and mobile app of TG18 are available at: http://www.jshbps.jp/modules/en/index.php?content_id=47. Related clinical questions and references are also included.

Legal intervention for non-adherent patients in the treatment of tuberculosis

BACKGROUND

The Philadelphia Department of Public Health Tuberculosis (TB) Control Program has a progressively severe, stepwise legal process for managing non-adherent TB patients, potentially culminating in incarceration.

OBJECTIVE

To review the application of legal procedures and to evaluate their effectiveness in the management of non-adherent TB patients.

METHODS

We evaluated this process by reviewing patients' records from 2001 to 2005 to identify all non-adherent patients and determine their treatment outcomes.

RESULTS

In this period, we initiated the legal process for 39 non-adherent patients. One patient died, and nine patients were lost. Twenty-nine patients became adherent after the use of a legal intervention. Our final completion percentage was 76.3%.

CONCLUSION

Our legal process improved the treatment completion rate for patients who would otherwise have been non-adherent. Increasing treatment completion rates reduce the risk of relapse and disease transmission as well as the growing rate of anti-tuberculosis drug resistance.

Fever of unknown origin caused by tuberculosis

Tuberculosis is an important cause of fever of unknown origin. Travel, age, dialysis, diabetes, birth in a country with a high prevalence of tuberculosis, and immunoincompetence are among the most salient risks. Associated physical findings, radiologic evaluation, and hematologic and endocrinologic abnormalities may provide clues to the diagnosis. Both noninvasive and invasive diagnostic modalities are reviewed. Because diagnosis may be elusive, therapeutic and diagnostic trials of antituberculous therapy should be considered in all patients with fever of unknown origin who defy diagnosis.

Extensively drug-resistant tuberculosis: are we learning from history or repeating it?

Tuberculosis (TB) is an enormous global public health problem. Cases of extensively drug-resistant TB (XDR-TB) are being reported in increasing numbers across the globe. A large outbreak of XDR-TB associated with rapid and nearly universal mortality has been reported among patients with human immunodeficiency virus infection or acquired immunodeficiency disease in South Africa who have been receiving standard TB therapy and antiretrovirals. Epidemiologic features of this outbreak make it highly suspicious for health care-associated transmission. We urge the Infectious Diseases Society of America and its members to increase involvement in ongoing international TB prevention and treatment efforts and to develop a registry of experts in infection control and laboratory and disease management. We urge advocacy for increased funding for domestic and global TB control programs, including expanded access to sputum culture and drug susceptibility testing, as well as funding for TB clinical trials and research capacity. We believe that substandard TB diagnostic tests are not acceptable for TB control in resource-poor countries. We urge the development of shorter, less toxic TB treatment and prevention regimens. Funding of TB control and research should be reassessed to prevent budget cuts at a time when the disease is killing as many as 2 million people a year.

Clinical approach to antibiotic failure

A systematic approach is presented for the patient with antibiotic failure. Noninfectious mimics of infection and nontreatable infections must first be excluded. Then, the clinician must identify those patients who have responded but have a surgical component of their infection or have complications separate from their initial infection. Such complications could include drug fever, phlebitis, decubiti, urinary tract infection, aspiration, and pulmonary embolism. Other patients may deteriorate clinically because of incorrect antibiotic coverage, failure of antibiotic to reach the site of infection, local inactivation of antibiotic, paradoxical response, immune compromise, or because they have reached the point of no return.

Infections from leisure-time activities

Leisure-time activities expose us to a variety of infections. The traveler confronts new pathogens and vectors. Camping, hiking and gardening have attendant risks, as does exposure to fresh and salt water. Adventuresome eating poses gastronomic threats, and pets, sexual exposure and organized sports each contribute distinctive infectious risks to participants.

Legionella and immunosuppression

Patients with defective immune systems are susceptible to Legionella infection, especially when the defect involves cell-mediated immunity. Thus, acquired immune deficiency syndrome (AIDS), corticosteroid administration, and hairy cell leukemia are risk factors for Legionellosis. Patients who have AIDS may be at risk for relapsing infections. Corticosteroid administration appears to predispose patients to simultaneous infection with multiple strains of Legionellae and development of lung abscess. Legionellosis also is found in patients who have humoral immune defects, but to a lesser extent. Thus, multiple myeloma, chronic lymphocytic leukemia, and chronic granulomatous disease have all been complicated by Legionella infection, although the risk seems to be minimal.

The Splendore-Hoeppli phenomenon in hepatic botryomycosis

A 68 year old diabetic man developed septicaemia and multiple liver abscesses due to Streptococcus intermedius. Liver biopsy revealed streptococcal botryomycosis which showed the Splendore-Hoeppli phenomenon. Diabetes mellitus is an example of the immunosuppressed states that have been associated with botryomycosis.

Streptococcus pneumoniae bacteremia in a community hospital

We reviewed 71 consecutive patients with Streptococcus pneumoniae bacteremia. The patients were analyzed by age, sex, ethnic background, and clinical presentation. Laboratory data reviewed included a CBC count, electrolyte levels, liver function studies, chest radiograph, HIV status, a sputum culture and Gram's stain, and sensitivities for the S pneumoniae isolated. Modalities of therapy, response to treatment, and ultimate outcome were examined. Many of the patients with pneumococcal bacteremia did not have cough, fever, or chills. HIV positivity was a risk factor for pneumococcal infection although it was not associated with increased mortality. Mortality correlated with elderly status, leukopenia, and lack of fever. Many patients had symptoms suggestive of atypical pneumonia including myalgia and mental status change. Hyponatremia and hyperbilirubinemia were commonly noted.

Fever and rash

The combination of fever and rash comprises an extensive differential diagnosis. Many of the causes of this presentation are life-threatening. In this article, rashes are categorized as petechial, maculopapular, vesicular, erythematous, and urticarial. Each type of rash is then divided into infectious etiologies, both treatable and nontreatable, and noninfectious etiologies. It is usually possible to arrive at a workable differential diagnosis when clinical, historical, and epidemiologic factors are considered.

[Pseudomesotheliomatous carcinoma in HIV infection]

HISTORY AND FINDINGS

A 32-year-old man, known to have been HIV-positive for 6 years, was admitted to hospital because of dyspnoea and dry cough. For 8 months he had an HIV illness in stage C3 (Center for Disease Control and Prevention, Atlanta) with fever, weight loss and obviously reduced general and nutritional state. There was almost total auscultatory dullness over the right hemithorax and the chest radiogram showed massive right pleural effusion, as well as broad pleural deposits which were suspicious of tumours. The first pleural aspiration recovered 1000 ml exudate. An infectious cause could not be identified. As the effusion was refractory to treatment (301 of effusion were drained over several days), thoracoscopy was performed despite the patient's poor general condition. It revealed extensive tumour masses over the right pleura.

COURSE

After the endoscopy the patient's condition deteriorated rapidly and he died 3 weeks after admission, only 1 1/2 months after onset of the first symptoms. Histological examination of the endoscopically obtained biopsy revealed large-cell carcinoma. The form of growth indicated that it was a pseudomesotheliomatous carcinoma.

CONCLUSION

No previous case of this type of tumour in an HIV-positive patient has been reported. This patient's course was less favourable than is expected in those without HIV infection.

Azithromycin and clarithromycin

Azithromycin and clarithromycin are alternatives to conventional macrolides in the routine treatment of many dermatologic, upper respiratory, and lower respiratory tract infections. In this role as alternative therapy, they are better tolerated, less toxic, and more convenient to take, although at a greater cost to the patient. This dosing convenience is an important consideration for the clinician; as shown by Nelson, patient compliance ranges from 95% with once-daily dosing to 58% with four-times-a-day dosing. Thus, less frequent dosing with both drugs as well as the shorter course of therapy possible with azithromycin may be therapeutically advantageous. In addition to their role as alternatives to conventional macrolide therapy, azithromycin and clarithromycin extend the spectrum of macrolides and offer new therapeutic options for H. influenzae, MAC in AIDS, MOTT, and leprosy. Finally, experimental therapy may extend their use for additional opportunistic infections, such as toxoplasmosis and cryptosporidiosis.

Multicenter trial of single-dose azithromycin vs. ceftriaxone in the treatment of uncomplicated gonorrhea. Azithromycin Gonorrhea Study Group

BACKGROUND AND OBJECTIVES

Azithromycin is a new, long-acting azalide antibiotic that is active against Neisseria gonorrhoeae. A single oral dose of 1.0 g is effective against uncomplicated genital infection with Chlamydia trachomatis.

GOAL OF THIS STUDY

To compare the efficacy and tolerance of single-dose treatment of uncomplicated gonorrhea with azithromycin, 2.0 g orally, and ceftriaxone, 250 mg intramuscularly.

STUDY DESIGN

Seven hundred twenty-four men and women with presumptive, uncomplicated gonorrhea were treated with azithromycin 2.0 g orally or ceftriaxone 250 mg intramuscularly in a 2:1 ratio in a multicenter, open, randomized control trial in 10 public sexually transmitted disease clinics in the United States. Patients were followed up in 5 to 9 days and, for a subset of patients, 12 to 18 days after treatment. The main outcome measures were the isolation of N. gonorrhoeae and C. trachomatis and patient-reported side effects.

RESULTS

Among infected patients who returned for follow-up, N. gonorrhoeae was eradicated from all anatomic sites in 370 of 374 (98.9%; 95% confidence interval [95%CI] 97.9%-100%) treated with azithromycin and 171 of 175 (97.7%; 95%CI 95.5%-99.9%) given ceftriaxone. Treatment with either drug was effective in all 73 patients infected with beta-lactamase-producing N. gonorrhoeae. Chlamydial infection was eradicated in all 17 patients given azithromycin who returned and were recultured at follow-up and in two of seven patients given ceftriaxone (P < 0.001). Gastrointestinal side effects occurred in 35.3% (95%CI 30.7%-39.8%) of patients given azithromycin; of those with symptoms, these were moderate in 10.1% and severe in 2.9%.

CONCLUSIONS

Azithromycin 2.0 g and ceftriaxone 250 mg are equally effective in the treatment of uncomplicated gonorrhea. Azithromycin was associated with a relatively high frequency of gastrointestinal side effects and is expensive, but it has the advantages of oral administration and efficacy against concomitant chlamydial infection.

An epidemic of avian and human psittacosis

Psittacosis may occur in epidemic or sporadic form. We report an outbreak of avian and human psittacosis associated with an aviary in Philadelphia, Pa. The epidemic spread among birds in the aviary and then to men and women who were in contact with the birds. Chlamydia psittaci was cultured from infected birds, and the human patients were evaluated clinically and serologically. After proper treatment of the birds, cleaning of their cages, and institution of appropriate bird-handling techniques, the outbreak among the birds resolved. The human patients were treated, and no subsequent cases have been seen.

Endophthalmitis in intravenous drug abuse

Endophthalmitis usually results from surgical trauma, and it rarely complicates intravenous drug abuse. A case is reported of an intravenous drug abuser who had staphylococcal endophthalmitis.

Aortitis caused by Mycobacterium fortuitum

Aortic valve replacement was complicated by sternal wound infection with Mycobacterium fortuitum. The wound was treated with débridement and antibiotic therapy. Five months later the patient developed fever, and blood cultures yielded M fortuitum. At surgery, aortitis with pseudo-aneurysm formation was encountered. Mycobacterium fortuitum grew from the aortic lesion. This is the first report of M fortuitum causing aortitis, although this organism is known to infect sternal wounds and mediastinum. Mediastinal infection can progress despite a normal wound appearance. Its manifestations may be delayed and may include infections of the aorta as well as of the sternum and mediastinum.

Manifestations of hereditary colorectal cancer

Seven families with hereditary colorectal cancer syndromes are presented. Four are of the nonpolyposis type, two with polyposis, and one with a mixed pattern. We have observed an early onset of hereditary colorectal cancer, the nonpolyposis type of which manifests itself mostly in the proximal colon, whereas the syndrome with polyposis manifests itself in the distal colon. In addition, the rest of the gastrointestinal tract may be involved. Therefore surveillance endoscopies in affected families should be started at least 20 years earlier than usual.

Culture-proved disseminated cat-scratch disease in acquired immunodeficiency syndrome

A male homosexual (positive for the human immunodeficiency virus) with a recent cat scratch developed fever, epitrochlear and axillary lymphadenopathy, and retinitis. Subsequently, he developed skin (epitheloid hemangioma) and mucosal lesions (Kaposi's sarcoma), multiple liver abscesses, and pleural effusion. Warthin-Starry stains and/or electron micrographs of lymph nodes and skin lesions demonstrated bacilli characteristic of those associated with cat-scratch disease. Cultures of lymph node, pleural fluid, and liver abscess specimens yielded organisms believed to be the causative agent of cat-scratch disease. We believe that disseminated cat-scratch disease may become an indicator of opportunistic infection signaling acquired immunodeficiency syndrome in a patient who is positive for the human immunodeficiency virus.

Comparison of once-daily cephalosporin regimens for community-acquired lower respiratory tract infections in patients with chronic lung disease

The efficacy of cefonicid and of ceftriaxone, administered once daily for the treatment of lower respiratory tract bacterial infections (pneumonia or bronchitis), was evaluated and compared in 118 patients with chronic lung disease. The patients were randomly assigned to receive 1 gm of either drug, intravenously or intramuscularly, daily for three to 11 days (mean, seven days). Pathogenic bacteria were isolated from sputum in 59% of patients; Haemophilus influenzae and Streptococcus pneumoniae predominated. Clinical cure or improvement was noted in 95% and 93% of patients treated with cefonicid and ceftriaxone, respectively, and bacteriologic cure or improvement in 69% and 81% (the differences were not significant). Side effects were infrequent and similar in the two treatment groups, except that diarrhea was more common in the ceftriaxone group (11%, versus 4.4% in the cefonicid group). It is concluded that patients with chronic lung disease who experience acute exacerbations associated with infection caused by H influenzae or S pneumoniae, or other susceptible organisms, can be effectively treated with once-daily administration of either cefonicid or ceftriaxone.

Periampullary, colorectal and gastric cancer in two siblings

We describe a sibship affected by subsequent periampullary, colorectal and gastric carcinoma. Three of 4 siblings (2 males, 1 female) developed a periampullary carcinoma at the age of 20, and the 2 brothers subsequently had colorectal and gastric carcinoma. One of them also had familial adenomatous polyposis. There is suggestive evidence of vertical transmission of a gene predisposing to a hereditary colorectal carcinoma syndrome.

Varicella pneumonia

Six normal adults with varicella pneumonia were treated successfully with acyclovir sodium. All patients showed resolution of roentgenographic and arterial blood gas abnormalities. In addition, five of the six patients demonstrated thrombocytopenia that resolved with therapy. Intravenous acyclovir therapy should be instituted as early as possible in patients who may have varicella pneumonia.

Legionella-like organisms

The family Legionellaceae contains the new genus and species Legionella pneumophila; organisms that resemble L pneumophila but differ in one or more phenotypes are called legionella-like organisms and constitute a growing list of new species now numbering over two dozen, and the characterization of additional species of legionellae continues to expand. Similar to L pneumophila, some of these new species have additional serogroups within the species. These new species have varying degrees of clinical and epidemiological importance. We will review historical, laboratory, and clinical aspects of Legionella species other than L pneumophila and L micdadei.

Disseminated sarcoidosis

A patient with sarcoidosis manifested by skeletal and cutaneous involvement had a normal chest x-ray and gallium scan of the lungs. The absence of pulmonic disease in spite of the extrapulmonic manifestations of sarcoidosis is rare. A normal chest x-ray does not exclude the diagnosis of sarcoidosis.