Photon Transport in a Bose-Hubbard Chain of Superconducting Artificial Atoms.

We demonstrate nonequilibrium steady-state photon transport through a chain of five coupled artificial atoms simulating the driven-dissipative Bose-Hubbard model. Using transmission spectroscopy, we show that the system retains many-particle coherence despite being coupled strongly to two open spaces. We find that cross-Kerr interaction between system states allows high-contrast spectroscopic visualization of the emergent energy bands. For vanishing disorder, we observe the transition of the system from the linear to nonlinear regime of photon blockade in excellent agreement with the input-output theory. Finally, we show how controllable disorder introduced to the system suppresses nonlocal photon transmission. We argue that proposed architecture may be applied to analog simulation of many-body Floquet dynamics with even larger arrays of artificial atoms paving an alternative way towards quantum supremacy.

Mesoscopic Stoner Instability in Open Quantum Dots: Suppression of Coleman-Weinberg Mechanism by Electron Tunneling.

The mesoscopic Stoner instability is an intriguing manifestation of symmetry breaking in isolated metallic quantum dots, underlined by the competition between single-particle energy and Heisenberg exchange interaction. Here we study this phenomenon in the presence of tunnel coupling to a reservoir. We analyze the spin susceptibility of electrons on the quantum dot for different values of couplings and temperature. Our results indicate the existence of a "quantum phase transition" at a critical value of the tunneling coupling, which is determined by the Stoner-enhanced exchange interaction. This quantum phase transition is a manifestation of the suppression of the Coleman-Weinberg mechanism of symmetry breaking, induced by coupling to the reservoir.

Is a stepdown unit safe for patients with mild traumatic intracranial hemorrhages?

PURPOSE: Traumatic brain injuries (TBIs) are a major source of disability in the United States. The ideal unit in the hospital for patients with mild traumatic intracranial hemorrhages (ICHs) has not been elucidated. We sought to investigate whether patients treated in the surgical stepdown area had worse outcomes than those treated in the surgical ICU. METHODS: We compared patients with ICHs and a Glasgow Coma Scale (GCS) upon admission of 14 or 15 who went to the ICU to those who went to the stepdown area from April 2014 to November 2016. We compared age, gender, Injury Severity Score (ISS), admission GCS (14 or 15), operative intervention, discharge destination, hospital length of stay (HLOS), mortality, and cost between these two groups. RESULTS: Patients admitted to the ICU had a significantly longer HLOS. Admission costs for patients admitted to ICU were also significantly higher than their stepdown area counterparts. This was true for both total charges (p = 0.0001) and for net revenue (p = 0.002) (Table 2). There was no statistically significant difference in mortality, operative intervention, or discharge destination. CONCLUSION: A surgical stepdown unit can be a safe disposition for patients with mild traumatic ICHs and represents an effective use of hospital resources.

Magnetic character of holmium atom adsorbed on platinum surface.

We address a recent controversy concerning the magnetic state of holmium adatom on platinum surface. Within a combination of the density functional theory (DFT) with the exact diagonalization (ED) of Anderson impurity model, the 〈J z 〉 = 0 paramagnetic ground state |J = 8, J z = ±8〉 is found. In an external magnetic field, this state is transformed to a spin-polarized state with 〈J z 〉 ≈ 6.7. We emphasize the role of 5d-4f interorbital exchange polarization in modification of the 4f shell energy spectrum.

Prehospital HMG Co-A reductase inhibitor use and reduced mortality in hemorrhagic shock due to trauma.

INTRODUCTION: 3-Hydroxy-3-methyl-glutaryl Co-A reductase inhibitors (HMG Co-A reductase inhibitors, statins) are commonly used medications for the control of serum cholesterol. Recent data suggests that these medications also modify the inflammatory pathways in sepsis, septic shock, and hemorrhagic shock due to ruptured abdominal aortic aneurysms. Statin use in hemorrhagic shock due to trauma, however, has conflicting data, with one study showing improvement, but only in certain subsets of patients. STUDY DESIGN: We retrospectively reviewed the medical records of patients from our institution's trauma registry database from January 2000 to December 2008. We included patients with an age greater than 45 years and an Injury Severity Score (ISS) greater than 15 with evidence of shock as follows: hypotension, elevated serum lactate, base deficit, metabolic acidosis, or objective evidence of end-organ malperfusion. We excluded patients with devastating head injury, patients with pre-existing advance directives directing against life-sustaining measures, patients for whom family or health care proxies withdrew support in 24 h or less, and patients who succumbed to their injuries in the first 24 h in the hospital. We compared age, gender, mortality, statin use, aspirin use, and Sequential Organ Failure Assessment (SOFA) scores. RESULTS: Mortality in the group without prehospital statin use was 38.1% (95% confidence interval [CI]: 28.4-48.8%) and mortality in the group with prehospital statin use was 8.3% (95% CI: 2.13-22.5%, P = 0.0009). The absolute risk reduction was 29.8% and the relative risk reduction was 78.1%. Survivors were statistically significantly younger than nonsurvivors in the group without prehospital statin use, but not in the group with documented prehospital statin use. There was no similar benefit to aspirin use. There were no significant differences in the SOFA scores, hospital length of stay (HLOS), or intensive care unit length of stay (ICU LOS) between statin users and nonusers. CONCLUSIONS: Prehospital HMG Co-A reductase use was associated with improved survival in a population with severe trauma and evidence of ongoing hemorrhagic shock.

Severe hyponatraemia in elderly hospitalized patients: prevalence, aetiology and outcome.

BACKGROUND: Hyponatraemia is the commonest electrolyte disorder in the elderly. Data on severe hyponatraemia and the prevalence of cerebral salt wasting syndrome (CSWS) in elderly hospitalized patients are lacking. We studied the incidence, frequency of various aetiologies, outcome and the possible role of CSWS in severe hyponatraemia in elderly medical patients. METHODS: A prospective, observational, non-interventional study conducted over a 5-month period in medical wards. Eighty-six patients aged over 65 years with serum sodium levels < or =125 mEq/L were included. All patients were examined by one of the authors, who also evaluated potential contributing factors. Demographic, clinical and outcome data were extracted from the medical records. RESULTS: The mean age of the patients was 82.1 + 8.7 years. The prevalence of hyponatraemia was 6.2% (8.1% women and 4.0% men (P < 0.001)). There was no increase in incidence of hyponatraemia with age. The leading cause of hyponatraemia was the syndrome of inappropriate antidiuretic hormone secretion (SIADH), whose aetiology could be determined in only 46% of cases. Aetiology was multifactorial in 51% of patients (1.7 aetiological factors per patient). All patients with thiazide-induced hyponatraemia had other contributing factors. Hyperglycaemia and hypoalbuminaemia were predictors of neurological manifestations of hyponatraemia. Overall in-hospital mortality was 19%. Only hypoalbuminaemia was found as an independent risk factor for death. In none of the patients was the hyponatraemia due to CSWS. CONCLUSION: Severe hyponatraemia in elderly hospitalized medical patients is more frequent in women and of multifactorial aetiology in 50% of cases. It is most commonly caused by SIADH; CSWS is an unlikely cause.

Rapid mycobacteria drug susceptibility testing using Gel Microdrop (GMD) Growth Assay and flow cytometry.

Control of multi-drug-resistant tuberculosis has been hampered by the lack of simple, rapid and sensitive methods for assessing bacterial growth and antimicrobial susceptibility. Due to the increasing incidence and high frequency of mutations, it is unlikely that culture methods will disappear in the foreseeable future. Therefore, the need to modernize methods for rapid detection of viable clinical isolates, at a minimum as a gold standard, will persist. Previously, we confirmed the feasibility of using the Gel Microdrop (GMD) Growth Assay for identifying sub-populations of resistant Mycobacteria by testing different laboratory strains. Briefly, this assay format relies on encapsulating single bacterium in agarose microspheres and identifying clonogenic growth using flow cytometry and fluorescent staining. In this study, we modified the GMD Growth Assay to make it suitable for clinical applications. We demonstrated the effectiveness and safety of this novel approach for detecting drug susceptibility in clinically relevant laboratory strains as well as clinical isolates of Mycobacterium tuberculosis. Correlation between results using the GMD Growth Assay format and results using two well characterized methods (Broth Microdilution MIC and BACTEC 460TB) was 87.5% and 90%, respectively. However, due to the inherent sensitivity of flow cytometry and the ability to detect small (<1%) sub-populations of resistant mycobacteria, the GMD Growth Assay identified more cases of drug resistance. Using 4 clinically relevant mycobacterial strains, we assessed susceptibility to primary anti-tuberculosis drugs using both the Broth Microdilution MIC method and the GMD Growth Assay. We performed 24 tests on isoniazid-resistant BCG, Mycobacterium tuberculosis H37Ra and Mycobacterium avium strains. The Broth Microdilution MIC method identified 7 cases (29.1%) of resistance to INH and EMB compared to the GMD Growth Assay which identified resistance in 10 cases (41.6%); in 3 cases (12.5%), resistance to INH and EMB was detected only with the GMD Growth Assay. In addition, using 20 Mycobacterium tuberculosis clinical isolates, we compared results using BACTEC 460TB method performed by collaborators and the GMD Growth Assay. Eight of 20 (40%) clinical isolates, which were not identified as drug-resistant using the conventional BACTEC 460TB method, were resistant to 1, 2, or 3 different concentrations of drugs using the GMD Growth Assay (13 cases of 140 experiments). In one case (isolate 1879), resistance to 10.0 microg/ml of STR detected using BACTEC 460TB method was not confirmed by the GMD Growth Assay. Thus, the overall agreement between these methods was 90% (14 discrepant results of 140 experiments). These data demonstrate that the GMD Growth Assay is an accurate and sensitive method for rapid susceptibility testing of Mycobacterium tuberculosis for use in clinical reference laboratory settings.

Evidence of zoonotic transmission of Cryptococcus neoformans from a pet cockatoo to an immunocompromised patient.

BACKGROUND: Although cryptococcosis has been associated with birds for almost 50 years, point sources for infection have not been identified. OBJECTIVE: To document zoonotic transmission of Cryptococcus neoformans. DESIGN: Case report. SETTING: A home in Boston, Massachusetts. PATIENT: A 72-year-old woman who received a diagnosis of cryptococcal meningitis in November 1998. The patient, who had been taking immunosuppressant drugs since undergoing renal transplantation in 1989, owned a pet cockatoo. MEASUREMENTS: Cryptococcus neoformans was isolated from the feces of the cockatoo. Isolates from excreta and from the patient were compared by using biochemical profiles, monoclonal antibody binding patterns, restriction fragment length polymorphism analysis, and karyotyping. RESULTS: The isolates from the patient and the cockatoo had identical biochemical profiles, the same monoclonal antibody immunofluorescence patterns, and indistinguishable patterns on restriction fragment length polymorphism analysis and karyotyping. CONCLUSIONS: The indistinguishable patient and cockatoo isolates strongly suggest that the patient's infection resulted from exposure to aerosolized cockatoo excreta. Although the incidence of cryptococcal infection due to such exposure is unknown, it may be prudent to advise immunocompromised patients to avoid pet birds and avian excreta.

Canine carotid allograft changes after photochemotherapy and external polyester sheathing.

BACKGROUND: The purpose of this study is to define and refine the changes in canine carotid allografts after photochemotherapy and polyester sheathing. Photochemotherapy with 8-methoxy psoralen (8MOP) and UVA (PUVA) was given alone or combined with intraluminal visible light (VL) 450 nm in proper dosages to speed the depopulation of endothelial (EC) and smooth muscle cells (SMC) and to modulate the immune response. METHODS: Novel apparati were made for photochemotherapy of 19 right canine carotid arterial allografts with 19 paired untreated controls in the left carotid. External UVA and internal visible light (VL 450 nm) were used with 8-methoxy psoralen (8-MOP) as a sensitizer. RESULTS: With moderate dosage of 8-MOP (1 microg/cc) and 2-4 J/cm2 of external UVA (PUVA), smooth muscle cells (SMC) disappeared faster from the media and fibroblasts (FB) appeared earlier in the adventitia of the treated right allografts, reducing but not eliminating the immune response. Intraluminal VL did not enhance the PUVA effect. At 68 days, treated and control allografts showed similar dimensions with subsided immune reactions. The media thickness was reduced from 0.38 mm to 0.18 mm and the host adventitia increased from 0.22 to 0.60 mm. Variable reactions peaked between two and three weeks and subsided after one month. All allografts remained open with canine carotid i.d.s of 2-3 mm and 80 to 100 cc/ minute arterial flows. Although the UVA dosage was moderate) similar doses sterilized log 7 of staph aureus cultures in saline. The allografts without smooth muscle showed moderate but stable cylindrical dilatation without spasm or stenosis and with an adequate adventitial buttress for a small vessel. A polyester sleeve around four treated grafts was inseparable from the allograft in less than 3 weeks and tolerated well over a 70-day period. CONCLUSIONS: Biodegradable graft sheaths with bioerodible hydrogels with growth factors (FGF) for local delivery may provide a faster and more complete matrix remodeling for a superior conduit in the future.

Surgical stress and the heat shock response: in vivo models of stress conditioning.

All forms of surgical therapy are stressful and injurious. The majority of surgical procedures are performed electively and provide an opportunity to condition the patient before surgery to maximize outcome. We have successfully protected the spinal cord and kidneys from warm ischemia-reperfusion injury with whole-body heat shock (42.5 degrees C, 15 min, HS) and recovery (37 degrees C, 6-8 h) before acute aortic occlusion. Control rabbits experienced an 88% incidence of paralysis (7/8) after acute spinal cord ischemia, while HS-pretreated animals never became paralyzed (0/9, p < 0.001). Control pig kidneys showed partial function (4/8 survival) after 90-min warm ischemia, while HS-pretreated kidneys always functioned (8/8 survival, p < 0.04). A positive temporal association was made between the HS-associated functional protection and the enhanced expression of inducible HSP70. The induction of the heat-shock response (cellular stress response) to protect tissues from lethal acute ischemia-reperfusion injury could be employed in a wide range of medical and surgical settings.

Quality control in nucleic acid amplification methods: use of elementary probability theory.

Since it is not possible to state with certainty that contamination has occurred during a nucleic acid amplification assay in the absence of a positive result for a negative control, methods of elementary probability theory are used to illustrate how to identify those runs in which the possibility of contamination should be considered. The use of binomial and Poisson distributions and an analysis of clusters are presented with illustrative examples to demonstrate their use.

Major open injuries of the talus.

Seventeen patients with 18 open talar fracture-dislocations or total dislocations of the talus were reviewed to determine the functional outcome and incidence of infection. Seven of 18 feet (38%) developed infection. Infection was associated with extrusion of the talar body through the open wound (p < 0.025). Final follow-up was achieved in 13 of 17 patients (14 of 18 feet) at an average of 7 years and 4 months after injury. According to the Boston Children's Hospital ankle grading system, the overall results were considered excellent in one, good in five, fair in two, and failures in six feet. The data suggest a greater proportion of failures in the infected group compared with the non-infected group (p = 0.05).

Evaluation of four commercially available enzyme immunoassays for laboratory diagnosis of Clostridium difficile-associated diseases.

Four commercial enzyme immunoassays (EIAs) for the detection of Clostridium difficile toxin A have recently been developed and marketed (Premier, Meridian Diagnostics, Cincinnati, Ohio; VIDAS, bioMerierux Vitek, Inc., Hazelwood, Mo.; Tox-A-Test, TechLab, Blacksburg, Va.; and Bartels, Baxter Diagnostics, McGaw Park, Ill.). The performances of these EIAs were compared with those of the tissue culture cytotoxicity assay and a definition of C. difficile-associated disease based on both laboratory and clinical criteria for 329 clinical specimens. Two EIAs (Premier and VIDAS) showed good overall agreement (96 and 95%, respectively) with the cytotoxicity assay. However, they were less sensitive (84 and 71%, respectively) than the Bartels (94%) or Tox-A-Test (93%) EIAs. The Bartels and Tox-A-Test assays were much less specific, resulting in poor positive predictive values (56%) of the two assays when compared with that of the cytotoxicity assay. Tox-A-Test had the added drawback of having a significant number of indeterminate results (6.4%). These data indicate that the four EIAs all have specific shortcomings. When using these EIAs, testing strategies that take these shortcomings into consideration should be developed.

Biosynthetic regulation of the human transferrin receptor by desferrioxamine in K562 cells.

Treatment of K562 cells with the iron chelator desferrioxamine results in the gradual increase in total cell receptors for transferrin. Receptor number rises 2.5-4.5-fold over 24 h and remains at the elevated level if the chelator is continuously present. Preincubation of the chelator with ferric chloride abolishes the effect. The drug has no effect on the 7-h half-life of the receptor. The increased number of receptors can be accounted for by a specific increase in the rate of receptor biosynthesis which reaches 3-4 times that seen in untreated cells by 6 h after the addition of the chelator. Isolation of mRNA from treated cells reveals that, after 8 h in the presence of desferrioxamine, there is a 3-fold increase in the specific translation of transferrin receptor over untreated cells. Total protein synthesis is not changed under these conditions.

Social class risk factors among children with Hodgkin's disease.

We compared the social class characteristics of 66 families with children diagnosed with Hodgkin's disease (HD) from 1959 through 1977 in a defined population with that of 182 "control families" identified by a random process from the population base. The 14 youngest cases (less than 10 years at diagnosis) were from somewhat lower social-class backgrounds than their 37 controls as evidenced by the distribution of median income, single-unit housing, and poverty level of their census tract of residence, as well as by the occupational class of head-of-household. In contrast, the social class characteristics of the 52 older children with HD (10-14 years) were quite similar to that of their 145 controls. This apparent shift from lower to average social class between younger and older children with HD Hodgkin's disease may reflect a shift in their age of exposure to common infections. If true, these findings are consistent with the hypothesis that HD may develop as a rare consequence of a common infection. However, these findings are based on small numbers of cases and on indirect measures of social class.