Experimental Hamiltonian identification for controlled two-level systems

We present a strategy to empirically determine the internal and control Hamiltonians for an unknown two-level system (black box) subject to various (piecewise constant) control fields when direct readout by measurement is limited to a single, fixed observable

Influence of Mortar Rheology on Aggregate Settlement

The influence of the rheology of fresh concrete on the settlement of aggregate is examined. Fresh concrete exhibits a yield stress that, under certain conditions, prevents the settlement of coarse aggregate, although its density is larger than that of the suspending mortar. Calculations, based on estimates of the yield stress obtained from slump tests, predict that aggregate normally used in concrete should not sink. To test this prediction, the settlement of a stone in fresh mortar is monitored. The stone does not sink in the undisturbed mortar (which has a high yield stress), but sinks when the mortar is vibrated, presumably due to a large reduction in its yield stress. This implies that during placement of concrete, the aggregate settles only while the concrete is being vibrated. A unique experimental method for measuring aggregate settlement is also introduced and demonstrated

Measurement-based approach to entanglement generation in coupled quantum dots

Measurements provide a novel mechanism for generating the entanglement resource necessary for performing scalable quantum computation. Recently, we proposed a method for performing parity measurements in a coupled quantum dot system. In this paper we generalise this scheme and perform a comprehensive analytic and numerical study of environmental factors. We calculate the effects of possible error sources including non-ideal photon detectors, ineffective spin-selective excitation and dot distinguishability (both spatial and spectral). Furthermore, we present an experimental approach for verifying the success of the parity measurement

STEC-HUS; Unusual presentation in an elderly female

Background: Hemolytic uremic syndrome (HUS) is a multisystem disease presenting as renal impairment, microangiopathic hemolytic anemia (MAHA) and thrombocytopenia with a peak incidence of 2.1 cases per 100,000 persons/year in general population. Case Description: 81-year-old female with history of Diabetes, presented to us with non-bloody emesis and loose stools. Labs on admission were significant for WBC 17000, Hb 12.5, PLT 241, BUN 74, Cr 8.9 and Lactate 12. She was admitted for severe metabolic acidosis and acute renal failure attributed to metformin use and undifferentiated shock. Patient developed acute worsening of respiratory status due to increasing acidosis requiring intubation. Bicarbonate infusion was started however patient had to undergo emergent dialysis for refractory acidosis. On 3rd day of admission patient developed dysentery which led to Hb drop to 7.1 and platelets to 96. Peripheral smear revealed thrombocytopenia and schistocytes. GI panel was positive for ETEC, EIEC, Shigella toxin producing E. coli (STEC) and Campylobacter. Diagnosis of STEC-HUS was made. Patient was supportively managed with fluid resuscitation, pressors, antibiotics, hemodialysis and transfusions. She demonstrated significant improvement, attained hemodynamical stability off pressors and was eventually extubated. Patient was discharged few days later at her baseline health. Conclusion: It is challenging to diagnose STEC-HUS in older patients as the prevalence is higher in children and adults present with higher hemoglobin and fibrinogen levels. However, we emphasize on considering it as a differential diagnosis especially in elderly presenting with acute renal failure and history of gastroenteritis

Bactrim Induced BRASH Syndrome In Elderly Female: A Case Report

Background: BRASH syndrome is a clinical entity comprising of bradycardia, renal failure, AV blockade, shock, and hyperkalemia. It is a vicious cycle in which AV nodal blockers and hyperkalemia act synergistically to precipitate bradycardia in patients with renal dysfunction resulting in cardiovascular collapse. Case Presentation: 89-year-old lady with history of Stage 4 CKD, hypertension, and diabetes mellitus presented with worsening generalized body weakness. On medication review, she was recently started on bactrim for treatment of a foot ulcer. Other home medications included diltiazem, lisinopril and dulaglutide. Initial vitals were significant for pulse 34, BP 90/35 mmHg and RR 19. Patient appeared somnolent but arousable. EKG was significant for third-degree heart block. Pertinent labs included potassium 6.7 and creatinine 5.8. She was treated with IV fluids and pressors for shock. She received calcium gluconate, insulin, dextrose and sodium polystyrene in the interim, until she was started on emergent dialysis. Following two sessions of dialysis, EKG reverted to sinus rhythm with resolution of complete heart block. She was eventually titrated off pressors. She was discharged on scheduled dialysis and follow up in a nephrology clinic. Conclusion: BRASH syndrome comprises of series of events that perpetuates itself. Caution should be exercised when prescribing bactrim as it might potentiate hyperkalemia, especially in patients with chronic kidney disease who are also on AV nodal blockers. Trimethoprim in Bactrim increases this risk by inhibiting potassium excretion from the kidneys. This could lead to a cycle of clinical events resulting in BRASH syndrome

From rods to helices: evidence of a screw-like nematic phase

Evidence of a special chiral nematic phase is provided using numerical simulation and Onsager theory for systems of hard helical particles. This phase appears at the high density end of the nematic phase, when helices are well aligned, and is characterized by the C$_2$ symmetry axes of the helices spiraling around the nematic director with periodicity equal to the particle pitch. This coupling between translational and rotational degrees of freedom allows a more efficient packing and hence an increase of translational entropy. Suitable order parameters and correlation functions are introduced to identify this screw-like phase, whose main features are then studied as a function of radius and pitch of the helical particles. Our study highlights the physical mechanism underlying a similar ordering observed in colloidal helical flagella [E. Barry et al. \textit{Phys. Rev. Lett.} \textbf{96}, 018305 (2006)] and raises the question of whether it could be observed in other helical particle systems, such as DNA, at sufficiently high densities.Comment: List of authors correcte

Diagnostic Medical Errors: Patient\u27s Perspectives on a Pervasive Problem

Introduction. The Institute of Medicine defines diagnostic error as the failure to establish an accurate or timely explanation for the patient\u27s health problem(s), or effectively communicate the explanation to the patient. To our knowledge, no studies exist characterizing diagnostic error from patient perspectives using this definition. Objective. We sought to characterize diagnostic errors experienced by patients and describe patient perspectives on causes, impacts, and prevention strategies. Methods. We screened 77 adult inpatients at University of Vermont Medical Center and conducted 27 structured interviews with patients who experienced diagnostic error in the past five years. We performed qualitative analysis using Grounded Theory. Results. In the past five years, 39% of interviewed patients experienced diagnostic error. The errors mapped to the following categories: accuracy (30%), communication (34%) and timeliness (36%). Poor communication (13 responses) and inadequate time with doctors (7) were the most identified causes of errors. Impacts of errors included emotional distress (17 responses), adverse health outcomes (7) and impaired activities of daily living (6). Patients suggested improved communication (11 responses), clinical management (7) and access to doctors (5) as prevention strategies. For communication, patients rated talk to your doctor highest (mean 8.4, on 1-10 Likert scale) and text message lowest (4.8). Conclusions/Recommendations. Diagnostic errors are common and have dramatic impact on patients\u27 well-being. We suggest routine surveillance to identify errors, support for patients who have experienced errors, and implementation of patient and provider checklists to enhance communication. Future studies should investigate strategies to allow care providers adequate time with patients.https://scholarworks.uvm.edu/comphp_gallery/1246/thumbnail.jp

HIV-1 protease-substrate coevolution in nelfinavir resistance

Resistance to various human immunodeficiency virus type 1 (HIV-1) protease inhibitors (PIs) challenges the effectiveness of therapies in treating HIV-1-infected individuals and AIDS patients. The virus accumulates mutations within the protease (PR) that render the PIs less potent. Occasionally, Gag sequences also coevolve with mutations at PR cleavage sites contributing to drug resistance. In this study, we investigated the structural basis of coevolution of the p1-p6 cleavage site with the nelfinavir (NFV) resistance D30N/N88D protease mutations by determining crystal structures of wild-type and NFV-resistant HIV-1 protease in complex with p1-p6 substrate peptide variants with L449F and/or S451N. Alterations of residue 30\u27s interaction with the substrate are compensated by the coevolving L449F and S451N cleavage site mutations. This interdependency in the PR-p1-p6 interactions enhances intermolecular contacts and reinforces the overall fit of the substrate within the substrate envelope, likely enabling coevolution to sustain substrate recognition and cleavage in the presence of PR resistance mutations. IMPORTANCE: Resistance to human immunodeficiency virus type 1 (HIV-1) protease inhibitors challenges the effectiveness of therapies in treating HIV-1-infected individuals and AIDS patients. Mutations in HIV-1 protease selected under the pressure of protease inhibitors render the inhibitors less potent. Occasionally, Gag sequences also mutate and coevolve with protease, contributing to maintenance of viral fitness and to drug resistance. In this study, we investigated the structural basis of coevolution at the Gag p1-p6 cleavage site with the nelfinavir (NFV) resistance D30N/N88D protease mutations. Our structural analysis reveals the interdependency of protease-substrate interactions and how coevolution may restore substrate recognition and cleavage in the presence of protease drug resistance mutations

A review of topical corticosteroid sprays for the treatment of inflammatory dermatoses

Background: Topical corticosteroids are available in many vehicles. However, patients' preference for vehicles are variable and could be tailored to maximize patient adherence. Spray vehicles may offer, convenience, and strong efficacy. Methods: A literature review was conducted using keywords: clobetasol, desoximetasone, betamethasone, triamcinolone, corticosteroid, topical, spray, vehicles, treatment, and clinical trial. Results: For moderate-to-severe plaque psoriasis, 87% of subjects achieved an Overall Disease Severity (ODS) Score ≤2 at week two and 78% achieved an ODS ≤1 after four weeks with clobetasol propionate (CP) 0.05% spray compared to 17% and 3% in the control group, respectively (P<0.001). For desoximetasone 0.25% spray, 31%-53% with moderate-to-severe psoriasis achieve Physician's Global Assessment (PGA) score ≤1 at day 28 versus 5%-18% in the vehicle spray group (P<0.01). For betamethasone dipropionate 0.05% spray, 19% with mild-to-moderate plaque psoriasis achieved an Investigator's Global Assessment (IGA) score ≤1 or a 2-grade reduction in IGA versus 2.3% in vehicle group (P≤0.001). For mild-to-severe steroid responsive inflammatory dermatoses, 64% using triamcinolone acetonide 0.2% spray achieved clear or almost clear skin at day 14 (no P value reported). Adverse events including burning, irritation, and dryness were similar across all corticosteroids

A Rare Case of Takotsubo Cardiomyopathy In An Elderly Lady During Hospital Stay

Introduction: Takotsubo Cardiomyopathy (TTC) is an acute, reversible form of left ventricular systolic dysfunction, most often triggered by a sudden physical, or less commonly emotional event. Here, we describe a patient who developed Takotsubo Cardiomyopathy during her hospital stay. Case Description: 74-year-old Hispanic lady, a nursing home resident presented to the ED with altered mental status. She was admitted for septic shock due to UTI. Echocardiogram demonstrated normal systolic function, with 60-65% LV ejection fraction. After initiation of antibiotic therapy, she showed clinical improvement with resolution of shock. On day 8 of hospitalization, patient became emotionally upset and her clinical status deteriorated. Troponin peaked at 7.2, CK-MB 29.9, and EKG demonstrated borderline ST-elevation in lateral leads. Repeat echocardiogram demonstrated a significant reduction in the LVEF to 15%, moderately dilated left ventricle with akinesis of the apex and middle third of LV with hyperkinetic base, consistent with Takotsubo Cardiomyopathy. Unfortunately, her condition continued to deteriorate, leading to cardiac arrest and the patient expired. Discussion/Conclusion: There is a paucity in the literature describing the in-hospital occurrence of TTC. A high index of suspicion should be exercised in patients with recent physical or emotional stress with new-onset or refractory shock as the clinical picture of TTS overlaps with ACS