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1.
AIDS Behav ; 25(5): 1626-1635, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33244641

RESUMO

Given the rapid development of HIV clinics in Vietnam, this study evaluates the infrastructure surrounding this expansion, identifying clinic-related factors that impact survival outcomes. A retrospective longitudinal study was conducted among people living with HIV (PLWH) who initiated antiretroviral therapy (ART) between 2011 and 2015 among 62 ART clinics in 15 provinces. The mortality rate during the 717674.1 person-years of observation (PYO) was 0.29/100 PYO. Location in rural areas (versus urban) and in Central Vietnam (versus Northern Vietnam) were associated with higher risk of mortality. The risk was lower among clinics that had peer-educators. As Vietnam's HIV/AIDS program continues to expand, this data supports increasing resource allocation for rural clinics, incorporation of ART with the community's existing healthcare infrastructure in its efforts to decentralize, and integration of services to reflect patients' anticipated needs.


Assuntos
Infecções por HIV , Povo Asiático , Infecções por HIV/tratamento farmacológico , Humanos , Estudos Longitudinais , Estudos Retrospectivos , Vietnã/epidemiologia
2.
Bioorg Chem ; 99: 103846, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32334195

RESUMO

A base-mediated cascade reaction between malonate esters and acrolein was developed to access complex polycyclic systems. This novel tandem reaction enables the simultaneous generation of up to seven new bonds and at least three new stereogenic centers. Mechanistic studies indicate a series of nucleophilic 1,4 and 1,6 Michael addition reactions occur, followed by an aldol condensation reaction, culminating in the formation of three fused rings. The compounds were characterized by NMR studies and the stereochemistry was confirmed by X-ray analysis. The ability to generate multigram quantities of such complex molecular scaffolds renders the method promising for medicinal chemistry campaigns. Herein, we also demonstrate that the lead compounds display promising anti-proliferative activities against human cancer cell models.


Assuntos
Acroleína/farmacologia , Antineoplásicos/farmacologia , Ésteres/farmacologia , Malonatos/farmacologia , Compostos Policíclicos/farmacologia , Acroleína/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclização , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Ésteres/química , Humanos , Malonatos/química , Modelos Moleculares , Estrutura Molecular , Compostos Policíclicos/síntese química , Compostos Policíclicos/química , Relação Estrutura-Atividade
3.
Phys Rev Lett ; 122(3): 030501, 2019 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-30735427

RESUMO

Trapped ions offer a pristine platform for quantum computation and simulation, but improving their coherence remains a crucial challenge. Here, we propose and analyze a new strategy to enhance the coherent interactions in trapped ion systems via parametric amplification of the ions' motion-by squeezing the collective motional modes (phonons), the spin-spin interactions they mediate can be significantly enhanced. We illustrate the power of this approach by showing how it can enhance collective spin states useful for quantum metrology, and how it can improve the speed and fidelity of two-qubit gates in multi-ion systems, important ingredients for scalable trapped ion quantum computation. Our results are also directly relevant to numerous other physical platforms in which spin interactions are mediated by bosons.

4.
Phys Rev Lett ; 122(5): 053603, 2019 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-30821989

RESUMO

We experimentally study electromagnetically induced transparency cooling of the drumhead modes of planar two-dimensional arrays with up to N≈190 Be^{+} ions stored in a Penning trap. Substantial sub-Doppler cooling is observed for all N drumhead modes. Quantitative measurements for the center-of-mass mode show near ground-state cooling with motional quantum numbers of n[over ¯]=0.3±0.2 obtained within 200 µs. The measured cooling rate is faster than that predicted by single particle theory, consistent with a quantum many-body calculation. For the lower frequency drumhead modes, quantitative temperature measurements are limited by frequency instabilities, but near ground-state cooling of the full bandwidth is strongly suggested. This advance will greatly improve the performance of large trapped ion crystals in quantum information and metrology applications.

5.
J Nat Prod ; 82(5): 1301-1311, 2019 05 24.
Artigo em Inglês | MEDLINE | ID: mdl-31084028

RESUMO

Natural products continue to provide a platform to study biological systems. A bioguided study of cancer cell models led us to a new member of the jatrophane natural products from Jatropha gossypiifolia, which was independently identified and characterized as jatrogossone A (1). Purification and structure elucidation was performed by column chromatography and high-performance liquid chromatography-mass spectrometry and NMR techniques, and the structure was confirmed via X-ray crystallography. The unique molecular scaffold of jatrogossone A prompted an evaluation of its mode of action. Cytotoxicity assays demonstrated that jatrogossone A displays selective antiproliferative activity against cancer cell models in the low micromolar range with a therapeutic window. Jatrogossone A (1) affects mitochondrial membrane potential (ΔΨm) in a time- and dose-dependent manner. This natural product induces radical oxygen species (ROS) selectively in cancer cellular models, with minimal ROS induction in noncancerous cells. Compound 1 induces ROS in the mitochondria, as determined by colocalization studies, and it induces mitophagy. It promotes also in vitro cell death by causing cell arrest at the G2/M stage, caspase (3/7) activation, and PARP-1 cleavage. The combined findings provide a potential mechanism by which 1 relies on upregulation of mitochondrial ROS to potentiate cytotoxic effects through intracellular signaling.


Assuntos
Antineoplásicos Fitogênicos/farmacologia , Neoplasias/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Acetilcisteína/farmacologia , Antineoplásicos Fitogênicos/química , Antioxidantes/farmacologia , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Humanos , Jatropha/química , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitofagia/efeitos dos fármacos , Poli(ADP-Ribose) Polimerase-1/efeitos dos fármacos , Poli(ADP-Ribose) Polimerase-1/metabolismo
6.
J Am Chem Soc ; 140(29): 9219-9229, 2018 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-29949370

RESUMO

Structural modifications of molecular cobalt catalysts have provided important insights into the structure-function relationship for the hydrogen evolution reaction. We have shown that replacement of equatorial pyridines with more basic and conjugate isoquinoline groups of a pentadentate ligand results in lower overpotential and higher catalytic activity for electro- and photolytic H2 production in aqueous solutions. To fully understand the electronic and steric effects of the axial group that lies trans to the proposed cobalt hydride intermediate, isoquinoline groups were introduced in two new pentadentate ligands, N, N-bis(2-pyridinylmethyl)[3-(2-pyridinyl)isoquinoline)]-1-methanamine (DPA-1-MPI) and N, N-bis(2-pyridinylmethyl)[1-(2-pyridinyl)-isoquinoline)]-3-methanamine (DPA-3-MPI). Despite a slight structural difference of the introduced isoquinoline group, the resulting cobalt complexes display drastic changes in their electro- and photochemical properties. There are positive shifts of 290 and 260 mV, respectively, for the CoII/CoI and CoIII-H/CoII-H couples from [Co(DPA-1-MPI)(H2O)](PF6)3 to [Co(DPA-3-MPI)(H2O)](PF6)3, with the former being ∼32 times as active as the latter in photocatalytic H2 production. Density functional theory (DFT) calculations show that the protonation of CoI to yield the CoIII-H species is energetically more favorable for [Co(DPA-1-MPI)(H2O)](PF6)3 than that of [Co(DPA-3-MPI)(H2O)](PF6)3. Both experimental results and DFT computations suggest that the presence of a planar conjugate bipyridyl unit or its isoquinoline derivative is a key feature for stabilizing low valent CoI species toward proton binding. The incorporation of an electron-donating group trans to the proposed Co-H species also facilitates proton binding and H-H bond formation, which is proposed to occur by the heterolytic coupling of CoII-H species. The overall catalytic H2 evolution is presented as the modified electron transfer (E)-proton transfer (C)-electron transfer (E)-proton transfer (C) (mod-ECEC) pathway. This study provides important new insight into the electronic and steric factors controlling catalytic H2 production by Co complexes with pentadentate ligands.

7.
Nature ; 484(7395): 489-92, 2012 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-22538611

RESUMO

The presence of long-range quantum spin correlations underlies a variety of physical phenomena in condensed-matter systems, potentially including high-temperature superconductivity. However, many properties of exotic, strongly correlated spin systems, such as spin liquids, have proved difficult to study, in part because calculations involving N-body entanglement become intractable for as few as N ≈ 30 particles. Feynman predicted that a quantum simulator--a special-purpose 'analogue' processor built using quantum bits (qubits)--would be inherently suited to solving such problems. In the context of quantum magnetism, a number of experiments have demonstrated the feasibility of this approach, but simulations allowing controlled, tunable interactions between spins localized on two- or three-dimensional lattices of more than a few tens of qubits have yet to be demonstrated, in part because of the technical challenge of realizing large-scale qubit arrays. Here we demonstrate a variable-range Ising-type spin-spin interaction, J(i,j), on a naturally occurring, two-dimensional triangular crystal lattice of hundreds of spin-half particles (beryllium ions stored in a Penning trap). This is a computationally relevant scale more than an order of magnitude larger than previous experiments. We show that a spin-dependent optical dipole force can produce an antiferromagnetic interaction J(i,j) proportional variant d(-a)(i,j), where 0 ≤ a ≤ 3 and d(i,j) is the distance between spin pairs. These power laws correspond physically to infinite-range (a = 0), Coulomb-like (a = 1), monopole-dipole (a = 2) and dipole-dipole (a = 3) couplings. Experimentally, we demonstrate excellent agreement with a theory for 0.05 ≲ a ≲ 1.4. This demonstration, coupled with the high spin count, excellent quantum control and low technical complexity of the Penning trap, brings within reach the simulation of otherwise computationally intractable problems in quantum magnetism.

8.
Nature ; 458(7241): 996-1000, 2009 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-19396139

RESUMO

Any quantum system, such as those used in quantum information or magnetic resonance, is subject to random phase errors that can dramatically affect the fidelity of a desired quantum operation or measurement. In the context of quantum information, quantum error correction techniques have been developed to correct these errors, but resource requirements are extraordinary. The realization of a physically tractable quantum information system will therefore be facilitated if qubit (quantum bit) error rates are far below the so-called fault-tolerance error threshold, predicted to be of the order of 10(-3)-10(-6). The need to realize such low error rates motivates a search for alternative strategies to suppress dephasing in quantum systems. Here we experimentally demonstrate massive suppression of qubit error rates by the application of optimized dynamical decoupling pulse sequences, using a model quantum system capable of simulating a variety of qubit technologies. We demonstrate an analytically derived pulse sequence, UDD, and find novel sequences through active, real-time experimental feedback. The latter sequences are tailored to maximize error suppression without the need for a priori knowledge of the ambient noise environment, and are capable of suppressing errors by orders of magnitude compared to other existing sequences (including the benchmark multi-pulse spin echo). Our work includes the extension of a treatment to predict qubit decoherence under realistic conditions, yielding strong agreement between experimental data and theory for arbitrary pulse sequences incorporating nonidealized control pulses. These results demonstrate the robustness of qubit memory error suppression through dynamical decoupling techniques across a variety of qubit technologies.

9.
Nat Commun ; 14(1): 6008, 2023 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-37770423

RESUMO

Fusion oncoproteins (FOs) arise from chromosomal translocations in ~17% of cancers and are often oncogenic drivers. Although some FOs can promote oncogenesis by undergoing liquid-liquid phase separation (LLPS) to form aberrant biomolecular condensates, the generality of this phenomenon is unknown. We explored this question by testing 166 FOs in HeLa cells and found that 58% formed condensates. The condensate-forming FOs displayed physicochemical features distinct from those of condensate-negative FOs and segregated into distinct feature-based groups that aligned with their sub-cellular localization and biological function. Using Machine Learning, we developed a predictor of FO condensation behavior, and discovered that 67% of ~3000 additional FOs likely form condensates, with 35% of those predicted to function by altering gene expression. 47% of the predicted condensate-negative FOs were associated with cell signaling functions, suggesting a functional dichotomy between condensate-positive and -negative FOs. Our Datasets and reagents are rich resources to interrogate FO condensation in the future.


Assuntos
Condensados Biomoleculares , Proteínas de Fusão Oncogênica , Humanos , Células HeLa , Carcinogênese , Transformação Celular Neoplásica
10.
Phys Rev Lett ; 108(21): 213003, 2012 May 25.
Artigo em Inglês | MEDLINE | ID: mdl-23003249

RESUMO

We demonstrate spectroscopy and thermometry of individual motional modes in a mesoscopic 2D ion array using entanglement-induced decoherence as a method of transduction. Our system is a ~400 µm-diameter planar crystal of several hundred 9Be(+) ions exhibiting complex drumhead modes in the confining potential of a Penning trap. Exploiting precise control over the 9Be(+) valence electron spins, we apply a homogeneous spin-dependent optical dipole force to excite arbitrary transverse modes with an effective wavelength approaching the interparticle spacing (~20 µm). Center-of-mass displacements below 1 nm are detected via the entanglement of spin and motional degrees of freedom.

11.
Nature ; 473(7345): 39-40, 2011 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-21544140
12.
Front Public Health ; 10: 848802, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35548085

RESUMO

Background: To develop effective antimicrobial stewardship programs (ASPs) for low- and middle-income countries (LMICs), it is important to identify key targets for improving antimicrobial use. We sought to systematically describe the prevalence and patterns of antimicrobial use in three LMIC hospitals. Methods: Consecutive patients admitted to the adult medical wards in three tertiary care hospitals in Tanzania, Kenya, and Sri Lanka were enrolled in 2018-2019. The medical record was reviewed for clinical information including type and duration of antimicrobials prescribed, indications for antimicrobial use, and microbiologic testing ordered. Results: A total of 3,149 patients were enrolled during the study period: 1,103 from Tanzania, 750 from Kenya, and 1,296 from Sri Lanka. The majority of patients were male (1,783, 56.6% overall) with a median age of 55 years (IQR 38-68). Of enrolled patients, 1,573 (50.0%) received antimicrobials during their hospital stay: 35.4% in Tanzania, 56.5% in Kenya, and 58.6% in Sri Lanka. At each site, the most common indication for antimicrobial use was lower respiratory tract infection (LRTI; 40.2%). However, 61.0% received antimicrobials for LRTI in the absence of LRTI signs on chest radiography. Among patients receiving antimicrobials, tools to guide antimicrobial use were under-utilized: microbiologic cultures in 12.0% and microbiology consultation in 6.5%. Conclusion: Antimicrobials were used in a substantial proportion of patients at tertiary care hospitals across three LMIC sites. Future ASP efforts should include improving LRTI diagnosis and treatment, developing antibiograms to direct empiric antimicrobial use, and increasing use of microbiologic tests.


Assuntos
Anti-Infecciosos , Gestão de Antimicrobianos , Adulto , Idoso , Antibacterianos/uso terapêutico , Anti-Infecciosos/uso terapêutico , Países em Desenvolvimento , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
13.
Cureus ; 13(5): e15133, 2021 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-34159035

RESUMO

Squamous cell carcinoma occurring in the rectum is one of the rare malignancies that has been discovered. Most squamous cell carcinomas that surface in the gastrointestinal tract tend to occur in either the esophagus or the anal canal. However, the rare incidence of rectal squamous cell carcinomas has raised quite a few questions on the hypothetical etiologies, prognosis, and optimal treatment sequence of such a disease course in modern medicine. In this report, we present the case of a 63-year-old gentleman who came to the clinic with change in bowel habits such as constipation and bright red blood in his stool. Colonoscopy revealed a 4.1 cm polyp in the distal rectum, which upon biopsy was confirmed to be a well-differentiated keratinizing squamous cell carcinoma. This case allows us to engage in discussions over potential etiologies and current treatment management for such a rare malignancy.

14.
Science ; 373(6555): 673-678, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34353950

RESUMO

Fully controllable ultracold atomic systems are creating opportunities for quantum sensing, yet demonstrating a quantum advantage in useful applications by harnessing entanglement remains a challenging task. Here, we realize a many-body quantum-enhanced sensor to detect displacements and electric fields using a crystal of ~150 trapped ions. The center-of-mass vibrational mode of the crystal serves as a high-Q mechanical oscillator, and the collective electronic spin serves as the measurement device. By entangling the oscillator and collective spin and controlling the coherent dynamics via a many-body echo, a displacement is mapped into a spin rotation while avoiding quantum back-action and thermal noise. We achieve a sensitivity to displacements of 8.8 ± 0.4 decibels below the standard quantum limit and a sensitivity for measuring electric fields of 240 ± 10 nanovolts per meter in 1 second. Feasible improvements should enable the use of trapped ions in searches for dark matter.

15.
J Med Chem ; 64(4): 1930-1950, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33556244

RESUMO

Murine double minute 2 (MDM2) and X-linked inhibitor of apoptosis protein (XIAP) are important cell survival proteins in tumor cells. As a dual MDM2/XIAP inhibitor reported previously, compound MX69 has low potency with an IC50 value of 7.5 µM against an acute lymphoblastic leukemia cell line EU-1. Herein, we report the structural optimization based on the MX69 scaffold, leading to the discovery of a 25-fold more potent analogue 14 (IC50 = 0.3 µM against EU-1). We demonstrate that 14 maintains its mode of action by dual targeting of MDM2 and XIAP through inducing MDM2 protein degradation and inhibiting XIAP mRNA translation, respectively, which resulted in cancer cell growth inhibition and cell death. The results strongly suggest that the scaffold based on 14 is promising for further optimization to develop a new therapeutic agent for leukemia and possibly other cancers where MDM2 and XIAP are dysregulated.


Assuntos
Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Quinolinas/farmacologia , Sulfonamidas/farmacologia , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/antagonistas & inibidores , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Masculino , Simulação de Acoplamento Molecular , Ligação Proteica , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Quinolinas/síntese química , Quinolinas/metabolismo , Ratos Sprague-Dawley , Sulfonamidas/síntese química , Sulfonamidas/metabolismo , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismo
16.
Antimicrob Resist Infect Control ; 10(1): 60, 2021 03 25.
Artigo em Inglês | MEDLINE | ID: mdl-33766135

RESUMO

BACKGROUND: Antimicrobial resistance has been named as one of the top ten threats to public health in the world. Hospital-based antimicrobial stewardship programs (ASPs) can help reduce antimicrobial resistance. The purpose of this study was to determine perceived barriers to the development and implementation of ASPs in tertiary care centers in three low- and middle-income countries (LMICs). METHODS: Interviews were conducted with 45 physicians at tertiary care hospitals in Sri Lanka (n = 22), Kenya (12), and Tanzania (11). Interviews assessed knowledge of antimicrobial resistance and ASPs, current antimicrobial prescribing practices, access to diagnostics that inform antimicrobial use, receptiveness to ASPs, and perceived barriers to implementing ASPs. Two independent reviewers coded the interviews using principles of applied thematic analysis, and comparisons of themes were made across the three sites. RESULTS: Barriers to improving antimicrobial prescribing included prohibitively expensive antimicrobials, limited antimicrobial availability, resistance to changing current practices regarding antimicrobial prescribing, and limited diagnostic capabilities. The most frequent of these barriers in all three locations was limited drug availability. Many physicians in all three sites had not heard of ASPs before the interviews. Improved education was a suggested component of ASPs at all three sites. The creation of guidelines was also recommended, without prompting, by interviewees at all three sites. Although most participants felt microbiological results were helpful in tailoring antibiotic courses, some expressed distrust of laboratory culture results. Biomarkers like erythrocyte sedimentation rate and c-reactive protein were not felt to be specific enough to guide antimicrobial therapy. Despite limited or no prior knowledge of ASPs, most interviewees were receptive to implementing protocols that would include documentation and consultation with ASPs regarding antimicrobial prescribing. CONCLUSIONS: Our study highlighted several important barriers to implementing ASPs that were shared between three tertiary care centers in LMICs. Improving drug availability, enhancing availability of and trust in microbiologic data, creating local guidelines, and providing education to physicians regarding antimicrobial prescribing are important steps that could be taken by ASPs in these facilities.


Assuntos
Gestão de Antimicrobianos , Países em Desenvolvimento , Implementação de Plano de Saúde , Adulto , Antibacterianos/administração & dosagem , Antibacterianos/economia , Antibacterianos/provisão & distribuição , Farmacorresistência Bacteriana , Humanos , Quênia , Médicos , Pesquisa Qualitativa , Sri Lanka , Tanzânia , Centros de Atenção Terciária
17.
J Pain Symptom Manage ; 61(3): 474-487, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-32889040

RESUMO

CONTEXT: Sickle cell disease (SCD), an autosomal recessive blood disorder, affects millions of people worldwide. Approximately 80% of all cases are located in Africa. OBJECTIVES: This cross-national, interdisciplinary, collaborative study investigated provider attitudes about, and practices for, managing (assessing and treating) SCD pain. METHODS: We conducted 111 quantitative surveys and 52 semistructured interviews with health-care providers caring for adults and/or children with SCD in Cameroon, Jamaica, and the U.S. RESULTS: Applying Haywood's scale for assessing SCD provider attitudes, the Jamaica site scored lower on "Negative Attitudes" than the Cameroonian and U.S. sites (P = 0.03 and <0.001, respectively). Providers at the U.S. site scored lower on "Positive Attitudes" than other sites (P < 0.001). "Red Flag" scores at the Cameroon sites were lower than at other sites (P < 0.001). Qualitative results across all three sites describe the current practices for SCD pain management, as well as the challenges surrounding management for health providers, including pain subjectivity, patient-provider and parent-provider relationships, resource availability, perceptions of drug-seeking behavior, and adherence. Providers also spontaneously offered solutions to reported challenges. CONCLUSION: Overall, findings reveal that SCD provider attitudes toward their patients differed across sites, yet at all three sites, treating SCD pain is multidimensional.


Assuntos
Anemia Falciforme , Manejo da Dor , Adulto , África , Anemia Falciforme/terapia , Atitude do Pessoal de Saúde , Criança , Humanos , Dor
18.
Phys Rev A (Coll Park) ; 101(6)2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34796312

RESUMO

Many quantum state preparation methods rely on a combination of dissipative quantum state initialization followed by unitary evolution to a desired target state. Here we demonstrate the usefulness of quantum measurement as an additional tool for quantum state preparation. Starting from a pure separable multipartite state, a control sequence, which includes rotation, spin squeezing via one-axis twisting, quantum measurement, and postselection, generates highly entangled multipartite states, which we refer to as projected squeezed (PS) states. Through an optimization method, we then identify parameters required to maximize the overlap fidelity of the PS states with the maximally entangled Greenberger-Horne-Zeilinger (GHZ) states. The method leads to an appreciable decrease in the state preparation time of GHZ states for successfully postselected outcomes when compared to preparation through unitary evolution with one-axis twisting only.

19.
Phys Rev A (Coll Park) ; 102: 053106-5310616, 2020 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-35024525

RESUMO

Two-dimensional crystals of ions stored in Penning traps are a leading platform for quantum simulation and sensing experiments. For small amplitudes, the out-of-plane motion of such crystals can be described by a discrete set of normal modes called the drumhead modes, which can be used to implement a range of quantum information protocols. However, experimental observations of crystals with Doppler-cooled and even near-ground-state-cooled drumhead modes reveal an unresolved drumhead-mode spectrum. In this work, we establish in-plane thermal fluctuations in ion positions as a major contributor to the broadening of the drumhead-mode spectrum. In the process, we demonstrate how the confining magnetic field leads to unconventional in-plane normal modes, whose average potential and kinetic energies are not equal. This property, in turn, has implications for the sampling procedure required to choose the in-plane initial conditions for molecular-dynamics simulations. For current operating conditions of the NIST Penning trap, our study suggests that the two-dimensional crystals produced in this trap undergo in-plane potential-energy fluctuations of the order of 10mK. Our study therefore motivates the need for designing improved techniques to cool the in-plane degrees of freedom.

20.
J Healthc Leadersh ; 11: 75-80, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31354375

RESUMO

Purpose: This study examined whether change in physician engagement affected outpatient or resident physician satisfaction using common US measures. Methods: Surveys were administered by Advisory Board Survey Solutions for staff physician engagement, Press Ganey for Clinician and Group Consumer Assessment of Healthcare Providers and Systems (CGCAHPS) for outpatient satisfaction, and Accreditation Council for Graduate Medical Education (ACGME) for the ACGME Resident/Fellow Survey. Survey sample sizes were 685, 697, and 763 for physician engagement and 621, 625, and 618 for resident satisfaction in 2014-2016, respectively; only respondents were available for CGCAHPS (24,302, 34,328, and 43,100 for 2014-2016, respectively). Two groups were analyzed across 3 years: (1) percentage of "engaged" staff physicians versus percentage of outpatient top box scores for physician communication, and (2) percentage of "engaged" staff physicians versus percentage of residents "positive" on program evaluation. For resident evaluation of faculty, the number of programs that met/exceeded ACGME national compliance scores were compared. Univariate chi-squared tests compared data between 2014, 2015, and 2016. Results: For 2014-2016, "engaged" physicians increased from 34% (169/497) to 44% (227/515) to 48% (260/542) (P<0.001) whereas CGCAHPS top box scores for physician communication remained unchanged at 90.9% (22,091/24,302), 90.8% (31,088/34,328), and 90.9% (39,178/43,100) (P=0.869). For the second group, "engaged" physicians increased from 33% (204/617) to 46% (318/692) to 50% (351/701) (P<0.001) and residents "positive" on program evaluation increased from 86% (534/618) in 2014 to 89% (556/624) in 2015 and 89% (550/615) in 2016 (P=0.174). The number of specialties that met/exceeded national compliance for all five faculty evaluation items grew from 44% (11/25) in 2014 to 68% (17/25) in 2015 and 64% (16/25) in 2016 (P=0.182). Conclusion: For our medical group, improvement in physician engagement across time did not coincide with meaningful change in the outpatient experience with physician communication or resident satisfaction with program and faculty.

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