Adopting Optimal Statistical Practices: Graduate Programs

In 2024, the Methodology Corner will briefly look at how we might foster enduring commitments from nurse education researchers to remain up-to-date on their statistical expertise and to use optimal statistical methods. The first column of the year specifically looks at how graduate programs might enrich their statistics curriculum in a manner that could foster an increasingly valid science of nursing education. [J Nurs Educ. 2024;63(3):197-198.].

Structural and non-coding variants increase the diagnostic yield of clinical whole genome sequencing for rare diseases

BACKGROUND

Whole genome sequencing is increasingly being used for the diagnosis of patients with rare diseases. However, the diagnostic yields of many studies, particularly those conducted in a healthcare setting, are often disappointingly low, at 25-30%. This is in part because although entire genomes are sequenced, analysis is often confined to in silico gene panels or coding regions of the genome.

METHODS

We undertook WGS on a cohort of 122 unrelated rare disease patients and their relatives (300 genomes) who had been pre-screened by gene panels or arrays. Patients were recruited from a broad spectrum of clinical specialties. We applied a bioinformatics pipeline that would allow comprehensive analysis of all variant types. We combined established bioinformatics tools for phenotypic and genomic analysis with our novel algorithms (SVRare, ALTSPLICE and GREEN-DB) to detect and annotate structural, splice site and non-coding variants.

RESULTS

Our diagnostic yield was 43/122 cases (35%), although 47/122 cases (39%) were considered solved when considering novel candidate genes with supporting functional data into account. Structural, splice site and deep intronic variants contributed to 20/47 (43%) of our solved cases. Five genes that are novel, or were novel at the time of discovery, were identified, whilst a further three genes are putative novel disease genes with evidence of causality. We identified variants of uncertain significance in a further fourteen candidate genes. The phenotypic spectrum associated with RMND1 was expanded to include polymicrogyria. Two patients with secondary findings in FBN1 and KCNQ1 were confirmed to have previously unidentified Marfan and long QT syndromes, respectively, and were referred for further clinical interventions. Clinical diagnoses were changed in six patients and treatment adjustments made for eight individuals, which for five patients was considered life-saving.

CONCLUSIONS

Genome sequencing is increasingly being considered as a first-line genetic test in routine clinical settings and can make a substantial contribution to rapidly identifying a causal aetiology for many patients, shortening their diagnostic odyssey. We have demonstrated that structural, splice site and intronic variants make a significant contribution to diagnostic yield and that comprehensive analysis of the entire genome is essential to maximise the value of clinical genome sequencing.

Improving Effect Size Interpretations

We encourage our community of nurse education researchers to remember to assign interpretations to their effect size estimates. In general, our community is asked to reduce the use of rules-of-thumb and, instead, are encouraged to use empirical and contextual methods to assign interpretations to effect size estimates. [J Nurs Educ. 2023;62(11):653-654.].

From η2 to ω2: Adopt a Better Measure of Effect

A cursory review of relevant research works published in the Journal of Nursing Education suggests that our community may unnecessarily rely on η2 when reporting results of their ANOVA models. Although η2 is convenient, the statistic possesses many limitations that warrant our community adopting a wider set of effect size statistics and practices to promote a valid science of nursing education. We specifically call attention in this article to ω2. [J Nurs Educ. 2023;62(9):532-533.].

Cohen's and Hedges' g

A cursory review of relevant research works published in the Journal of Nursing Education suggests our community relies heavily on Cohen's d. Although Cohen's d is a valuable effect size, it possesses a number of limitations that warrants our community adopting a wider set of effect size statistics to help promote a valid science of nursing education. We specifically call attention to Hedges' g. [J Nurs Educ. 2023;62(5):316-317.].

Remember to Leverage Effect Size Estimates

In 2023, the Methodology Corner column has opted to promote the efficacious use of effect sizes among our community of researchers. In this first entry of the year, we call attention to broad improvement in effect size reporting germane to our community, including more consistent reporting of effect sizes and their interpretations. [J Nurs Educ. 2023;62(2):116.].

Repair Your Missing Data

This Methodology Corner encourages nurse educators to include reparative techniques in their analyses that better allay threats to validity introduced by missing data. This article specifically highlights the extra dependent variable technique that is accessible to researchers due to the simplicity of the approach and availability of popular software capable of implementing the repair. [J Nurs Educ. 2022;61(9):549-550.].

Study Your Missing Data

This installment of the Methodology Corner raises the concern that our community may not be adequately attending to the threat missingness poses to valid nursing education research. To encourage the adoption of increasingly sound methodological practices, we highlight for our community that counts and relative frequencies and simple bivariate analyses are easily implemented tools that help formulate valid responses to missing data. [J Nurs Educ. 2022;61(5):280-281.].

Missing Data

If left unattended, missingness can undermine the conclusions nurse researchers draw in their studies. Unfortunately, a cursory review of quantitative and mixed methods works recently published in the Journal of Nursing Education suggests missing data is left relatively unattended within our community. This column has recommended our researcher mitigate the emergence of missing data as much as possible, describe any missingness thoroughly, and adopt modern missing data techniques that help mitigate threats to validity introduced by missing data. Reviewers and editors are also encouraged to request from authors clear descriptions of the missingness in their studies as well as how they responded to any missingness. [J Nurs Educ. 2022;61(2):65-66.].

More Power Analyses Are Needed

Nurse researchers have long been encouraged to consult a priori power analyses to help design studies that are robust to type II errors. Unfortunately, a cursory look at Journal of Nursing Education articles published in 2020 suggests that a priori power analyses may be used infrequently in our community. Consequently, this column requested that authors conduct power analyses using increasingly rigorous standards (e.g., power levels) and report their findings well to readers. When a priori power analyses are missing or not reported clearly, reviewers and editors are encouraged to request authors ameliorate the shortfalls in their manuscripts. [J Nurs Educ. 2021;60(11):605-606.].

Coefficient Omega

This article raises the concern that nursing education research may be unduly subject to several limitations inherited from an overreliance on Cronbach's α. Consequently, researchers are encouraged to make greater use of coefficient omega since it is expected to perform just as well as or better than Cronbach's α, especially when tau-equivalence goes unmet. Several resources are noted that may help researchers estimate omega for composite measurements. [J Nurs Educ. 2021;60(8):429-430.].

Nursing Professionals' Stress Level During Coronavirus Disease 2019: A Looming Workforce Issue

The purpose of this study was to assess the impact of coronavirus disease 2019 on perceived stress experienced by nurse practitioners/nurses and their desire to remain employed as health care providers. A cross-sectional survey of 40 questions was administered between May and September 2020 to a convenience sample of 433 nurse practitioners and nurses in Missouri and Georgia through a Qualtrics (Provo, UT) link provided via their professional organization listserv. Anxiety-related symptoms and perceived helplessness were correlated with personal protective equipment concerns and management approachability. Problematic stress was associated with willingness to leave their current job or the nursing profession altogether.

Student perceptions of online and in-person microbiology laboratory experiences in undergraduate medical education

Background: Universities are facing increased budget constraints, often resulting in reduced funds to support microbiology laboratories. Online mock laboratory activities are often instituted as a cost-effective alternative to traditional wet labs for medical students.Objective: The purpose of this study was to examine students' perceptions of online and in-person microbiology lab learning experiences.Design: We investigated undergraduate medical student perception of the in-person and online microbiology lab experience; 164 first-year medical students participated in newly designed online labs, while 83 second-year medical students continued to use in-person labs. An online survey was administered to collect student opinions of the lab experience.Results: In terms of student self-reported learning styles, those students who attended the lab in person were more likely to report a tactile learning style (33% vs 16%) while those students who learned the material online reported a visual learning style preference (77% vs 61%; n = 264). Students felt that the online microbiology lab was more convenient for their schedules when compared to the in-person lab. A greater proportion of online students (12%) felt that they encountered brand-new material on the final quiz than in-person students (1%; n = 245). Even so, 43% of the online educated students and 37% of the in-person educated students perceived their assigned lab experiences to be the optimal lab design, and over 89% of both groups reported a desire for at least some in-person instruction in a wet-laboratory environment.Conclusions: Our findings suggest that, while students are strongly supportive of digital online lab activities, the overwhelming majority of students still report a desire for a blend of online and in-person, hands-on laboratory activities. These findings will further research directed towards student perception of the lab experience and aid in the adaptation of microbiology curriculums to accommodate both student and university needs.

Infection by Hepatitis Delta Virus

Hepatitis delta virus (HDV) and hepatitis B virus (HBV) are blood-borne viruses that infect human hepatocytes and cause significant liver disease. Infections with HBV are more damaging when there is a coinfection with HDV. The genomes and modes of replication of these two viruses are fundamentally different, except for the fact that, in nature, HDV replication is dependent upon the envelope proteins of HBV to achieve assembly and release of infectious virus particles, ones that use the same host cell receptor. This review focuses on what has been found of the various ways, natural and experimental, by which HDV particles can be assembled and released. This knowledge has implications for the prevention and treatment of HDV infections, and maybe for an understanding of the origin of HDV.

Remission of Inflammatory Bowel Disease in Glucose-6-Phosphatase 3 Deficiency by Allogeneic Haematopoietic Stem Cell Transplantation

Mendelian disorders in glucose-6-phosphate metabolism can present with inflammatory bowel disease [IBD]. Using whole genome sequencing we identified a homozygous variant in the glucose-6-phosphatase G6PC3 gene [c.911dupC; p.Q305fs*82] in an adult patient with congenital neutropenia, lymphopenia and childhood-onset, therapy-refractory Crohn's disease. Because G6PC3 is expressed in several haematopoietic and non-haematopoietic cells it was unclear whether allogeneic stem cell transplantation [HSCT] would benefit this patient with intestinal inflammation. We show that HSCT resolves G6PC3-associated immunodeficiency and the Crohn's disease phenotype. It illustrates how even in adulthood, next-generation sequencing can have a significant impact on clinical practice and healthcare utilization in patients with immunodeficiency and monogenic IBD.

Delineation of dominant and recessive forms of LZTR1-associated Noonan syndrome

Noonan syndrome (NS) is characterised by distinctive facial features, heart defects, variable degrees of intellectual disability and other phenotypic manifestations. Although the mode of inheritance is typically dominant, recent studies indicate LZTR1 may be associated with both dominant and recessive forms. Seeking to describe the phenotypic characteristics of LZTR1-associated NS, we searched for likely pathogenic variants using two approaches. First, scrutiny of exomes from 9624 patients recruited by the Deciphering Developmental Disorders (DDDs) study uncovered six dominantly-acting mutations (p.R97L; p.Y136C; p.Y136H, p.N145I, p.S244C; p.G248R) of which five arose de novo, and three patients with compound-heterozygous variants (p.R210*/p.V579M; p.R210*/p.D531N; c.1149+1G>T/p.R688C). One patient also had biallelic loss-of-function mutations in NEB, consistent with a composite phenotype. After removing this complex case, analysis of human phenotype ontology terms indicated significant phenotypic similarities (P = 0.0005), supporting a causal role for LZTR1. Second, targeted sequencing of eight unsolved NS-like cases identified biallelic LZTR1 variants in three further subjects (p.W469*/p.Y749C, p.W437*/c.-38T>A and p.A461D/p.I462T). Our study strengthens the association of LZTR1 with NS, with de novo mutations clustering around the KT1-4 domains. Although LZTR1 variants explain ~0.1% of cases across the DDD cohort, the gene is a relatively common cause of unsolved NS cases where recessive inheritance is suspected.

Abstract WP387: Diagnosis and Surgical Management of Rotational Vertebral Artery Occlusion in Children

Background: Rotational vertebral artery occlusion (RVAO) is associated with significant posterior circulation morbidity, recurrence, and lacks evidenced based treatment recommendations. Upper cervical spine abnormalities, lack of traumatic history, and dynamic vessel imaging aid in diagnosis and treatment options. Here, we evaluate our cohort of children with RVAO for associated musculoskeletal, angiographic, and arterial tortuosity factors in light of management strategies and outcomes.

Methods: Five pediatric patients with RVAO were evaluated with dynamic arterial compression with either CT based angiography or digital subtraction angiography. Solitary factors such as ponticulous posticus, hypermobility comorbidities, 3D-print models and arterial tortuosity index were examined in relation to management strategies.

Results: Musculoskeletal abnormalities were associated in all cases presenting with evidence of dynamic angiographic compression. Not all cases had evidence angiographic compression. A mild elevation in arterial tortuosity index was observed. All five patients were managed with treatment approaches including antiplatelet/coagulation therapies, vertebral artery decompression, and/or posterior cervical fusion.

Conclusion: Treatment strategies relied on identifiable compression factors associated with the level of vertebral artery dissection. In children, upper cervical bony abnormalities and dynamic compression at the VA3 level are common to RVAO diagnosis. Further examination of arterial tortuosity as an index in understanding the susceptibility of children towards RVAO is required.

Efimov States of Strongly Interacting Photons

We demonstrate the emergence of universal Efimov physics for interacting photons in cold gases of Rydberg atoms. We consider the behavior of three photons injected into the gas in their propagating frame, where a paraxial approximation allows us to consider them as massive particles. In contrast to atoms and nuclei, the photons have a large anisotropy between their longitudinal mass, arising from dispersion, and their transverse mass, arising from diffraction. Nevertheless, we show that, in suitably rescaled coordinates, the effective interactions become dominated by s-wave scattering near threshold and, as a result, give rise to an Efimov effect near unitarity. We show that the three-body loss of these Efimov trimers can be strongly suppressed and determine conditions under which these states are observable in current experiments. These effects can be naturally extended to probe few-body universality beyond three bodies, as well as the role of Efimov physics in the nonequilibrium, many-body regime.

Predicting symptomatic cerebral vasospasm after aneurysmal subarachnoid hemorrhage with an artificial neural network in a pediatric population

PURPOSE

Artificial neural networks (ANN) are increasingly applied to complex medical problem solving algorithms because their outcome prediction performance is superior to existing multiple regression models. ANN can successfully identify symptomatic cerebral vasospasm (SCV) in adults presenting after aneurysmal subarachnoid hemorrhage (aSAH). Although SCV is unusual in children with aSAH, the clinical consequences are severe. Consequently, reliable tools to predict patients at greatest risk for SCV may have significant value. We applied ANN modeling to a consecutive cohort of pediatric aSAH cases to assess its ability to predict SCV.

METHODS

A retrospective chart review was conducted to identify patients < 21 years of age who presented with spontaneously ruptured, non-traumatic, non-mycotic, non-flow-related intracranial arterial aneurysms to our institution between January 2002 and January 2015. Demographics, clinical, radiographic, and outcome data were analyzed using an adapted ANN model using learned value nodes from the adult aneurysmal SAH dataset previously reported. The strength of the ANN prediction was measured between - 1 and 1 with - 1 representing no likelihood of SCV and 1 representing high likelihood of SCV.

RESULTS

Sixteen patients met study inclusion criteria. The median age for aSAH patients was 15 years. Ten underwent surgical clipping and 6 underwent endovascular coiling for definitive treatment. One patient experienced SCV and 15 did not. The ANN applied here was able to accurately predict all 16 outcomes. The mean strength of prediction for those who did not exhibit SCV was - 0.86. The strength for the one patient who did exhibit SCV was 0.93.

CONCLUSIONS

Adult-derived aneurysmal SAH value nodes can be applied to a simple AAN model to accurately predict SCV in children presenting with aSAH. Further work is needed to determine if ANN models can prospectively predict SCV in the pediatric aSAH population in toto; adapted to include mycotic, traumatic, and flow-related origins as well.

Threshold Dynamics of a Semiconductor Single Atom Maser

We demonstrate a single atom maser consisting of a semiconductor double quantum dot (DQD) that is embedded in a high-quality-factor microwave cavity. A finite bias drives the DQD out of equilibrium, resulting in sequential single electron tunneling and masing. We develop a dynamic tuning protocol that allows us to controllably increase the time-averaged repumping rate of the DQD at a fixed level detuning, and quantitatively study the transition through the masing threshold. We further examine the crossover from incoherent to coherent emission by measuring the photon statistics across the masing transition. The observed threshold behavior is in agreement with an existing single atom maser theory when small corrections from lead emission are taken into account.

Precise spatio-temporal control of rapid optogenetic cell ablation with mem-KillerRed in Zebrafish

The ability to kill individual or groups of cells in vivo is important for studying cellular processes and their physiological function. Cell-specific genetically encoded photosensitizing proteins, such as KillerRed, permit spatiotemporal optogenetic ablation with low-power laser light. We report dramatically improved resolution and speed of cell targeting in the zebrafish kidney through the use of a selective plane illumination microscope (SPIM). Furthermore, through the novel incorporation of a Bessel beam into the SPIM imaging arm, we were able to improve on targeting speed and precision. The low diffraction of the Bessel beam coupled with the ability to tightly focus it through a high NA lens allowed precise, rapid targeting of subsets of cells at anatomical depth in live, developing zebrafish kidneys. We demonstrate that these specific targeting strategies significantly increase the speed of optoablation as well as fish survival.

Observation of optomechanical buckling transitions

Correlated phases of matter provide long-term stability for systems as diverse as solids, magnets and potential exotic quantum materials. Mechanical systems, such as buckling transition spring switches, can have engineered, stable configurations whose dependence on a control variable is reminiscent of non-equilibrium phase transitions. In hybrid optomechanical systems, light and matter are strongly coupled, allowing engineering of rapid changes in the force landscape, storing and processing information, and ultimately probing and controlling behaviour at the quantum level. Here we report the observation of first- and second-order buckling transitions between stable mechanical states in an optomechanical system, in which full control of the nature of the transition is obtained by means of the laser power and detuning. The underlying multiwell confining potential we create is highly tunable, with a sub-nanometre distance between potential wells. Our results enable new applications in photonics and information technology, and may enable explorations of quantum phase transitions and macroscopic quantum tunnelling in mechanical systems.

Optomechanical systems could form logic gates, but key requirements are two stable static states and the ability to switch between them. Here, the authors observe radiation-pressure induced buckling transitions in an optomechanical system, and control this transition by varying laser power and detuning.

A Versatile Method for Immunofluorescent Staining of Cells Cultured on Permeable Membrane Inserts

BACKGROUND Obtaining high-quality images of cellular structures via immunofluorescence staining is critical for cellular localization studies. Often, these studies cannot be performed in parallel with certain oncology, virology, pharmacokinetic, and drug absorption studies due to model system technicalities requiring the cells to be cultured on porous membranes rather than glass or plastic. MATERIAL AND METHODS Here, we report a method of immunofluorescent staining of cells cultured on permeable membranes. RESULTS As proof of principle, HeLa cells grown on Transwell® membrane supports were stained with fluorescently labeled antibodies using this modified immunofluorescence staining method and visualized by fluorescent microscopy. CONCLUSIONS This protocol is a convenient alternative to staining cells on glass coverslips, thereby expanding the scope and applications of this important research tool.

Sisyphus Thermalization of Photons in a Cavity-Coupled Double Quantum Dot

We investigate the nonclassical states of light that emerge in a microwave resonator coupled to a periodically driven electron in a nanowire double quantum dot (DQD). Under certain drive configurations, we find that the resonator approaches a thermal state at the temperature of the surrounding substrate with a chemical potential given by a harmonic of the drive frequency. Away from these thermal regions we find regions of gain and loss, where the system can lase, or regions where the DQD acts as a single-photon source. These effects are observable in current devices and have broad utility for quantum optics with microwave photons.

Abstract WP408: Temporal Trends in Pediatric Stroke Hospitalization From 2000 - 2009: Analysis of the KID Inpatient Database

Background/Hypothesis: Stroke in children ≤18 years is an important public health problem. The incidence of stroke in adults has been falling over several decades, likely attributable to better management of vascular risk factors. Children have different risk factors for cerebrovascular disease, however we wanted to see if similar trends were observed in pediatric stroke. We examined pediatric hospital discharges for stroke over the last decade.

Methods: We used the Kids’ Inpatient Database (KID) for 2000, 2003, 2006, and 2009 using the published weighting guidelines to estimate the number of overall discharges and number of discharges due to stroke. To identify stroke we queried primary position discharge ICD-9 stroke codes 430, 431, 432.9, 434.X1, 434.9, and 435.9; previously identified to have high PPV for detection of stroke in children in a physician-verified epidemiology stroke study. We calculated incidence for stroke among hospitalized children as number of stroke discharges / total number of discharges, and expressed the ratio per 100,000 discharges. We compared trends in stroke type, age, race and sex over the decade.

Results: Stroke incidence in 2000 was 26.4 (95% CI 23.2-29.6). In the 2009 sample, incidence was 30.9 (27.7-34.1) showing a non-significant increasing trend over time. Ischemic stroke was increasingly diagnosed over the same interval with a statistically significantly higher incidence in 2006 and 2009 compared to 2000 (Figure 1). Groups with highest stroke incidence in hospitalized children were 10-14 year olds, males, and children identifying with the racial group “black.”

Conclusion: In the KID database, we identified a rising incidence of ischemic stroke diagnosis over the past decade, however the overall rate of pediatric stroke has not increased significantly. The increasing rate of an ischemic stroke discharge diagnosis may be the result of increased awareness of childhood stroke.

Optical Control of Donor Spin Qubits in Silicon

We show how to achieve optical, spin-selective transitions from the ground state to excited orbital states of group-V donors (P, As, Sb, Bi) in silicon. We consider two approaches based on either resonant, far-infrared (IR) transitions of the neutral donor or resonant, near-IR excitonic transitions. For far-IR light, we calculate the dipole matrix elements between the valley-orbit and spin-orbit split states for all the goup-V donors using effective mass theory. We then calculate the maximum rate and amount of electron-nuclear spin-polarization achievable through optical pumping with circularly polarized light. We find this approach is most promising for Bi donors due to their large spin-orbit and valley-orbit interactions. Using near-IR light, spin-selective excitation is possible for all the donors by driving a two-photon Λ-transition from the ground state to higher orbitals with even parity. We show that externally applied electric fields or strain allow similar, spin-selective Λ-transition to odd-parity excited states. We anticipate these results will be useful for future spectroscopic investigations of donors, quantum control and state preparation of donor spin qubits, and for developing a coherent interface between donor spin qubits and single photons.

Hepatitis D Virus Replication

This work reviews specific related aspects of hepatitis delta virus (HDV) reproduction, including virion structure, the RNA genome, the mode of genome replication, the delta antigens, and the assembly of HDV using the envelope proteins of its helper virus, hepatitis B virus (HBV). These topics are considered with perspectives ranging from a history of discovery through to still-unsolved problems. HDV evolution, virus entry, and associated pathogenic potential and treatment of infections are considered in other articles in this collection.

Injection Locking of a Semiconductor Double Quantum Dot Micromaser

Emission linewidth is an important figure of merit for masers and lasers. We recently demonstrated a semiconductor double quantum dot (DQD) micromaser where photons are generated through single electron tunneling events. Charge noise directly couples to the DQD energy levels, resulting in a maser linewidth that is more than 100 times larger than the Schawlow-Townes prediction. Here we demonstrate a linewidth narrowing of more than a factor 10 by locking the DQD emission to a coherent tone that is injected to the input port of the cavity. We measure the injection locking range as a function of cavity input power and show that it is in agreement with the Adler equation. The position and amplitude of distortion sidebands that appear outside of the injection locking range are quantitatively examined. Our results show that this unconventional maser, which is impacted by strong charge noise and electron-phonon coupling, is well described by standard laser models.

Tibiotalocalcaneal arthrodesis with a compressive retrograde nail: A retrospective study of 59 nails

BACKGROUND

Tibiotalocalcaneal arthrodesis is an important salvage method for patients with complex hindfoot problems. This study reports the elective results of combined subtalar and ankle arthrodesis using one design of retrograde intramedullary compression nail.

METHODS

Retrospective review identified 58 patients undergoing 59 tibiotalocalcaneal arthrodesis procedures. Mean follow up was 9.15 (3-36) months with average age 60.7 (22-89) years. A function and subjective patient satisfaction questionnaire was achieved in 89%.

RESULTS

53 patients (93%) achieved union at a mean time of 4.17 months. Four patients (8%) subjectively thought the procedure was of no benefit while 42 (84%) had an excellent or good result. The mean visual analogue scale (VAS) score for preoperative functional pain was 7.46 compared to 1.98 post-operatively (p<0.001).

CONCLUSIONS

This device and technique offers an effective treatment of hindfoot pathology giving reliable compression and subsequent fusion with excellent patient satisfaction and pain relief.

LEVEL OF EVIDENCE

IV case series.

Phonon-assisted gain in a semiconductor double quantum dot maser

We develop a microscopic model for the recently demonstrated double-quantum-dot maser. In characterizing the gain of this device we find that, in addition to the direct stimulated emission of photons, there is a large contribution from the simultaneous emission of a photon and a phonon, i.e., the phonon sideband. We show that this phonon-assisted gain typically dominates the overall gain, which leads to masing. Recent experimental data are well fit with our model.

Transcription of the Rous sarcoma virus genome in vitro and in vivo

RNA-directed DNA synthesis by detergent-disrupted virions of Rous sarcoma virus (RSV) initiates by the covalent attachment of pdA to the 3'-terminal rA of a 4S RNA hydrogen-bonded to the 70S RNA template. This 4S "primer" has structural features of tRNA and can be aminoacylated with methionine. Synthesis and integration of provirus DNA can be monitored in both permissive (duck) and nonpermissive (mouse) cells acutely infected with RSV. The results of these studies, as well as data obtained with RSV-infected mammalian cells which have reverted from a transformed to a pheno-typically normal state, indicate that integration of viral genes into the host chromosome is not sufficient cause for transformation. Pertinent features of virus-specific RNA-directed DNA synthesis in vitro and in vivo are reviewed and compared.

Smoking, internalized heterosexism, and HIV disease management among male couples

High rates of cigarette smoking have been observed among HIV-positive individuals. Smoking has been linked to HIV-related medical complications and non-AIDS defining cancers and negatively impacts on immune function and virologic control. Although internalized heterosexism has been related to smoking behaviors, little is known about associations between partners' reports of smoking, internalized heterosexism, and HIV medication management in male couples with HIV. A sample of 266 male couples completed baseline assessments for a cohort study examining relationship factors and HIV treatment. A computer-based survey assessed self-reported smoking behaviors, alcohol use, internalized heterosexism, and antiretroviral therapy (ART) adherence. HIV-positive men also provided blood samples to assess viral load. Approximately 30% of the sample reported that they are currently smoking cigarettes. After adjusting for demographic characteristics, men in a primary relationship with a partner who reported currently smoking had more than five-fold greater odds of reporting smoking. Higher levels of internalized heterosexism and financial hardship were each independently associated with greater odds of reporting smoking. Among HIV-positive men on ART (n = 371), having a partner who reported smoking was associated with almost three-fold greater odds of having a detectable viral load. Our findings add new support to the evidence of romantic partners influencing each other's health behaviors, and demonstrate an association between smoking and disease management within male couples. Future research should explore the interpersonal and social contexts of smoking in order to develop interventions that meet the unique needs of male couples.

Psychometric analysis of the Ten-Item Perceived Stress Scale

Although the 10-item Perceived Stress Scale (PSS-10) is a popular measure, a review of the literature reveals 3 significant gaps: (a) There is some debate as to whether a 1- or a 2-factor model best describes the relationships among the PSS-10 items, (b) little information is available on the performance of the items on the scale, and (c) it is unclear whether PSS-10 scores are subject to gender bias. These gaps were addressed in this study using a sample of 1,236 adults from the National Survey of Midlife Development in the United States II. Based on self-identification, participants were 56.31% female, 77% White, 17.31% Black and/or African American, and the average age was 54.48 years (SD = 11.69). Findings from an ordinal confirmatory factor analysis suggested the relationships among the items are best described by an oblique 2-factor model. Item analysis using the graded response model provided no evidence of item misfit and indicated both subscales have a wide estimation range. Although t tests revealed a significant difference between the means of males and females on the Perceived Helplessness Subscale (t = 4.001, df = 1234, p < .001), measurement invariance tests suggest that PSS-10 scores may not be substantially affected by gender bias. Overall, the findings suggest that inferences made using PSS-10 scores are valid. However, this study calls into question inferences where the multidimensionality of the PSS-10 is ignored.

Topologically robust transport of photons in a synthetic gauge field

Electronic transport is localized in low-dimensional disordered media. The addition of gauge fields to disordered media leads to fundamental changes in the transport properties. We implement a synthetic gauge field for photons using silicon-on-insulator technology. By determining the distribution of transport properties, we confirm that waves are localized in the bulk and localization is suppressed in edge states. Our system provides a new platform for investigating the transport properties of photons in the presence of synthetic gauge fields.

Photon emission from a cavity-coupled double quantum dot

We study a voltage biased InAs double quantum dot (DQD) that is coupled to a superconducting transmission line resonator. Inelastic tunneling in the DQD is mediated by electron phonon coupling and coupling to the cavity mode. We show that electronic transport through the DQD leads to photon emission from the cavity at a rate of 10 MHz. With a small cavity drive field, we observe a gain of up to 15 in the cavity transmission. Our results are analyzed in the context of existing theoretical models and suggest that it may be necessary to account for inelastic tunneling processes that proceed via simultaneous emission of a phonon and a photon.

Host RNA circles and the origin of hepatitis delta virus

Recent reports show that many cellular RNAs are processed to form circular species that are relatively abundant and resistant to host nucleases. In some cases, such circles actually bind host microRNAs. Such depletion of available microRNAs appears to have biological roles; for instance, in homeostasis and disease. These findings regarding host RNA circles support a speculative reappraisal of the origin and mode of replication of hepatitis delta virus, hepatitis delta virus (HDV), an agent with a small circular RNA genome; specifically, it is proposed that in hepatocytes infected with hepatitis B virus (HBV), some viral RNA species are processed to circular forms, which by a series of chance events lead to an RNA that can be both replicated by host enzymes and assembled, using HBV envelope proteins, to form particles some of which are infectious. Such a model also may provide some new insights into the potential pathogenic potential of HDV infections. In return, new insights into HDV might provide information leading to a better understanding of the roles of the host RNA circles.

Ultra-sensitive chip-based photonic temperature sensor using ring resonator structures

Resistance thermometry provides a time-tested method for taking temperature measurements. However, fundamental limits to resistance-based approaches has produced considerable interest in developing photonic temperature sensors to leverage advances in frequency metrology and to achieve greater mechanical and environmental stability. Here we show that silicon-based optical ring resonator devices can resolve temperature differences of 1 mK using the traditional wavelength scanning methodology. An even lower noise floor of 80 μK for measuring temperature difference is achieved in the side-of-fringe, constant power mode measurement.

Personal or relational? Examining sexual health in the context of HIV serodiscordant same-sex male couples

Couples' ability to adopt a "we" orientation has been associated with optimal health outcomes. This study examined how personal and relational motivations are uniquely associated with unprotected anal intercourse (UAI), protected anal intercourse (PAI), and the absence of sexual activity within HIV-serodiscordant same-sex male couples. HIV-positive men and their HIV-negative partners (N = 116 couples, 232 men) completed questionnaires and HIV-positive men had blood drawn for viral load. Results of a multinomial logistic regression illustrated that sexual satisfaction was positively associated with PAI among HIV-negative partners and negatively associated with PAI among HIV-positive partners. Endorsing a "we" orientation was positively associated with PAI among HIV-positive partners. Findings suggest that HIV-positive partners who espouse a "we" orientation may be willing to forgo their personal interests to protect their HIV-negative partners from HIV transmission. Couples-based interventions are warranted to help strengthen relationship dynamics to enhance the sexual health of serodiscordant couples.

Personal or relational? Examining sexual health in the context of HIV serodiscordant same-sex male couples

Couples' ability to adopt a "we" orientation has been associated with optimal health outcomes. This study examined how personal and relational motivations are uniquely associated with unprotected anal intercourse (UAI), protected anal intercourse (PAI), and the absence of sexual activity within HIV-serodiscordant same-sex male couples. HIV-positive men and their HIV-negative partners (N = 116 couples, 232 men) completed questionnaires and HIV-positive men had blood drawn for viral load. Results of a multinomial logistic regression illustrated that sexual satisfaction was positively associated with PAI among HIV-negative partners and negatively associated with PAI among HIV-positive partners. Endorsing a "we" orientation was positively associated with PAI among HIV-positive partners. Findings suggest that HIV-positive partners who espouse a "we" orientation may be willing to forgo their personal interests to protect their HIV-negative partners from HIV transmission. Couples-based interventions are warranted to help strengthen relationship dynamics to enhance the sexual health of serodiscordant couples.

Virus entry mediated by hepatitis B virus envelope proteins

Hepatitis B virus (HBV), a major cause of human liver disease worldwide, encodes three envelope proteins needed for the attachment and entry of the virus into susceptible host cells. A second virus, hepatitis delta virus, which is known to enhance liver disease in HBV infected patients, diverts the same HBV envelope proteins to achieve its own assembly and infection. In the lab, lentiviral vectors based on human immunodeficiency virus type 1 can be assembled using the HBV envelope proteins, and will similarly infect susceptible cells. This article provides a partial review and some personal reflections of how these three viruses infect and of how recipient cells become susceptible, along with some consideration of questions that remain to be answered.

Long-term clinical and functional outcome following treatment for Paget–Schroetter syndrome

Background

Effort-related thrombosis of the axillosubclavian vein (Paget–Schroetter syndrome, PSS) is uncommon. It tends to affect young, active individuals and yet consensus on management is lacking. The aim here was to analyse late outcomes in a series of patients treated for PSS using a standard protocol.

Methods

The medical records of patients treated for PSS over 16 years were analysed. Patients were divided into four groups according to their management. Clinical and functional outcomes were analysed regarding residual venous defects after treatment, and Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire scores, respectively.

Results

Some 117 patients (52 men and 65 women, mean age 32 years) were included. Catheter-directed thrombolysis was successful in 42 of 56 treated patients. Thoracic outlet decompression surgery was performed in 95 patients. DASH scores improved significantly in patients treated surgically (P &lt; 0.001 to P = 0·009); early surgery had a better outcome than delayed surgery (P = 0·040). Patients who were managed conservatively showed no improvement (P = 0·116). Where venoplasty was necessary, it was successful in 18 of 25 patients. A short duration of lysis (less than 24 h) increased the risk of rethrombosis (P = 0·020). The method of postoperative anticoagulation had no influence on the rate of rethrombosis.

Conclusion

Patients treated surgically for PSS had better functional outcomes than those managed conservatively. Prompt thrombolysis and surgery was superior to delayed management with respect to rethrombosis and functional outcome.

Self-consistent measurement and state tomography of an exchange-only spin qubit

Quantum-dot spin qubits characteristically use oscillating magnetic or electric fields, or quasi-static Zeeman field gradients, to realize full qubit control. For the case of three confined electrons, exchange interaction between two pairs allows qubit rotation around two axes, hence full control, using only electrostatic gates. Here, we report initialization, full control, and single-shot readout of a three-electron exchange-driven spin qubit. Control via the exchange interaction is fast, yielding a demonstrated 75 qubit rotations in less than 2 ns. Measurement and state tomography are performed using a maximum-likelihood estimator method, allowing decoherence, leakage out of the qubit state space, and measurement fidelity to be quantified. The methods developed here are generally applicable to systems with state leakage, noisy measurements and non-orthogonal control axes.