Parent's anxiety links household stress and young children's behavioral dysregulation

Young children rely heavily on their caregivers to gain information about the environment, especially during times of duress. Therefore, considering parental assessments of behavior in the context of stressful environments may better facilitate our understanding of the longstanding association between early environmental stressors and changes in child behavior and physiology. Confirming many previous reports, a higher degree of household stress exposure was associated with elevated mental health symptoms in 2‐ to 6‐year‐old children (N = 115; anxiety and externalizing behaviors), which were verified in a subset of children with laboratory‐based behaviors (N = 46). However, these associations were mediated by parental anxiety symptoms, which were also associated with increased cortisol levels in children. A closer look at the stressors indicated that it was the adult‐targeted, and not the child‐targeted, stressors that correlated most with children's behavior problems. These results highlight the importance of considering the mediating effect of parents, when examining associations between household stress and young children's behavioral development.     

Comparing standard care with a physician and pharmacist team approach for uncontrolled hypertension

OBJECTIVE: To assess the effect of a physician and pharmacist teamwork approach to uncontrolled hypertension in a medical resident teaching clinic, for patients who failed to meet the recommended goals of the fifth Joint National Commission on Detection, Evaluation and Treatment of High Blood Pressure. HYPOTHESIS: Physician and pharmacist teamwork can improve the rate of meeting national blood pressure goals in patients with previously uncontrolled hypertension. DESIGN: A single-blinded randomized controlled trial lasting 6 months. SETTING: A primary care outpatient teaching clinic. PATIENTS: A sample of 95 adult hypertensive patients who failed to meet national blood pressure goals based on three consecutive visits over a 6-month period. INTERVENTION: Patients were randomly assigned to a control arm of standard medical care or to an intervention arm in which a physician and pharmacist worked together as a team. MAIN RESULTS: At study completion, the percentage of patients achieving national goals due to intervention was more than double the percentage in the control arm (55% vs 20%, p < .001). Systolic blood pressure declined 23 mm Hg in the intervention arm versus 11 mm Hg in the control arm (p < .01). Diastolic blood pressure declined 14 and 3 mm Hg in the intervention and control arms, respectively (p < .001). The intervention worked equally as well in men and women and demonstrated noticeable promise in a minority of mixed-ancestry Hawaiians in whom hypertension is of special concern. CONCLUSIONS: Patients who fail to achieve national blood pressure goals under standard outpatient medical care may benefit from a program that includes a physician and pharmacist teamwork approach. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Queen’s Medical Center. This work was supported by a grant from the Queen’s Medical Center, Honolulu, Hawaii and by a Research Centers in Minorities Institutions Award (P20 RR 11091) from the National Institutes of Health.     

Quantitative assessment of aortic regurgitation by colour flow Doppler in an open chest canine model

Colour flow Doppler maps the extent of the flow velocity disturbance of aortic regurgitation onto the two dimensional echocardiographic image of the left ventricular cavity. The spatial extent of this flow velocity disturbance expressed as a percentage of end diastolic left ventricular cavity area (CD%) was compared to regurgitant fraction (RF), measured volumetrically, in nine open chest dogs with varying degrees of surgically created aortic regurgitation (RF 0-85%). Right heart bypass controlled venous return to the left atrium and hence net left ventricular output, while total left ventricular output was measured with an aortic electromagnetic flow probe under various loading conditions, achieving mean diastolic transvalvular pressure gradients of 23-114 mm Hg, net left ventricular outputs of 750-3000 ml.min-1 and diastolic filling periods of 162-320 ms. A linear correlation between CD% and RF (r = 0.89) was demonstrated over this wide range of loading conditions. At a given transvalvular diastolic pressure gradient [68(SD9) mm Hg] CD% was linearly proportional to regurgitant aortic orifice area (r = 0.87). Thus CD% is proportional to the volumetric severity of aortic regurgitation under a wide range of haemodynamic conditions and varies appropriately with regurgitant aortic orifice area when diastolic transvalvular pressure gradient is held constant. The application of these principles to the non-invasive quantitation of valvular regurgitation by colour Doppler appears feasible.     

Giant exciton-enhanced shift currents and direct current conduction with subbandgap photo excitations produced by many-electron interactions

Shift current is a direct current generated from nonlinear light–matter interaction in a noncentrosymmetric crystal and is considered a promising candidate for next-generation photovoltaic devices. The mechanism for shift currents in real materials is, however, still not well understood, especially if electron–hole interactions are included. Here, we employ a first-principles interacting Green’s-function approach on the Keldysh contour with real-time propagation to study photocurrents generated by nonlinear optical processes under continuous wave illumination in real materials. We demonstrate a strong direct current shift current at subbandgap excitation frequencies in monolayer GeS due to strongly bound excitons, as well as a giant excitonic enhancement in the shift current coefficients at above bandgap photon frequencies. Our results suggest that atomically thin two-dimensional materials may be promising building blocks for next-generation shift current devices.

When continuous wave light is shone on a noncentrosymmetric crystal, a direct current (DC) can arise due to a second-order optical response of the crystal. The origin of this current is interpreted to be related to the “shift” (1–4) of the intracell coordinates of the excited electron. This so-called shift current is proposed as an alternative to the photocurrent generated by traditional semiconductor p–n junctions (i.e., a junction between hole-doped [p-type] and electron-doped [n-type] semiconductors) for photovoltaic applications (5, 6). Unlike conventional photovoltaic devices, shift current is a bulk phenomenon, which does not require a p–n junction to separate the optically generated electron–hole pair for a DC. Moreover, recent studies reveal that the photocarriers in shift current can have long travel distances, which is distinct from the usual drift transport mechanism in traditional solar cells (7, 8) and makes shift current a promising candidate for efficient energy conversion.Despite many investigations over the past decade, a basic understanding of shift currents is far from complete. Most theoretical studies to date rely on the assumption of having noninteracting particles (3–6, 9–11). Given that it is well known that light-induced electron–hole pairs can form bound or resonant excitons (correlated electron–hole states), which dominate and qualitatively change the absorption features of semiconductors, electron–hole interactions or excitons are expected to play a large role in shift currents, especially for reduced dimensional systems. However, it is not straight forward to generalize existing ab initio methods [such as the ab initio GW plus Bethe-Salpeter equation (GW-BSE) approach (12)], used to understand and compute excitonic effects in linear optical absorption, to study nonlinear optical responses. Different model approaches to investigate the effects of many-electron interactions on nonlinear optical responses of materials have been proposed. For instance, a Floquet-based model Hamiltonian formalism showed that excitonic effects enhance nonlinear response (13). In the specific case of second harmonic generation, first-principles approaches have been developed and applied to real materials, for instance, by making an approximation to the full many-body perturbation theory treatment (14, 15) or to the time-dependent density function theory, in which electron interaction effects are taken into account via simplified kernels (16). A real-time formulation based on propagating the time-dependent Schrodinger equation has also been developed (17) and applied to second harmonic generation (18). For shift currents in real materials, only one recent study considered the effects of excitons on the linear optical coefficient that might influence shift currents, but these authors included only the effects of excitons on the electromagnetic field profile in a bulk sample, and the crucial process of shift current generation itself is still treated within an independent-particle picture (11). Thus, there is still no first-principles calculation and understanding of the role of many-electron interactions, particularly those due to excitons, on shift currents.Here, we show from first principles that 1) bound exciton states in the band gap can generate substantial shift currents, and 2) excitonic effects in the electron–hole continuum part of the spectrum can also greatly enhance shift currents due to the enhancement of the optical matrix elements from the coherence of the electron–hole pairs and to interexciton couplings that arose in the nonlinear responses.