Nanomechanical resonances coupled to microwave cavities can be excited, measured, and controlled simultaneously using electromechanical back-action phenomena. Examples of these effects include sideband cooling and amplification, which are commonly described through linear equations of motion governed by an effective optomechanical Hamiltonian. However, this linear approximation is invalid when the pump-induced cavity microwave field is large enough to trigger optomechanical nonlinearities, resulting in phenomena like frequency combs. Here, we employ a niobium-based superconducting electromechanical device to explore the generation of microwave frequency combs. We observe the formation of combs around a microwave resonant frequency (3.78 GHz) with 8-MHz frequency spacing, equal to the mechanical resonant frequency. We investigate their dynamics for different optomechanical parameters, including detuning, pump powers, and cavity decay rates. Our experimental results show excellent agreement with numerical modeling. These electromechanical frequency combs can be beneficial in nanomechanical sensing applications that require precise electrical tracking of mechanical resonant frequencies.
Objectives: The likelihood of providing care to a spouse in middle and older ages has increased as life expectancy increases, but knowledge about how the caregiver and care recipient influence each other's mental health is limited. This study examined whether a partner's physical, cognitive, and mental health in a spousal caregiving dyad are associated with the other partner's depressive symptoms in China and whether the dyadic effects vary by gender. Methods: This study used data from Wave 3 (2015) and Wave 4 (2018) follow-up surveys of the China Health and Retirement Longitudinal Study (CHARLS). The analytic sample featured 1,245 dyads of care recipients aged 45 or older and their spouse caregivers. The Actor-Partner Interdependence Model was used to test the dyadic effects among all couples in the analytic sample, couples with wife caregivers and couples with husband caregivers, respectively. Results: We found that caregiver's depressive symptoms at Wave 3 were significantly associated with care recipient's depressive symptoms at Wave 4 in the full sample. Regardless of caregiver or care recipient roles, wives' mental health was impacted by their husbands' depressive symptoms, but not vice versa. Wife recipient's cognitive impairment was associated with husband caregiver's lower depressive symptoms. Conclusion: This study sheds light on the mental health of couples in the context of caregiving in China. The findings indicate that interventions to support couples in a caregiving dyad need to consider the influence they have on each other, and the gender and health conditions of each in the dyad.
Summer flounder Paralichthys dentatus supports one of the most valuable commercial and recreational fisheries along the Atlantic Coast of the U.S. However, in recent decades the management of this species has proven to be one of the most contentious for any exploited marine resource in the region. A coastwide catch quota is imposed annually for summer flounder of which 60% is allocated to the commercial fishery and 40% to the recreational fishery. The allocation is further divided among the individual coastal states from North Carolina to Massachusetts based on their landings in the 1980s. This process, based on political jurisdictions, does not consider the species’ biological stock structure. Previous genetic studies (allozyme, mtDNA, and SNPs) provided contradictory results regarding the possible population structure of summer. To address this issue, we used DNA microsatellite analysis at 9 loci to define the coastwide population structure of summer flounder. In total, 1182 specimens were analyzed from 18 collection sites. Most collections were from the Continental Shelf during the fall-winter spawning season. These were supplemented with additional samples from inshore waters from North Carolina to Florida, and inshore sites which support significant recreational fisheries at Nantucket Shoals, Massachusetts and Fire Island, New York. The overall level of genetic differentiation in pairwise comparisons between collections was very low, mean FST= 0.001. There was no evidence of genetic differentiation between collections from north and south of Cape Hatteras. Our microsatellite results are consistent with an earlier SNP study which failed to find significant allelic heterogeneity among coastwide collections of summer flounder. However, a subset of pairwise FST comparisons between some collections proved statistically significant. Furthermore, in STRUCTURE analysis we found evidence of two genetic clusters within the species’ northern landings area, however, this finding was not supported by DPAC analysis. We conclude that summer flounder most likely constitute a single population along their entire Atlantic Coast distribution.
The COVID-19 pandemic has had substantial health, social, and economic effects on families. Consequent lockdowns and school closures heightened the burden on parents of school-age children. Many parents, while working from home, had to care for their children with restricted access to caregiver resources and to support their children’s education through homeschooling or remote learning provided by their schools. These duties created challenges and pressures on parents. Using online survey data collected from 197 parents of school-age (Prek-12) children during the first three months of the COVID-19 pandemic in the U.S., this preliminary study examined the relations among COVID-19-related stressors, including fear of COVID-19 and problems associated with school closures, parenting stress, and parental psychological well-being. Fear of COVID-19 and various issues associated with school closures were related to parenting stress and parental well-being. Parents with less instrumental and emotional support reported higher levels of parenting stress and lower levels of psychological well-being. The results of hierarchical multiple regressions revealed that parenting stress was the strongest predictor of parental psychological distress. Social support was associated with parental well-being but did not mediate the relation between parenting stress and parental well-being. The findings suggest that parenting stress during the COVID-19 lockdowns might take a toll on the mental health of parents of school-age children. Parents of school-age children need multiple layers of support, including targeted support addressing stressors related to school closures and parenting under quarantine.
Acute lymphoblastic leukemia (ALL) is a neoplastic disease characterized by the malignant proliferation of lymphoid cells in the blood and bone marrow. It accounts for approximately 75% of childhood leukemia. Lymphoblastic lymphoma (LBL) is a type of non-Hodgkin's lymphoma characterized by rapid growth and highly aggressive characteristics that occurs most commonly in adolescents and young adults. Asparaginase is primarily used to treat patients with ALL or LBL. Because allergic reactions occur in patients treated with bacterial-derived asparaginase, it is important to develop an alternative asparaginase preparation for patients allergic to asparaginase. Recombinant asparaginase Erwinia chrysanthemi-rywn (JZP-458) is a recombinant Erwinia asparaginase that uses a novel Pseudomonas fluorescens expression platform in the production process. JZP-458 has the same amino acid sequence as E. chrysanthemi-derived asparaginase (ERW) and its in vitro activity is similar to that of ERW. JZP-458 is highly efficacious in patients allergic to asparaginase. Data from a phase I clinical trial indicated that following the intramuscular or intravenous administration of JZP-458 to volunteers, serum asparaginase activity ≥ 0.1 IU/mL was observed in 100% of the volunteers 72 hours after administration. In this review, we summarize the mechanism of action and the related research data obtained with JZP-458 for the treatment of ALL or LBL.
Hydroxylammonium nitrate (HAN) is a potential propellant candidate for dual-mode propulsion systems that combine chemical and electrospray thrust capabilities for spacecraft applications. However, the electrospray dynamics of HAN is currently not well understood. Capitalizing on electrospray ionization guided-ion beam tandem mass spectrometry and collision-induced dissociation measurements, and augmented by extensive molecular dynamics simulations, this work characterized the structures and reaction dynamics of the species present in the electrosprays of HAN under different conditions, which mimic those possibly occurring in low earth orbit and outer space. While being ionic in nature, the HAN monomer, however, adopts a stable covalent structure HONH2·HNO3 in the gas phase. Spontaneous proton transfer between the HONH2 and HNO3 moieties within the HAN monomer can be induced in the presence of a NO3-, a water ligand or a second HAN monomer within 3-5 Å or a H+ within 8 Å, regardless of their collision impact parameters. These facts imply that HAN proton transfer is trigged by a charge and/or a dipole of the collision partner without the need of chemical interaction or physical contact. Moreover, the addition of NO3- to HAN leads to the formation of a stable -O3N·HONH3+·NO3- anion in negative electrosprays. In contrast, when a proton approaches the HONH2·HNO3 structure, dissociative reactions occur that lead to the H2O, NO2 and HONH2 fragments (and their cations) but not intact HAN species in positive electrosprays.
The use of scanning electrochemical microscopy (SECM) for nanoscale imaging of photoelectrochemical processes at semiconductor surfaces has recently been demonstrated. To illuminate a microscopic portion of the substrate surface facing the SECM probe, a glass-sealed, polished tip simultaneously served as a nanoelectrode and a light guide. One issue affecting nanoscale photo-SECM experiments is mechanical interactions of the rigid optical fiber with the tip motion controlled by the piezo-positioner. Here we report an improved experimental setup in which the tip is mechanically decoupled from the fiber and light is delivered to the back of the tip capillary using a complex lens system. The advantages of this approach are evident from the improved quality of the approach curves and photo-SECM images. The light intensity delivered from the optical fiber to the tip is not changed significantly by their decoupling.
We report on unusual regimes of operation of a laser with a gain medium with a large Raman scattering cross-section, which is often inherent in new types of gain media such as colloidal and epitaxial quantum dots and perovskite materials. These media are characterized by a strong electron–phonon coupling. Using the Fröhlich Hamiltonian to describe the electron–phonon coupling in such media, we analyze the operation of the system above the lasing threshold. We show that below a critical value of the Fröhlich constant, the laser can only operate in the conventional regime: namely, there are coherent cavity photons but no coherent phonons. Above the critical value, a new pump rate threshold appears. Above this threshold, either joint self-oscillations of coherent phonons in the gain medium and photons in a cavity or a chaotic regime are established. We also find a range of the values of the Fröhlich constant, the pump rate, and the resonator eigenfrequency, in which more than one dynamical regime of the system is stable. In this case the laser dynamics is determined by the initial values of the resonator field, the active medium polarization, the population inversion, and phonon amplitude.
A mechanistic study is reported for the reactions of singlet oxygen (1O2) with alkene surfactants of tunable properties. Singlet oxygen was generated either top-down (photochemically) by delivery as a gas to an air-water interface or bottom-up (chemically) by transport to the air-water interface as a solvated species. In both cases, reactions were carried out in the presence of 7-carbon (7C), 9-carbon (9C), or 11-carbon (11C) prenylsurfactants [(CH3)2C═CH(CH2)nSO3- Na+ (n = 4, 6, 8)]. Higher "ene" hydroperoxide regioselectivities (secondary ROOH 2 to tertiary ROOH 3) were reached in delivering 1O2 top-down through air as compared to bottom-up via aqueous solution. In the photochemical reaction, ratios of 2:3 increased from 2.5:1 for 7C, to 2.8:1 for 9C, and to 3.2:1 for 11C. In contrast, in the bubbling system that generated 1O2 chemically, the selectivity was all but lost, ranging only from 1.3:1 to 1:1. The phase-dependent regioselectivities appear to be correlated with the "ene" reaction with photochemically generated, drier 1O2 at the air-water interface vs those with wetter 1O2 from the bubbling reactor. Density functional theory-calculated reaction potential energy surfaces (PESs) were used to help rationalize the reaction phase dependence. The reactions in the gas phase are mediated by perepoxide transition states with 32-41 kJ/mol binding energy for C═C(π)···1O2. The perepoxide species, however, evolve to well-defined stationary structures in the aqueous phase, with covalent C-O bonds and 85-88 kJ/mol binding energy. The combined experimental and computational evidence points to a unique mechanism for 1O2 "ene" tunability in a perepoxide continuum from a transition state to an intermediate.
The objective of this research is to investigate the feasibility of applying behavioral predictive analytics to optimize patient engagement in diabetes self-management, and to gain insights on the potential of infusing a chatbot with NLP technology for discovering health-related social needs. In the U.S., less than 25% of patients actively engage in self-health management, even though self-health management has been reported to associate with improved health outcomes and reduced healthcare costs. The proposed behavioral predictive analytics relies on manifold clustering to identify subpopulations segmented by behavior readiness characteristics that exhibit non-linear properties. For each subpopulation, an individualized auto-regression model and a population-based model were developed to support self-management personalization in three areas: glucose self-monitoring, diet management, and exercise. The goal is to predict personalized activities that are most likely to achieve optimal engagement. In addition to actionable self-health management, this research also investigates the feasibility of detecting health-related social needs through unstructured conversational dialog. This paper reports the result of manifold clusters based on 148 subjects with type 2 diabetes and shows the preliminary result of personalization for 22 subjects under different scenarios, and the preliminary results on applying Latent Dirichlet Allocation to the conversational dialog of ten subjects for discovering social needs in five areas: food security, health (insurance coverage), transportation, employment, and housing.
While lung cancer is the leading cause of mortality among all cancer types for both men and women, breast cancer dominates cancer diagnosis among women patients. Never in mitosis gene A (NIMA)-related kinase 2 (Nek2) is a member of NEK family, a Ser/Thr kinase, that is overabundant in both cancer types. Studies from our laboratory have shown that abnormal expression of Nek2 kinase can promote aggressive tumor behavior and metastasis. Nek2 overexpression also drives drug resistance. These tumors also overexpress another key oncogene, epidermal growth factor receptor (EGFR), that has shown to induce cell proliferation, angiogenesis, and tumorigenesis. Hence, concomitant inhibition of Nek2 and EGFR kinases can potentially be a promising therapeutic strategy for both lung and breast cancers. Our goal is to develop anticancer agents that targets inhibition of both Nek2 and EGFR activities. Our hypothesis is such dual-action inhibitory agents will provide superior efficacy due to a more predictable PK/PD profile in vivo. In this work, we first test our hypothesis that dual inhibition of Nek2 and EGFR kinases by small molecules will indeed yield net signaling output that results in synergistic cancer cell death in A549 (lung) and MDA-MB-231 (breast) cells. Using a novel drug-like pharmacophore identified in our laboratory, we have also developed small molecule inhibitors that inhibits both Nek2 and EGFR activities. We anticipate that these findings will render new opportunities toward development of targeted small molecule therapeutics for both lung and breast cancers.
The objective of this research is to investigate the feasibility of applying behavioral predictive analytics to optimize diabetes self-management. This research also presents a use case on the application of the anaytics technology platform to deliver an online diabetes prevention program developed by the CDC. The goal of personalized self-management is to affect individuals on behavior change toward actionable health activities on glucose self-monitoring, diet management, and exercise. In conjunction with personalizing self-management, the content of the CDC diabetes prevention program was delivered online directly to a mobile device. The proposed behavioral predictive analytics relies on manifold clustering to identify subpopulations by behavior readiness characteristics exhibiting non-linear properties. Utilizing behavior readiness data of 148 subjects, subpopulations are created using manifold clustering to target personalized actionable health activities. This paper reports the preliminary result of personalizing self-management for 22 subjects under different scenarios and the outcome on improving diabetes self-efficacy of 34 subjects.
NP-hard combinatorial optimization problems are in general hard problems that their computational complexity grows faster than polynomial scaling with the size of the problem. Thus, over the years there has been a great interest in developing unconventional methods and algorithms for solving such problems. Here, inspired by the nonlinear optical process of q-photon down-conversion, in which a photon is converted into q degenerate lower energy photons, we introduce a nonlinear dynamical model that builds on coupled single-variable phase oscillators and allows for efficiently approximating the ground state of the classical q-state planar Potts Hamiltonian. This reduces the exhaustive search in the large discrete solution space of a large class of combinatorial problems that are represented by the Potts Hamiltonian to solving a system of coupled dynamical equations. To reduce the problem of trapping into local minima, we introduce two different mechanisms by utilizing controlled chaotic dynamics and by dynamical formation of the cost function through adiabatic parameter tuning. The proposed algorithm is applied to graph-q-partitioning problems on several complex graphs.
This research explores how the implementation of a single bus rapid transit (BRT) corridor affected transit ridership change in Winnipeg, Manitoba, Canada. Key issues in measuring ridership change resulting from BRT include (1) understanding stop-level- rather than corridor-level change; (2) examining the ridership impacts of new infrastructure where there is no comparable pre-BRT infrastructure; and (3) assessing piecemeal implementation of BRT. To address these issues, we undertook a quasi-experimental study using agglomerative hierarchical clustering (AHC), propensity score matching (PSM), and t-tests with Cohen’s d to determine BRT’s causal ridership impact. The use of AHC and PSM in what we refer to as cluster-level modeling provided an improved method for measuring causal ridership change at the stop cluster level in areas with no pre-BRT stations. The results revealed no statistical evidence that BRT caused increased transit ridership for stop clusters directly along the BRT corridor. However, the results did indicate that stop clusters for routes connecting to a BRT station experienced an increase in transit ridership. The importance of such findings is grounded in understanding that a limited number of stops along a single corridor may not be enough to affect transit ridership, yet BRT’s flexibility in being able to operate off the BRT corridor does enhance transit ridership.
Primarily caused by chronic cigarette smoking (CS), emphysema is characterized by loss of alveolar cells comprising lung units involved in gas exchange and inflammation that culminate in airspace enlargement. Dysregulation of sphingolipid metabolism with increases of ceramide relative to sphingosine-1 phosphate (S1P) signaling has been shown to cause lung cell apoptosis and is emerging as a potential therapeutic target in emphysema. We sought to determine the impact of augmenting S1P signaling via S1P receptor 1 (S1P1) in a mouse model of CS-induced emphysema. DBA2 mice were exposed to CS for 4 or 6 months and treated with pharmacological agonists of S1P1: phosphonated FTY720 (FTY720-1S and 2S analogs; 0.01-1.0 mg/kg) or GSK1838303A (10 mg/kg). Pharmacological S1P1 agonists ameliorated CS-induced lung parenchymal apoptosis and airspace enlargement as well as loss of body weight. S1P1 agonists had modest inhibitory effects on CS-induced airspace inflammation and lung functional changes measured by Flexivent, improving lung tissue resistance. S1P1 abundance was reduced in chronic CS-conditions and remained decreased after CS-cessation or treatment with FTY720-1S. These results support an important role for S1P-S1P1 axis in maintaining the structural integrity of alveoli during chronic CS exposure and suggest that increasing both S1P1 signaling and abundance may be beneficial to counteract the effects of chronic CS exposure.
It has been shown previously in protonated, deprotonated and ionized guanine–cytosine base pairs that intra-base pair proton transfer from the N1-H at the Watson-Crick edge of guanine to the complementary...
Through a historical case study, this paper explores the political potential of volunteerism in urban natural resources management. As governments continue to rely on unpaid labor to perform essential services, volunteerism has proliferated in urban protected lands during the neoliberal era. It is therefore worthwhile to study the power that volunteers may wield at their service sites, alongside the scholarly attention already paid to the inefficacy and the inadequacy of volunteer labor. By drawing on science and technology studies literature, especially concerning the role of citizen science in activist movements, this article analyzes how volunteer stewards influenced natural resources policy in the Forest Preserve District of Cook County. A local agency, the district is responsible for nearly 70,000 acres in the county that encompasses Chicago, IL. For most of the twentieth century, forestation constituted the district's official land management policy, as leaders sought to match its ecologically diverse holdings to the agency's name. In the late 1970s, volunteers won permission from the district to begin restoring prairies in the forest preserves. Working autonomously, volunteer stewards cultivated expert credibility in the science of ecological restoration. Over several decades, they drew on their scientific authority to convince forest preserve leaders to adopt ecological restoration as the district's primary land management policy, a process culminating in the early twenty-first century. The paper also explores the fragility of volunteer authority rooted in scientific expertise, by tracking how an anti-restoration movement and, later, forest preserve staff members successfully undercut volunteer expertise in ecological restoration.
Glioblastoma multiforme (GBM) also categorized as a grade IV astrocytoma, is an aggressive brain tumor which invades the surrounding brain tissue. Hyperthermia is known to be effective for chemo-radiotherapy to sensitize cancer cells to radiation as a treatment option for patients with GBM. The current study was performed in order to assess and compare the properties of the astrocyte and cancer stem cells isolated from glioblastoma exposed to hyperthermia. Astrocytes and cancer stem cells were isolated from human glioblastoma tissue. Glioblastoma tissues were digested and cultured in culture medium supplemented with B27, basic fibroblast growth factor and epidermal growth factor. The morphology and specific markers were evaluated in astrocyte and cancer stem cell of human glioblastoma through immunocytochemistry and quantitative real-time RT-PCR. The multipotentiality of cancer stem cells was presented using differentiation potential into neurons, oligodendrocytes, and astrocytes. For hyperthermia, cells were exposed to temperatures at 4246 °C for 1 h using a water bath. Cell survival rate by MTT assay and apoptosis using quantitative real-time RT-PCR and western blot were evaluated. Results demonstrated that there were two morphology types in cell culture including epithelioid morphology and fibroblastic morphology. Astrocytes were confirmed via expression of the Glial fibrillary acidic protein (GFAP) protein; whereas, cancer stem cells (CSCs) were round and floating in the culture medium. Immunocytochemical staining indicated that nestin, CD133 and SRY-box 2 (SOX2) antigens were positively expressed in primary neurospheres. Results indicated that cancer stem cells of glioblastoma are multipotent and are able to differentiate into neurons, oligodendrocytes, and astrocytes. The current study obtained evidence via apoptosis evaluation that CSCs are resistant to hyperthermia when compared to astrocytes isolated from glioblastoma. Furthermore, hyperthermia was demonstrated to decrease cell resistance, which may be effective for chemo-radiotherapy to sensitize cancer cells to radiation. Taken together, CSCs of glioblastoma could be used as a powerful tool for evaluating the tumorigenesis process in the brain and developing novel therapies for treatment of GBM.
Objectives Cardiometabolic comorbidities have been associated with lower levels of physical activity (PA) among people living with HIV (PLWH). However, little is known about the longitudinal relationship between cardiometabolic comorbidities and PA participation. Therefore, the aim of this study was to determine the longitudinal association between cardiometabolic comorbidities and PA in PLWH. Methods PLWH from New York City and with complete PA and cardiometabolic comorbidity data between December 2016 and October 2020 were included. PA was evaluated using energy expenditure from the Minnesota Leisure Time Physical Activity Questionnaire (MLTPAQ). Body composition was measured using body mass index (BMI) and different waist circumference measures. Diabetes and hyperlipidemia were determined by physician diagnosis. Hemoglobin A1c (HbA1c) was evaluated through blood samples. Linear mixed-effects models analyses were conducted to assess the longitudinal relationship between cardiometabolic comorbidities and PA. Results A total of 164 participants (mean age 59.6 years; 48.2% females) were included. The mean follow-up period was 22.7 months (SD = 7.9). Higher BMI was associated with lower levels of PA in kcals/week (p < .05). An obese BMI was associated with lower levels of physical activity in kcals/week (p < .05). Higher mid-waist and umbilical circumference were associated with lower levels of PA in kcals/week (p < .05). Having hyperlipidemia was associated with lower levels of PA in kcals/week (p < .01). Having a diabetes diagnosis and elevated HbA1c were also associated with lower levels of PA in kcals/week (p < .05). Conclusion Cardiometabolic comorbidities can have repercussions on PA participation among PLWH, which can in turn increase the risk of cardiovascular disease and mortality.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.