Search

In this research note, we describe the results of the first validation study of the U.S. Census Bureau's new Community Resilience Estimates (CRE), which uses Census microdata to develop a tract-level vulnerability index for the United States. By employing administrative microdata to link Social Security Administration mortality records to CRE, we show that CRE quartiles provide more stable predictions of COVID-19 excess deaths than single demographic categorizations such as race or age, as well as other vulnerability measures including the U.S. Centers for Disease Control and Prevention's Social Vulnerability Index (SVI) and the Federal Emergency Management Agency's National Risk Index (NRI). We also use machine learning techniques to show that CRE provides more predictive power of COVID-19 excess deaths than standard socioeconomic predictors of vulnerability such as poverty and unemployment, as well as SVI and NRI. We find that a 10-percentage-point increase in a key CRE risk measure is associated with one additional death per neighborhood during the initial outbreak of COVID-19 in the United States. We conclude that, compared with alternative measures, CRE provides a more accurate predictor of community vulnerability to a disaster such as a pandemic., (Copyright © 2024 The Authors.)

U.S. Commuting Zones (CZs) are an aggregation of county-level data that researchers commonly use to create less arbitrary spatial entities and to reduce spatial autocorrelation. However, by further aggregating data, researchers lose point data and the associated detail. Thus, the choice between using counties or CZs often remains subjective with insufficient empirical evidence guiding researchers in the choice. This article categorizes regional data as entrepreneurial, economic, social, demographic, or industrial and tests for the existence of local spatial autocorrelation in county and CZ data. We find CZs often reduce-but do not eliminate and can even increase-spatial autocorrelation for variables across categories. We then test the potential for regional variation in spatial autocorrelation with a series of maps and find variation based on the variable of interest. We conclude that the use of CZs does not eliminate the need to test for spatial autocorrection, but CZs may be useful for reducing spatial autocorrelation in many cases., Competing Interests: The authors have declared that no competing interests exist.

We model the locational determinants of nine categories of healthcare services in the contiguous United States using restricted access federal establishment data. These data enable close examination of rural health services, which are subject to suppression in publicly published data sources. After reviewing differences in public and unsuppressed restricted data and testing underlying data generation processes for each healthcare industry, including the Poisson, negative binomial, and their zero-inflated counterparts, we estimate marginal effects for four categories of independent variables: place-based factors, financial access, characteristics of population, and industry interdependencies. Findings show establishments are less likely to be found with high concentrations of Medicare and Medicaid recipients, while agglomerations are associated with more establishments. Nonemployer establishments serve a broader spectrum of people, but the rural poor still experience less access to health care., (© 2021 John Wiley & Sons Ltd.)

The goal of the field of haptics is to create technologies that manipulate the sense of touch. In virtual and augmented reality, haptic devices are for touch what loudspeakers and RGB displays are for hearing and vision. Haptic systems that utilize micromotors or other miniaturized mechanical devices (e.g., for vibration and pneumatic actuation) produce interesting effects, but are quite far from reproducing the feeling of real materials. They are especially deficient in recapitulating surface properties: fine texture, friction, viscoelasticity, tack, and softness. The central argument of this Progress Report is that to reproduce the feel of everyday objects requires chemistry: molecular control over the properties of materials and ultimately design of materials which can change these properties in real time. Stimuli-responsive organic materials, such as polymers and composites, are a class of materials which can change their oxidation state, conductivity, shape, and rheological properties, and thus might be useful in future haptic technologies. Moreover, the use of such materials in research on tactile perception could help elucidate the limits of human tactile sensitivity. The work described represents the beginnings of this new area of inquiry, in which the defining approach is the marriage of materials science and psychology.

This paper describes a type of haptic device that delivers two modes of stimulation simultaneously and at the same locations on the skin. The two modes of stimulation are mechanical (delivered pneumatically by inflatable air pockets embedded within a silicone elastomer) and electrical (delivered by a conductive polymer). The key enabling aspect of this work is the use of a highly plasticized conductive polymer based on poly(3,4-ethylenedioxythiphene) (PEDOT) blended with elastomeric polyurethane (PU). To fabricate the "electropneumotactile" device, the polymeric electrodes are overlaid directly on top of the elastomeric pneumatic actuator pockets. Co-placement of the pneumatic actuators and the electrotactile electrodes is enabled by the stretchability of the PEDOT:OTs/PU blend, allowing the electrotactiles to conform to underlying pneumatic pockets under deformation. The blend of PEDOT and PU has a Young's modulus of ~150 MPa with little degradation in conductivity following repeated inflation of the air pockets. The ability to perceive simultaneous delivery of two sensations to the same location on the skin are supported by experiments using human subjects. These results show that participants can successfully detect the location of pneumatic stimulation and whether electrotactile stimulation is delivered (yes/no) at a rate significantly above chance (mean accuracy = 94%)., Competing Interests: Conflict of interest The authors declare no financial or commercial conflicts of interest.

Haptic devices are in general more adept at mimicking the bulk properties of materials than they are at mimicking the surface properties. This paper describes a haptic glove capable of producing sensations reminiscent of three types of near-surface properties: hardness, temperature, and roughness. To accomplish this mixed mode of stimulation, three types of haptic actuators were combined: vibrotactile motors, thermoelectric devices, and electrotactile electrodes made from a stretchable conductive polymer synthesized in our laboratory. This polymer consisted of a stretchable polyanion which served as a scaffold for the polymerization of poly(3,4-ethylenedioxythiophene) (PEDOT). The scaffold was synthesized using controlled radical polymerization to afford material of low dispersity, relatively high conductivity (0.1 S cm -1 ), and low impedance relative to metals. The glove was equipped with flex sensors to make it possible to control a robotic hand and a hand in virtual reality (VR). In psychophysical experiments, human participants were able to discern combinations of electrotactile, vibrotactile, and thermal stimulation in VR. Participants trained to associate these sensations with roughness, hardness, and temperature had an overall accuracy of 98%, while untrained participants had an accuracy of 85%. Sensations could similarly be conveyed using a robotic hand equipped with sensors for pressure and temperature.

In engineering, the "softness" of an object, as measured by an indenter, manifests as two measurable parameters: (i) indentation depth and (ii) contact area. For humans, softness is not well defined, although it is believed that perception depends on the same two parameters. Decoupling their relative contributions, however, has not been straightforward because most bulk-"off-the-shelf"-materials exhibit the same ratio between the indentation depth and contact area. Here, we decoupled indentation depth and contact area by fabricating elastomeric slabs with precise thicknesses and microstructured surfaces. Human subject experiments using two-alternative forced-choice and magnitude estimation tests showed that the indentation depth and contact area contributed independently to perceived softness. We found an explicit relationship between the perceived softness of an object and its geometric properties. Using this approach, it is possible to design objects for human interaction with a desired level of perceived softness.

The word "haptics" refers to technologies designed to stimulate the tactile and kinesthetic senses. Kinesthesia-the sense of motion-is triggered by imposing forces upon the joints, tendons, and muscles to recreate the geometry and stiffness of objects, as may be useful in physical therapy or virtual reality. Here, we introduce a form of kinesthetic feedback by manipulating the mechanical properties of spandex impregnated with a thermoplastic polymer. Heating or cooling this textile-thermoplastic composite just above or below its glass transition temperature ( T g ) dramatically changes its mechanical properties (corresponding to a decrease in storage modulus from 36 MPa to 0.55 MPa). In the form of a glove, the composite can also be healed after inadvertent overextension in its stiffened state by heating it above its T g . When fitted with thermoelectric devices for active heating and cooling, the flexible or stiffened state of a glove can be perceived by human subjects. As an example of a human-machine interface, the glove is used to control a robotic finger. When the robotic finger makes contact with a wall, a signal is sent to thermoelectric devices in the glove to cool (stiffen the finger) and thus provide kinesthetic feedback to the user.

Most advantages of organic electronic materials are enabled by mechanical deformability, as flexible (and stretchable) devices made from these materials must be able to withstand roll-to-roll printing and survive mechanical insults from the external environment. Cohesion and adhesion are two properties that dictate the mechanical reliability of a flexible organic electronic device. In this paper, progressive-load scratch tests are used for the first time to correlate the cohesive and adhesive behavior of poly(3-alkylthiophenes) (P3ATs) with respect to two molecular parameters: length of the alkyl side chain and molecular weight. In contrast to metrological techniques based on buckling or pull testing of pseudofreestanding films, scratch tests reveal information about both the cohesive and adhesive properties of thin polymeric films from a single procedure. Our data show a decrease in cohesion and adhesion, that is, a decrease in overall mechanical robustness, with increasing length of the side chain. This behavior is likely due to increases in free volume and concomitant decreases in the glass transition temperature. In contrast, we observe increases in both the cohesion and adhesion with increasing molecular weight. This behavior is attributed to an increased density of entanglements with high molecular weight, which manifests as increased extensibility. These observations are consistent with the results of molecular dynamics simulations. Interestingly, the normal (applied) forces associated with cohesive and adhesive failure are directly proportional to the average degree of polymerization, as opposed to simply the molecular weight, as the length of the alkyl side chain increases the molecular weight without increasing the degree of polymerization.

We report the application of a nonvolatile ionic gel as a soft, conductive interface for electrotactile stimulation. Materials characterization reveals that, compared to a conventional ionic hydrogel, a glycerol-containing ionic gel does not dry out in air, has better adhesion to skin, and exhibits a similar impedance spectrum in the range of physiological frequencies. Moreover, psychophysical experiments reveal that the nonvolatile gel also exhibits a wider window of comfortable electrotactile stimulation. Finally, a simple pixelated device is fabricated to demonstrate spatial resolution of the haptic signal., Competing Interests: The authors declare no competing financial interest.

Extracting the unique information on ultradense nuclear matter from the gravitational waves emitted by merging neutron-star binaries requires robust theoretical models of the signal. We develop a novel effective-one-body waveform model that includes, for the first time, dynamic (instead of only adiabatic) tides of the neutron star as well as the merger signal for neutron-star-black-hole binaries. We demonstrate the importance of the dynamic tides by comparing our model against new numerical-relativity simulations of nonspinning neutron-star-black-hole binaries spanning more than 24 gravitational-wave cycles, and to other existing numerical simulations for double neutron-star systems. Furthermore, we derive an effective description that makes explicit the dependence of matter effects on two key parameters: tidal deformability and fundamental oscillation frequency.

RBC membrane-cloaked polymeric nanoparticles represent an emerging nanocarrier platform with extended circulation in vivo. A lipid-insertion method is employed to functionalize these nanoparticles without the need for direct chemical conjugation. Insertion of both folate and the nucleolin-targeting aptamer AS1411 shows receptor-specific targeting against model cancer cell lines.

Fracture of cusps on posterior teeth, especially those carious or restored, is a major cause of tooth loss, Nonfunctional cusps fracture more often than the functional; mandibular cusps fracture more often than maxillary cusps. This study examined functional and nonfunctional cusps of the maxillary and mandibular posterior teeth in four different parameters; (1) buccolingual width, (2) angle of cuspal inclination, (3) thickness of enamel, and (4) angle of inclination of the dentinoenamel junction. Measurements of functional cusps, except those in maxillary premolars established differences that may explain the frequency of frequency of fracture. These parameters of functional and nonfunctional cusps suggest that the cuspal anatomy has a relationship to the fracture potential of cusps.

This article presents a new method of excision of olecranon and prepatellar bursae using an arthroscopic technique. Six cases, three in each anatomic location, are retrospectively reviewed with an average follow-up of 6.25 months (1.5-15 months). When the etiology of the bursitis was traumatic, all four cases did well. Unsatisfactory results were obtained, for both a patient with CREST syndrome (Calcinosis, Raynaud's phenomenon, Esophageal hypomobility, Sclerodactyl, Telangietasia) and a patient with gouty bursitis. The results from this limited series would suggest reserving this technique for those cases of bursitis secondary to trauma, and not responding to conservative treatment.

Twenty subjects receiving Le Fort I downfracture osteotomies stabilized with rigid fixation were studied for relapse. The analysis was based on longitudinal cephalometric radiographs taken within 2 weeks presurgically, 1 week postsurgically, and after a minimum period of 6 months postsurgically. Vertical and sagittal changes in the maxilla were evaluated in reference to the Frankfort horizontal plane. It was found that the mean postsurgical relapse was minimal and not significant. It was smaller than that reported for patients who had received stabilization of the maxilla with intraosseous and maxillomandibular wiring. It was concluded that the rigid fixation technique is dependable and yields stable postsurgical results in the maxilla.

An extremely short instrumental response function for a single-photon-counting system has been obtained by using a low-jitter photomultiplier tube, fast amplification of the single photoelectron pulse from this photomultiplier, a constant fraction discriminator with a wide bandwidth input, and a stable reference timing signal. This synchronously mode-locked laser system has been shown to be capable of measuring the fluorescence lifetimes of compounds from 66 psec to 4.5 nsec. The estimated error in these determinations is 6% or 10 psec, whichever is greater. This apparatus has proved itself to be superior to the previously used nitrogen flashlamp apparatus for the determination of subnanosecond lifetimes. The validity of using deconvolution to determine lifetimes shorter than the instrumental response function has been verified.

Although the number of patients with Rh isoimmunization in pregnancy has been decreasing in recent years, intrauterine transfusion is still an important form of therapy for those patients whose infants have erythroblastosis. We have used both gray-scale and real-time ultrasonography for the last ten cases in which intrauterine transfusion was necessary. These techniques were used in preference to fluoroscopy and x-ray control to identify the placental site and fetal abdomen and to direct the insertion and placement of the transfusion needle. We were able to visualize the needle when it entered the amniotic cavity and the fetal abdomen. The technique afforded continuous visualization and a cross-sectional image of the fetus, steps which increase the efficiency and safety of the procedure and decrease radiation to the fetus.

Three cases in which wrist pain developed in skeletally immature competitive gymnasts are presented. In all three cases there is radiographic evidence of premature growth plate closure, resulting in shortening of the radius and alterations in the normal distal radioulnar articulation. Repetitive compressive loading of the distal growth plate of the radius is proposed as a potential etiology of this condition. Treatment goals, including an example of successful ulnar shortening, are reviewed. The authors suggest activity limitation with the onset of symptoms, in order to avoid the permanent structural changes observed in our patients.

The long-term effects of intrauterine transfusion (IUT) are still being assessed since the procedure was first reported in 1963. Therefore, we undertook a follow-up study on the survivors of 57 infants who received IUT's between 1966 and 1975. Forty-two infants were born alive, but 15 died in the neonatal period. Overall survival was 27/57 (48%). An extensive follow-up examination was carried out at age 22 months to 10 years in 21/27 survivors. Height was below the third percentile in one child and head circumference above the mean and 2 SD in another. Of 21 children, 19 had normal vision, one was slightly myopic, and one had hyperopia. One child had unilateral high-frequency hearing loss. All had normal EEG's and none have mental retardation but 2/21 have "major" and 6/21 have "minor" neurologic signs. No evidence of passive antibody transfer was found, but minor disturbances of immunoglobulin levels were present.

A 30 year old woman was seen at 32 weeks of gestation because of severe abdominal pain. A sonogram revealed an irregular, 5 cm-diameter cystic structure in the placenta. Examination of the placenta after cesarean section showed an extremely large maternal lake.

Real-time ultrasound was used as an aid in intrauterine transfusions for patients with Rh isoimmunization. It was preferred to fluoroscopy and x-ray control to identify the placental site and fetal abdomen and to direct the insertion and placement of the transfusion needle. The technique was used 22 times in 12 patients and resulted in increased efficiency and safety, including decreased radiation to the fetus.

Between 1955 and 1962, 145 maternal deaths were reported in the Province of British Columbia. One hundred of them were due to obstetrical causes. Of these deaths, hemorrhage was by far the commonest cause (40 cases), followed in frequency by vascular accidents (23 cases), infections (17 cases), toxemia (10 cases), anesthetic deaths (five cases), and other causes (five cases). Significant avoidable factors were noted in 80%. Indirect obstetrical deaths accounted for 29 cases, or 20% of all maternal mortalities. The most frequently encountered causes of indirect obstetrical deaths were cardiac (nine cases) and vascular accidents (six cases). Avoidable factors were considered to be present in 19 of the 29, an incidence of 65%.When all deaths were considered together, 72% were felt to have significant avoidable factors when judged against an academic standard. It was also apparent that some 40% to 50% of deaths were intimately involved with social factors.