Scale-free, programmable design of morphable chain loops of kilobots and colloidal motors.

Micron-scale robots require systems that can morph into arbitrary target configurations controlled by external agents such as heat, light, electricity, and chemical environment. Achieving this behavior using conventional approaches is challenging because the available materials at these scales are not programmable like their macroscopic counterparts. To overcome this challenge, we propose a design strategy to make a robotic machine that is both programmable and compatible with colloidal-scale physics. Our strategy uses motors in the form of active colloidal particles that constantly propel forward. We sequence these motors end-to-end in a closed chain forming a two-dimensional loop that folds under its mechanical constraints. We encode the target loop shape and its motion by regulating six design parameters, each scale-invariant and achievable at the colloidal scale. We demonstrate the plausibility of our design strategy using centimeter-scale robots called kilobots We use Brownian dynamics simulation to explore the large design space beyond that possible with kilobots, and present an analytical theory to aid the design process. Multiple loops can also be fused together to achieve several complex shapes and robotic behaviors, demonstrated by folding a letter shape "M," a dynamic gripper, and a dynamic pacman The material-agnostic, scale-free, and programmable nature of our design enables building a variety of reconfigurable and autonomous robots at both colloidal scales and macroscales.

Scaling up psychology via Scientific Regret Minimization.

Do large datasets provide value to psychologists? Without a systematic methodology for working with such datasets, there is a valid concern that analyses will produce noise artifacts rather than true effects. In this paper, we offer a way to enable researchers to systematically build models and identify novel phenomena in large datasets. One traditional approach is to analyze the residuals of models-the biggest errors they make in predicting the data-to discover what might be missing from those models. However, once a dataset is sufficiently large, machine learning algorithms approximate the true underlying function better than the data, suggesting, instead, that the predictions of these data-driven models should be used to guide model building. We call this approach "Scientific Regret Minimization" (SRM), as it focuses on minimizing errors for cases that we know should have been predictable. We apply this exploratory method on a subset of the Moral Machine dataset, a public collection of roughly 40 million moral decisions. Using SRM, we find that incorporating a set of deontological principles that capture dimensions along which groups of agents can vary (e.g., sex and age) improves a computational model of human moral judgment. Furthermore, we are able to identify and independently validate three interesting moral phenomena: criminal dehumanization, age of responsibility, and asymmetric notions of responsibility.

Does repeat synthesis in materials chemistry obey a power law?

Finding examples where experimental measurements have been repeated is a powerful strategy for assessing reproducibility of scientific data. Here, we collect quantitative data to assess how often synthesis of a newly reported material is repeated in the scientific literature. We present a simple power-law model for the frequency of repeat syntheses and assess the validity of this model using a specific class of materials, metal-organic frameworks (MOFs). Our data suggest that a power law describes the frequency of repeat synthesis of many MOFs but that a small number of "supermaterials" exist that have been replicated many times more than a power law would predict. Our results also hint that there are many repeat syntheses that have been performed but not reported in the literature, which suggests simple steps that could be taken to greatly increase the number of reports of replicate experiments in materials chemistry.

Impact of intrinsic framework flexibility for selective adsorption of sarin in non-aqueous solvents using metal-organic frameworks.

Molecular modeling of mixture adsorption in nanoporous materials can provide insight into the molecular-level details that underlie adsorptive separations. Modeling of adsorption often employs a rigid framework approximation for computational convenience. All real materials, however, have intrinsic flexibility due to thermal vibrations of their atoms. In this article, we examine quantitative predictions of the adsorption selectivity for a dilute concentration of a chemical warfare agent, sarin, from bulk mixtures with aqueous and non-aqueous (methanol, isopropyl alcohol) solvents using metal-organic frameworks (MOFs). These predictions were made in MOFs approximated as rigid and also in MOFs allowed to have intrinsic flexibility. Including framework flexibility appears to have important consequences for quantitative predictions of adsorption selectivity, particularly for sarin/water mixtures. Our observations suggest the intrinsic flexibility of MOFs can have a nontrivial impact on adsorption modeling of molecular mixtures, especially for mixtures containing polar species and molecules of different sizes.

Classification of mechanisms of strut malapposition after angiographically optimized stent implantation: An optical coherence tomography study.

AIMS: To elucidate causes and extent of strut malapposition in angiographically optimized stenting. METHODS AND RESULTS: Using a new classification system for strut malapposition, the mechanisms of stent strut malapposition were classified as localized lumen enlargement, vessel asymmetry, stent undersizing, strut underexpansion and stent deployment issue. Stent implantations (n = 110) in 100 consecutive patients undergoing optical coherence tomography (OCT) after the operator considered the stent as optimally deployed angiographically were reviewed to determine if strut apposition was complete. 127,894 stent struts in 110 stents were analyzed. There were 6,644 struts malapposed (5.2% ±7.3%), with strut malapposition found in 82 of 110 stents (74.5%). Localized lumen enlargement was the most common cause of malapposition (74.4% of malapposition clusters). Stent undersizing was the second most common cause (46.3%) followed by strut under-expansion in 29.3%, stent deployment issue in 18.2%, and vessel asymmetry in 9.7%. CONCLUSION: Malapposition of any degree is common after angiographic stent optimization, occurring in up to three-quarters of stents. The most frequent mechanism was localized lumen enlargement. The second most common cause of strut malapposition was stent undersizing, which was angiographically invisible. Whether performing OCT after angiographic optimization improves short- and long-term outcomes requires further study. © 2017 Wiley Periodicals, Inc.

Tunable emergent structures and traveling waves in mixtures of passive and contact-triggered-active particles.

We investigate emergent behavior in binary mixtures comprised of passive particles and contact-triggered active particles (CAPs), where a propulsion force is applied on CAPs towards passive particles when the two are in contact. We show that such mixtures phase separate into distinct dense and dilute phases with as few as 10% CAPs. Furthermore, the structure of the dense phase can be tuned by varying the fraction of CAPs and the strength of their propulsion force. The dense phase is classified into seven structure types, which includes both 6-fold and 4-fold ordered crystals, and kinetically arrested gels and clusters. Mixtures with fewer than 35% CAPs exhibit traveling density waves such that one end of the dense phase recedes while the other propagates. This phenomenon results from the spontaneous symmetry breaking of particle flux at the dense-dilute interface. We show that contact-triggered activity can be employed to develop materials with a wide range of structures and dynamics.

The myocardium supplied by a chronic total occlusion is a persistently ischemic zone.

UNLABELLED: Well-developed collaterals to a myocardial segment supplied by a chronic total occlusion (CTO) and/or left ventricular dysfunction in the CTO regions in patients with chronic stable angina suggest that severe ischemia is unlikely to be present. We evaluated the presence and severity of ischemia using fractional flow reserve (FFR) of the myocardium supplied by a CTO in patients and compared the results with a non-CTO control group. METHODS: Patients undergoing FFR and successful percutaneous coronary intervention (PCI) of a CTO were evaluated and compared to a matched non-CTO control group. RESULTS: One hundred patients were included (50 CTO/50 controls). CTO lesions were longer (31.6 ± 18.9 vs 20.2 ± 14.9 mm, P = 0.004) and required more stents (2.2 ± 0.8 vs 1.2 ± 0.5, P = 0.001). FFR was lower (P = 0.0003) with CTO (0.45 ± 0.15) than controls (0.58 ± 0.17) prior to intervention but similar after PCI (CTO 0.91 ± 0.05 vs non-CTO 0.90 ± 0.08). All CTO patients demonstrated an ischemic FFR, even with severe regional dysfunction or well-developed collaterals. Resting ischemia was present in 78% (39/50) of CTO patients as evidenced by a resting Pd /Pa of <0.80. CONCLUSION: In symptomatic patients, a CTO, even with regional left ventricular impairment and/or excellent collateral development, reveals an ischemic zone. This ischemic zone can be normalized by PCI with outcomes appearing to be comparable to non-CTO patients.

Use of propranolol for hypersexual behavior in an adolescent with autism.

OBJECTIVE: To report a case of an adolescent with autism with clinically significant hypersexual behaviors in whom a trial of low-dose propranolol led to major clinical improvement. CASE SUMMARY: This case report describes a 13-year-old boy with a history of autism who presented to the outpatient psychiatric clinic for hypersexual behaviors that started at the onset of puberty. The behaviors affected his functioning both at school and home. A trial of low-dose propranolol, 0.3 mg/kg/d (10 mg twice a day), targeting hypersexual behavior led to remarkable clinical improvement. The behaviors remained stable on this dose of propranolol for 1 year. DISCUSSION: Hypersexual behavior exhibited by adolescent patients with autism can be a big challenge to manage. The literature on pharmacological options to manage these behaviors in children and adolescents with autism is limited. Clinical data of propranolol use are novel. CONCLUSION: To our knowledge, this is the first case report of low-dose propranolol leading to clinically significant improvement in hypersexual behaviors in an adolescent with autism. Propranolol use may expand the choice of treatment option in this patient population.

Reversal of ischemia of donor artery myocardium after recanalization of a chronic total occlusion.

BACKGROUND: Case reports have shown that an intermediate stenosis in the donor artery collateralizing the myocardium of a chronic total occlusion (CTO) can produce an ischemic fractional flow reserve (FFR) value which may revert to non-ischemic with CTO revascularization. METHODS: A consecutive series of patients with severe angina in which a donor artery with intermediate stenosis (30-70%) had FFR measured before and after successful CTO recanalization were studied. RESULTS: Fourteen of 50 consecutive CTO patients with successful PCI fulfilled the study criteria. Eight had CTO of the right coronary artery (RCA), three circumflex (LCx), and three RCA and LCx. Left anterior descending artery was the donor artery in 13 and LCx in 1 patient. Of nine donor ischemic FFR patient's pre-PCI, six reverted to non-ischemic (FFR pre-PCI 0.76 ± 0.04 and 0.86 ± 0.03 post-PCI). Five patients had normal FFR in the donor artery pre- and post-CTO PCI. CONCLUSIONS: In patients with a CTO and an intermediate donor artery stenosis, the frequency of ischemia in the donor artery territory is relatively high and often normalized by successful CTO recanalization. These data recommend recanalizing the CTO first whenever possible as a preferred therapeutic strategy to avoid the need for PCI to the donor artery or multivessel bypass surgery.

Identification of provider characteristics influencing prescription of analgesics: a systematic literature review.

PURPOSE: Pain is a comorbid and aggravating symptom that in many conditions can be perceived differently and should therefore be managed accordingly. Numerous factors, both social and cultural, are thought to influence the analgesic prescription. However, elucidation of such areas is limited. We therefore conducted a systematic literature review to test the hypothesis that variations in provider characteristics predict the prescription of pain medication. METHODS: A MEDLINE and PsycINFO database search from 1960 to 2009 was conducted using the search terms of "pain" or "pain treatment" along with culture, ethnicity, race, minority, gender/sex, knowledge, attitudes, physician-patient relationship, stereotype, and physician practices. Twelve original research articles based on predefined inclusion criteria were identified and analyzed to test the hypothesis of provider characteristics influencing analgesics prescription. RESULTS: Of the 12 studies, 11 were cross-sectional in design, and 10 used a survey instrument or clinical vignettes to measure different pain management responses. A randomized sampling methodology was used in 5 of the studies. The majority of providers were male (64.9% in 8 studies), white (73.5% in 5 studies), internal medicine physicians (37.4% in 11 studies), and located in the United States (75% across all 12 studies). Ten studies identified at least one provider characteristic that influenced prescription practices; age, level of experience, as well as sex were listed most frequently as contributing factors. The interplay of the sex of the provider and patient characteristics were found to be important variables in pain management. CONCLUSIONS: Our systematic review of existing literature highlights that provider's age, sex, experience, specialty, and the interplay between provider and patient characteristics are important variables in pain management. However, generalizations relating to these findings are limited by the heterogeneity of the studies and the paucity of literature in this field.

Concomitant Vaginal Laceration and Urinary Bladder Injury With Pubic Diastasis: A Case Report on a Rare Complication During Obstructed Labor.

A serious uro-obstetric emergency is the concurrent rupture of the uterine and urine bladder following a protracted difficult delivery. In the absence of circumstances that would make the bladder more likely to cling to the lower uterine segment, the involvement of the urinary bladder in a primigravida is unique and relatively infrequent. We discuss a case of a 21-year-old patient who had an obstructed labor complicated with bladder and vaginal injury. At laparotomy, we found a pubic bone diastasis, a vaginal injury, and a bladder injury at the urethrovesical junction. As a result, bladder neck repair with urethrovesical anastomosis and vaginal repair with an external fixator were carried out for pubic bone diastasis.

Stress, intertemporal choice, and mitigation behavior during the COVID-19 pandemic.

Delayed gratification is an important focus of research, given its potential relationship to forms of behavior, such as savings, susceptibility to addiction, and pro-social behaviors. The COVID-19 pandemic may be one of the most consequential recent examples of this phenomenon, with people's willingness to delay gratification affecting their willingness to socially distance themselves. COVID-19 also provides a naturalistic context by which to evaluate the ecological validity of delayed gratification. This article outlines four large-scale online experiments (total N = 12, 906) where we ask participants to perform Money Earlier or Later (MEL) decisions (e.g., $5 today vs. $10 tomorrow) and to also report stress measures and pandemic mitigation behaviors. We found that stress increases impulsivity and that less stressed and more patient individuals socially distanced more throughout the pandemic. These results help resolve longstanding theoretical debates in the MEL literature as well as provide policymakers with scientific evidence that can help inform response strategies in the future. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Modeling Surface Vibrations and Their Role in Molecular Adsorption: A Generalized Langevin Approach.

The atomic vibrations of a solid surface can play a significant role in the reactions of surface-bound molecules, as well as their adsorption and desorption. Relevant phonon modes can involve the collective motion of atoms over a wide array of length scales. In this paper, we demonstrate how the generalized Langevin equation can be utilized to describe these collective motions weighted by their coupling to individual sites. Our approach builds upon the generalized Langevin oscillator (GLO) model originally developed by Tully. We extend the GLO by deriving parameters from atomistic simulation data. We apply this approach to study the memory kernel of a model platinum surface and demonstrate that the memory kernel has a bimodal form due to coupling to both low-energy acoustic modes and high-energy modes near the Debye frequency. The same bimodal form was observed across a wide variety of solids of different elemental compositions, surface structures, and solvation states. By studying how these dominant modes depend on the simulation size, we argue that the acoustic modes are frozen in the limit of macroscopic lattices. By simulating periodically replicated slabs of various sizes, we quantify the influence of phonon confinement effects in the memory kernel and their concomitant effect on simulated sticking coefficients.

Calculation of Self, Corrected, and Transport Diffusivities of Isopropyl Alcohol in UiO-66.

The UiO-6x family of metal-organic frameworks has been extensively studied for applications in chemical warfare agent (CWA) capture and destruction. An understanding of intrinsic transport phenomena, such as diffusion, is key to understanding experimental results and designing effective materials for CWA capture. However, the relatively large size of CWAs and their simulants makes diffusion in the small-pored pristine UiO-66 very slow and hence impractical to study directly with direct molecular simulations because of the time scales required. We used isopropanol (IPA) as a surrogate for CWAs to investigate the fundamental diffusion mechanisms of a polar molecule within pristine UiO-66. IPA can form hydrogen bonds with the µ3-OH groups bound to the metal oxide clusters in UiO-66, similar to some CWAs, and can be studied by direct molecular dynamics simulations. We report self, corrected, and transport diffusivities of IPA in pristine UiO-66 as a function of loading. Our calculations highlight the importance of the accurate modeling of the hydrogen bonding interactions on diffusivities, with about an order of magnitude decrease in diffusion coefficients when the hydrogen bonding between IPA and the µ3-OH groups is included. We found that a fraction of the IPA molecules have very low mobility during the course of a simulation, while a small fraction are highly mobile, exhibiting mean square displacements far greater than the ensemble average.

Ileal neobladder adenocarcinoma occurring twenty-five years post ileocystoplasty: a case report.

De-tubularised ileum is one of the most common segments used for augmentation cystoplasty. It is associated with complications such as metabolic disturbances, recurrent urinary tract infections, and stone formation. However, adenocarcinoma arising in an augmented bladder is a rare occurrence. We report a 37-year-old female, case of ileocystoplasty 25 years ago due to a thimble bladder (genitourinary tuberculosis) who presented with hematuria for one month. Cystoscopy showed bladder mass in the transposed ileal segments. The patient underwent transurethral resection of the bladder lesion, and the histopathology was suggestive of adenocarcinoma of the ileum. Subsequently, she underwent anterior pelvic exenteration and post-operative recovery was uneventful. The 6-month follow-up showed that the patient was asymptomatic without recurrence. In conclusion, even though adenocarcinoma in the ileal neobladder is rare, life-long with close follow-up with routine cytologic, radiologic, and cystoscopic evaluation for early cancer detection and treatment at an early stage is crucial.

Thoracoscopic decompression in Pott's spine and its long-term follow-up.

PURPOSE: Video-assisted thoracoscopic surgery (VATS) has become an alternative tool for a variety of spinal conditions as this approach minimises much morbidity related to conventional thoracotomy. The purpose of this study was to determine the efficacy of VATS and its long-term results in patients with dorsal spinal tuberculosis. MATERIALS AND METHODS: This retrospective long-term follow-up study of VATS-assisted surgical treatment of dorsal spine tuberculosis included 30 patients with a mean age of 33.5 years (range 15-60). Patients with dorsal spine tuberculosis who were suitable surgical candidates for VATS underwent a three-portal thoracoscopy for decompression with/without fusion of the spine along with routine chemotherapy for tuberculosis (TB). Patients were assessed for blood loss, duration of surgery, postoperative incision pain, duration of hospital stay, neurological recovery, and progression of deformity. Patients were observed for a minimum of five years. RESULTS: The mean duration of surgery was 158.8 min (range 90-220 min) with mean blood loss of 296.7 ml (range 200-450 ml). Complications were seen in ten patients. The mean follow-up was 80 months (range 60-90 months) with neurological improvement and return of ambulatory power in all patients at final follow-up. There was an average increase in kyphus angle by 7.5° at final follow-up and 95% of patients achieved an excellent or good subjective outcome. CONCLUSION: VATS-assisted surgical decompression can be a safe and effective technique for anterior debridement and fusion in tuberculosis of the dorsal spine to achieve neurological recovery with reduced morbidity, blood loss, and hospital stay compared to thoracotomy.

Use of technetium(99m)-ciprofloxacin scan in Pott's spine to assess the disease activity.

PURPOSE: The World Health Organisation has declared tuberculosis (TB) a global emergency and spinal tuberculosis is one of the most common forms. There is still controversy regarding optimum duration of treatment in osteoarticular tuberculosis due to the lack of well-defined criteria for the end point of treatment. Emergence of multi drug resistant tuberculosis, primarily due to use of poor drug regimens, further illustrates the need of newer and more effective diagnostic methods, particularly in developing countries. METHODS: This prospective clinical study to evaluate the role of technetium ((99m)Tc)-ciprofloxacin scan as a tool to assess disease activity involved in 15 cases of TB spine with a mean age of 32.2 years (range 21-72). Following a clinico-radiological diagnosis, all patients were treated with standard anti tubercular treatment and a scan was done at zero, three and six months of treatment with tracer activity being recorded and compared in sequential scans along with a parallel evaluation of clinical and radiological profile at regular intervals. RESULTS: Out of 15 cases, nine had an initially positive bone scan. Two patients (22%) converted to negative scans at three months, whereas the remaining seven (78%) turned negative at six months. The end of six months treatment was also accompanied by clinico-radiological resolution in all cases. CONCLUSION: In conclusion, technetium ((99m)Tc)-ciprofloxacin scan could be a promising tool for monitoring disease activity in selected cases of tuberculosis spine as an alternative for therapeutic drug monitoring; however, due to the small sample size, studies with a large number of patients might be of help in defining these cases in a better way.

Common peroneal nerve palsy secondary to peroneus longus abscess: case report.

Muscle abscess presenting as nerve palsy is rare and has not been previously reported in the common peroneal nerve (CPN). The objective of this case report is to describe the diagnosis and treatment of an uncommon presentation of peroneal abscess in the leg of an otherwise healthy man. We present a case of CPN palsy in a 50-year-old immunocompetent man with no other comorbid medical condition secondary to peroneus longus abscess. The diagnosis was suggested by magnetic resonance imaging examination and confirmed by intraoperative findings. After surgical drainage of the abscess, the patient made a complete recovery. A review of the literature confirms that peroneus longus abscess giving rise to CPN palsy has not been described. Early diagnosis and surgical drainage of the compressing abscess can produce a favorable outcome.

The temporal dynamics of opportunity costs: A normative account of cognitive fatigue and boredom.

Cognitive fatigue and boredom are two phenomenological states that reflect overt task disengagement. In this article, we present a rational analysis of the temporal structure of controlled behavior, which provides a formal account of these phenomena. We suggest that in controlling behavior, the brain faces competing behavioral and computational imperatives, and must balance them by tracking their opportunity costs over time. We use this analysis to flesh out previous suggestions that feelings associated with subjective effort, like cognitive fatigue and boredom, are the phenomenological counterparts of these opportunity cost measures, instead of reflecting the depletion of resources as has often been assumed. Specifically, we propose that both fatigue and boredom reflect the competing value of particular options that require foregoing immediate reward but can improve future performance: Fatigue reflects the value of offline computation (internal to the organism) to improve future decisions, while boredom signals the value of exploration (external in the world). We demonstrate that these accounts provide a mechanistically explicit and parsimonious account for a wide array of findings related to cognitive control, integrating and reimagining them under a single, formally rigorous framework. (PsycInfo Database Record (c) 2022 APA, all rights reserved).