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Anion exchange membranes prepared through cyclopolymerization of crosslinking of diallylammonium precursors were subjected to various physical, mechanical, and chemical stability property analysis for anion exchange membrane water electrolyzers.

Thermally switchable ladder-like poly(silsesquioxane) (LPSQ) adhesives based on Diels–Alder reaction were prepared and utilized as reversible adhesion materials.

Daily experience suggests that we perceive distances near us linearly. However, the actual geometry of spatial representation in the brain is unknown. Here we report that neurons in the CA1 region of rat hippocampus that mediate spatial perception represent space according to a non-linear hyperbolic geometry. This geometry uses an exponential scale and yields greater positional information than a linear scale. We found that the size of the representation matches the optimal predictions for the number of CA1 neurons. The representations also dynamically expanded proportional to the logarithm of time that the animal spent exploring the environment, in correspondence with the maximal mutual information that can be received. The dynamic changes tracked even small variations due to changes in the running speed of the animal. These results demonstrate how neural circuits achieve efficient representations using dynamic hyperbolic geometry.

Design of high energy density lithium storage materials is one of the everlasting issues in energy storage systems to realize a fully clean and sustainable energy grid. Here, 2,9-dimethyl quinacridone was selected as a precursor to prepare carbon-based electrode via low temperature heat-treatment process from 750 °C to 1050 °C. The pyro-polymerization of 2,9-dimethyl quinacridone induced a distinctive morphological transformation from rice husk-shaped 2,9-dimethyl quinacridone to carbon nanofibers. Electrode fabricated from pigment derived carbon nanofibers (PCNF) pyrolyzed at 750 °C maintained 878 mAh g-1 at a current density of 1 A g-1 and good Coulombic efficiency up to 98% after 1000 cycles. Furthermore, it delivered 337 mAh g-1 at a high current density of 25 A g-1. The superior performance was attributed to the stable structure of pristine 2,9-dimethyl quinacridone giving high thermal stability and crystallinity owing to well-defined π-π and hydrogen bonding interactions, thus rendering a stable microstructure with a large d-spacing of (002) plane of 3.580 A, as well as efficient surface redox reactions. Density functional theory calculations indicated that the large interlayer distance could facilitate fast lithium ion insertion/extraction because of a ∼38% lower energy barrier for lithium ion insertion than compared with graphite.

The hippocampus is critical for recollecting and imagining experiences. This is believed to involve voluntarily drawing from hippocampal memory representations of people, events, and places, including the hippocampus’ map-like representations of familiar environments. However, whether the representations in such “cognitive maps” can be volitionally and selectively accessed is unknown. We developed a brain-machine interface to test if rats could control their hippocampal activity in a flexible, goal-directed, model-based manner. We show that rats can efficiently navigate or direct objects to arbitrary goal locations within a virtual reality arena solely by activating and sustaining appropriate hippocampal representations of remote places. This should provide insight into the mechanisms underlying episodic memory recall, mental simulation/planning, and imagination, and open up possibilities for high-level neural prosthetics utilizing hippocampal representations.

Language and culture play a critical role in international commercial relations. Since the 19th century, the English language has undeniably held the prominent position as the global lingua franca to facilitate communication between nations. However, China’s contemporary re-emergence as an economic superpower has expanded its global influence. Consequently, awareness of Chinese culture and language is becoming important not only globally, but also in the Caribbean, where China’s economic footprint has expanded considerably in recent years. This article conceptually explores the important role of language and culture within the growing Sino-Caribbean commercial relationship. Specifically, it discusses the potential impact of language on the trade and tourism sectors, which are two key industries that drive the economies of English-speaking Caribbean small island developing states. It does this by charting the development of the English and Chinese languages as dominant languages. It then briefly looks at the current level of Chinese engagement with the region in trade and, more contemporarily, the potential of greater Chinese tourism in the Caribbean. It discusses the value of deeper cultural and linguistic understanding in nurturing and expanding these relationships. Finally, the article concludes by providing meaningful recommendations on ways to mitigate cultural and linguistic barriers in order to promote deeper Sino-Caribbean trade and tourism.

Individual neurons in prefrontal cortex – a key brain area involved in cognitive functions – are selective for variables such as space or time, as well as more cognitive aspects of tasks, such as learned categories. Many neurons exhibit mixed selectivity, that is, they show selectivity for multiple variables. A fundamental question is whether neurons are functionally specialized for particular variables and how selectivity for different variables intersects across the population. Here, we analyzed neural correlates of space and time in rats performing a navigational task with two behaviorally important categories – starts and goals. Using simultaneous recordings of many medial prefrontal cortex (mPFC) neurons during behavior, we found that population codes for elapsed time were invariant to different locations within categories, and subsets of neurons had functional preferences for time or space across categories. Thus, mPFC exhibits structured selectivity, which may facilitate complex behaviors by efficiently generating informative representations of multiple variables.

The interaction energy of base-acid plays a key role in acid retention of phosphoric acid (PA)-doped polymer electrolytes under fuel cell operating conditions. Here, we investigate the energetics of proton-accepting and hydroxide-donating organic bases using density functional theory calculations. Because of their weak basicity, proton-accepting organic bases such as benzimidazole have relatively low interaction energy with the acid in the absence of water (15.3-28.0 kcal mol-1). Energetics of the proton-accepting base-PA complex increases by adding water, indicating that the interactions in the base-acid complex strengthen in the presence of water. On the other hand, hydroxide-donating organic bases, such as tetramethylammonium hydroxide, have high interaction energy with PA (∼110 kcal mol-1), which remains high in the presence of water. The chemical shifts of 31P NMR support the energetics of the base-acid complexes. This study further discusses the benefit of incorporating hydroxide-donating organic bases into the polymeric structure over proton-accepting bases as a way to increase acid retention.

Hydrogen fuel cells are attractive devices for automotive applicationswith benefits such as extended driving range, swiftrefuelling time and clean exhausts1. Although passenger fuelcell electric vehicles have been successfully launched, further technologicalinnovations are needed for the next-generation fuel cellplatform to evolve for heavy-duty vehicles (HDVs)2–4. One of thedifficulties encountered in HDV operation is adequate heat rejection.As current low-temperature polymer electrolyte membranefuel cells (LT-PEMFCs) operate at ~80 °C, the waste heat needs tobe rejected across a 40 °C temperature difference5. Heat rejection inHDVs is facilitated by high cell voltage at rated power (≥0.76 V)6,which translates to lower power densities (100 °C due to high water partial vapour pressure10.Therefore, extensive research efforts to develop polymerelectrolytes for high-temperature polymer electrolyte membranefuel cells (HT-PEMFCs) have been undertaken over the pastdecade. HT-PEMFCs typically use phosphoric acid-doped polybenzimidazole(PA-PBI)11–13. However, PA-PBI-based fuel cells arechallenging to operate below 140 °C or during frequent startup/shutdown14 without suffering a loss of phosphoric acid, which makesHT-PEMFCs unfavourable for automotive applications. We previouslyreported that HT-PEMFCs based on quaternary ammoniumbiphosphate ion-pair coordination (ion-pair HT-PEMFCs) exhibitedexcellent phosphoric acid retention in the temperature range80–200 °C, but the performance of the ion-pair HT-PEMFCs waspoor15–17. Therefore, further performance improvement is requiredfor the ion-pair HT-PEMFCs to be commercially viable for HDVapplications18 (Table 1).Here we report on a protonated phosphonated ionomer thatincreases proton conductivity more than an order of magnitudecompared with a non-protonated phosphonated ionomer. We showexperimental and theoretical evidence of the protonation of phosphonicacids that is distinct from the hydrogen bonding of phosphonicacids18. Based on this concept, we designed protonatedphosphonic acid electrodes that enable remarkable power densityand are well suited for HDV fuel cells.

Place cells are believed to organize memory across space and time, inspiring the idea of the cognitive map. Yet unlike the structured activity in the associated grid and head-direction cells, they remain an enigma: their responses have been difficult to predict and are complex enough to be statistically well-described by a random process. Here we report one step toward the ultimate goal of understanding place cells well enough to predict their fields. Within a theoretical framework in which place fields are derived as a conjunction of external cues with internal grid cell inputs, we predict that even apparently random place cell responses should reflect the structure of their grid inputs and that this structure can be unmasked if probed in sufficiently large neural populations and large environments. To test the theory, we design experiments in long, locally featureless spaces to demonstrate that structured scaffolds undergird place cell responses. Our findings, together with other theoretical and experimental results, suggest that place cells build memories of external inputs by attaching them to a largely prespecified grid scaffold.

Polymerase chain reaction (PCR) is an important means by which to study the urine microbiome and is emerging as possible alternative to urine cultures to identify pathogens that cause urinary tract infection (UTI). However, PCR is limited by its inability to differentiate DNA originating from viable, metabolically active versus non-viable, inactive bacteria. This drawback has led to concerns that urobiome studies and PCR-based diagnosis of UTI are confounded by the presence of relic DNA from non-viable bacteria in urine. Propidium monoazide (PMA) dye can penetrate cells with compromised cell membranes and covalently bind to DNA, rendering it inaccessible to amplification by PCR. Although PMA has been shown to differentiate between non-viable and viable bacteria in various settings, its effectiveness in urine has not been previously studied. We sought to investigate the ability of PMA to differentiate between viable and non-viable bacteria in urine.Varying amounts of viable or non-viable uropathogenicPMA's efficiency in excluding DNA signal from non-viable bacteria was significantly higher in bacterial samples in phosphate-buffered saline (PBS, dCWe have successfully developed PMA-based PCR methods for amplifying DNA from live bacteria in urine. Our results suggest that non-PMA bound DNA from live bacteria can be present in urine, even after antibiotic treatment. This indicates that viable but non-culturable

Significance Cellular membranes span a wide range of spatial dimensions, from the plasma membrane with a scale of microns to vesicles on the nanometer scale. The work presented here identifies a molecular mechanism, based on common features of cellular signaling enzymes, that causes the average enzymatic catalytic rate to exhibit reaction size dependency. This effect stems from stochastic variation, but the final results can be essentially deterministic. In competitive enzymatic reaction cycles, the final product can depend on the size of the reaction system. The simplicity of the mechanism suggests that size-dependent reaction rates may be widespread among signaling enzymes and thus enable reaction size to be an important factor in signal regulation at the membrane., Here, we present detailed kinetic analyses of a panel of soluble lipid kinases and phosphatases, as well as Ras activating proteins, acting on their respective membrane surface substrates. The results reveal that the mean catalytic rate of such interfacial enzymes can exhibit a strong dependence on the size of the reaction system—in this case membrane area. Experimental measurements and kinetic modeling reveal how stochastic effects stemming from low molecular copy numbers of the enzymes alter reaction kinetics based on mechanistic characteristics of the enzyme, such as positive feedback. For the competitive enzymatic cycles studied here, the final product—consisting of a specific lipid composition or Ras activity state—depends on the size of the reaction system. Furthermore, we demonstrate how these reaction size dependencies can be controlled by engineering feedback mechanisms into the enzymes.

The phosphatidylinositol 4-phosphate 5-kinase (PIP5K) family of lipid modifying enzymes generate the majority of phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) lipids found at the plasma membrane in eukaryotic cells. PI(4,5)P2 lipids serve a critical role in regulating receptor activation, ion channel gating, endocytosis, and actin nucleation. Here we describe how PIP5K activity is regulated by cooperative binding to PI(4,5)P2 lipids and membrane-mediated dimerization of the kinase domain. In contrast to constitutively dimeric phosphatidylinositol 5-phosphate 4-kinase (PIP4K, type II PIPK), solution PIP5K exists in a weak monomer-dimer equilibrium. PIP5K monomers can associate with PI(4,5)P2 containing membranes and dimerize in a protein density dependent manner. Although dispensable for PI(4,5)P2 binding and lipid kinase activity, dimerization enhances the catalytic efficiency of PIP5K through a mechanism consistent with allosteric regulation. Additionally, dimerization amplifies stochastic variation in the kinase reaction velocity and strengthens effects such as the recently described stochastic geometry sensing. Overall, the mechanism of PIP5K membrane binding creates a broad dynamic range of lipid kinase activities that are coupled to the density of PI(4,5)P2 and membrane bound kinase.

Background: Cerebral palsy with medically refractory spasticity and dystonia is a condition that often benefits from intrathecal baclofen pump therapy to treat these symptoms. In this case report, an intracranial baclofen catheter was placed in the prepontine space to improve withdrawal symptoms in a patient unable to undergo new lumbar catheter placement due to infection. Case Description: A 22-year-old female with past medical history of cerebral palsy presented with baclofen pump failure and was unable to undergo placement of a new lumbar baclofen catheter due to an infection in her lower back precluding safe and efficacious catheter placement. It was decided the patient would benefit from intrathecal baclofen administered in the prepontine space as a means to avoid a lumbar catheter and thus bypass this prior infection site. An endoscopic third ventriculostomy (ETV) was performed with the endoscope and the distal end of the baclofen pump catheter was fed through this ETV into the prepontine space. Placement in the prepontine space was confirmed by a follow-up head computed tomography. There was a significant improvement in autonomic symptoms and spasticity. By postoperative day 5, the patient was surgically and medically cleared for discharge. Conclusion: In cases of severe baclofen withdrawal due to dysfunctional pumps, immediate reversal is preferred but may not be feasible due to factors such as infection. This case report has demonstrated that prepontine catheter placement can be effective for the administration of baclofen to reverse withdrawal symptoms in these types of patients.

INTRODUCTION To examine the impact of COVID-19 pandemic on the presentation, management and outcome of testicular torsion at our institution.A retrospective review of a prospectively maintained testicular torsion database was performed. Patients ≤ 18 years of age evaluated in our emergency room between 3/11/2020 to 10/1/2020 (during-COVID-19) and the same period in 2018 and 2019 (pre-COVID-19) with US diagnosed and OR confirmed testicular torsion were included. Basic demographics, timing of presentation, referral rate, time to OR and orchiectomy rate were extracted and compared. P0.05 was considered statistically significant.A total of 82 torsions were included in the study; 55 pre-COVID-19 and 27 during-COVID-19. The incidence of testicular torsion remained the same; 3.93 cases/month pre-COVID-19 versus 3.86 cases/month during-COVID-19 (p = 0.791). However, there were significantly fewer delayed (24 hours) presentations (11.1% versus 45.5% , p = 0.003), shorter time from onset of symptoms to presentation (median 15.5 hours versus 8 hours, p = 0.001), and a lower but not statistically significant overall orchiectomy rate (33.3% versus 50.9% p = 0.1608) during-COVID-19. Among those presenting acutely with torsion (24 hours from onset), no statistical differences were found in the median time from US diagnosis to OR, from ED to OR, referral rate, or orchiectomy rate between the two groups. Lastly, SARS-CoV2 testing did not delay median time from ED to OR.There was a notably less delayed presentation of testicular torsion and shorter ischemia time on presentation during-COVID, however, no significant change of time to OR or orchiectomy rate in those with acute testicular torsion were observed.

Non-aqueous lithium-ion redox flow batteries (Li-RFBs) have recently garnered much interest because of their high operating voltage and energy density. Albeit these outstanding advantages, challenges, such as poor cyclability and efficiency, still remain in employing the practical application. In an attempt to address these problems, a series of 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) and TEMPO derivatives catholytes were prepared and investigated as redox-active materials. Electrochemical evaluation exhibited that the introduction of polar and electron-withdrawing substituents to TEMPO was able to enhance the rate capability and cycling stability, when compared to those with the neat TEMPO. Extensive analysis of the electrochemical properties revealed that the electrophilic heteroatom stabilized the radical as well as alleviated the catholyte degradation. Overall, a careful selection of redox-active species demonstrates great promise in improving the current redox flow battery technology.

Poly(2,6-dimethyl-1,4-phenylene ether) (PPE)/Nylon 66 blends have been considered as the potential heat resistant engineering plastics with high mechanical toughness and flame retardancy, suitable for high temperature applications. However, incompatibility between PPE and Nylon 66 and poor thermal stability of Nylon 66 degrade mechanical toughness and flame retardancy. In this work, for the first time, the PPE/Nylon 66 blends with high mechanical toughness and flame retardancy simultaneously have been prepared through newly synthesized compatibilizer of PPE grafted with fumaric acid (PPE-g-FA) and environmental-friendly non-halogen organic phosphinate flame retardant. The PPE/Nylon 66 blend achieved not only V0 grade flame retardancy with the help of improved fire resistance through the solid phase reaction of non-halogenic flame retardant, but also large impact strength larger than 10 kJ/m2 due to the strong compatibility of PPE-g-FA.

Objective To inform the development of strategies to improve adherence to guidelines, we sought to identify characteristics of pediatric patients with nephrolithiasis associated with completing 24-hour urine analyses. Materials and Methods We performed a retrospective cohort study of patients with nephrolithiasis aged 3-18years treated in a large pediatric healthcare system from May 2012 to May 2017. Multivariable Cox models were fit to estimate the association between patient characteristics and completion of a 24-hour urine analysis. Results Among 623 patients, 317 (50.9%) completed a 24-hour urine collection. Median age was 14.4years (interquartile range [IQR] 10.5, 16.3). In adjusted analyses, age at diagnosis (hazard ratio [HR] 1.03; 95% confidence interval [CI] 1.01-1.07), renal colic on presentation (HR 1.72; 95% CI 1.15-2.58), and family history of nephrolithiasis (HR 1.50; 95% CI 1.17-1.93) were associated with an increased likelihood of completion of a 24-hour urine. Public/government assistance insurance (HR 0.68; 95% CI 0.48-0.96) was associated with decreased likelihood of completing a 24-hour urine. Conclusion Patients who had prior painful experiences with stones (renal colic), and potential better understanding of nephrolithiasis (family history, older age on presentation) were more likely to complete a 24-hour urine. Those patients with public insurance/government assistance were less likely to complete a 24-hour urine. These results can be used to develop strategies to improve pediatric patients’ adherence to completing 24-hour urine collections.

Electrophysiology is the most used approach for the collection of functional data in basic and translational neuroscience, but it is typically limited to either intracellular or extracellular recordings. The integration of multiple physiological modalities for the routine acquisition of multimodal data with microelectrodes could be useful for biomedical applications, yet this has been challenging owing to incompatibilities of fabrication methods. Here, we present a suite of glass pipettes with integrated microelectrodes for the simultaneous acquisition of multimodal intracellular and extracellular information in vivo, electrochemistry assessments, and optogenetic perturbations of neural activity. We used the integrated devices to acquire multimodal signals from the CA1 region of the hippocampus in mice and rats, and show that these data can serve as ground-truth validation for the performance of spike-sorting algorithms. The microdevices are applicable for basic and translational neurobiology, and for the development of next-generation brain-machine interfaces.

Silica nanoparticles were chemically grafted onto a porous polyethylene separator to improve the adhesion strength, thermal stability, and electrochemical performance of a polyolefin separator. A surface activation via UVO plasma treatment, followed by silane hybridization yielded a polymeric binder-free, thin coating of SiO2 nanoparticles onto the separator. The chemical grafting provided a much stronger adhesive strength (> 2.5 N/cm), reduced thermal shrinkage (