Membranes Matter: Preventing Ammonia Crossover during Electrochemical Ammonia Synthesis.

The electrochemical nitrogen and nitrate reduction reactions (E-NRR and E-NO3RR) promise to provide decentralized and fossil-fuel-free ammonia synthesis, and as a result, E-NRR and E-NO3RR research has surged in recent years. Membrane NH3/NH4+ crossover during E-NRR and E-NO3RR decreases Faradaic efficiency and thus the overall yield. During catalyst evaluation, such unaccounted-for crossover results in measurement error. Herein, several commercially available membranes were screened and evaluated for use in ammonia-generating electrolyzers. NH3/NH4+ crossover of the commonly used cation-exchange membrane (CEM) Nafion 212 was measured in an H-cell architecture and found to be significant. Interestingly, some anion exchange membranes (AEMs) show negligible NH4+ crossover, addressing the problem of measurement error due to NH4+ crossover. Further investigation of select membranes in a zero-gap gas diffusion electrode (GDE)-cell determines that most membranes show significant NH3 crossover when the cell is in an open circuit. However, uptake and crossover of NH3 are mitigated when -1.6 V is applied across the GDE-cell. The results of this study present AEMs as a useful alternative to CEMs for H-cell E-NRR and E-NO3RR electrolyzer studies and present critical insight into membrane crossover in zero-gap GDE-cell E-NRR and E-NO3RR electrolyzers.

Cluster scaling and critical points: A cautionary tale.

Many systems in nature are conjectured to exist at a critical point, including the brain and earthquake faults. The primary reason for this conjecture is that the distribution of clusters (avalanches of firing neurons in the brain or regions of slip in earthquake faults) can be described by a power law. Because there are other mechanisms such as 1/f noise that can produce power laws, other criteria that the cluster critical exponents must satisfy can be used to conclude whether or not the observed power-law behavior indicates an underlying critical point rather than an alternate mechanism. We show how a possible misinterpretation of the cluster scaling data can lead one to incorrectly conclude that the measured critical exponents do not satisfy these criteria. Examples of the possible misinterpretation of the data for one-dimensional random site percolation and the one-dimensional Ising model are presented. We stress that the interpretation of a power-law cluster distribution indicating the presence of a critical point is subtle and its misinterpretation might lead to the abandonment of a promising area of research.

Post-mortem radiology in fetal and neonatal death: the diagnostic value of post-mortem MRI versus autopsy regarding non-cardiac thoracic and abdominal abnormalities.

AIM: To compare the diagnostic value and accuracy of post-mortem magnetic resonance imaging (PMMRI) and autopsy for non-cardiac thoracic and abdominal abnormalities in fetal death. MATERIALS AND METHODS: This single-institution retrospective study included all consecutive cases of fetal and perinatal death between January 2015 and December 2021 for which PMMRI followed by autopsy was conducted. These cases comprised fetuses at >18 weeks of gestation and preterm and term neonates who lived for <24 h. All PMMRI and autopsy reports were re-assessed and scored for seven non-cardiac thoracic and 52 abdominal abnormalities, and concordance between autopsy and PMMRI findings was determined as the primary outcome. RESULTS: Eighty cases were included in this study. Fetal loss was caused by termination of pregnancy in 80% of cases. Further, the mean gestational age was 166 days (23 weeks and 5 days, range 126-283 days). The concordance between PMMRI and autopsy for non-cardiac thoracic and abdominal abnormalities was 83.1% (95% confidence interval [CI] 71.3-83.3) and 76.3% (95% CI 65.8-84.2%), respectively, with a substantial and moderate strength of agreement (Cohen's kappa = 0.63 and 0.51 respectively). CONCLUSION: PMMRI exhibited good overall diagnostic value for non-cardiac thoracic and abdominal abnormalities, specifically large structural abnormalities. PMMRI may offer parents and physicians a valuable addition to autopsy for the detection of non-cardiac thoracic and abdominal abnormalities, or even an alternative option when parents do not consent to autopsy.

Mean-field theory of an asset exchange model with economic growth and wealth distribution.

We develop a mean-field theory of the growth, exchange, and distribution (GED) model introduced by Liu et al. [K. K. L. Liu et al., preceding paper, Phys. Rev. E 104, 014150 (2021)10.1103/PhysRevE.104.014150] that accurately describes the phase transition in the limit that the number of agents N approaches infinity. The GED model is a generalization of the yard-sale model in which the additional wealth added by economic growth is nonuniformly distributed to the agents according to their wealth in a way determined by the parameter λ. The model is shown numerically to have a phase transition at λ=1 and be characterized by critical exponents and critical slowing down. Our mean-field treatment of the GED model correctly predicts the existence of the phase transition, a critical slowing down, and the values of the critical exponents and introduces an energy whose probability satisfies the Boltzmann distribution for λ<1, implying that the system is in thermodynamic equilibrium in the limit that N→∞. We show that the values of the critical exponents obtained by varying λ for a fixed value of N do not satisfy the usual scaling laws, but do satisfy scaling if a combination of parameters, which we refer to as the Ginzburg parameter, is much greater than one and is held constant. We discuss possible implications of our results for understanding economic systems and the subtle nature of the mean-field limit in systems with both additive and multiplicative noise.

Simulation of a generalized asset exchange model with economic growth and wealth distribution.

The agent-based yard-sale model of wealth inequality is generalized to incorporate exponential economic growth and its distribution. The distribution of economic growth is nonuniform and is determined by the wealth of each agent and a parameter λ. Our numerical results indicate that the model has a critical point at λ=1 between a phase for λ<1 with economic mobility and exponentially growing wealth of all agents and a nonstationary phase for λ≥1 with wealth condensation and no mobility. We define the energy of the system and show that the system can be considered to be in thermodynamic equilibrium for λ<1. Our estimates of various critical exponents are consistent with a mean-field theory [see W. Klein et al., following paper, Phys. Rev. E 104, 014151 (2021)10.1103/PhysRevE.104.014151]. The exponents do not obey the usual scaling laws unless a combination of parameters that we refer to as the Ginzburg parameter is held fixed as the phase transition is approached. The model illustrates that both poorer and richer agents benefit from economic growth if its distribution does not favor the richer agents too strongly. This work and the following theoretical paper contribute to our understanding of whether the methods of equilibrium statistical mechanics can be applied to economic systems.

Intermediates and products of the reaction of Zn(ii) organyls with tetrel element Zintl ions: cluster extension versus complexation.

The discovery of low-valent Zn compounds resulted in the renaissance of organometallic Zn complexes. Polyhedral clusters of tetrel elements can interact with Zn atoms either as Lewis donors or by incorporation of the Zn atoms as additional cluster vertices. Herein we report the reactions of ZnR2 (R = ethyl (Et), pentamethylcyclopentadiene (Cp*), phenyl (Ph) and 1,3,5-trimethylbenzene (Mes)) with Zintl ions of the types [E4]4- (E = Ge, Sn) and [Ge9]4- in liquid ammonia. Besides the desired Zintl ion complexes, intermediates were isolated that give insight into the reaction of organo Zn compounds in liquid ammonia. Three ions, [(η3:η3-Ge4)(ZnEt)2]2- (1a), [(η2-Sn4)Zn(η2-Sn4)]6- (2a) and [(η4-Ge9)(ZnEt)]3- (3a), were obtained and characterized by means of single crystal X-ray diffraction analysis. Furthermore, amides [(ZnPh2)2(µ2-NH2)2]2- (4a) and {[Zn(µ2-NH2)4][(ZnEt)2(µ2-NH2)2]2}2- (5a) were formed during the reactions, together with the addition products [ZnPh3]- (6a) and [ZnMes3]- (7a) and an anion [Cp*]- (8a), suggesting the following reaction sequence: in liquid ammonia the Zintl anions form amides, which then serve as ligands for ZnR2 molecules. The NH2- ligands weaken the corresponding Zn-R bonds, and thus bond cleavage and the addition of the Zintl anion to the Zn ion can take place, additionally promoted by the trapping of the leaving group R- by unreacted Zn organyls with the formation of [ZnR3]-.

Effective ergodicity breaking phase transition in a driven-dissipative system.

We show that the Olami-Feder-Christensen model exhibits an effective ergodicity breaking transition as the noise is varied. Above the critical noise, the system is effectively ergodic because the time-averaged stress on each site converges to the global spatial average. In contrast, below the critical noise, the stress on individual sites becomes trapped in different limit cycles, and the system is not ergodic. To characterize this transition, we use ideas from the study of dynamical systems and compute recurrence plots and the recurrence rate. The order parameter is identified as the recurrence rate averaged over all sites and exhibits a jump at the critical noise. We also use ideas from percolation theory and analyze the clusters of failed sites to find numerical evidence that the transition, when approached from above, can be characterized by exponents that are consistent with hyperscaling.

Prediction in a driven-dissipative system displaying a continuous phase transition using machine learning.

Prediction in complex systems at criticality is believed to be very difficult, if not impossible. Of particular interest is whether earthquakes, whose distribution follows a power-law (Gutenberg-Richter) distribution, are in principle unpredictable. We study the predictability of event sizes in the Olmai-Feder-Christensen model at different proximities to criticality using a convolutional neural network. The distribution of event sizes satisfies a power law with a cutoff for large events. We find that predictability decreases as criticality is approached and that prediction is possible only for large, nonscaling events. Our results suggest that earthquake faults that satisfy Gutenberg-Richter scaling are difficult to forecast.

High-Performance Bipolar Membrane Development for Improved Water Dissociation.

Bipolar membranes (BPMs) are the enabling component of many promising electrochemical devices used for separation and energy conversion. Here, we describe the development of high-performance BPMs, including two-dimensional BPMs (2D BPMs) prepared by hot-pressing two preformed membranes and three-dimensional BPMs (3D BPMs) prepared by electrospinning ionomer solutions and polyethylene oxide. Graphene oxide (GOx) was introduced into the BPM junction as a water-dissociation catalyst. We assessed electrochemical performance of the prepared BPMs by voltage-current (V-I) curves and galvanostatic electrochemical impedance spectroscopy. We found the optimal GOx loading in 2D BPMs to be 100 µg cm-2, which led to complete coverage of GOx at the interface. The integration of GOx beyond this loading moderately improved electrochemical performance but significantly compromised mechanical strength. GOx-catalyzed 2D BPMs showed comparable performance with a commercially available Fumasep BPM at current densities up to 500 mA cm-2. The 3D BPMs exhibited even better performance: lower resistance and higher efficiency for water dissociation and substantially higher stability under repeated cycling up to high current densities. The improved electrochemical performance and mechanical stability of the 3D BPMs make them suitable for incorporation into CO2 electrolysis devices where high current densities are necessary.

Low-Cost, Efficient, and Durable H2 Production by Photoelectrochemical Water Splitting with CuGa3Se5 Photocathodes.

Photoelectrochemical (PEC) water splitting is an elegant method of converting sunlight and water into H2 fuel. To be commercially advantageous, PEC devices must become cheaper, more efficient, and much more durable. This work examines low-cost polycrystalline chalcopyrite films, which are successful as photovoltaic absorbers, for application as PEC absorbers. In particular, Cu-Ga-Se films with wide band gaps can be employed as top cell photocathodes in tandem devices as a realistic route to high efficiencies. In this report, we demonstrate that decreasing Cu/Ga composition from 0.66 to 0.31 in Cu-Ga-Se films increased the band gap from 1.67 to 1.86 eV and decreased saturated photocurrent density from 18 to 8 mA/cm2 as measured by chopped-light current-voltage (CLIV) measurements in a 0.5 M sulfuric acid electrolyte. Buffer and catalyst surface treatments were not applied to the Cu-Ga-Se films, and they exhibited promising stability, evidenced by unchanged CLIV after 9 months of storage in air. Finally, films with Cu/Ga = 0.36 (approximately stoichiometric CuGa3Se5) and 1.86 eV band gaps had exceptional durability and continuously split water for 17 days (∼12 mA/cm2 at -1 V vs RHE). This is equivalent to ∼17 200 C/cm2, which is a world record for any polycrystalline PEC absorber. These results indicate that CuGa3Se5 films are prime candidates for cheaply achieving efficient and durable PEC water splitting.

Biochemical Effects on the Liver of 1 Month of Alcohol Abstinence in Moderate Alcohol Consumers.

SHORT SUMMARY: : In this study in healthy moderate alcohol consumers, we observe that one month of alcohol abstinence results in decreased gamma-glutamyl transferase levels, which return to baseline levels after resumption of alcohol consumption.

Dutch guideline for clinical foetal-neonatal and paediatric post-mortem radiology, including a review of literature.

Clinical post-mortem radiology is a relatively new field of expertise and not common practice in most hospitals yet. With the declining numbers of autopsies and increasing demand for quality control of clinical care, post-mortem radiology can offer a solution, or at least be complementary. A working group consisting of radiologists, pathologists and other clinical medical specialists reviewed and evaluated the literature on the diagnostic value of post-mortem conventional radiography (CR), ultrasonography, computed tomography (PMCT), magnetic resonance imaging (PMMRI), and minimally invasive autopsy (MIA). Evidence tables were built and subsequently a Dutch national evidence-based guideline for post-mortem radiology was developed. We present this evaluation of the radiological modalities in a clinical post-mortem setting, including MIA, as well as the recently published Dutch guidelines for post-mortem radiology in foetuses, neonates, and children. In general, for post-mortem radiology modalities, PMMRI is the modality of choice in foetuses, neonates, and infants, whereas PMCT is advised in older children. There is a limited role for post-mortem CR and ultrasonography. In most cases, conventional autopsy will remain the diagnostic method of choice. CONCLUSION: Based on a literature review and clinical expertise, an evidence-based guideline was developed for post-mortem radiology of foetal, neonatal, and paediatric patients. What is Known: • Post-mortem investigations serve as a quality check for the provided health care and are important for reliable epidemiological registration. • Post-mortem radiology, sometimes combined with minimally invasive techniques, is considered as an adjunct or alternative to autopsy. What is New: • We present the Dutch guidelines for post-mortem radiology in foetuses, neonates and children. • Autopsy remains the reference standard, however minimal invasive autopsy with a skeletal survey, post-mortem computed tomography, or post-mortem magnetic resonance imaging can be complementary thereof.

Disclosure of cardiac variants of uncertain significance results in an exome cohort.

This study examined the impact of disclosing subclassifications of genetic variants of uncertain significance (VUS) on behavioral intentions. We studied return of VUS results to 79 individuals with a cardiomyopathy-associated VUS, subclassified into VUS-high or VUS-low. Primary outcomes were perceived risk (absolute and comparative), perceived severity, perceived value of information, self-efficacy, decision regret, and behavioral intentions to share results and change behaviors. There was no significant difference between the 2 subclasses in overall behavioral intentions (t = 0.023, P = .982) and each of the individual items on the behavioral intentions scale; absolute (t = -1.138, P = .259) or comparative (t = -0.463, P = .645) risk perceptions; perceived value of information (t = 0.582, P = .563) and self-efficacy (t = -0.733, P = .466). Decision regret was significantly different (t = 2.148, P = .035), with VUS-low (mean = 17.24, SD = 16.08) reporting greater regret. Combining the subclasses, perceived value of information was the strongest predictor of behavioral intentions (ß = 0.524, P < .001). Participants generally understood the meaning of a genetic VUS result classification and reported satisfaction with result disclosure. No differences in behavioral intentions were found, but differences in decision regret suggest participants distinguish subclasses of VUS results. The perceived value of VUS may motivate recipients to pursue health-related behaviors.

Radiological imaging of teratological fetuses: what can we learn?

OBJECTIVES: To determine the advantages of radiological imaging of a collection of full-term teratological fetuses in order to increase their scientific and educational value. BACKGROUND : Anatomical museums around the world exhibit full-term teratological fetuses. Unfortunately, these museums are regularly considered as "morbid cabinets". Detailed dysmorphological information concerning the exhibited specimens is often lacking. Moreover, fetuses with severe and complex congenital anomalies are frequently diagnosed incompletely, incorrectly or not at all. METHODS: In order to verify diagnoses and to enrich their educational and scientific value, we imaged 41 out of the 72 teratological specimens present in the collection of our Anatomy and Pathology Museum in Nijmegen (The Netherlands) by means of magnetic resonance imaging (MRI) and computed tomography (CT). Additionally, contemporary dysmorphological insights and 3D models are implemented in the teratology education of medical students and residents. CONCLUSIONS: Full-term teratological fetuses have become increasingly rare and deserve a prominent place in every anatomical museum; they are suitable for contemporary teratological research and education. Modern radiological techniques markedly enhance their scientific and didactic value. TEACHING POINTS: • To explore the scientific and educational potential of institutionalised teratological collections • To understand the additional value of radiological imaging in diagnosing teratological specimens • To learn about the specific settings of MRI parameters when scanning fixed specimens • To recognise specific internal dysmorphology in several congenital anomalies.

Formation of the intermetalloid cluster [AgSn18]7- - the reactivity of coinage metal NHC compounds towards [Sn9]4.

In recent years the formation of intermetalloid clusters by reacting homoatomic tetrel cluster anions with transition metal complexes has become a promising synthetic route. Nevertheless a better understanding of the processes occurring in solution is necessary. Here we present a series of novel polyanionic coinage metal NHC Zintl clusters [NHCDippM(η4-Sn9)]3- (M: Cu, Ag, Au; Dipp: diisopropylphenyl) which are obtained at low temperatures from the reaction of K4Sn9 with NHCDippMCl (M: Cu-Au) in liquid ammonia. For M = Ag a larger intermetalloid AgI-bridged nonastannide dimer [(η4-Sn9)Ag(η1-Sn9)]7- is also formed. The stepwise formation of the intermetalloid cluster [AgSn18]7- is discussed and compared with that of previously reported intermetalloid stannides.

PUGS: A novel scale to assess perceptions of uncertainties in genome sequencing.

Expectations of results from genome sequencing by end users are influenced by perceptions of uncertainty. This study aimed to assess uncertainties about sequencing by developing, evaluating, and implementing a novel scale. The Perceptions of Uncertainties in Genome Sequencing (PUGS) scale comprised ten items to assess uncertainties within three domains: clinical, affective, and evaluative. Participants (n=535) from the ClinSeq® NIH sequencing study completed a baseline survey that included the PUGS; responses (mean = 3.4/5, SD=0.58) suggested modest perceptions of certainty. A confirmatory factor analysis identified factor loadings that led to elimination of two items. A revised eight-item PUGS scale was used to test correlations with perceived ambiguity (r = -0.303, p < 0.001), attitudinal ambivalence (r = -0.111, p = 0.011), and ambiguity aversion (r = -0.093, p = 0.033). Results support nomological validity. A correlation with the MICRA uncertainty subscale was found among 175 cohort participants who had received results (r = -0.335, p < 0.001). Convergent and discriminant validity were also satisfied in a second sample of 208 parents from the HudsonAlpha CSER Project who completed the PUGS (mean = 3.4/5, SD = 0.72), and configural invariance was supported across the two datasets. As such, the PUGS is a promising scale for evaluating perceived uncertainties in genome sequencing, which can inform interventions to help patients form realistic expectations of these uncertainties.

Foreshock and aftershocks in simple earthquake models.

Many models of earthquake faults have been introduced that connect Gutenberg-Richter (GR) scaling to triggering processes. However, natural earthquake fault systems are composed of a variety of different geometries and materials and the associated heterogeneity in physical properties can cause a variety of spatial and temporal behaviors. This raises the question of how the triggering process and the structure interact to produce the observed phenomena. Here we present a simple earthquake fault model based on the Olami-Feder-Christensen and Rundle-Jackson-Brown cellular automata models with long-range interactions that incorporates a fixed percentage of stronger sites, or asperity cells, into the lattice. These asperity cells are significantly stronger than the surrounding lattice sites but eventually rupture when the applied stress reaches their higher threshold stress. The introduction of these spatial heterogeneities results in temporal clustering in the model that mimics that seen in natural fault systems along with GR scaling. In addition, we observe sequences of activity that start with a gradually accelerating number of larger events (foreshocks) prior to a main shock that is followed by a tail of decreasing activity (aftershocks). This work provides further evidence that the spatial and temporal patterns observed in natural seismicity are strongly influenced by the underlying physical properties and are not solely the result of a simple cascade mechanism.

Evidence that small molecule enhancement of ß-hexosaminidase activity corrects the behavioral phenotype in Dutch APP(E693Q) mice through reduction of ganglioside-bound Aß.

Certain mutant Alzheimer's amyloid-ß (Aß) peptides (that is, Dutch mutant APP(E693Q)) form complexes with gangliosides (GAß). These mutant Aß peptides may also undergo accelerated aggregation and accumulation upon exposure to GM2 and GM3. We hypothesized that increasing ß-hexosaminidase (ß-hex) activity would lead to a reduction in GM2 levels, which in turn, would cause a reduction in Aß aggregation and accumulation. The small molecule OT1001 is a ß-hex-targeted pharmacological chaperone with good bioavailability, blood-brain barrier penetration, high selectivity for ß-hex and low cytotoxicity. Dutch APP(E693Q) transgenic mice accumulate oligomeric Aß as they age, as well as Aß oligomer-dose-dependent anxiety and impaired novel object recognition (NOR). Treatment of Dutch APP(E693Q) mice with OT1001 caused a dose-dependent increase in brain ß-hex levels up to threefold over those observed at baseline. OT1001 treatment was associated with reduced anxiety, improved learning behavior in the NOR task and dramatically reduced GAß accumulation in the subiculum and perirhinal cortex, both of which are brain regions required for normal NOR. Pharmacological chaperones that increase ß-hex activity may be useful in reducing accumulation of certain mutant species of Aß and in preventing the associated behavioral pathology.

Parameter uncertainty analysis of a biokinetic model of caesium.

Parameter uncertainties for the biokinetic model of caesium (Cs) developed by Leggett et al. were inventoried and evaluated. The methods of parameter uncertainty analysis were used to assess the uncertainties of model predictions with the assumptions of model parameter uncertainties and distributions. Furthermore, the importance of individual model parameters was assessed by means of sensitivity analysis. The calculated uncertainties of model predictions were compared with human data of Cs measured in blood and in the whole body. It was found that propagating the derived uncertainties in model parameter values reproduced the range of bioassay data observed in human subjects at different times after intake. The maximum ranges, expressed as uncertainty factors (UFs) (defined as a square root of ratio between 97.5th and 2.5th percentiles) of blood clearance, whole-body retention and urinary excretion of Cs predicted at earlier time after intake were, respectively: 1.5, 1.0 and 2.5 at the first day; 1.8, 1.1 and 2.4 at Day 10 and 1.8, 2.0 and 1.8 at Day 100; for the late times (1000 d) after intake, the UFs were increased to 43, 24 and 31, respectively. The model parameters of transfer rates between kidneys and blood, muscle and blood and the rate of transfer from kidneys to urinary bladder content are most influential to the blood clearance and to the whole-body retention of Cs. For the urinary excretion, the parameters of transfer rates from urinary bladder content to urine and from kidneys to urinary bladder content impact mostly. The implication and effect on the estimated equivalent and effective doses of the larger uncertainty of 43 in whole-body retention in the later time, say, after Day 500 will be explored in a successive work in the framework of EURADOS.