Neutral State Research Articles

Exploring mass transfer mechanisms in reverse osmosis membranes: A comparative study of SDM and DSPM-DE models

Thin-film composite reverse osmosis (RO) membranes have dominated desalination technology for decades, with the solution diffusion model (SDM) serving as the gold standard for interpreting mass transfer phenomena since its inception. However, debates still persist regarding the effect of charge on separation performance, owing to the SDM's inability to explore membrane charge. In this study, polyethyleneimine (PEI) was utilized to modify the surface of a commercial seawater desalination membrane (SW30, Dupont Company), imparting regulatable charge properties based on the solution pH. The separation performance of the modified RO membrane was experimentally validated under varying NaCl feed salinities. Specifically, the Donnan-steric pore model with dielectric exclusion (DSPM-DE), known as a charge-responsive model, was employed and juxtaposed with SDM to authenticate the experimental findings. The results indicated that the dielectric effect primarily governed ion distribution (Na+ and Cl−) within the membrane, followed by the steric effect, and ultimately, the Donnan effect. Consequently, DSPM-DE aligned well with the observed salt rejection only when the membrane was strongly charged (that is, under acidic or alkaline conditions), but performed poorly in the neutral state. This observation, rarely revealed in previous research, stems from conventional desalination membranes being negatively charged in most natural water environments. Conversely, the SDM aligned well with the experimental data because it solely considered the solutes' solubility parameters and diffusion coefficient, independently of the surface charge of the desalination membranes. Given the extensive research on surface modification, our study demonstrates the limited influence of charge effects on the selective enhancement of RO membranes.

Ingestible pills reveal gastric correlates of emotions.

Although it is generally held that gastrointestinal (GI) signals are related to emotions, direct evidence for such a link is currently lacking. One of the reasons why the internal milieu of the GI system is poorly investigated is because visceral organs are difficult to access and monitor. To directly measure the influence of endoluminal markers of GI activity on the emotional experience, we asked a group of healthy male participants to ingest a pill that measured pH, pressure, and temperature of their GI tract while they watched video clips that consistently induced disgust, fear, happiness, sadness, or a control neutral state. In addition to the objective physiological markers of GI activity, subjective ratings of perceived emotions and visceral (i.e. gastric, respiratory and cardiac) sensations were recorded, as well as changes in heart rate (HR), heart rate variability (HRV) and spontaneous eyes blinks as non-gastric behavioral and autonomic markers of the emotional experience. We found that when participants observed fearful and disgusting video clips, they reported to perceive not only cardiac and respiratory sensations but also gastric sensations, such as nausea. Moreover, we found that there was a clear relation between the physiology of the stomach and the perceived emotions. Specifically, when disgusting video clips were displayed, the more acidic the pH, the more participants reported feelings of disgust and fear; the less acidic the pH, the more they reported happiness. Complementing the results found in the deep gastric realm, we found that disgusting stimuli induced a significant increase in HRV compared to the neutral scenarios, and together with fearful video clips a decrease in HR. Our findings suggest that gastric signals contribute to unique emotional states and that ingestible pills may open new avenues for exploring the deep-body physiology of emotions.

Polarization‐Dependent and Color‐Tunable Electrochromic Smart Windows: Uniaxially Oriented and Polymer‐Stabilized Viologen‐Based Liquid Crystal Networks

AbstractViologen‐based reactive mesogen (VRM) is newly designed and synthesized for the development of polarization‐dependent, color‐tunable, and transparent electrochromic (EC) smart windows. By controlling electric field, the color of VRM can be intentionally tuned due to the formation of dication (D state), cation‐radical (C state), and neutral state (N state). Based on the deep understanding of phase transition of VRM, a uniaxially oriented VRM hierarchical nanostructure is successfully constructed on the macroscopic area by simple coating and self‐assembly processes. The subsequent photopolymerization significantly improves thermal, mechanical, and chemical stabilities of the VRM thin film. In addition to the control of color, the transmittance of uniaxially oriented VRM‐based EC smart window can be precisely tuned by rotating a linear polarizer.

Physical analysis of aspirin in different phases and states using density functional theory

This study analyzed the aspirin molecule (C9H8O4) using Density Functional Theory (DFT) on Gaussian 09W software. First, the structure of aspirin was optimized using the DFT method with the B3LYP functional and the 6-311+G (d,p) basis set. A global reactivity study was employed to understand the reactivity of aspirin in gas and solvent water for both anion and neutral states. To understand the involvement of orbitals in chemical stability and electron conductivity, we calculated the HOMO-LUMO. The thermodynamic function of a molecule was understood using thermochemistry. Molecular Electrostatic Potential (MEP) was employed to understand the physiochemical properties of aspirin. We observed the Mulliken atomic charge to calculate the atomic charge of aspirin. Finally, the title molecule's UV–Vis, FTIR, and Raman spectra are analyzed and compared with the experimental data.

Computational Insights Into Betanin for Dsscs: Unraveling Deprotonation Variations and Identifying Optimal Anchoring Sites on TiO2

AbstractBetanin (Bn), a natural dye in the Betalains family, predominantly takes on a cationic form known as Bn+. However, it exists in a neutral state as Bn_C2, Bn_C15, and Bn_C17 by losing an H+ from one of its carboxylic acids. Density functional theory (DFT) and Time‐dependent density functional theory (TD‐DFT) studies evaluate the efficiency of each betanin form and pinpoint the most probable anchoring point to TiO2. The Bn_C17 variant stands out as a highly promising candidate for DSSC cells, demonstrating a distinctive combination of electron injection efficiency, electrochemical performance, hole transport capabilities, and photovoltaic behavior. Considering factors like adsorption energy, binding mode, structural compatibility, electronic properties, and absorption characteristics, Bn_C17@TiO2 emerges as the most favorable dye@TiO2 complex among the studied betanin forms for DSSC applications. Contrastingly, the C2‐COOH anchoring point presents challenges with monodentate binding, a different orientation, and potential load distribution issues. This behavior, resembling that of a p‐type dye, differs from the n‐type behavior exhibited by the C15‐COOH and C17‐COOH forms, making the latter two more suitable as sensitizers. Consequently, C2‐COOH may not be the optimal anchoring point for TiO2 in the investigated betanin forms, especially when compared to the more favorable C17‐COOH anchoring point.

Exploring the Relative Importance of the MJO and ENSO to North Pacific Subseasonal Predictability

AbstractHere we explore the relative contribution of the Madden‐Julian Oscillation (MJO) and El Niño Southern Oscillation (ENSO) to midlatitude subseasonal predictive skill of upper atmospheric circulation over the North Pacific, using an inherently interpretable neural network applied to pre‐industrial control runs of the Community Earth System Model version 2. We find that this interpretable network generally favors the state of ENSO, rather than the MJO, to make correct predictions on a range of subseasonal lead times and predictand averaging windows. Moreover, the predictability of positive circulation anomalies over the North Pacific is comparatively lower than that of their negative counterparts, especially evident when the ENSO state is important. However, when ENSO is in a neutral state, our findings indicate that the MJO provides some predictive information, particularly for positive anomalies. We identify three distinct evolutions of these MJO states, offering fresh insights into opportune forecasting windows for MJO teleconnections.

Sensitive detection and imaging of H2O density through Rydberg resonant femtosecond laser induced photofragmentation fluorescence.

A femtosecond laser induced photofragmentation fluorescence (fs-LIPF) scheme for the sensitive detection and imaging of water vapor is presented. Two photons of 244.3nm excite water to the D̃ state and produce hydroxyl radicals in the fluorescing à state. Two more photons promote electrons from the D̃ state to a neutral Rydberg state of the (1b2)-1 ionic core through a 2 + 2 doubly resonant process. The resulting high-lying Rydberg state undergoes neutral dissociation, and the energetic hydrogen fragments are detected from their Balmer series fluorescence. These channels (in the low-pressure limit) have detection sensitivities around 1012 molecules per cubic centimeters, orders of magnitude more sensitive than laser-induced fluorescence based approaches, allowing for sensitive non-invasive detection and imaging of water density for many important processes.

Longitudinal-transverse splitting and fine structure of Fermi polarons in two-dimensional semiconductors

Interaction of excitons with resident charge carriers in semiconductors gives rise to bound three-particle complexes, trions, whose optical response is conveniently described in the framework of many-body correlated Fermi polaron states. These states are formed as a result of correlation of photocreated trion with the Fermi sea hole and possess the angular momentum component of ±1 depending on the helicity of the photon. We study theoretically the energy spectrum fine structure of Fermi polarons in two-dimensional semiconductors based on transition metal dichalcogenides. We demonstrate both by the symmetry analysis and microscopic calculation that the Fermi polarons with nonzero in-plane wavevector k are split, similarly to the neutral exciton states, into the linearly polarized longitudinal and transverse, with respect to the k, states. The origin of this longitudinal-transverse splitting is the long-range electron-hole exchange interaction that can be also described as the interaction of Fermi polarons with their induced electromagnetic field. The effective Hamiltonian describing the Fermi polaron fine structure is derived, and its parameters are determined from the microscopic model.

Reference Energies for Valence Ionizations and Satellite Transitions.

Upon ionization of an atom or a molecule, another electron (or more) can be simultaneously excited. These concurrently generated states are called "satellites" (or shakeup transitions) as they appear in ionization spectra as higher-energy peaks with weaker intensity and larger width than the main peaks associated with single-particle ionizations. Satellites, which correspond to electronically excited states of the cationic species, are notoriously challenging to model using conventional single-reference methods due to their high excitation degree compared to the neutral reference state. This work reports 42 satellite transition energies and 58 valence ionization potentials (IPs) of full configuration interaction quality computed in small molecular systems. Following the protocol developed for the quest database [Véril, M.; Scemama, A.; Caffarel, M.; Lipparini, F.; Boggio-Pasqua, M.; Jacquemin, D.; and Loos, P.-F. Wiley Interdiscip. Rev.: Comput. Mol. Sci. 2021, 11, e1517], these reference energies are computed using the configuration interaction using a perturbative selection made iteratively (CIPSI) method. In addition, the accuracy of the well-known coupled-cluster (CC) hierarchy (CC2, CCSD, CC3, CCSDT, CC4, and CCSDTQ) is gauged against these new accurate references. The performances of various approximations based on many-body Green's functions (GW, GF2, and T-matrix) for IPs are also analyzed. Their limitations in correctly modeling satellite transitions are discussed.

Optional but not qualified: Neutrality, the UN Charter and humanitarian objectives

Abstract Neutral States must abstain from supporting a party to a conflict with military equipment and assistance. This core aspect of the law of neutrality has not changed with the adoption of the UN Charter in 1945, or with the brutal Russian aggression against Ukraine. That said, by reviewing the changes to neutrality law over time, this article finds plausible reasons to believe that neutrality has – for better or worse – become optional for the vast majority of States, which can today opt to be non-belligerent States – i.e., States that are neither neutral nor parties to the armed conflict. All States have to cooperate to bring to an end serious violations of international law, including humanitarian law, and this duty of cooperation has abolished “sitting-still neutrality”, but it does not render neutrality law moot. This reading of “optional but not qualified” neutrality maintains the core neutrality idea of abstaining in military matters. In this article, I argue that views of “obsolete” or “qualified” neutrality are not new at all but depart from well-accepted rules of legal interpretation and raise concerns about double standards. Viewing neutrality as optional but unqualifiable offers greater conceptual clarity, is more honest than alternative views, and comes with advantages for humanitarian action.

Omega-3 alleviates behavioral and molecular changes in a mouse model of stress-induced juvenile depression

IntroductionDepression is increasingly diagnosed in adolescence, necessitating specific prevention and treatment methods. However, there is a lack of animal models mimicking juvenile depression. This study explores a novel model using ultrasound (US) stress in juvenile mice. MethodsWe employed the US stress model in one-month-old C57/BL6 mice, exposing them to alternating ultrasound frequencies (20–25 kHz and 25–45 kHz) for three weeks. These frequencies correspond to negative and neutral emotional states in rodents and can induce a depressive-like syndrome. Concurrently, mice received either an omega-3 food supplement (FS) containing eicosapentaenoic acid (EPA; 0.55 mg/kg/day) and docosahexaenoic acid (DHA; 0.55 mg/kg/day) or a vehicle. Post-stress, we evaluated anxiety- and depressive-like behaviors, blood corticosterone levels, brain expression of pro-inflammatory cytokines, and conducted metabolome analysis of brain, liver and blood plasma. ResultsUS-exposed mice treated with vehicle exhibited decreased sucrose preference, a sign of anhedonia, a key feature of depression, increased anxiety-like behavior, elevated corticosterone levels, and enhanced TNF and IL-1β gene expression in the brain. In contrast, US-FS mice did not display these changes. Omega-3 supplementation also reduced anxiety-like behavior in non-stressed mice. Metabolomic analysis revealed US-induced changes in brain energy metabolism, with FS increasing brain sphingomyelin. Liver metabolism was affected by both US and FS, while plasma metabolome changes were exclusive to FS. Brain glucose levels correlated positively with activity in anxiety tests. ConclusionChronic omega-3 intake counteracted depressive- and anxiety-like behaviors in a US model of juvenile depression in mice. These effects likely stem from the anti-inflammatory properties of the supplement, suggesting potential therapeutic applications in juvenile depression.

3,6‐Divinyl‐N‐arylcarbazoles‐bridged diruthenium complexes bearing two Ru(CO)Cl(PiPr3)2 moieties: Polyelectrochromism and electronic coupling

A series of five 3,6‐divinyl‐N‐arylcarbazoles‐bridged diruthenium complexes with a general formula of [{Ru(CO)Cl(PiPr3)2}2(μ‐(CH=CH)2‐(N‐arylcarbazole)‐3,6); aryl = 4‐anisyl; [1a], 4‐tolyl; [1b], phenyl; [1c], 4‐(trifluoromethyl)phenyl; [1d], and 4‐nitrophenyl; [1e]] were successfully synthesized. These new square‐pyramidal bis(ruthenium‐vinyl)‐type complexes were characterized in their neutral state via classical NMR, UV/Vis, and IR spectroscopic techniques and in their three various accessible oxidized states via electrochemical techniques and ESR spectroscopy along with UV/Vis/NIR and IR spectroelectrochemistry as well as with DFT calculations. Our obtained results were compared with the closely related bis(ruthenium‐vinyl)‐appended N‐(4‐anisyl)diphenylamine TAARu2 counterpart of [1a]. Electrochemical studies on complexes [1a]–[1e] revealed three consecutive, chemically and electrochemically, well‐separated, reversible one‐electron oxidation processes at low and well‐accessible potentials. Their half‐wave potential separations ΔE½ between the individual redox waves and the derived comproportionation constants Kc1–Kc3 attribute to noteworthy stability of every oxidized intermediate state. The concert electrochemical and UV/Vis/NIR/IR spectro(electro)scopic results on these rotationally restricted N‐arylcarbazoles‐bridged bis(ruthenium‐alkenyl)‐type complexes [1a]–[1e] confirmed the relative weakness influence of altering the para‐substituent on the peripheral aryl ring. This is most probably due to the sizable torsion with nearly 55° between the co‐planarity of the carbazole heterocycle core and the peripheral N‐bound aryl ring. In their mixed‐valent (MV) radical states [1a]+–[1e]+, the observed pattern of two well‐separated Ru(C≡O) bands mirrors the uneven distribution of the uni‐positive charge over the two chemically equivalent bis(ruthenium‐vinyl) moieties as indicated by classical class II of Robin–Day classification of MV states.

Strategies for Reliable Stress Recognition: A Machine Learning Approach Using Heart Rate Variability Features.

Stress recognition, particularly using machine learning (ML) with physiological data such as heart rate variability (HRV), holds promise for mental health interventions. However, limited datasets in affective computing and healthcare research can lead to inaccurate conclusions regarding the ML model performance. This study employed supervised learning algorithms to classify stress and relaxation states using HRV measures. To account for limitations associated with small datasets, robust strategies were implemented based on methodological recommendations for ML with a limited dataset, including data segmentation, feature selection, and model evaluation. Our findings highlight that the random forest model achieved the best performance in distinguishing stress from non-stress states. Notably, it showed higher performance in identifying stress from relaxation (F1-score: 86.3%) compared to neutral states (F1-score: 65.8%). Additionally, the model demonstrated generalizability when tested on independent secondary datasets, showcasing its ability to distinguish between stress and relaxation states. While our performance metrics might be lower than some previous studies, this likely reflects our focus on robust methodologies to enhance the generalizability and interpretability of ML models, which are crucial for real-world applications with limited datasets.

Interatomic potential for sodium and chlorine in both neutral and ionic states

Interatomic potential for sodium and chlorine in both neutral and ionic states

Temporal dynamics of positive emotion regulation: insights from facial electromyography.

Emotion regulation (ER) is a complex process that manifests gradually over time. This study investigated the temporal dynamics of ER in modifying positive emotions in terms of both negative affect (NA) and positive affect (PA) dimensions. After participants had been exposed to pleasant pictures for 8,000 ms, they received instructions to either continue viewing the picture (no regulation) or reappraise it with a neutral meaning (neutralize goal) or negative meaning (transform goal) for another 8,000 ms. We obtained corrugator supercilii and zygomaticus major electromyography (EMG) as objective measures of NA and PA. For the no-regulation condition, upon instruction onset, we observed maintained low levels of corrugator and high levels of zygomaticus EMG reactivity, indicating sustained PA activation. Compared to the no-regulation condition, for the neutralize goal, we observed no change in corrugator reactivity, which remained at a low level, while zygomaticus reduction started at 1,000 ms after instruction onset, indicating decreased PA and generation of a neutral emotional state. For the transform goal, we observed corrugator increase and zygomaticus decrease both starting at 1,500 ms after instruction onset and co-existing throughout the regulation period. These results indicate increased NA and decreased PA, relating to generation of a negative emotional state. The transform goal differed from the neutralize goal in terms of corrugator increase starting at 2,500 ms after instruction onset. Albeit simultaneous onset of changes on corrugator and zygomaticus reactivity under the transform goal, model-fitting analyses indicated that the best-fitting trajectory was one that first emphasized PA reduction until, at 3,000 ms, it turned into primary NA increase. These distinct temporal patterns highlight the possibility of effecting one-dimensional PA change with the neutralize goal and sequential two-dimensional change (first decreasing PA, then increasing NA) with the transform goal. This research sheds light on the time course of emotional change brought about by different regulatory goals.

Sadness and fear, but not happiness, motivate inhibitory behaviour: the influence of discrete emotions on the executive function of inhibition

ABSTRACT Inhibition, an executive function, is critical for achieving goals that require suppressing unwanted behaviours, thoughts, or distractions. One hypothesis of the emotion and goal compatibility theory is that emotions of sadness and fear enhance inhibitory control. Across Experiments 1–4, we tested this hypothesis by inducing a happy, sad, fearful, and neutral emotional state prior to completing an inhibition task that indexed a specific facet of inhibition (oculomotor, resisting interference, behavioural, and cognitive). In Experiment 4, we included an anger induction to examine whether valence or motivational-orientation best-predicted performance. We found support that fear and sadness enhanced inhibition except when inhibition required resisting interference. We argue that sadness and fear enhance inhibitory control aiding the detection and analysis of problems (i.e. sadness) or threats (i.e. fear) within one’s environment. In sum, this work highlights the importance of identifying how negative emotions can be beneficial for and interact with specific executive functions influencing down-stream processing including attention, cognition, and memory.

Strategy and Challenges for Turkmenistan’s participation in the Central Asia Integration

After gaining independence, Turkmenistan actively pursued the status of a "permanently neutral state", aiming to leverage a neutral foreign policy for enhanced stability and peace in Central Asia.Turkmenistan has formulated distinct engagement policies at various stages of Central Asian integration, ensuring the country's flexible position in the region based on national interests, neutrality, and the decisions of the supreme Leader. However, Turkmenistan encounters significant practical obstacles in engaging in Central Asian integration due to the uncertain prospects of regional integration and its unitary economic structure. If Turkmenistan can sustain its engagement, strategically adjust its foreign policy, and optimize its economic reforms, it will be able to assume a more significant role in the process of Central Asian integration.

Extended N-centered ensemble density functional theory of double electronic excitations.

A recent work (arXiv:2401.04685) has merged N-centered ensembles of neutral and charged electronic ground states with ensembles of neutral ground and excited states, thus providing a general and in-principle exact (so-called extended N-centered) ensemble density functional theory of neutral and charged electronic excitations. This formalism made it possible to revisit the concept of density-functional derivative discontinuity, in the particular case of single excitations from the highest occupied Kohn-Sham (KS) molecular orbital, without invoking the usual "asymptotic behavior of the density" argument. In this work, we address a broader class of excitations, with a particular focus on double excitations. An exact implementation of the theory is presented for the two-electron Hubbard dimer model. A thorough comparison of the true physical ground- and excited-state electronic structures with that of the fictitious ensemble density-functional KS system is also presented. Depending on the choice of the density-functional ensemble as well as the asymmetry of the dimer and the correlation strength, an inversion of states can be observed. In some other cases, the strong mixture of KS states within the true physical system makes the assignment "single excitation" or "double excitation" irrelevant.

PNA-Functionalized, Silica Nanowires-Filled Glass Microtube for Ultrasensitive and Label-Free Detection of miRNA-21.

MicroRNAs (miRNAs) are endogenous and noncoding single-stranded RNA molecules with a length of approximately 18-25 nucleotides, which play an undeniable role in early cancer screening. Therefore, it is very important to develop an ultrasensitive and highly specific method for detecting miRNAs. Here, we present a bottom-up assembly approach for modifying glass microtubes with silica nanowires (SiNWs) and develop a label-free sensing platform for miRNA-21 detection. The three-dimensional (3D) networks formed by SiNWs make them abundant and highly accessible sites for binding with peptide nucleic acid (PNA). As a receptor, PNA has no phosphate groups and exhibits an overall electrically neutral state, resulting in a relatively small repulsion between PNA and RNA, which can improve the hybridization efficiency. The SiNWs-filled glass microtube (SiNWs@GMT) sensor enables ultrasensitive, label-free detection of miRNA-21 with a detection limit as low as 1 aM at a detection range of 1 aM-100 nM. Noteworthy, the sensor can still detect miRNA-21 in the range of 102-108 fM in complex solutions containing 1000-fold homologous interference of miRNAs. The high anti-interference performance of the sensor enables it to specifically recognize target miRNA-21 in the presence of other miRNAs and distinguish 1-, 3-mismatch nucleotide sequences. Significantly, the sensor platform is able to detect miRNA-21 in the lysate of breast cancer cell lines (e.g., MCF-7 cells and MDA-MB-231 cells), indicating that it has good potential in the screening of early breast cancers.

Tunable optoelectronic performances of fluorinated benzene-EDOT based hybrid electrochromic polymers

Due to its high electronegativity and small atomic radius without undesirable steric hindrance, the incorporation of fluorine atoms into the benzene unit which started from the commercially available compounds is a feasible way to tune the energy levels of polymers, and its electrochromic application is expected to achieve a new breakthrough. Herein, in this paper, benzene units with different fluorine atom numbers were selected as the core and 3,4-ethylenedioxythiophene (EDOT) as the terminal unit, three fluorinated electrochromic precursors (FPh-EDOT, 2FPh-EDOT, and 4FPh-EDOT) were designed and synthesized by Stille coupling reaction, and the corresponding fluorinated π-conjugated electrochromic polymers (P(FPh-EDOT), P(2Ph-EDOT), and P(4FPh-EDOT)) were prepared by electrochemical polymerization method. The effects of different fluorinated benzene units on the photophysics, electrochemistry, and electrochromic properties of precursors and polymers were systematically investigated, and the structure-property relationship was further revealed. All of them have low initial oxidation potentials {FPh-EDOT (0.65 V), 2FPh-EDOT (0.72 V), and 4FPh-EDOT (0.70 V)}, which makes it easy to obtain high-quality new fluorinated polymers at low polymerization potential. With the increase of the number of F atoms, the UV–vis absorption spectra and emission spectra of fluorinated monomer firstly red-shifted and then blue-shifted. The corresponding fluorinated polymers have good electrochemical activity and stability (the P(2Ph-EDOT) activity remained 82.7% after 500 cycles), making it possible to realize their electrochromic devices. All these three fluorinated polymers show obvious color change from the neutral state to the fully oxidized state (P(FPh-EDOT) changes from brown to grayish blue, P(2FPh-EDOT) changes from brown to gray, and P(4FPh-EDOT) changes from dark blue to light blue). The kinetic study further shows that all of them have distinguish electrochromic properties with good optical stability, very short response time (0.9 s for P(2FPh-EDOT) at 700 nm), and favorable coloration efficiency (130.7 cm2 C−1 for P(FPh-EDOT) at 503 nm). Overall, all these three fluorinated polymers have low optical band gap, good redox stability and electrochromic properties, are very promising electrochromic materials, which is worthy for the further research and development.