Interactions between Polyelectrolyte Brushes and Hofmeister Ions: Chaotropes versus Kosmotropes

We have investigated the interactions between the positively charged poly[2-(methacryloyloxy)ethyltrimethylammonium chloride] (PMETAC) brushes and the Hofmeister anions and the interactions between the negatively charged poly(3-sulfopropyl methacrylate potassium) (PSPMA) brushes and the Hofmeister cations using a combination of quartz crystal microbalance with dissipation and spectroscopic ellipsometry. A V-shaped anion series is observed in terms of the ion-specific interactions between the PMETAC brushes and the Hofmeister anions. We have found that the chaotropic and kosmotropic anions interact with the PMETAC brushes in different manners. The ion-specific interactions between the PMETAC brushes and the chaotropic anions are dominated by the direct interactions between the anions and the positively charged quaternary ammonium group via ion pairing mediated by ionic hydration strength or polarizability, whereas the ion-specific interactions between the PMETAC brushes and the kosmotropic anions are dominated by the competition for water molecules between the anions and the brushes. The ion-specific interactions between the PMETAC brushes and the anions have significant influences on both the hydration and the conformation of the brushes. The cations exhibit weaker specific ion effects on the PSPMA brushes in comparison with the specific anion effects on the PMETAC brushes.

Ion specificities of artificial macromolecules

Artificial macromolecules are well-defined synthetic polymers, with a relatively simple structure as compared to naturally occurring macromolecules. This review focuses on the ion specificities of artifical macromolecules. Ion specificities are influenced by solvent-mediated indirect ion-macromolecule interactions and also by direct ion-macromolecule interactions. In aqueous solutions, the role of water-mediated indirect ion-macromolecule interactions will be discussed. The addition of organic solvents to aqueous solutions significantly changes the ion specificities due to the formation of water-organic solvent complexes. For direct ion-macromolecule interactions, we will discuss specific ion-pairing interactions for charged macromolecules and specific ion-neutral site interactions for uncharged macromolecules. When the medium conditions change from dilute solutions to crowded environments, the ion specificities can be modified by either the volume exclusion effect, the variation of dielectric constant, or the interactions between ions, macromolecules, and crowding agents.

Reorganization of hydrogen bond network makes strong polyelectrolyte brushes pH-responsive

Weak polyelectrolytes have found extensive practical applications owing to their rich pH-responsive properties. In contrast, strong polyelectrolytes have long been regarded as pH-insensitive based on the well-established fact that the average degree of charging of strong polyelectrolyte chains is independent of pH. The possible applications of strong polyelectrolytes in smart materials have, thus, been severely limited. However, we demonstrate that almost all important properties of strong polyelectrolyte brushes (SPBs), such as chain conformation, hydration, stiffness, surface wettability, lubricity, adhesion, and protein adsorption are sensitive to pH. The pH response originates from the reorganization of the interchain hydrogen bond network between the grafted chains, triggered by the pH-mediated adsorption-desorption equilibrium of hydronium or hydroxide with the brushes. The reorganization process is firmly identified by advanced sum-frequency generation vibrational spectroscopy. Our findings not only provide a new understanding of the fundamental properties of SPBs but also uncover an extensive family of building blocks for constructing pH-responsive materials.

Anion Specificity of Polyzwitterionic Brushes with Different Carbon Spacer Lengths and Its Application for Controlling Protein Adsorption

Both ion-specific interaction and carbon spacer length have strong effects on the properties of polyzwitterions. In this work, we have investigated the anion specificity of poly(sulfobetaine methacrylamide) (PSBMAm) brushes with different carbon spacer lengths. The effectiveness of anions to enhance the hydration of the PSBMAm brushes increases from kosmotropic to chaotropic anions. The interactions between the anions and the PSBMAm brushes are strongly influenced by carbon spacer length because the strength of inter/intrachain association of the PSBMAm brushes decreases with increasing carbon spacer length. The inter/intrachain association of the PSBMAm brushes with a longer carbon spacer is easier to break by the external anions in the high salt concentration regime. On the other hand, a longer carbon spacer is more favorable for the zwitterionic groups to form cyclic intramolecular structures. As a result, the addition of anions can more effectively enhance the hydration of the PSBMAm brushes with a medium-length carbon spacer compared with that of the PSBMAm brushes with a either shorter or longer carbon spacer in the low salt concentration regime, determined by the balance between the inter/intrachain association and the formation of cyclic intramolecular structures. Our study also demonstrates that both anion identity and carbon spacer length can be used to control protein adsorption on the surface of the PSBMAm brushes.

The cross-talk of NLRP3 inflammasome activation and necroptotic hepatocyte death in acetaminophen-induced mice acute liver injury

Overdose acetaminophen (APAP) can result in severe liver injury, which is responsible for nearly half of drug-induced liver injury in western countries. Previous studies have found that there existed massive hepatocellular necrosis and severe inflammatory response in APAP-induced liver injury. However, the mechanistic linkage between necroptosis and NLRP3 inflammasome pathway in APAP-induced hepatotoxicity remains poorly understood. In order to investigate the relationship between inflammation and hepatocytes death in APAP hepatotoxicity, a time-course model for APAP hepatotoxicity in C57/BL6 mice was established by intraperitoneal (i.p) injection of 300 mg/kg APAP in this study. The activity of serum enzymes and pathological changes of APAP-treated mice were evaluated, and the critical molecules in necroptosis and NF-κB-NLRP3 inflammasome signaling pathway were determined by immunoblot and immunofluorescence analysis. The results demonstrated that APAP overdose resulted in a severe liver injury. Furthermore, the expression of critical molecules in NLRP3 inflammasome and necroptosis pathways peaked at 12-24 h, and then was decreased gradually, which is consistent with the pattern of pathological injury induced by APAP. Our further investigation found that the level of IL-1β in mouse liver was closely correlated with the level of phosphorylated MLKL following exposure to APAP. Furthermore, inhibition of necroptosis with necrostatin-1 significantly suppressed the activation of NLRP3 inflammasome signaling. Taken together, our results highlighted that the cross-talk between necroptosis and NLRP3 inflammasome played a critical role for promoting APAP-induced liver injury. Inhibition of the interaction of inflammation and necroptosis by pharmaceutical methods may represent a promising therapeutic strategy for APAP-induced liver injury.

Immunolocalization and possible effect of a moth allatotropin-like substance in a fly, Phormia regina (Diptera: Calliphoridae)

Insect allatotropin upregulates the biosynthesis of juvenile hormones by the corpus allatum. We raised two rabbit antisera against the allatotropin of Manduca sexta (Mas AT) using a synthetic, multiple-antigenic-peptide that contains a branching heptalysine core and eight Mas AT molecules. Both antisera recognized specifically the same neurons in the larval brain, frontal ganglion and terminal abdominal ganglion of M. sexta as previously reported by others. Immunoassay showed reactivity specific to the Mas AT. Very low or nearly no cross-reactivity was found for two Mas AT-like peptides, a myotropin from Locusta migratoria and a Mas AT-like peptide deduced from the DNA sequence of Aedes aegypti, respectively. Immunopositive neurons also were identified in adult Phormia regina, Dacus dorsalis, Oncopeltus fasciatus, and Mythimna loreyi, and in larval M. loreyi, Bombyx mori, and Andraca bipunctata. At 20 pmol per 25 µl incubation medium (i.e. 8x10(-7) M), synthetic Mas AT significantly stimulated in vitro juvenile hormone biosynthesis by the corpus allatum of adult, sugar-fed females of P. regina to 2.64-fold that of controls. Thus, this study provides the first demonstration that at the higher end of the physiological concentration range, the Mas AT has allatotropic effect in vitro to CA of non-lepidopterans. However, in vivo functions of Mas AT and/or Mas AT-like peptide in P. regina remain to be defined.

Counterion Specificity of Polyelectrolyte Brushes: Role of Specific Ion-Pairing Interactions

We demonstrate here that the properties of poly (2-(methacryloyloxy) ethyl trimethylammonium chloride) brushes can be tuned by counterion species. When the brushes are exposed to external chloride (Cl^- ) counterions, obvious dehydration and collapse are only observed at high salt concentrations. In the presence of very strongly chaotropic perchlorate (ClO₄^- ), the brushes strongly dehydrate and collapse at a very low salt concentration. For the strongly chaotropic thiocyanate ion (SCN^- ), the changes in hydration and conformation of the brushes are similar to those observed for ClO₄^- but at a smaller extent at very low salt concentrations. With the addition of kosmotropic acetate (Ac^- ), hydration of the brushes increases, accompanied by a swelling of the brushes in the low-salt-concentration regime. In contrast, the brushes dehydrate and collapse with increasing concentration of Ac^- in the high-salt-concentration regime. The counterion specificity of the brushes demonstrated here is determined by specific ion-pairing interactions through modulating the osmotic pressure within the brushes and the hydrophobicity of the ion pairs.

Allatotropic activity in the brain of female Phormia regina (Diptera: Calliphoridae)

In Phormia regina, the rate of juvenile hormone (JH) synthesis rises rapidly after the ingestion of an adequate protein meal. In a previous publication we have localized the neurons containing Manduca sexta allatotropin (Mas-AT)-like substances in the brain of P. regina and demonstrated the allatotropic effect of synthetic Mas-AT in sugar-fed flies in vitro. In this current study, we examined the possible role of the brain of P. regina after the fly received a protein meal. In vitro studies showed that the brain releases, at 8 h after a protein meal, a factor(s) with a strong allatotropic effect. This factor(s) stimulates the corpus allatum (CA) to produce 6.9 times more juvenile hormones (JHs) than the control CA. Time course studies showed that the release of this allatotropic factor(s) is temporally controlled. Only the brains collected from flies at 6 and 8 h after the onset of a liver meal release allatotropic factor(s). Injection of anti-Mas-AT antiserum partially suppressed the fly follicle development in vivo. Presence of anti-Mas-AT antiserum decreased the allatotropic effect of the brain released allatotropic factor(s) in vitro. In addition to a Mas-AT-like substance, it is possible that the brains of liver-fed P. regina females may synthesize other allatotropic factors that are chemically unrelated or partially related to Mas-AT, which cannot be recognized/neutralized by our anti-Mas-AT antiserum.

Effects of calcium channel antagonists on the corpora allata of adult male loreyi leafworm Mythimna loreyi: juvenile hormone acids release and intracellular calcium level

The effects of voltage-dependent calcium channel (VDCC) antagonists and the non-specific calcium channel antagonists on both juvenile hormone acids (JHA) release and cytosolic free calcium concentration ([Ca2+]i) are investigated in the corpora allata (CA) of the adult males loreyi leafworm Mythimna loreyi. The VDCC antagonists used in this study are: the L-type antagonists diltiazem, nifedipine, and verapamil, the N-type antagonist omega-Conotoxin (CgTx) GVIA, the N- and P/Q-type antagonist omega-CgTx MVIIC, and the T-type antagonist amiloride. The non-specific calcium channel antagonists used in this study were cadmium (Cd2+), cobalt (Co2+), nickle (Ni2+), and lanthanum (La3+). The results show that both the DHPs-sensitive L-type antagonist nifedipine and the N-type antagonist omega-CgTx GVIA were able to inhibit JHA release, but only omega-CgTx GVIA was able to reduce the [Ca2+]i. Among the non-specific calcium channel antagonists, Cd2+ is the most potent in reducing JHA release but without obvious effect on the [Ca2+]i, La3+ significantly increases the [Ca2+]i but without effect on JHA release.

Allatotropic activity in the suboesophageal ganglia and corpora cardiaca of the adult male loreyi leafworm, Mythimna loreyi

Allatotropic activity was found in the methanolic extract of the suboesophageal ganglia (SOG) and the corpora cardiaca (CC) of the Mythimna loreyi virgin males. No allatotropic activity was observed in the extract of brain or corpora allata (CA). Although CA can be activated by the SOG and CC extract, respectively, CC extract inhibited the response to the SOG extract. A significant in vitro allatotropic effect was exerted by the SOG and CC extract within 10 and 15 min, respectively, and this effect can be sustained for several hours even after transferring to fresh medium without extracts. The time course pattern of the CA activation ratio in both the SOG and CC extract-treated group is very similar to, but with significantly higher level than, that in the control group, suggesting the existence of an intrinsic pacemaker or an in vitro effect that controls the fluctuation of the CA biosynthetic activity. Synthetic Manduca sexta allatotropin had no significant effect on the M. loreyi CA. The results of treatment with the adenylate cyclase activator forskolin, the phosphodiesterase inhibitor IBMX, and the cAMP analogue dibutyryl-cAMP did not indicate that cAMP might be involved in the allatotropic control of CA. Arch.

Explainable machine-learning algorithms to differentiate bipolar disorder from major depressive disorder using self-reported symptoms, vital signs, and blood-based markers

BACKGROUND AND OBJECTIVE

Caused by shared genetic risk factors and similar neuropsychological symptoms, bipolar disorder (BD) and major depressive disorder (MDD) are at high risk of misdiagnosis, which is associated with ineffective treatment and worsening of outcomes. We aimed to develop a machine learning (ML)-based diagnostic system, based on electronic medical records (EMR) data, to mimic the clinical reasoning of human physicians to differentiate MDD and BD (especially BD depressive episodes) patients about to be admitted to a hospital and, hence, reduce the misdiagnosis of BD as MDD on admission. In addition, we examined to what extent our ML model could be made interpretable by quantifying and visualizing the features that drive the predictions.

METHODS

By identifying 16,311 patients admitted to a hospital located in western China between 2009 and 2018 with a recorded main diagnosis of MDD or BD, we established three sub-cohorts with different combinations of features for both the MDD-BD cohort and the MDD-BD depressive episodes cohort, respectively. Four different ML algorithms (logistic regression, extreme gradient boosting (XGBoost), random forest, and support vector machine) and four train-test splits were used to train and validate diagnostic models, and explainable methods (SHAP and Break Down) were utilized to analyze the contribution of each of the features at both population-level and individual-level, including feature importance, feature interaction, and feature effect on prediction decision for a specific subject.

RESULTS

The XGBoost algorithm provided the best test performance (AUC: 0.838 (0.810-0.867), PPV: 0.810 and NPV: 0.834) for separating patients with BD from those with MDD. Core predictors included symptoms (mood-up, exciting, bad sleep, loss of interest, talking, mood-down, provoke), along with age, job, myocardial enzyme markers (creatine kinase, hydroxybutyrate dehydrogenase), diabetes-associated marker (glucose), bone function marker (alkaline phosphatase), non-enzymatic antioxidant (uric acid), markers of immune/inflammation (white blood cell count, lymphocyte count, basophil percentage, monocyte count), cardiovascular function marker (low density lipoprotein), renal marker (total protein), liver biochemistry marker (indirect bilirubin), and vital signs like pulse. For separating patients with BD depressive episodes from those with MDD, the test AUC was 0.777 (0.732-0.822), with PPV 0.576 and NPV 0.899. Additional validation in models built with self-reported symptoms removed from the feature set, showed test AUC of 0.701 (0.666-0.736) for differentiating BD and MDD, and AUC of 0.564 (0.515-0.614) for detecting patients in BD depressive episodes from MDD patients. Validation in the datasets without removing the patients with comorbidity showed an AUC of 0.826 (0.806-0.846).

CONCLUSION

The diagnostic system accurately identified patients with BD in various clinical scenarios, and differences in patterns of peripheral markers between BD and MDD could enrich our understanding of potential underlying pathophysiological mechanisms of them.

Tuning the Light Response of Strong Polyelectrolyte Brushes with Counterions

In this work, a negatively charged poly(3-sulfopropyl methacrylate potassium) (PSPMA) brush has been employed as a model system to demonstrate the tuning of the light response of strong polyelectrolyte brushes (SPBs) with counterions. The substitution of K⁺ counterions by azobenzene-containing counterions (Azo-N⁺) renders the PSPMA brush light-responsive in aqueous solutions. Nevertheless, the strength of the light response of the PSPMA brush is weak due to the inefficient disassembly of the micelle-like aggregates in the brush upon irradiation with ultraviolet light. Counterion mixtures of Azo-N⁺ and K⁺ are employed to realize a strong light response of the PSPMA brush by incorporating a reasonable amount of Azo-N⁺ counterions into the brush. The strength of the light response of the PSPMA brush can be tuned by the mole ratio of Azo-N⁺ to K⁺. Furthermore, properties including the hydration and conformation of the PSPMA brush can be reversibly switched via alternating ultraviolet and visible light irradiation. This work opens up the opportunities available for the use of counterions to tune the light response of SPBs.

Controlling Hydrogel Properties by the Cooperative Harvesting of the Components of Sunlight

The utilization of the full spectrum of sunlight from ultraviolet to infrared to cooperatively control the properties of hydrogels is the key to developing efficient sunlight-responsive hydrogels, but there are significant challenges. The photoresponsive hydrogel developed here formed by azobenzene-containing polyzwitterionic chains possesses capabilities for simultaneously utilizing light from the ultraviolet to the infrared to cooperatively facilitate the gel-to-sol transitions. The ultraviolet and visible light can be converted into mechanical energy simultaneously to synergistically power the dynamic wagging of azobenzene groups, while the infrared light can be converted into kinetic energy of the zwitterionic groups to promote the wagging of the azobenzene groups. Cooperative action between the major components of sunlight can be applied to control a range of important properties of the hydrogel including wettability, adhesion, molecular release, self-healing, and mineralization. The work presented here demonstrates a novel strategy for harvesting all the major components of sunlight to control the properties of photoresponsive materials.

Cost-Effective Machine Learning Based Clinical Pre-Test Probability Strategy for DVT Diagnosis in Neurological Intensive Care Unit

In order to overcome the shortage of the current costly DVT diagnosis and reduce the waste of valuable healthcare resources, we proposed a new diagnostic approach based on machine learning pre-test prediction models using EHRs. We examined the sociodemographic and clinical factors in the prediction of DVT with 518 NICU admitted patients, including 189 patients who eventually developed DVT. We used cross-validation on the training data to determine the optimal parameters, and finally, the applied ROC analysis is adopted to evaluate the predictive strength of each model. Two models (GLM and SVM) with the strongest ROC were selected for DVT prediction, based on which, we optimized the current intervention and diagnostic process of DVT and examined the performance of the proposed approach through simulations. The use of machine learning based pre-test prediction models can simplify and improve the intervention and diagnostic process of patients in NICU with suspected DVT, and reduce the valuable healthcare resource occupation/usage and medical costs.

Counterion-Tunable Thermosensitivity of Strong Polyelectrolyte Brushes

In this work, poly(sodium styrene sulfonate) brushes have been employed as a precursor to prepare thermosensitive strong polyelectrolyte brushes (SPBs) through a counterion exchange strategy. The substitution of hydrophilic Na⁺ counterions by hydrophobic tetraalkylphosphonium counterions leads to a thermoresponsivity of the SPBs. The thermosensitive properties including hydration, stiffness, and surface water wettability of the SPBs can be modulated by the type of the tetraalkylphosphonium counterions. Nevertheless, the wet thickness of the SPBs with tetraalkylphosphonium counterions does not exhibit an obvious temperature dependency due to the high steric barrier in the crowded environment of SPBs generated by the large tetraalkylphosphonium counterions. The mixtures of small Na⁺ counterions and large tetraalkylphosphonium counterions are employed to realize the thermosensitive wet thickness without sacrificing other thermoresponsive properties of the SPBs because the mixed counterions can bring both a certain hydrophobicity and some free space to the brushes. This work opens up the opportunities available for the use of counterions to tune the thermosensitivity of SPBs.

The economic burden of coronary heart disease in mainland China

OBJECTIVES

The aim of this study was to systematically evaluate the current economic burden of coronary heart disease (CHD) in mainland China and provide a reference for the formulation of policies to reduce the economic burden of CHD.

STUDY DESIGN

A systematic literature review was conducted of empirical studies on the economic burden of CHD over the past 20 years.

METHODS

PubMed, Web of Science, Embase, China Knowledge Resource Integrated Database and the WANFANG database were comprehensively searched for relevant articles published between 1 January 2000 and 22 December 2021. Content analysis was used to extract the data, and Stata 17.0 software was used for analysis. The median values were used to describe trends.

RESULTS

A total of 35 studies were included in this review. The annual median per-capita hospitalisation expense and the average expense per hospitalisation were $3544.40 ($891.64-$18,371.46) and $5407.34 ($1139.93-$8277.55), respectively. The median ratio on medical consumables expenses, drug expenses, medical examination expenses and treatment expenses were 41.59% (12.40%-63.73%), 26.90% (7.30%-60.00%), 9.45% (1.65%-33.40%) and 10.10% (2.36%-66.00%), respectively. The median per-capita hospitalisation expense in the eastern, central and western regions were $9374.45 ($2056.13-$18,371.46), $4751.5 ($2951.95-$8768.93) and $3251.25 ($891.64-$13,986.38), respectively. The median average expense per hospitalisation in the eastern and central regions were $6177.15 ($1679.15-$8277.55) and $1285.49 ($1239.93-$2197.36), respectively. The median average length of stay in the eastern, central and western regions were 9.3 days, 15.2 days and 16.1 days, respectively.

CONCLUSIONS

The economic burden of CHD is more severe in mainland China than in developed countries, especially in terms of the direct economic burden. In terms of the types of direct medical expenses, a proportion of medical examination expenses, treatment expenses and drug expenses were lowest in the eastern region, but medical consumables expenses were the highest in this region. This study provides guidance for the formulation of policies to reduce the economic burden of CHD in mainland China.

Predicting Conversion From Unipolar Depression to Bipolar Disorder and Schizophrenia: A 10-Year Retrospective Cohort Study on 12,182 Inpatients

Background: The initial stages of bipolar disorder (BD) and schizophrenia (SCZ) often exhibit depressive symptoms and syndromes, leading to potential misdiagnosis and treatment for unipolar depression (UD). However, no consensus exists on individualized and time-varying intervenable conversion predictors for both BD and SCZ. Methods: This study examined the rate of true conversion from UD to BD and SCZ, considering factors such as sex, family history of mental illness, psychotic features, recurrent depression, and treatment patterns. The objective was to develop predictive models for short-, medium-, and long-term risk stratification for BD/SCZ conversion. Data were extracted from electronic medical records (EMRs) between January 2009 and December 2020 in a large academic medical center-based health system in China. Participants included 12,182 depressive inpatients without previous or comorbid diagnoses of BD and SCZ. The outcome measure was a subsequent admission record with a diagnostic code reflective of BD or SCZ. Four machine-learning algorithms using sociodemographic, clinical, laboratory, vital signs, symptoms, and treatment features were applied to predict this outcome. Explainable methodologies, specifically SHapley Additive exPlanations (SHAP) and Break Down, were employed to analyze the contribution of each individual feature. Results: Among 12,182 individuals, 344 (2.82%) and 64 (0.53%) received a subsequent diagnosis of BD and SCZ, respectively. Higher risk factors for BD progression included being female, having severe depression, being prescribed mood stabilizers, β receptor blockers (e.g., metoprolol tartrate and propranolol hydrochloride), and antipsychotics (e.g., sulpiride and quetiapine). Higher risk factors for SCZ progression included being male, exhibiting psychotic symptoms, being prescribed antipsychotics (e.g., risperidone and sulpiride), antiside effects drugs (e.g., trihexyphenidyl and hemp seed pill), and undergoing psychotherapy. Individuals with a family history of mental illness were particularly susceptible to conversion to BD and SCZ. Conclusions: The model's performance on the test dataset declined over time, with area under the curve (AUC) values for predicting BD conversion decreasing from 0.771 in 1 year to 0.749 in 2 years and 0.733 in 7 years, and for SCZ conversion, from 0.866 in 1 year to 0.829 in 3 years and 0.752 in 7 years. A key finding is that individuals with refractory (particularly psychotic) UD had an elevated risk of transitioning to BD and SCZ, with social-demographic factors, lifestyle behaviors, vital signs, and blood markers becoming significant risk factors over follow-up. Upon further validation, these models could provide clinicians with dynamic information regarding a patient's risk of disease conversion.

[Purification and some properties of superoxide dismutase from Fusarium moniliform]

Superoxide dismutase from Fusarium moniliform was purified by the steps including heating, ammonium sulfate fractionation, Sephedax G-100 gel filtration and DEAE-Sephadex A-50 chromatography. The results showed that the enzyme was a Mn-SOD with the specific activity of 2640 U/mg and had two homogenous subunits whose molecular mass were 14.5 kD. The wave length of max. absorbing peak in ultraviolet spectrum was 276 nm which was not similar with other resource of SOD. The composition of amino acid was also analyzed.