Gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2.

Materials research has driven the development of modern nano-electronic devices. In particular, research in magnetic thin films has revolutionized the development of spintronic devices1,2 because identifying new magnetic materials is key to better device performance and design. Van der Waals crystals retain their chemical stability and structural integrity down to the monolayer and, being atomically thin, are readily tuned by various kinds of gate modulation3,4. Recent experiments have demonstrated that it is possible to obtain two-dimensional ferromagnetic order in insulating Cr2Ge2Te6 (ref. 5) and CrI3 (ref. 6) at low temperatures. Here we develop a device fabrication technique and isolate monolayers from the layered metallic magnet Fe3GeTe2 to study magnetotransport. We find that the itinerant ferromagnetism persists in Fe3GeTe2 down to the monolayer with an out-of-plane magnetocrystalline anisotropy. The ferromagnetic transition temperature, Tc, is suppressed relative to the bulk Tc of 205 kelvin in pristine Fe3GeTe2 thin flakes. An ionic gate, however, raises Tc to room temperature, much higher than the bulk Tc. The gate-tunable room-temperature ferromagnetism in two-dimensional Fe3GeTe2 opens up opportunities for potential voltage-controlled magnetoelectronics7-11 based on atomically thin van der Waals crystals.

A wireless, skin-interfaced biosensor for cerebral hemodynamic monitoring in pediatric care.

The standard of clinical care in many pediatric and neonatal neurocritical care units involves continuous monitoring of cerebral hemodynamics using hard-wired devices that physically adhere to the skin and connect to base stations that commonly mount on an adjacent wall or stand. Risks of iatrogenic skin injuries associated with adhesives that bond such systems to the skin and entanglements of the patients and/or the healthcare professionals with the wires can impede clinical procedures and natural movements that are critical to the care, development, and recovery of pediatric patients. This paper presents a wireless, miniaturized, and mechanically soft, flexible device that supports measurements quantitatively comparable to existing clinical standards. The system features a multiphotodiode array and pair of light-emitting diodes for simultaneous monitoring of systemic and cerebral hemodynamics, with ability to measure cerebral oxygenation, heart rate, peripheral oxygenation, and potentially cerebral pulse pressure and vascular tone, through the utilization of multiwavelength reflectance-mode photoplethysmography and functional near-infrared spectroscopy. Monte Carlo optical simulations define the tissue-probing depths for source-detector distances and operating wavelengths of these systems using magnetic resonance images of the head of a representative pediatric patient to define the relevant geometries. Clinical studies on pediatric subjects with and without congenital central hypoventilation syndrome validate the feasibility for using this system in operating hospitals and define its advantages relative to established technologies. This platform has the potential to substantially enhance the quality of pediatric care across a wide range of conditions and use scenarios, not only in advanced hospital settings but also in clinics of lower- and middle-income countries.

Photocurable bioresorbable adhesives as functional interfaces between flexible bioelectronic devices and soft biological tissues.

Flexible electronic/optoelectronic systems that can intimately integrate onto the surfaces of vital organ systems have the potential to offer revolutionary diagnostic and therapeutic capabilities relevant to a wide spectrum of diseases and disorders. The critical interfaces between such technologies and living tissues must provide soft mechanical coupling and efficient optical/electrical/chemical exchange. Here, we introduce a functional adhesive bioelectronic-tissue interface material, in the forms of mechanically compliant, electrically conductive, and optically transparent encapsulating coatings, interfacial layers or supporting matrices. These materials strongly bond both to the surfaces of the devices and to those of different internal organs, with stable adhesion for several days to months, in chemistries that can be tailored to bioresorb at controlled rates. Experimental demonstrations in live animal models include device applications that range from battery-free optoelectronic systems for deep-brain optogenetics and subdermal phototherapy to wireless millimetre-scale pacemakers and flexible multielectrode epicardial arrays. These advances have immediate applicability across nearly all types of bioelectronic/optoelectronic system currently used in animal model studies, and they also have the potential for future treatment of life-threatening diseases and disorders in humans.

Coexistence of large conventional and planar spin Hall effect with long spin diffusion length in a low-symmetry semimetal at room temperature.

The spin Hall effect (SHE) is usually observed as a bulk effect in high-symmetry crystals with substantial spin-orbit coupling (SOC), where the symmetric spin-orbit field imposes a widely encountered trade-off between spin Hall angle (θSH) and spin diffusion length (Lsf), and spin polarization, spin current and charge current are constrained to be mutually orthogonal. Here, we report a large θSH of 0.32 accompanied by a long Lsf of 2.2 µm at room temperature in a low-symmetry few-layered semimetal MoTe2, thus identifying it as an excellent candidate for simultaneous spin generation, transport and detection. In addition, we report that longitudinal spin current with out-of-plane polarization can be generated by both transverse and vertical charge current, due to the conventional and a newly observed planar SHE, respectively. Our study suggests that manipulation of crystalline symmetries and strong SOC opens access to new charge-spin interconversion configurations and spin-orbit torques for spintronic applications.

A nomogram incorporating functional and tubular damage biomarkers to predict the risk of acute kidney injury for septic patients.

BACKGROUND: Combining tubular damage and functional biomarkers may improve prediction precision of acute kidney injury (AKI). Serum cystatin C (sCysC) represents functional damage of kidney, while urinary N-acetyl-ß-D-glucosaminidase (uNAG) is considered as a tubular damage biomarker. So far, there is no nomogram containing this combination to predict AKI in septic cohort. We aimed to compare the performance of AKI prediction models with or without incorporating these two biomarkers and develop an effective nomogram for septic patients in intensive care unit (ICU). METHODS: This was a prospective study conducted in the mixed medical-surgical ICU of a tertiary care hospital. Adults with sepsis were enrolled. The patients were divided into development and validation cohorts in chronological order of ICU admission. A logistic regression model for AKI prediction was first constructed in the development cohort. The contribution of the biomarkers (sCysC, uNAG) to this model for AKI prediction was assessed with the area under the receiver operator characteristic curve (AUC), continuous net reclassification index (cNRI), and incremental discrimination improvement (IDI). Then nomogram was established based on the model with the best performance. This nomogram was validated in the validation cohort in terms of discrimination and calibration. The decision curve analysis (DCA) was performed to evaluate the nomogram's clinical utility. RESULTS: Of 358 enrolled patients, 232 were in the development cohort (69 AKI), while 126 in the validation cohort (52 AKI). The first clinical model included the APACHE II score, serum creatinine, and vasopressor used at ICU admission. Adding sCysC and uNAG to this model improved the AUC to 0.831. Furthermore, incorporating them significantly improved risk reclassification over the predictive model alone, with cNRI (0.575) and IDI (0.085). A nomogram was then established based on the new model including sCysC and uNAG. Application of this nomogram in the validation cohort yielded fair discrimination with an AUC of 0.784 and good calibration. The DCA revealed good clinical utility of this nomogram. CONCLUSIONS: A nomogram that incorporates functional marker (sCysC) and tubular damage marker (uNAG), together with routine clinical factors may be a useful prognostic tool for individualized prediction of AKI in septic patients.

Combining Serum Cystatin C and Urinary N-Acetyl-Beta-D-Glucosaminidase Improves the Precision for Acute Kidney Injury Diagnosis after Resection of Intracranial Space-Occupying Lesions.

BACKGROUND: Postoperative acute kidney injury (AKI) is frequent and associated with adverse outcomes. Unfortunately, the early diagnosis of AKI remains a challenge. Combining functional and tubular damage biomarkers may provide better precision for AKI detection. However, the diagnostic accuracy of this combination for AKI after neurosurgery is unclear. Serum cystatin C (sCysC) and urinary albumin/creatinine ratio (uACR) are considered functional biomarkers, while urinary N-acetyl-ß-D-glucosaminidase (uNAG) represents tubular damage. We aimed to assess the performances of these clinical available biomarkers and their combinations for AKI prediction after resection of intracranial space-occupying lesions. METHODS: A prospective study was conducted, enrolling adults undergoing resection of intracranial space-occupying lesions and admitted to the neurosurgical intensive care unit. The discriminative abilities of postoperative sCysC, uNAG, uACR, and their combinations in predicting AKI were compared using the area under the receiver operating characteristic curve (AUC-ROC), continuous net reclassification index (cNRI), and incremental discrimination improvement (IDI). RESULTS: Of 605 enrolled patients, AKI occurred in 67 patients. The cutoff values of sCysC, uNAG, and uACR to predict postoperative AKI were 0.72 mg/L, 19.98 U/g creatinine, and 44.21 mg/g creatinine, respectively. For predicting AKI, the composite of sCysC and uNAG (AUC-ROC = 0.785) outperformed either individual biomarkers or the other two panels (uNAG plus uACR or sCysC plus uACR). Adding this panel to the predictive model improved the AUC-ROC to 0.808. Moreover, this combination significantly improved risk reclassification over the clinical model alone, with cNRI (0.633) and IDI (0.076). Superior performance of this panel was further confirmed with bootstrap internal validation. CONCLUSIONS: Combination of functional and tubular damage biomarkers improves the predictive accuracy for AKI after resection of intracranial space-occupying lesions.

The effect of glucocorticoids on serum cystatin C in identifying acute kidney injury: a propensity-matched cohort study.

BACKGROUND: Glucocorticoids may impact the accuracy of serum cystatin C (sCysC) in reflecting renal function. We aimed to assess the effect of glucocorticoids on the performance of sCysC in detecting acute kidney injury (AKI) in critically ill patients. METHODS: A prospective observational cohort study was performed in a general intensive care unit (ICU). Using propensity score matching, we successfully matched 240 glucocorticoid users with 960 non-users among 2716 patients. Serum creatinine (SCr) and sCysC were measured for all patients at ICU admission. Patients were divided into four groups based on cumulative doses of glucocorticoids within 5 days before ICU admission (Group I: non-users; Group II: 0 mg < prednisone ≤50 mg; Group III: 50 mg < prednisone ≤150 mg; Group IV: prednisone > 150 mg). We compared the performance of sCysC for diagnosing and predicting AKI in different groups using the area under the receiver operator characteristic curve (AUC). RESULTS: A total of 240 patients received glucocorticoid medication within 5 days before ICU admission. Before and after matching, the differences of sCysC levels between glucocorticoid users and non-users were both significant (P <  0.001). The multiple linear regression analysis revealed that glucocorticoids were independently associated with sCysC (P <  0.001). After matching, the group I had significantly lower sCysC levels than the group III and group IV (P <  0.05), but there were no significant differences in sCysC levels within different glucocorticoids recipient groups (P > 0.05). Simultaneously, we did not find significant differences in the AUC between any two groups in the matched cohort (P > 0.05). CONCLUSIONS: Glucocorticoids did not impact the performance of sCysC in identifying AKI in critically ill patients.

Impact of thyroid function on cystatin C in detecting acute kidney injury: a prospective, observational study.

BACKGROUND: Cystatin C (Cys C) used clinically for detecting early acute kidney injury (AKI) was reported to be associated with thyroid function. Therefore, whether the performance of Cys C is affected by thyroid hormones has raised concern in critically ill patients. This study aimed to investigate the impact of thyroid hormones on the diagnostic and predictive accuracy of Cys C for AKI, and hence optimize the clinical application of Cys C. METHODS: A prospective observational study was conducted in the general intensive care units (ICUs). Serum creatinine (SCr), Cys C, and thyroid function were documented for all patients at ICU admission. Patients were separated into five quintiles based on free triiodothyronine (FT3) and total triiodothyronine (TT3), and two categories according to the presence of low T3 syndrome or not. The impact of thyroid function on the performance of Cys C in diagnosing and predicting AKI was assessed by area under the receiver operating characteristic curve (AUC). RESULTS: The AKI incidence was 30.0% (402/1339); 225 patients had AKI upon entry, and 177 patients developed AKI during the subsequent 7 days. The AUCs for Cys C in detecting total AKI, established AKI, and later-onset AKI was 0.753, 0.797, and 0.669, respectively. The multiple linear regression analysis demonstrated that TT3 and FT3 were independently associated with Cys C. Overall, although Cys C did not yield any significant difference in AUCs for detecting AKI among patients with different thyroid hormones, the optimal cut-off value of Cys C to detect AKI was markedly different between patients with and without low T3 syndrome. CONCLUSIONS: The thyroid function had no significant impact on the diagnostic and predictive accuracy of Cys C in detecting AKI in ICU patients. However, the optimal cut-off value of Cys C to detect AKI could be affected by thyroid function.

Impact of blood glucose levels on the accuracy of urinary N-acety-ß-D-glucosaminidase for acute kidney injury detection in critically ill adults: a multicenter, prospective, observational study.

BACKGROUND: The performance of urinary N-acetyl-ß-D-glucosaminidase (uNAG) for the detection of acute kidney injury (AKI) was controversial. uNAG is positively correlated with blood glucose levels. Hyperglycemia is common in the critically ill adults. The influence of blood glucose levels on the accuracy of uNAG in AKI detection has not yet been reported. The present study evaluated the effect of blood glucose levels on the diagnostic accuracy of uNAG to detect AKI. METHODS: A total of 1585 critically ill adults in intensive care units at three university hospitals were recruited in this prospective observational study. uNAG, serum glucose, and glycosylated hemoglobin (HbA1c) were measured at ICU admission. Patients were categorized based on the history of diabetes and blood glucose levels. The performance of uNAG to detect AKI in different groups was assessed by the area under the receiver operator characteristic curve. RESULTS: Four hundred and twelve patients developed AKI, of which 109 patients were severe AKI. uNAG was significantly correlated with the levels of serum glucose (P < 0.001) and HbA1c (P < 0.001). After stratification based on the serum glucose levels, no significant difference was observed in the AUC of uNAG in detecting AKI between any two groups (P > 0.05). Stratification for stress hyperglycemic demonstrated similar results.However, among non-diabetic patients, the optimal cut-off value of uNAG for detecting AKI was higher in stress hyperglycemic patients as compared to those without stress hyperglycemia. CONCLUSIONS: The blood glucose levels did not significantly affect the performance of uNAG for AKI detection in critically ill adults. However, the optimal cut-off value of uNAG to detect AKIwas affected by stress hyperglycemia in non-diabetic patients.

The influence of glycemic status on the performance of cystatin C for acute kidney injury detection in the critically ill.

OBJECTIVE: Serum cystatin C (sCysC) used clinically for detecting early acute kidney injury (AKI) was reported to be independently associated with hemoglobin (HbA1c) levels, diabetes, and prediabetes. We aimed to assess the influence of HbA1c levels, diabetes, or prediabetes on the performance of sCysC for AKI detection in critically ill adults. METHODS: A prospective observational study was conducted in a mixed medical-surgical intensive care unit (ICU). Patients were divided into four quartiles based on levels of HbA1c or serum glucose at ICU admission, respectively. Additionally, patients were stratified into four subgroups according to HbA1c levels and history of diabetes, namely recognized diabetes (previous diagnosis of diabetes), unrecognized diabetes, prediabetes, and normal glycemic status. Comparisons were made using the area under the receiver operator characteristic curve (AUC) for AKI detection, and reassessed after patient stratification by above-mentioned glycemic status. RESULTS: Multivariable linear regression revealed that HbA1c levels and history of diabetes were positively related with sCysC (all p < .05). Although stratification for above-mentioned glycemic status displayed no significant difference between AUC of sCysC (all p > .05), sCysC yielded the highest AUCs for detecting AKI in diabetic patients. Moreover, higher optimal cutoff values of sCysC to detect AKI were observed in patients with versus without diabetes. CONCLUSION: Glycemic status has no significant impact on the accuracy of sCysC for AKI detection in critically ill adults and a higher optimal cutoff value of sCysC for AKI detection should be considered in diabetic patients.

Manipulation of hippocampal CA3 firing via luminopsins modulates spatial and episodic short-term memory, especially working memory, but not long-term memory.

The CA3 subregion of the hippocampus is important for rapid encoding, storage and retrieval of associative memories. Lesions and pharmacological inhibitions of hippocampal CA3 suggest that it is essential for different memories. However, how CA3 functions in spatial and episodic memory in different time scales (i.e. short-term versus long term) without permanent lesions has not been systematically investigated yet. Taking advantage of the chemogenetic access to opsins, this study used luminopsins, fusion proteins of luciferase and optogenetic elements, to manipulate neuronal activity in CA3 during memory tasks over a range of spatial and temporal scales. In this study, we found that excitation or inhibition of CA3 neurons had no significant effects on long-term spatial or episodic memory, but had remarkable effects on spatial working memory, spatial short-term memory as well as episodic short-term memory. In addition, stimulation of CA3 neurons altered the expression levels of NR2A. Intracerebral injection of receptor inhibitors further confirmed that NR2A is crucial to spatial working memory, which is consistent with the luminopsins experiments. These findings indicate that CA3 maintains a specific role on spatial and episodic memory over a short period of time.

Application of image processing on struvite recovery from swine wastewater by using the fluidized bed.

Fluidized granulation is one of the common methods used in wastewater treatment and resource recovery with harvesting millimeter-scale large particles. Presently, effective methods are lacking to measure the fluidized granules ranging from micro- to millimeter scales, with the consequence of ineffectively controlling and optimizing the granulation process. In this work, recovering struvite (MgNH4PO4·6H2O) from swine wastewater by using a fluidized bed was taken as an example. Image processing was applied to analyze the properties of different types of struvite granules, including morphology, particle size distribution, number density and mass concentration. Four stages of the struvite crystal evolution were therefore defined: aggregation, aggregate compaction, cluster-agglomerating and coating growth. These stages could occur simultaneously or sequentially. Up-flow rates of 30-80 mm/s in the fluidized bed sustained 600-876 g/L granular solids. Results revealed that the coating-growth granules were formed with compact aggregates or cluster-agglomerating granules as the nuclei. The growth rates for the different types of particles, including population growth, mass increase and particle size enlargement, were determined. In final, a schematic illustration for struvite granulation process is also presented.

Sorption behavior of tetracyclines on suspended organic matters originating from swine wastewater.

Tetracyclines (TCs) discharged from livestock wastewater have aroused public concerns due to their pharmacological threats to ecosystems and human health. As an important medium in the wastewater, suspended organic matters (SOMs) play vital roles in antibiotics transport and degradation. However, limited information has been reported in the relevant literature. This study investigated TCs sorption behavior on SOM, withdrawn from swine wastewater. High TCs sorption capacities were detected, with the maximum values ranging from 0.337 to 0.679mg/g. Increasing pH and temperature led to the decline of sorption capacity. Results from three-dimensional excitation-emission matrix fluorescence spectroscopy and Fourier transform infrared spectrometry revealed that amide and carboxyl groups were the main functional groups for TCs adsorption. The interactions between SOM and TCs were clarified as predominated by hydrogen-bonding and cation-exchange in acid conditions, and electrostatic repulsion in neutral or alkaline conditions. Adsorption kinetics modeling was conducted, and a satisfactory fitting was achieved with the Freundlich equation. These results indicated that the adsorption process was a rather complex process, involving a combination of cation-exchange and hydrogen-bonding. The results will provide a better understanding of the capability of SOM for TCs transport and abatement in the wastewater treatment process.

Evaluation of clinically available renal biomarkers in critically ill adults: a prospective multicenter observational study.

BACKGROUND: Although serum cystatin C (sCysC), urinary N-acetyl-ß-D-glucosaminidase (uNAG), and urinary albumin/creatinine ratio (uACR) are clinically available, their optimal combination for acute kidney injury (AKI) detection and prognosis prediction remains unclear. We aimed to assess the discriminative abilities of these biomarkers and their possible combinations for AKI detection and intensive care unit (ICU) mortality prediction in critically ill adults. METHODS: A multicenter, prospective observational study was conducted in mixed medical-surgical ICUs at three tertiary care hospitals. One thousand eighty-four adult critically ill patients admitted to the ICUs were studied. We assessed the use of individual biomarkers (sCysC, uNAG, and uACR) measured at ICU admission and their combinations with regard to AKI detection and prognosis prediction. RESULTS: AUC-ROCs for sCysC, uNAG, and uACR were calculated for total AKI (0.738, 0.650, and 0.683, respectively), severe AKI (0.839, 0.706, and 0.771, respectively), and ICU mortality (0.727, 0.793, and 0.777, respectively). The panel of sCysC plus uNAG detected total and severe AKI with significantly higher accuracy than either individual biomarkers or the other two panels (uNAG plus uACR or sCysC plus uACR). For detecting total AKI, severe AKI, and ICU mortality at ICU admission, this panel yielded AUC-ROCs of 0.756, 0.863, and 0.811, respectively; positive predictive values of 0.71, 0.31, and 0.17, respectively; and negative predictive values of 0.81, 0.97, and 0.98, respectively. Moreover, this panel significantly contributed to the accuracy of the clinical models for AKI detection and ICU mortality prediction, as measured by the AUC-ROC, continuous net reclassification index, and incremental discrimination improvement index. The comparable performance of this panel was further confirmed with bootstrap internal validation. CONCLUSIONS: The combination of a functional marker (sCysC) and a tubular damage marker (uNAG) revealed significantly superior discriminative performance for AKI detection and yielded additional prognostic information on ICU mortality.

Bio-inspired hierarchical wearable patch for fast sweat collection.

Sweat contains abundant physiological and metabolic data to evaluate an individual's physical health. Since the non-exercise sweat secretion rate is low, with an average value of 1-10 µl h-1 cm-2, sweat is generally collected during exercise for existing wearable sweat sensors. To expand their applications to include daily scenarios, these sensors developed for sports and fitness are challenged by the difficulty of collecting trace amounts of sweat. This study proposes a wearable patch inspired by the hierarchical structure of Sarracenia trichomes, allowing for the spontaneous and fast collection of a small amount of secreted sweat. The patch contains microfluidic channels featuring a 20 µm-wide rib structure, fully utilizing the capillary force, thereby eliminating the issue of sweat hysteresis. Furthermore, with only 0.5 µl of the sweat secreted at the collection site, it can converge on the detection medium located within the center reservoir. Volunteer verification demonstrated a twofold increase in sweat collection efficiency compared to traditional wearable patches. This patch serves as an efficient sweat-collection configuration, promising potential for diverse in situ sweat colorimetric analyses.

Ultrathin, Transferred Layers of Silicon Oxynitrides as Tunable Biofluid Barriers for Bioresorbable Electronic Systems.

Bio/ecoresorbable electronic systems create unique opportunities in implantable medical devices that serve a need over a finite time period and then disappear naturally to eliminate the need for extraction surgeries. A critical challenge in the development of this type of technology is in materials that can serve as thin, stable barriers to surrounding ground water or biofluids, yet ultimately dissolve completely to benign end products. This paper describes a class of inorganic material (silicon oxynitride, SiON) that can be formed in thin films by plasma-enhanced chemical vapor deposition for this purpose. In vitro studies suggest that SiON and its dissolution products are biocompatible, indicating the potential for its use in implantable devices. A facile process to fabricate flexible, wafer-scale multilayer films bypasses limitations associated with the mechanical fragility of inorganic thin films. Systematic computational, analytical, and experimental studies highlight the essential materials aspects. Demonstrations in wireless light-emitting diodes both in vitro and in vivo illustrate the practical use of these materials strategies. The ability to select degradation rates and water permeability through fine tuning of chemical compositions and thicknesses provides the opportunity to obtain a range of functional lifetimes to meet different application requirements.

Growth Control Strategy of Hydrogen-Containing Nanocrystalline Carbon Films during Plasma-Enhanced Chemical Vapor Deposition based on Molecular Dynamics-Monte Carlo Simulations.

Hydrogen-containing nanocrystalline carbon films (n-C:H) with amorphous-nanocrystalline hydrocarbon composite structures exhibit excellent properties in diverse applications. Plasma-enhanced chemical vapor deposition (PECVD) is commonly employed to prepare n-C:H films due to its ability to create an adjustable deposition environment and control film compositions. However, the atomic-scale growth mechanism of n-C:H remains poorly understood, obstructing the design of the appropriate deposition parameters and film compositions. This paper employs a state-of-the-art hybrid molecular dynamics-time-stamped force-biased Monte Carlo model (MD/tfMC) to simulate the plasma-assisted growth of n-C:H. Our results reveal that optimizing the energy of ion bombardments, deposition temperature, and precursor's H:C ratio is crucial for achieving the nucleation and growth of highly ordered n-C:H films. These findings are further validated through experimental observations and density functional theory calculations, which show that hydrogen atoms can promote the formation of nanocrystalline carbon through chemical catalytic processes. Additionally, we find that the crystallinity reaches its optimum when the H/C ratio is equal to 1. These theoretical insights provide an effective strategy for the controlled preparation of hydrogen-containing nanocrystalline carbon films.

Reward prediction error in learning-related behaviors.

Learning is a complex process, during which our opinions and decisions are easily changed due to unexpected information. But the neural mechanism underlying revision and correction during the learning process remains unclear. For decades, prediction error has been regarded as the core of changes to perception in learning, even driving the learning progress. In this article, we reviewed the concept of reward prediction error, and the encoding mechanism of dopaminergic neurons and the related neural circuities. We also discussed the relationship between reward prediction error and learning-related behaviors, including reversal learning. We then demonstrated the evidence of reward prediction error signals in several neurological diseases, including Parkinson's disease and addiction. These observations may help to better understand the regulatory mechanism of reward prediction error in learning-related behaviors.

Mediodorsal thalamus-projecting anterior cingulate cortex neurons modulate helping behavior in mice.

Many species living in groups can perform prosocial behaviors via voluntarily helping others with or without benefits for themselves. To provide a better understanding of the neural basis of such prosocial behaviors, we adapted a preference lever-switching task in which mice can prevent harm to others by switching from using a lever that causes shocks to a conspecific one that does not. We found the harm avoidance behavior was mediated by self-experience and visual and social contact but not by gender or familiarity. By combining single-unit recordings and analysis of neural trajectory decoding, we demonstrated the dynamics of anterior cingulate cortex (ACC) neural activity changes synchronously with the harm avoidance performance of mice. In addition, ACC neurons projected to the mediodorsal thalamus (MDL) to modulate the harm avoidance behavior. Optogenetic activation of the ACC-MDL circuit during non-preferred lever pressing (nPLP) and inhibition of this circuit during preferred lever pressing (PLP) both resulted in the loss of harm avoidance ability. This study revealed the ACC-MDL circuit modulates prosocial behavior to avoid harm to conspecifics and may shed light on the treatment of neuropsychiatric disorders with dysfunction of prosocial behavior.

3D-printed epidermal sweat microfluidic systems with integrated microcuvettes for precise spectroscopic and fluorometric biochemical assays.

Systems for capture, storage and analysis of eccrine sweat can provide insights into physiological health status, quantify losses of water, electrolytes, amino acids and/or other essential species, and identify exposures to adverse environmental species or illicit drugs. Recent advances in materials and device designs serve as the basis for skin-compatible classes of microfluidic platforms and in situ colorimetric assays for precise assessments of sweat rate, sweat loss and concentrations of wide-ranging types of biomarkers in sweat. This paper presents a set of findings that enhances the performance of these systems through the use of microfluidic networks, integrated valves and microscale optical cuvettes formed by three dimensional printing in hard/soft hybrid materials systems, for accurate spectroscopic and fluorometric assays. Field studies demonstrate the capability of these microcuvette systems to evaluate the concentrations of copper, chloride, and glucose in sweat, along with the pH of sweat, with laboratory-grade accuracy and sensitivity.