Atomistic study of an ideal metal/thermoelectric contact: the full-Heusler/half-Heusler interface

Half-Heusler alloys such as the (Zr,Hf)NiSn intermetallic compounds are important thermoelectric materials for converting waste heat into electricity. Reduced electrical resistivity at the hot interface between the half-Heusler material and a metal contact is critical for device performance, however this has yet to be achieved in practice. Recent experimental work suggests that a coherent interface between half-Heusler and full-Heusler compounds can form due to diffusion of transition metal atoms into the vacant sublattice of the half-Heusler lattice. We study theoretically the structural and electronic properties of such an interface using a first-principles based approach that combines {\it ab initio} calculations with macroscopic modeling. We find that the prototypical interface HfNi$_2$Sn/HfNiSn provides very low contact resistivity and almost ohmic behavior over a wide range of temperatures and doping levels. Given the potential of these interfaces to remain stable over a wide range of temperatures, our study suggests that full-Heuslers might provide nearly ideal electrical contacts to half-Heuslers that can be harnessed for efficient thermoelectric generator devices.Comment: 8 pages, 8 figure

Electroconvulsive therapy for agitation in schizophrenia: Meta-analysis of randomized controlled trials

Background: Agitation poses a significant challenge in the treatment of schizophrenia. Electroconvulsive therapy (ECT) is a fast, effective and safe treatment for a variety of psychiatric disorders, but no meta-analysis of ECT treatment for agitation in schizophrenia has yet been reported. Aims: To systematically evaluate the efficacy and safety of ECT alone or ECT-antipsychotics (APs) combination for agitation in schizophrenia. Methods: Systematic literature search of randomized controlled trials (RCTs) was performed. Two independent evaluators selected studies, extracted data about outcomes and safety with available data, conducted quality assessment and data synthesis. The Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) was used to judge the level of the overall evidence of main outcomes. Results: Seven RCTs from China, including ECT alone (4 RCTs with 5 treatment arms, n=240) and ECT-APs combination (3 RCTs, n=240), were identified. Participants in the studies were on average 34.3(4.5) years of age and lasted an average of 4.3(3.1) weeks of treatment duration. All 7 RCTs were non-blinded, and were rated as low quality based on Jadad scale. Meta-analysis of the pooled sample found no significant difference in the improvement of the agitation sub-score of the Positive and Negative Syndrome Scale (PANSS) when ECT alone (weighted mean difference=-0.90, (95% confidence interval (CI): -2.91, 1.11), p=0.38) or ECT-APs combination (WMD=-1.34, (95%CI: -4.07, 1.39), p=0.33) compared with APs monotherapy. However, ECT alone was superior to APs monotherapy regarding PANSS total score (WMD=-7.13, I2=0%, p=0.004) and its excitement sub-score (WMD=-1.97, pI2=0%, p=0.004) and its excitement sub-score at 7 and 14 days (WMD=-1.97 to -1.92, p=0.002 to 0.0001) after ECT. The ECT-APs combination was superior to APs monotherapy with respect to the PANSS total score at treatment endpoint (WMD=-10.40, p=0.03) and 7 days (WMD=-5.01, p=0.02). Headache ( number-needed-to-harm (NNH)=3, 95%CI=2-4) was more frequent in the ECT alone group compared to AP monotherapy. According to the GRADE approach, the evidence levels of main outcomes were rated as ‘‘very low’’ (37.5%) and “low” (50%). Conclusion: Pooling of the data based on 7 RCTs from China found no advantage of ECT alone or ECT-APs combination in the treatment of agitation related outcomes in schizophrenia patients. However, ECT alone or ECT-APs combination were associated with significant reduction in the PANSS total score. High-quality RCTs are needed to confirm the current interpretations. Review registration number: CRD4201400668

Beyond the call of duty: Why customers contribute to firm-hosted commercial online communities

Firm-hosted commercial online communities, in which customers interact to solve each other's service problems, represent a fascinating context to study the motivations of collective action in the form of knowledge contribution to the community. We extend a model of social capital based on Wasko and Faraj (2005) to incorporate and contrast the direct impact of commitment to both the online community and the host firm, as well as reciprocity, on quality and quantity of knowledge contribution. In addition, we examine the moderating influence of three individual attributes that are particularly relevant to the firm-hosted community context: perceived informational value, sportsmanship, and online interaction propensity. We empirically test our framework using self-reported and objective data from 203 members of a firm-hosted technical support community. In addition to several interesting moderating effects, we find that a customer's online interaction propensity, commitment to the community, and the informational value s/he perceives in the community are the strongest drivers of knowledge contribution

Mechanosensitive fluorescence lifetime probes for investigating the dynamic mechanism of ferroptosis

Deciphering the dynamic mechanism of ferroptosis can provide insights into pathogenesis, which is valuable for disease diagnosis and treatment. However, due to the lack of suitable time-resolved mechanosensitive tools, researchers have been unable to determine the membrane tension and morphology of the plasma membrane and the nuclear envelope during ferroptosis. With this research, we propose a rational strategy to develop robust mechanosensitive fluorescence lifetime probes which can facilitate simultaneous fluorescence lifetime imaging of the plasma membrane and nuclear envelope. Fluorescence lifetime imaging microscopy using the unique mechanosensitive probes reveal a dynamic mechanism for ferroptosis: The membrane tension of both the plasma membrane and the nuclear envelope decreases during ferroptosis, and the nuclear envelope exhibits budding during the advanced stage of ferroptosis. Significantly, the membrane tension of the plasma membrane is always larger than that of the nuclear envelope, and the membrane tension of the nuclear envelope is slightly larger than that of the nuclear membrane bubble. Meanwhile, the membrane lesions are repaired in the low-tension regions through exocytosis.</p

Leveraging wearable sensors for human daily activity recognition with stacked denoising autoencoders

Activity recognition has received considerable attention in many research fields, such as industrial and healthcare fields. However, many researches about activity recognition have focused on static activities and dynamic activities in current literature, while, the transitional activities, such as stand-to-sit and sit-to-stand, are more difficult to recognize than both of them. Consider that it may be important in real applications. Thus, a novel framework is proposed in this paper to recognize static activities, dynamic activities, and transitional activities by utilizing stacked denoising autoencoders (SDAE), which is able to extract features automatically as a deep learning model rather than utilize manual features extracted by conventional machine learning methods. Moreover, the resampling technique (random oversampling) is used to improve problem of unbalanced samples due to relatively short duration characteristic of transitional activity. The experiment protocol is designed to collect twelve daily activities (three types) by using wearable sensors from 10 adults in smart lab of Ulster University, the experiment results show the significant performance on transitional activity recognition and achieve the overall accuracy of 94.88% on three types of activities. The results obtained by comparing with other methods and performances on other three public datasets verify the feasibility and priority of our framework. This paper also explores the effect of multiple sensors (accelerometer and gyroscope) to determine the optimal combination for activity recognition

Mechanical behaviour of brushite and hydroxyapatite coatings electrodeposited on newly developed FeMnSiPd alloys

Calcium phosphate coatings (CaP) (i.e., brushite and hydroxyapatite) were grown by pulsed current electrodeposition on FeMnSiPd alloys, a newly developed material proposed for biomedical implants. The electrolytic baths contained Ca(NO₃)₂·4H₂O and NH₄H₂PO₄ as precursors. Bath additives, such as H₂O₂ and NaOH, were used to promote hydroxyapatite (HAp) coating formation directly from the bath. The effect of the electrodeposition parameters on the structure, morphology and mechanical performance of the coatings was investigated. Increasing the electrodeposition time from 900s to 3600s resulted in an increase of HAp over the dominant brushite structure. Addition of 2000 ppm of NaOH or 3000 ppm of H₂O₂ also promoted an increase of HAp fraction when compared to the coatings obtained from the additive-free bath. Nonetheless, pure HAp was only achieved with the addition of 4000 ppm of NaOH to the electrolyte. The morphologies of the CaP particles in the coatings ranged from needle- to plate-like structures depending on the electrodeposition parameters and the resulting phases. The mechanical behaviour of the coatings was studied by scratch testing and nanoindentation. As a general trend, the Young's modulus and hardness values of the electrodeposited coatings were lower than those reported for fully-dense HAp, independently of the deposition conditions, because of the porous morphology of the coatings. No signs of cracking or delamination were observed during nanoindentation or scratch tests except for the coating prepared form the electrolyte containing 3000 ppm of H₂O₂

AudioLDM 2: Learning Holistic Audio Generation with Self-supervised Pretraining

Although audio generation shares commonalities across different types of audio, such as speech, music, and sound effects, designing models for each type requires careful consideration of specific objectives and biases that can significantly differ from those of other types. To bring us closer to a unified perspective of audio generation, this paper proposes a framework that utilizes the same learning method for speech, music, and sound effect generation. Our framework introduces a general representation of audio, called "language of audio" (LOA). Any audio can be translated into LOA based on AudioMAE, a self-supervised pre-trained representation learning model. In the generation process, we translate any modalities into LOA by using a GPT-2 model, and we perform self-supervised audio generation learning with a latent diffusion model conditioned on LOA. The proposed framework naturally brings advantages such as in-context learning abilities and reusable self-supervised pretrained AudioMAE and latent diffusion models. Experiments on the major benchmarks of text-to-audio, text-to-music, and text-to-speech demonstrate state-of-the-art or competitive performance against previous approaches. Our code, pretrained model, and demo are available at https://audioldm.github.io/audioldm2.Comment: AudioLDM 2 project page is https://audioldm.github.io/audioldm

Synthesis of α-Fe2O3 and Fe-Mn oxide foams with highly tunable magnetic properties by the replication method from polyurethane templates

Open cell foams consisting of Fe and Fe-Mn oxides are prepared from metallic Fe and Mn powder precursors by the replication method using porous polyurethane (PU) templates. First, reticulated PU templates are coated by slurry impregnation. The templates are then thermally removed at 260 °C and the debinded powders are sintered at 1000 °C under N2 atmosphere. The morphology, structure, and magnetic properties are studied by scanning electron microscopy, X-ray diffraction and vibrating sample magnetometry, respectively. The obtained Fe and Fe-Mn oxide foams possess both high surface area and homogeneous open-cell structure. Hematite (α-Fe2O3) foams are obtained from the metallic iron slurry independently of the N2 flow. In contrast, the microstructure of the FeMn-based oxide foams can be tailored by adjusting the N2 flow. While the main phases for a N2 flow rate of 180 L/h are α-Fe2O3 and FeMnO3, the predominant phase for high N2 flow rates (e.g., 650 L/h) is Fe2MnO4. Accordingly, a linear magnetization versus field behavior is observed for the hematite foams, while clear hysteresis loops are obtained for the Fe2MnO4 foams. Actually, the saturation magnetization of the foams containing Mn increases from 5 emu/g to 52 emu/g when the N2 flow rate (i.e., the amount of Fe2MnO4) is increased. The obtained foams are appealing for a wide range of applications, such as electromagnetic absorbers, catalysts supports, thermal and acoustic insulation systems or wirelessly magnetically-guided porous objects in fluids