Homogeneity and Sparsity Analysis for High Dimensional Panel Data Models

In this paper, we are interested in detecting latent group structures and significant covariates in a high-dimensional panel data model with both individual and time fixed effects. The slope coefficients of the model are assumed to be subject dependent, and there exist group structures where the slope coefficients are homogeneous within groups and heterogeneous between groups. We develop a penalized estimator for recovering the group structures and the sparsity patterns simultaneously. We propose a new algorithm to optimize the objective function. Furthermore, we propose a strategy to reduce the computational complexity by pruning the penalty terms in the objective function, which also improves the accuracy of group structure detection. The proposed estimator can recover the latent group structures and the sparsity patterns consistently in large samples. The finite sample performance of the proposed estimator is evaluated through Monte Carlo studies and illustrated with a real data set.</p

A hybrid ionic liquid crystal comprising imidazolium surfactant-graphene oxide

To produce graphene oxide liquid crystal composites with better controllability, imidazolium surfactant with biphenyl mesogenic core (CBphCM) has been synthesised and used to modify the negatively charged surface of graphene oxide (GO) to obtain a hybrid ionic liquid crystal (CBphCM-GO). The process of GO and CBphCM recombination was monitored by various experimental techniques such as FT-IR, Uv-vis, Raman and XPS. The experimental results indicated that the C=O bonds on GO sheets are all reduced and C−O bonds are partially reduced due to the imidazolium units being electrically active and nitrogen-rich, and the presence of the N−O bonds indicates that a new hybrid is formed between CBphCM and GO. The recombination destroys the electrostatic repulsion balance among the GO lattices, and the CBphCM-GO is observed a fluffy appearance by TEM. The liquid crystal properties of CBphCM and CBphCM-GO were investigated by DSC, polarised optical microscopy (POM) and variable temperature X-ray diffraction, respectively. As an ionic liquid crystal, CBphCM has SmA as well as the rare SmC phases exhibits de Vries-like behaviour with a layer shrinkage. The liquid crystal properties of CBphCM-GO are derived from CBphCM, and the layer shrinkage behaviour from SmA to SmC phase has also been observed.</p

Insights into the Biogenic Amine Metabolic Landscape during Industrial Semidry Chinese Rice Wine Fermentation

Inspired by concerns about food safety, the metabolic landscape of biogenic amines (BAs) was elucidated during industrial semidry Chinese rice wine fermentation. The main fermentation process represented the largest contribution to BA formation, which corresponded to 69.1% (54.3 mg/L). Principal component analysis revealed that total acid and ethanol were strongly correlated with BAs, indicating that BA formation favored acidic and stressful conditions. Other than putrescine (PUT), spermidine (SPD), and spermine (SPM), 5 BAs exhibited strong relationships with the precursor amino acids (<i>R</i>² > 0.85). PUT was mainly decarboxylated from arginine (89.6%) whereas SPD (100%) and SPM (83.1%) were obtained from ornithine. Interestingly, some SPD could convert back to PUT (24.3%). All 8 BAs showed good relationships with lactic acid bacteria (LAB) (<i>R</i>² around 0.75). Moreover, among the five main LAB genera, <i>Lactobacillus</i> had a positive correlation with BA formation

Few-Layer Hydroxyl-Functionalized Boron Nitride Nanosheets for Nanoscale Thermal Management

Boron nitride nanosheets (BNNSs) are widely used as fillers to increase the thermal conductivity of a substrate. However, the solvent resistance of BNNSs limits their widespread application. In this paper, hydroxyl functionalized boron nitride nanosheets (OH-BNNSs) were prepared through a one-step aqueous shear exfoliation process. The dangling bonds were formed during the exfoliation process and were attacked by water molecules, and thereby hydroxyl functionalization of BNNSs was achieved. The OH-BNNSs were added to poly­(vinyl alcohol) (PVA) to prepare a nanocomposite with high thermal conductivity. The high-speed dispersive homogenizer was selected as the shear-exfoliating device, water as solvent, and sodium dodecyl sulfate (SDS) as surfactant. The effects of operating conditions on the concentration of few-layer OH-BNNSs were systematically studied. Under the optimized conditions, 0.88 mg/mL of OH-BNNSs was obtained. The as-obtained OH-BNNSs were filled in PVA to obtain composite film. The in-plane thermal diffusivity of OH-BNNSs-PVA films reached 9.03 mm2/s, which was 40-times the in-plane thermal diffusivity of the pure PVA film and 1.6-times the in-plane thermal diffusivity of the PVA composites filled by BNNSs prepared from ultrasonic exfoliation. The reasons were attributed to better dispersibility in PVA aqueous solution for OH-BNNSs. This paper provided a simple, scalable, and environmentally friendly preparation method for OH-BNNSs

Ultrastretchable, Highly Conductive, Rapid Self-Recovery, and Antiswelling Hydrogels as Multifunctional Wearable Electronic Devices

The development of wearable electronic devices requires stretchable, highly conductive, self-recovery, and ideally environmentally resistant sensors. Hydrogels are ideal candidates for fabricating flexible sensors due to their stretchability and unique ionic conduction pathways. However, the intrinsic incompatibility of the conductive and elastic networks in hydrogels and the high hydrophilicity of the hydrogel network led to difficulties in obtaining hydrogels with strong mechanical properties, high conductivity, rapid self-recovery ability, and antiswelling properties. Based on the single-core multidentate coordination strategy, single-core multidentate coordinated chitosan/poly(acrylic acid)/Al3+ (CPAL) hydrogels were prepared with Al3+ as a metal coordination center and the amino group of chitosan (CS) and the carboxyl group of poly(acrylic acid) (PAA) as coordination atoms. The obtained hydrogels exhibit excellent tensile stress/strain: 1.11 ± 0.04 MPa/2472.79 ± 99.27%, rapid self-recovery capability (mechanical properties were fully recovered in 10 min), antifatigue property, good conductivity (1.09 ± 0.02 S/m), and antiswelling property. Furthermore, flexible sensors based on CPAL hydrogels demonstrated multiplex mode sensing. It was worth noting that the flexible devices based on CPAL hydrogel could not only use Morse code table to realize mechanical-information visualization but also detect the human condition in multiple dimensions, including temperature, electromyographic (EMG), and electrocardiogram (ECG). In this work, we reported a single-core multidentate coordination strategy that provided a pathway for fabricating the ideal hydrogel-based flexible sensors, showing great potential for wearable electronic devices

Highly Conductive Liquid Metal-Based Shape Memory Material with an Ultrasensitive Fire Warning Response

Fire warning materials always play an important role in safeguarding people’s lives and property. In general, existing approaches to realize supersensitive fire warning responses are typically focused on how to reduce response times. However, most strategies to effectively achieve fire warning require a high trigger temperature of over 180 °C that is unsuitable for fire warning of materials with a low flash point. Herein, a liquid metal-based shape memory material (LM-SMM) is fabricated by integrating liquid metal (LM), polydimethylsiloxane (PDMS), and polyurethane foam. The phase transition function of the LM contributes to better shape fixation properties. Meanwhile, the flexibility of PDMS assures good shape recovery performance. In particular, the LM-SMM still owns favorable electrical conductivity that could facilitate its application in advanced electronics. The combination of switchable structure and excellent electrical conductivity makes this LM-SMM appropriate for an ultrasensitive fire warning response. With the help of such performance, the LM-SMM can achieve the lowest fire-warning response temperature in a fast response time, which displays promising application in the safe storage of flammable materials. More importantly, this work could not only achieve the fabrication of highly conductive LM-SMM but also expand applications, thus providing possibilities for the next-generation supersensitive fire-warning response materials

Additional file 4: Table S4. of Comparative RNA-seq based transcriptomic analysis of bud dormancy in grape

Up and down regulated differentially expressed genes in cluster analysis. (XLSX 326 kb

Table_9_Metabolomic and transcriptomic analyses reveal the effects of grafting on blood orange quality.xlsx

IntroductionBlood orange (Citrus sinensis L.) is a valuable source of nutrition because it is enriched in anthocyanins and has high organoleptic properties. Grafting is commonly used in citriculture and has crucial effects on various phenotypes of the blood orange, including its coloration, phenology, and biotic and abiotic resistance. Still, the underlying genetics and regulatory mechanisms are largely unexplored.MethodsIn this study, we investigated the phenotypic, metabolomic, and transcriptomic profiles at eight developmental stages of the lido blood orange cultivar (Citrus sinensis L. Osbeck cv. Lido) grafted onto two rootstocks.Results and discussionThe Trifoliate orange “Zhiyang Xingcheng” rootstock provided the best fruit quality and flesh color for Lido blood orange. Comparative metabolomics suggested significant differences in accumulation patterns of metabolites and we identified 295 differentially accumulated metabolites. The major contributors were flavonoids, phenolic acids, lignans and coumarins, and terpenoids. Moreover, transcriptome profiling resulted in the identification of 4179 differentially expressed genes (DEGs), and 54 DEGs were associated with flavonoids and anthocyanins. Weighted gene co-expression network analysis identified major genes associated to 16 anthocyanins. Furthermore, seven transcription factors (C2H2, GANT, MYB-related, AP2/ERF, NAC, bZIP, and MYB) and five genes associated with anthocyanin synthesis pathway (CHS, F3H, UFGT, and ANS) were identified as key modulators of the anthocyanin content in lido blood orange. Overall, our results revealed the impact of rootstock on the global transcriptome and metabolome in relation to fruit quality in lido blood orange. The identified key genes and metabolites can be further utilized for the quality improvement of blood orange varieties.</p

Additional file 7: Table S7. of Comparative RNA-seq based transcriptomic analysis of bud dormancy in grape

Differentially expressed genes involved in KEGG pathways between paradormancy vs endodormancy. (XLSX 24 kb