Metal-Halogen Interactions Inducing Phase Separation for Self-Healing and Tough Ionogels with Tunable Thermoelectric Performance.

Ionic liquid-based thermoelectric gels become a compelling candidate for thermoelectric power generation and sensing due to their giant thermopower, good thermal stability, high flexibility, and low-cost production. However, the materials reported to date suffer from canonical trade-offs between self-healing ability, stretchability, strength, and ionic conductivity. Herein, a self-healing and tough ionogel (PEO/LiTFSI/EmimCl) with tunable thermoelectric properties by tailoring metal-halogen bonding interactions, is developed. Different affinities between polymer matrix and salts are exploited to induce phase separation, resulting in simultaneous enhancement of ionic conductivity and mechanical strength. Molecular dynamics (MD) simulations and spectroscopic analyses show that Cl- ions impair the lithium-ether oxygen coordination, leading to changes in chain conformation. The migration difference between cations and anions is thus widened and a transition from n-type to p-type thermoelectric ionogels is realized. Furthermore, the dynamic interactions of metal-ligand coordination and hydrogen bonding yield autonomously self-healing capability, large stretchability (2000%), and environment-friendly recyclability. Benefiting from these fascinating properties, the multifunctional PEO-based ionogels are applied in sensors, supercapacitors, and thermoelectric power generation modules. The strategy of tuning solvation dominance to address the trade-offs in thermoelectric ionogels and optimize their macroscopic properties offers new possibilities for the design of advanced ionogels.

Ordered mesoporous nanofibers mimicking vascular bundles for lithium metal batteries.

Hierarchical self-assembly with long-range order above centimeters widely exists in nature. Mimicking similar structures to promote reaction kinetics of electrochemical energy devices is of immense interest, yet remains challenging. Here, we report a bottom-up self-assembly approach to constructing ordered mesoporous nanofibers with a structure resembling vascular bundles via electrospinning. The synthesis involves self-assembling polystyrene (PS) homopolymer, amphiphilic diblock copolymer, and precursors into supramolecular micelles. Elongational dynamics of viscoelastic micelle solution together with fast solvent evaporation during electrospinning cause simultaneous close packing and uniaxial stretching of micelles, consequently producing polymer nanofibers consisting of oriented micelles. The method is versatile for the fabrication of large-scale ordered mesoporous nanofibers with adjustable pore diameter and various compositions such as carbon, SiO2, TiO2 and WO3. The aligned longitudinal mesopores connected side-by-side by tiny pores offer highly exposed active sites and expedite electron/ion transport. The assembled electrodes deliver outstanding performance for lithium metal batteries.

Translation and validation of the Chinese version of Palliative Care Self-Efficacy Scale.

OBJECTIVES: Accurately assessing the self-efficacy levels of palliative care professionals' is crucial, as low levels of self-efficacy may contribute to the suboptimal provision of palliative care. However, there is currently lacking a reliable and valid instrument for evaluating the self-efficacy of palliative care practitioners in China. Therefore, this study aimed to translate, adapt, and validate the Palliative Care Self-Efficacy Scale (PCSS) among Chinese palliative care professionals. METHODS: This study involved the translation and cross-cultural adaptation of the PCSS, and the evaluation of its psychometric properties through testing for homogeneity, content validity, construct validity, known-groups validity, and reliability. RESULTS: A total of 493 palliative care professionals participated in this study. The results showed the critical ratio value of each item was >3 (p < 0.01), and the corrected item-total correlation coefficients of all items ranged from 0.733 to 0.818, indicating a good homogeneity of the items with the scale. Additionally, the scale was shown to have good validity, with item-level content validity index ranged from 0.857 to 1.000, and scale-level content validity index/Ave was 0.956. The exploratory factor analysis and confirmatory factor analysis (CFA) confirmed the 2-factor structure of the Chinese version of PCSS (C-PCSS), explaining 74.19% of the variance. CFA verified that the 2-factor model had a satisfactory model fit, with χ2/df = 2.724, RMSEA = 0.084, GFI = 0.916, CFI = 0.967, and TLI = 0.952. The known-groups validity of C-PCSS was demonstrated good with its sensitive in differentiating levels of self-efficacy between professionals with less than 1 year of palliative care experience (p < 0.001) or without palliative care training (p = 0.014) and their counterparts. Furthermore, the C-PCSS also exhibited an excellent internal consistency, with the Cronbach's α for the total scale of 0.943. SIGNIFICANCE OF RESULTS: The findings from this study affirmed good validity and reliability of the C-PCSS. It can be emerged as a valuable and reliable instrument for assessing the self-efficacy levels of palliative care professionals in China.

Cross-cultural adaptation and psychometric validation of point-of-care outcome assessment tools in Chinese palliative care clinical practice.

BACKGROUND: A standardized national approach to routinely assessing palliative care patients helps improve patient outcomes. However, a quality improvement program-based on person centered outcomes within palliative care is lacking in Mainland China. The well-established Australian Palliative Care Outcome Collaboration (PCOC) national model improves palliative care quality. This study aimed to culturally adapt and validate three measures that form part of the PCOC program for palliative care clinical practice in China: The PCOC Symptom Assessment Scale (PCOC SAS), Palliative Care Problem Severity Scale (PCPSS), Palliative Care Phase. METHODS: A study was conducted on cross-cultural adaptation and validation of PCOC SAS, PCPSS and Palliative Care Phase, involving translation methods, cognitive interviewing, and psychometric testing through paired assessments. RESULTS: Cross-cultural adaptation highlighted the need to strengthen the link between the patient's care plan and the outcome measures to improve outcomes, and the concept of distress in PCOC SAS. Analysis of 368 paired assessments (n = 135 inpatients, 22 clinicians) demonstrated that the PCOC SAS and PCPSS had good and acceptable coherence (Cronbach's a = 0.85, 0.75 respectively). Palliative Care Phase detected patients' urgent needs. PCOC SAS and PCPSS showed fair discriminant and concurrent validity. Inter-rater reliability was fair for Palliative Care Phase (k = 0.31) and PCPSS (k = 0.23-0.30), except for PCPSS-pain, which was moderate (k = 0.53). CONCLUSIONS: The Chinese version of PCOC SAS, PCPSS, and Palliative Care Phase can be used to assess outcomes as part of routine clinical practice in Mainland China. Comprehensive clinical education regarding the assessment tools is necessary to help improve the inter-rater reliability.

Fully inkjet-printed Ag2Se flexible thermoelectric devices for sustainable power generation.

Flexible thermoelectric devices show great promise as sustainable power units for the exponentially increasing self-powered wearable electronics and ultra-widely distributed wireless sensor networks. While exciting proof-of-concept demonstrations have been reported, their large-scale implementation is impeded by unsatisfactory device performance and costly device fabrication techniques. Here, we develop Ag2Se-based thermoelectric films and flexible devices via inkjet printing. Large-area patterned arrays with microscale resolution are obtained in a dimensionally controlled manner by manipulating ink formulations and tuning printing parameters. Printed Ag2Se-based films exhibit (00 l)-textured feature, and an exceptional power factor (1097 µWm-1K-2 at 377 K) is obtained by engineering the film composition and microstructure. Benefiting from high-resolution device integration, fully inkjet-printed Ag2Se-based flexible devices achieve a record-high normalized power (2 µWK-2cm-2) and superior flexibility. Diverse application scenarios are offered by inkjet-printed devices, such as continuous power generation by harvesting thermal energy from the environment or human bodies. Our strategy demonstrates the potential to revolutionize the design and manufacture of multi-scale and complex flexible thermoelectric devices while reducing costs, enabling them to be integrated into emerging electronic systems as sustainable power sources.

Embedding Multiple Magnetic Components in Carbon Nanostructures via Metal-Oxo Cluster Precursor for High-Efficiency Low-/Middle-Frequency Electromagnetic Wave Absorption.

With the advent of wireless technology, magnetic-carbon composites with strong electromagnetic wave (EMW) absorption capability in low-/middle-frequency range are highly desirable. However, it remains challenging for rational construction of such absorbers bearing multiple magnetic components that show uniform distribution and favorable magnetic loss. Herein, a facile metal-oxo cluster (MOC) precursor strategy is presented to produce high-efficiency magnetic carbon composites. Nanosized MOC Fe15 shelled with organic ligands is employed as a novel magnetic precursor, thus allowing in situ formation and uniform deposition of multicomponent magnetic Fe/Fe3O4@Fe3C and Fe/Fe3O4 nanoparticles on graphene oxides (GOs) and carbon nanotubes (CNTs), respectively. Owing to the good dispersity and efficient magnetic-dielectric synergy, quaternary Fe/Fe3O4@Fe3C-GO exhibits strong low-frequency absorption with RLmin of -53.5 dB at C-band and absorption bandwidth covering 3.44 GHz, while ultrahigh RLmin of -73.2 dB is achieved at X-band for ternary Fe/Fe3O4-CNT. The high performance for quaternary and ternary composites is further supported by the optimal specific EMW absorption performance (-15.7 dB mm-1 and -31.8 dB mm-1) and radar cross-section reduction (21.72 dB m2 and 34.37 dB m2). This work provides a new avenue for developing lightweight low-/middle-frequency EMW absorbers, and will inspire the investigation of more advanced EMW absorbers with multiple magnetic components and regulated microstructures.

Physiological, Photosynthetic, and Transcriptomics Insights into the Influence of Shading on Leafy Sweet Potato.

Leafy sweet potato is a new type of sweet potato, whose leaves and stems are used as green vegetables. However, sweet potato tips can be affected by pre-harvest factors, especially the intensity of light. At present, intercropping, greenhouse planting, and photovoltaic agriculture have become common planting modes for sweet potato. Likewise, they can also cause insufficient light conditions or even low light stress. This research aimed to evaluate the influence of four different shading levels (no shading, 30%, 50%, and 70% shading degree) on the growth profile of sweet potato leaves. The net photosynthetic rate, chlorophyll pigments, carbohydrates, and polyphenol components were determined. Our findings displayed that shading reduced the content of the soluble sugar, starch, and sucrose of leaves, as well as the yield and Pn. The concentrations of Chl a, Chl b, and total Chl were increased and the Chl a/b ratio was decreased for the more efficient interception and absorption of light under shading conditions. In addition, 30% and 50% shading increased the total phenolic, total flavonoids, and chlorogenic acid. Transcriptome analysis indicated that genes related to the antioxidant, secondary metabolism of phenols and flavonoids, photosynthesis, and MAPK signaling pathway were altered in response to shading stresses. We concluded that 30% shading induced a high expression of antioxidant genes, while genes related to the secondary metabolism of phenols and flavonoids were upregulated by 50% shading. And the MAPK signaling pathway was modulated under 70% shading, and most stress-related genes were downregulated. Moreover, the genes involved in photosynthesis, such as chloroplast development, introns splicing, and Chlorophyll synthesis, were upregulated as shading levels increased. This research provides a new theoretical basis for understanding the tolerance and adaptation mechanism of leafy sweet potato in low light environments.

Exceptional n-type thermoelectric ionogels enabled by metal coordination and ion-selective association.

Ionic liquid-based ionogels emerge as promising candidates for efficient ionic thermoelectric conversion due to their quasi-solid state, giant thermopower, high flexibility, and good stability. P-type ionogels have shown impressive performance; however, the development of n-type ionogels lags behind. Here, an n-type ionogel consisting of polyethylene oxide (PEO), lithium salt, and ionic liquid is developed. Strong coordination of lithium ion with ether oxygen and the anion-rich clusters generated by ion-preferential association promote rapid transport of the anions and boost Eastman entropy change, resulting in a huge negative ionic Seebeck coefficient (-15 millivolts per kelvin) and a high electrical conductivity (1.86 millisiemens per centimeter) at 50% relative humidity. Moreover, dynamic and reversible interactions among the ternary mixtures endow the ionogel with fast autonomous self-healing capability and green recyclability. All PEO-based ionic thermoelectric modules are fabricated, which exhibits outstanding thermal responses (-80 millivolts per kelvin for three p-n pairs), demonstrating great potential for low-grade energy harvesting and ultrasensitive thermal sensing.

Modulating Electronic Structures of Iron Clusters through Orbital Rehybridization by Adjacent Single Copper Sites for Efficient Oxygen Reduction.

The atom-cluster interaction has recently been exploited as an effective way to increase the performance of metal-nitrogen-carbon catalysts for oxygen reduction reaction (ORR). However, the rational design of such catalysts and understanding their structure-property correlations remain a great challenge. Herein, we demonstrate that the introduction of adjacent metal (M)-N4 single atoms (SAs) could significantly improve the ORR performance of a well-screened Fe atomic cluster (AC) catalyst by combining density functional theory (DFT) calculations and experimental analysis. The DFT studies suggest that the Cu-N4 SAs act as a modulator to assist the O2 adsorption and cleavage of O-O bond on the Fe AC active center, as well as optimize the release of OH* intermediates to accelerate the whole ORR kinetic. The depositing of Fe AC with Cu-N4 SAs on nitrogen doped mesoporous carbon nanosheet are then constructed through a universal interfacial monomicelles assembly strategy. Consistent with theoretical predictions, the resultant catalyst exhibits an outstanding ORR performance with a half-wave potential of 0.92 eV in alkali and 0.80 eV in acid, as well as a high power density of 214.8 mW cm-2 in zinc air battery. This work provides a novel strategy for precisely tuning the atomically dispersed poly-metallic centers for electrocatalysis.

Syntheses, Structures, and Photoluminescence of Copper-Based Halides.

Copper-based halides have been found to be a new family of lead-free materials with high stability and superior optoelectrical properties. In this work, we report the photoluminescence of the known (C8H14N2)CuBr3 and the discovery of three new compounds, (C8H14N2)CuCl3, (C8H14N2)CuCl3·H2O, and (C8H14N2)CuI3, which all exhibit efficient light emissions. All these compounds have monoclinic structures with the same space group (P21/c) and zero-dimensional (0D) structures, which can be viewed as the assembly of promising aromatic molecules and different copper halide tetrahedrons. Upon the irradiation of deep ultraviolet light, (C8H14N2)CuCl3, (C8H14N2)CuBr3,, and (C8H14N2)CuI3 show green emission peaking at ∼520 nm with a photoluminescent quantum yield (PLQY) of 3.38, 35.19, and 17.81%, while (C8H14N2)CuCl3·H2O displays yellow emission centered at ∼532 nm with a PLQY of 2.88%. A white light-emitting diode (WLED) was successfully fabricated by employing (C8H14N2)CuBr3 as a green emitter, demonstrating the potential of copper halides for applications in the green lighting field.

High-efficiency and reliable same-parent thermoelectric modules using Mg3Sb2-based compounds.

Thermoelectric modules can convert waste heat directly into useful electricity, providing a clean and sustainable way to use fossil energy more efficiently. Mg3Sb2-based alloys have recently attracted considerable interest from the thermoelectric community due to their nontoxic nature, abundance of constituent elements and excellent mechanical and thermoelectric properties. However, robust modules based on Mg3Sb2 have progressed less rapidly. Here, we develop multiple-pair thermoelectric modules consisting of both n-type and p-type Mg3Sb2-based alloys. Thermoelectric legs based on the same parent fit into each other in terms of thermomechanical properties, facilitating module fabrication and ensuring low thermal stress. By adopting a suitable diffusion barrier layer and developing a new joining technique, an integrated all-Mg3Sb2-based module demonstrates a high efficiency of 7.5% at a temperature difference of 380 K, exceeding the state-of-the-art same-parent thermoelectric modules. Moreover, the efficiency remains stable during 150 thermal cycling shocks (∼225 h), demonstrating excellent module reliability.

Comparative analysis of the MYB gene family in seven Ipomoea species.

The MYB transcription factors regulate plant growth, development, and defense responses. However, information about the MYB gene family in Ipomoea species is rare. Herein, we performed a comprehensive genome-wide comparative analysis of this gene family among seven Ipomoea species, sweet potato (I. batatas), I. trifida, I. triloba, I. nil, I. purpurea, I. cairica, and I. aquatic, and identified 296, 430, 411, 291, 226, 281, and 277 MYB genes, respectively. The identified MYB genes were classified into five types: 1R-MYB (MYB-related), 2R-MYB (R2R3-MYB), 3R-MYB (R1R2R3-MYB), 4R-MYB, and 5R-MYB, and the MYB-related or R2R3-MYB type was the most abundant MYB genes in the seven species. The Ipomoea MYB genes were classed into distinct subgroups based on the phylogenetic topology and the classification of the MYB superfamily in Arabidopsis. Analysis of gene structure and protein motifs revealed that members within the same phylogenetic group presented similar exon/intron and motif organization. The identified MYB genes were unevenly mapped on the chromosomes of each Ipomoea species. Duplication analysis indicated that segmental and tandem duplications contribute to expanding the Ipomoea MYB genes. Non-synonymous substitution (Ka) to synonymous substitution (Ks) [Ka/Ks] analysis showed that the duplicated Ipomoea MYB genes are mainly under purifying selection. Numerous cis-regulatory elements related to stress responses were detected in the MYB promoters. Six sweet potato transcriptome datasets referring to abiotic and biotic stresses were analyzed, and MYB different expression genes' (DEGs') responses to stress treatments were detected. Moreover, 10 sweet potato MYB DEGs were selected for qRT-PCR analysis. The results revealed that four responded to biotic stress (stem nematodes and Ceratocystis fimbriata pathogen infection) and six responded to the biotic stress (cold, drought, and salt). The results may provide new insights into the evolution of MYB genes in the Ipomoea genome and contribute to the future molecular breeding of sweet potatoes.

Genome-wide comparative analysis of the valine glutamine motif containing genes in four Ipomoea species.

BACKGROUND: Genes with valine glutamine (VQ) motifs play an essential role in plant growth, development, and resistance to biotic and abiotic stresses. However, little information on the VQ genes in sweetpotato and other Ipomoea species is available. RESULTS: This study identified 55, 58, 50 and 47 VQ genes from sweetpotato (I. batatas), I.triflida, I. triloba and I. nil, respectively. The phylogenetic analysis revealed that the VQ genes formed eight clades (I-VII), and the members in the same group exhibited similar exon-intron structure and conserved motifs distribution. The distribution of the VQ genes among the chromosomes of Ipomoea species was disproportional, with no VQ genes mapped on a few of each species' chromosomes. Duplication analysis suggested that segmental duplication significantly contributes to their expansion in sweetpotato, I.trifida, and I.triloba, while the segmental and tandem duplication contributions were comparable in I.nil. Cis-regulatory elements involved in stress responses, such as W-box, TGACG-motif, CGTCA-motif, ABRE, ARE, MBS, TCA-elements, LTR, and WUN-motif, were detected in the promoter regions of the VQ genes. A total of 30 orthologous groups were detected by syntenic analysis of the VQ genes. Based on the analysis of RNA-seq datasets, it was found that the VQ genes are expressed distinctly among different tissues and hormone or stress treatments. A total of 40 sweetpotato differentially expressed genes (DEGs) refer to biotic (sweetpotato stem nematodes and Ceratocystis fimbriata pathogen infection) or abiotic (cold, salt and drought) stress treatments were detected. Moreover, IbVQ8, IbVQ25 and IbVQ44 responded to the five stress treatments and were selected for quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis, and the results were consistent with the transcriptome analysis. CONCLUSIONS: Our study may provide new insights into the evolution of VQ genes in the four Ipomoea genomes and contribute to the future molecular breeding of sweetpotatoes.

Highly efficient silica coated perovskite nanocrystals with the assistance of ionic liquids for warm white LEDs.

Given the inherent characteristics of defect-tolerant, tunable emission performance, and high extinction coefficient, lead halide perovskite nanocrystals (NCs) have attracted widespread attention as a promising material in optoelectronic fields. However, their poor structural stability greatly impedes their practical applications. Herein, a novel strategy for synthesizing stable CsPbBr3@SiO2 NCs via the hydrolytic polycondensation of (3-aminopropyl)triethoxysilane (APTES) in the presence of ionic liquids (ILs) is deliberately designed. The problems of fluorescence quenching and undesirable agglomeration of NCs resulting from ligand loss and surface erosion existing in common encapsulation methods can be effectively resolved. The fast and controllable growth of the SiO2 shell around the CsPbBr3 NCs is realized owing to the high polarity and hygroscopicity of the IL. Moreover, the dual effects of the IL for passivating the surface defects and avoiding the structural degradation of NCs during the hydrolysis process of APTES are demonstrated. As a result, CsPbBr3@SiO2 NCs with a high photoluminescence quantum yield of 85.7% and excellent stability are realized. Furthermore, this method proves to be a versatile tool to obtain CsPbX3@SiO2 NCs with different halide compositions, realizing a broad tunable wavelength from 421.2 nm to 651.6 nm. A warm white LED with a high color rending index was assembled through packaging CsPbBr3@SiO2 NCs and Cu-In-Zn-S/ZnS/PVP composites on a commercial blue chip. These findings are expected to facilitate the development of perovskite NCs, which provides access to their optoelectronic applications.

Genome-wide comparative analysis of the nucleotide-binding site-encoding genes in four Ipomoea species.

The nucleotide-binding site (NBS)-encoding gene is a major type of resistance (R) gene, and its diverse evolutionary patterns were analyzed in different angiosperm lineages. Until now, no comparative studies have been done on the NBS encoding genes in Ipomoea species. In this study, various numbers of NBS-encoding genes were identified across the whole genome of sweet potato (Ipomoea batatas) (#889), Ipomoea trifida (#554), Ipomoea triloba (#571), and Ipomoea nil (#757). Gene analysis showed that the CN-type and N-type were more common than the other types of NBS-encoding genes. The phylogenetic analysis revealed that the NBS-encoding genes formed three monophyletic clades: CNL, TNL, and RNL, which were distinguished by amino acid motifs. The distribution of the NBS-encoding genes among the chromosomes was non-random and uneven; 83.13, 76.71, 90.37, and 86.39% of the genes occurred in clusters in sweet potato, I. trifida, I. triloba, and I. nil, respectively. The duplication pattern analysis reveals the presence of higher segmentally duplicated genes in sweet potatoes than tandemly duplicated ones. The opposite trend was found for the other three species. A total of 201 NBS-encoding orthologous genes were found to form synteny gene pairs between any two of the four Ipomea species, suggesting that each of the synteny gene pairs was derived from a common ancestor. The gene expression patterns were acquired by analyzing using the published datasets. To explore the candidate resistant genes in sweet potato, transcriptome analysis has been carried out using two resistant (JK20 and JK274) and susceptible cultivars (Tengfei and Santiandao) of sweet potato for stem nematodes and Ceratocystis fimbriata pathogen, respectively. A total of 11 differentially expressed genes (DEGs) were found in Tengfei and JK20 for stem nematodes and 19 DEGs in Santiandao and JK274 for C. fimbriata. Moreover, six DEGs were further selected for quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis, and the results were consistent with the transcriptome analysis. The results may provide new insights into the evolution of NBS-encoding genes in the Ipomoea genome and contribute to the future molecular breeding of sweet potatoes.

In situ passivation of Pb0 traps by fluoride acid-based ionic liquids enables enhanced emission and stability of CsPbBr3 nanocrystals for efficient white light-emitting diodes.

A great hurdle restricting the optoelectronic applications of cesium lead halide perovskite (CsPbX3) nanocrystals (NCs) is due to the uncoordinated lead atoms (Pb0) on the surface, where most attempts to address the challenges in the literature depend on complicated post-treatment processes. Here we report a simple in situ surface engineering strategy to obtain highly fluorescent and stable perovskite NCs, wherein the introduction of the multifunctional additive 1-butyl-3-methyl-imidazolium tetrafluoroborate ([Bmim]BF4) can significantly eliminate the Pb0 traps. The photoluminescence quantum yield (PLQY) of the as-synthesized NCs was improved from 63.82% to 94.63% due to the good passivation of the surface defects. We also confirm the universality of this in situ passivation pathway to remove Pb0 deep traps by using fluoride acid-based ionic liquids (ILs). Due to the high hydrophobicity of the cations of ILs, the as-prepared CsPbBr3 NCs exhibit robust water resistance stability, maintaining 67.5% of the initial photoluminescence (PL) intensity after immersion in water for 21 days. A white light emitting diode (LED), assembled by mixing the as-synthesized CsPbBr3 NCs and red K2SiF6:Mn4+ phosphors onto a blue chip, exhibits high luminous efficiency (100.07 lm W-1) and wide color gamut (140.64% of the National Television System Committee (NTSC) standard). This work provides a promising and facile technique to eliminate the Pb0 traps and improve the optical performance and stability of halide perovskite NCs, facilitating their applications in optoelectronic fields.

Genome-Wide Characterization of Nitrogenase Reductase (nifH) Genes in the Sweet Potato [Ipomoea batatas (L.) Lam] and Its Wild Ancestors.

The sweet potato (Ipomoea batatas (L.) Lam.) is an important and widely grown crop, and the nitrogenase reductase (nifH) gene is the most widely sequenced marker gene used to identify nitrogen-fixing bacteria and archaea. There have been many examples of the isolation of the diazotrophic endophytes in sweet potatoes, and there has been no report on whether sweet potatoes and their wild ancestors harbored nifH genes. In this study, a comprehensive analysis of nifH genes has been conducted on these species by using bioinformatics and molecular biology methods. A total of 20, 19 and 17 nifH genes were identified for the first time in sweet potatoes, I. trifida and I. triloba, respectively. Based on a phylogenetic analysis, all of the nifH genes, except for g10233.t1, itf14g14040.t1 and itb14g15470.t1, were clustered into five independent clades: I, II, III, IV and V. The nifH genes clustered in the same phylogenetic branch showed a more similar distribution of conserved motifs and exons-introns than those of the other ones. All of the identified genes were further mapped on the 15 chromosomes of the sweet potato, I. trifida and I. triloba. No segmental duplication was detected in each genome of three Ipomoea species, and 0, 8 and 7 tandemly duplicated gene pairs were detected in the genome of the sweet potato, I. trifida and I. triloba, respectively. Synteny analysis between the three Ipomoea species revealed that there were 7, 7 and 8 syntenic gene pairs of nifH genes detected between the sweet potato and I. trifida, between the sweet potato and I. triloba and between I. trifida and I. triloba, respectively. All of the duplicated and syntenic nifH genes were subjected to purifying selection inside duplicated genomic elements during speciation, except for the tandemly duplicated gene pair itf11g07340.t2_itf11g07340.t3, which was subjected to positive selection. Different expression profiles were detected in the sweet potato, I. trifida and I. triloba. According to the above results, four nifH genes of the sweet potato (g950, g16683, g27094 and g33987) were selected for quantitative real-time polymerase chain reaction (qRT-PCR) analysis in two sweet potato cultivars (Eshu 15 and Long 9) under nitrogen deficiency (N0) and normal (N1) conditions. All of them were upregulated in the N1 treatment and were consistent with the analysis of the RNA-seq data. We hope that these results will provide new insights into the nifH genes in the sweet potato and its wild ancestors and will contribute to the molecular breeding of sweet potatoes in the future.

IbMYB308, a Sweet Potato R2R3-MYB Gene, Improves Salt Stress Tolerance in Transgenic Tobacco.

The MYB (v-myb avian myeloblastosis viral oncogene homolog) transcription factor family plays an important role in plant growth, development, and response to biotic and abiotic stresses. However, the gene functions of MYB transcription factors in sweet potato (Ipomoea batatas (L.) Lam) have not been elucidated. In this study, an MYB transcription factor gene, IbMYB308, was identified and isolated from sweet potato. Multiple sequence alignment showed that IbMYB308 is a typical R2R3-MYB transcription factor. Further, quantitative real-time PCR (qRT-PCR) analysis revealed that IbMYB308 was expressed in root, stem, and, especially, leaf tissues. Moreover, it showed that IbMYB308 had a tissue-specific profile. The experiment also showed that the expression of IbMYB308 was induced by different abiotic stresses (20% PEG-6000, 200 mM NaCl, and 20% H2O2). After a 200 mM NaCl treatment, the expression of several stress-related genes (SOD, POD, APX, and P5CS) was upregulation in transgenic plants, and the CAT activity, POD activity, proline content, and protein content in transgenic tobacco had increased, while MDA content had decreased. In conclusion, this study demonstrated that IbMYB308 could improve salt stress tolerance in transgenic tobacco. These findings lay a foundation for future studies on the R2R3-MYB gene family of sweet potato and suggest that IbMYB308 could potentially be used as an important positive factor in transgenic plant breeding to improve salt stress tolerance in sweet potato plants.

Impact of Obesogenic Environments on Sugar-Sweetened Beverage Consumption among Preschoolers: Findings from a Cross-Sectional Survey in Beijing.

The excessive consumption of sugar-sweetened beverages (SSBs) has been proven to be critical for obesity among preschoolers. This study aimed to describe the SSB consumption rates among preschoolers in the Dongcheng District of Beijing, China, and to explore the association between obesogenic environmental determinants and consumption. We applied a stratified cluster sampling method and recruited 3057 primary caregivers of preschoolers in June 2019 to participate in the survey. The caregivers reported their children's consumption rates of six categories of SSBs and their exposure rates to SSB-related obesogenic environments. The associations between them were tested using multivariate logistic regression models. The mean (SD) age of the children was 5.6 (0.6) years and nearly half (48.3%) were girls. About 84.5% of the children had consumed SSBs over the past three months, and sugar-sweetened milk beverages had the highest consumption rate. Higher exposure to advertisements for the corresponding SSB categories in children, higher frequency rates of consuming SSBs and of taking children to fast-food restaurants in caregivers, and lower frequency rates of reading the Nutrition Facts Panels by caregivers were associated with higher SSB consumption rates among children (p < 0.05 in all of the SSB categories investigated, except for the Nutrition Facts Panel reading behaviors for the sports and energy beverages). SSB consumption among preschoolers is of concern, and comprehensive policy actions and education are urgently needed.

Identification of miRNAs in Response to Sweet Potato Weevil (Cylas formicarius) Infection by sRNA Sequencing.

The sweet potato weevil (Cylas formicarius) is an important pest in the growing and storage of sweet potatoes. It is a common pest in the sweet potato production areas of southern China, causing serious harm to the development of the sweet potato industry. For the existing cultivars in China and abroad, there is no sweet potato variety with complete resistance to the sweet potato weevil. Thus, understanding the regulation mechanisms of sweet potato weevil resistance is the prerequisite for cultivating sweet potato varieties that are resistant to the sweet potato weevil. However, very little progress has been made in this field. In this study, we inoculated adult sweet potato weevils into sweet potato tubers. The infected sweet potato tubers were collected at 0, 24, 48, and 72 h. Then, a miRNA library was constructed for Eshu 6 and Guang 87 sweet potato tubers infected for different lengths of time. A total of 407 known miRNAs and 298 novel miRNAs were identified. A total of 174 differentially expressed miRNAs were screened out from the known miRNAs, and 247 differentially expressed miRNAs were screened out from the new miRNAs. Moreover, the targets of the differentially expressed miRNAs were predicted and their network was further investigated through GO analysis and KEGG analysis using our previous transcriptome data. More importantly, we screened 15 miRNAs and their target genes for qRT-PCR verification to confirm the reliability of the high-throughput sequencing data, which indicated that these miRNAs were detected and most of the expression results were consistent with the sequencing results. These results provide theoretical and data-based resources for the identification of miRNAs in response to sweet potato weevil infection and an analysis of the molecular regulatory mechanisms involved in insect resistance.