Study on the stability of molecular chirality and the configuration protection of dihydromyricetin in vine tea.

This study aims to investigate the impact of four key factors, namely, temperature, water source, metal ion, and pH, on the stability of molecular chirality of dihydromyricetin (DMY) and proposed effective strategies for configuration protection. The findings reveal that temperatures exceeding 80°C could accelerate the racemization process of DMY, with a significant increase in racemization observed at 100°C. In addition, DMY exhibited heightened stability in ultrapure water as compared to various water sources, including pure water-1, pure water-2, mineral water, and running water. Notably, the presence of Fe2+ displayed an inhibitory effect on the racemization of DMY, whereas Mg2+, Ca2+, and Mn2+ showed a substantial promotional effect. Additionally, acidic conditions (pH < 5.0) were found to be protective for maintaining the stability of DMY, whereas alkaline conditions (pH > 9.0) were observed to be detrimental. Meanwhile, we first identified the presence of another pair of DMY isomers in this work.

Pathogenic and Comparative Genomic Analysis of Ralstonia pseudosolanacearum Isolated from Casuarina.

Casuarina equisetifolia is crucial in protecting coastal regions of China against typhoon attacks, but has faced a substantial challenge due to wilt disease caused by pathogens of the Ralstonia solanacearum species complex (RSSC). Although the initial outbreak of Casuarina wilt in 1970s was effectively controlled by disease-resistant C. equisetifolia varieties, the disease has recently re-emerged in coastal regions of Guangdong. In this study, we report the isolation, characterization, and comparative genomic analysis of 11 RSSC strains from diseased C. equisetifolia at various locations along the coast of Guangdong. Phylogenomic analysis showed that the strains were closely related and clustered with phylotype I strains previously isolated from peanuts. Single-gene based analysis further suggested these strains could be derived from strains present in Guangdong since the 1980s, indicating a historical context to their current pathogenicity. Casuarina-isolated strains exhibited notably higher virulence against C. equisetifolia and peanuts than representative RSSC strains GMI1000 and EP1, suggesting host-specific adaptations which possibly contributed to the recent outbreak. Comparative genomic analysis among RSSC strains revealed a largely conserved genome structure and high levels of conservation in gene clusters encoding extracellular polysaccharides biosynthesis, secretion systems, and quorum sensing regulatory systems. However, we also found a number of unique genes in the Casuarina-isolated strains that were absent in GMI1000 and EP1, and vice versa, pointing to potential genetic factors underpinning their differential virulence. These unique genes offer promising targets for future functional studies. Overall, our findings provide crucial insights into the RSSC pathogens causing Casuarina wilt in Guangdong, guiding future efforts in disease control and prevention.

Second Boost of Omicron SARS-CoV-2 S1 Subunit Vaccine Induced Broad Humoral Immune Responses in Elderly Mice.

Currently approved COVID-19 vaccines prevent symptomatic infection, hospitalization, and death from the disease. However, repeated homologous boosters, while considered a solution for severe forms of the disease caused by new SARS-CoV-2 variants in elderly individuals and immunocompromised patients, cannot provide complete protection against breakthrough infections. This highlights the need for alternative platforms for booster vaccines. In our previous study, we assessed the boost effect of the SARS-CoV-2 Beta S1 recombinant protein subunit vaccine (rS1Beta) in aged mice primed with an adenovirus-based vaccine expressing SARS-CoV-2-S1 (Ad5.S1) via subcutaneous injection or intranasal delivery, which induced robust humoral immune responses (1). In this follow-up study, we demonstrated that a second booster dose of a non-adjuvanted recombinant Omicron (BA.1) S1 subunit vaccine with Toll-like receptor 4 (TLR4) agonist RS09 (rS1RS09OM) was effective in stimulating strong S1-specific immune responses and inducing significantly high neutralizing antibodies against the Wuhan, Delta, and Omicron variants in 100-week-old mice. Importantly, the second booster dose elicits cross-reactive antibody responses, resulting in ACE2 binding inhibition against the spike protein of SARS-CoV-2 variants, including Omicron (BA.1) and its subvariants. Interestingly, the levels of IgG and neutralizing antibodies correlated with the level of ACE2 inhibition in the booster serum samples, although Omicron S1-specific IgG level showed a weaker correlation compared to Wuhan S1-specific IgG level. Furthermore, we compared the immunogenic properties of the rS1 subunit vaccine in young, middle-aged, and elderly mice, resulting in reduced immunogenicity with age, especially an impaired Th1-biased immune response in aged mice. Our findings demonstrate that the new variant of concern (VOC) rS1 subunit vaccine as a second booster has the potential to offer cross-neutralization against a broad range of variants and to improve vaccine effectiveness against newly emerging breakthrough SARS-CoV-2 variants in elderly individuals who were previously primed with the authorized vaccines.

Fourth dose of microneedle array patch of SARS-CoV-2 S1 protein subunit vaccine elicits robust long-lasting humoral responses in mice.

The COVID-19 pandemic has underscored the pressing need for safe and effective booster vaccines, particularly in considering the emergence of new SARS-CoV-2 variants and addressing vaccine distribution inequalities. Dissolving microneedle array patches (MAP) offer a promising delivery method, enhancing immunogenicity and improving accessibility through the skin's immune potential. In this study, we evaluated a microneedle array patch-based S1 subunit protein COVID-19 vaccine candidate, which comprised a bivalent formulation targeting the Wuhan and Beta variant alongside a monovalent Delta variant spike proteins in a murine model. Notably, the second boost of homologous bivalent MAP-S1(WU + Beta) induced a 15.7-fold increase in IgG endpoint titer, while the third boost of heterologous MAP-S1RS09Delta yielded a more modest 1.6-fold increase. Importantly, this study demonstrated that the administration of four doses of the MAP vaccine induced robust and long-lasting immune responses, persisting for at least 80 weeks. These immune responses encompassed various IgG isotypes and remained statistically significant for one year. Furthermore, neutralizing antibodies against multiple SARS-CoV-2 variants were generated, with comparable responses observed against the Omicron variant. Overall, these findings emphasize the potential of MAP-based vaccines as a promising strategy to combat the evolving landscape of COVID-19 and to deliver a safe and effective booster vaccine worldwide.

Translation, cultural adaptation, and validation of the Chinese standardized outcomes in nephrology-hemodialysis fatigue (C-SONG-HD fatigue) scale: a study of Chinese patients undergoing hemodialysis.

OBJECTIVE: This study aimed to translate and culturally adapt the standardized outcomes in nephrology-hemodialysis fatigue (SONG-HD fatigue) scale and to assess the psychometric properties of the Chinese version of the SONG-HD fatigue (C-SONG-HD fatigue) scale. METHODS: Forward and back translations were used to translate the SONG-HD fatigue scale into Chinese. We used the C-SONG-HD fatigue scale to survey Chinese patients undergoing hemodialysis (HD) in China. We examined the distribution of responses and floor and ceiling effects. Cronbach's alpha and McDonald's omega coefficient, intraclass coefficients, and Spearman correlations were used to assess internal consistency reliability, test-retest reliability, and convergent validity, respectively. Responsiveness was also evaluated. RESULTS: In total, 489 participants across southeast China, northwest China, and central China completed the study. The C-SONG-HD fatigue scale had good internal consistency (Cronbach's alpha coefficient 0.861, omega coefficient 0.916), test-retest reliability (intraclass correlation coefficient 0.695), and convergent validity (Spearman correlation 0.691). The analysis of all first-time HD patients did not show notable responsiveness, and only patients with temporary vascular access had good responsiveness with an effect size (ES) of 0.54, a standardized response mean (SRM) of 0.85, and a standard error of measurement (SEM) of 0.77. CONCLUSION: The Chinese version of the SONG-HD fatigue scale showed satisfactory reliability and validity in patients undergoing hemodialysis (HD) in China. It could be used as a tool to measure the fatigue of Chinese HD patients.

A High-Resolution Linkage Map Construction and QTL Analysis for Morphological Traits in Anthurium (Anthurium andraeanum Linden).

Anthurium andraeanum Linden is a prominent ornamental plant belonging to the family Araceae and is cultivated worldwide. The morphology characteristics are crucial because they significantly impact ornamental values, commercial properties, and the efficiency of space utilization in production. However, only a few related investigations have been conducted in anthurium to date. In this study, an F1 genetic segregation population containing 160 progenies was generated through hybridization between potted and cut anthurium varieties. Fifteen morphological traits were assessed and revealed substantial levels of genetic variation and widespread positive correlation. Based on specific length amplified fragment (SLAF) sequencing technology, 8171 single nucleotide polymorphism (SNP) markers were developed, and the high-density linkage map of 2202.27 cM in length distributed on 15 linkage groups was constructed successfully, with an average distance of 0.30 cM. Using the inclusive composite interval mapping (ICIM) method, 59 QTLs related to 15 key morphological traits were successfully identified, which explained phenotypic variance (PVE) ranging from 6.21% to 17.74%. Thirty-three of those associated with 13 traits were designated as major QTLs with PVE > 10%. These findings offer valuable insights into the genetic basis of quantitative traits and are beneficial for molecular marker-assisted selection (MAS) in anthurium breeding.

Effects of Interaction between Claroideogolmus etuicatum and Bacillus aryabhattai on the Utilization of Organic Phosphorus in Camellia oleifera Abel.

Arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) are involved in phosphorus (P) mobilization and turnover; however, the impact of their interaction on plant P absorption and organic P mineralization in the hyphosphere (rootless soil) are unknown. This study examined the interactive effects of two native microorganisms, namely Claroideogolmus etuicatum and Bacillus aryabhattai, and the effects of co-inoculation of both microorganisms on organic P mineralization and the subsequent transfer to Camellia oleifera, using a three-compartment microcosm with a nylon mesh barrier. The results demonstrated that the co-inoculation treatment (AMF + PSB) significantly increased the plant P content and biomass accumulation in C. oleifera compared to those of the non-inoculated control. Furthermore, co-inoculation boosted soil phosphatase and phytase activities as well as the liable P content. Compared to the non-inoculated control, inoculation of AMF decreased the NaOH-Po content. A correlation analysis showed that AMF colonization and hyphal density was significantly positively correlated with H2O-P and NaHCO3-Pi and negatively correlated with NaOH-Po. It was shown that co-inoculation could increase phosphatase activity, phytase activity, and promote the liable P content, thus increasing the phosphorus content and biomass accumulation of C. oleifera. In conclusion, AMF and PSB interactively enhanced the mineralization of soil organic P, and therefore positively affected P uptake and plant growth.

Tetravalent SARS-CoV-2 S1 subunit protein vaccination elicits robust humoral and cellular immune responses in SIV-infected rhesus macaque controllers.

IMPORTANCE: The study provides important insights into the immunogenicity and efficacy of a tetravalent protein subunit vaccine candidate against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The vaccine induced both humoral and cellular immune responses in nonhuman primates with controlled SIVagm infection and was able to generate Omicron variant-specific antibodies without specifically vaccinating with Omicron. These findings suggest that the tetravalent composition of the vaccine candidate could provide broad protection against multiple SARS-CoV-2 variants while minimizing the risk of immune escape and the emergence of new variants. Additionally, the use of rhesus macaques with controlled SIVsab infection may better represent vaccine immunogenicity in humans with chronic viral diseases, highlighting the importance of preclinical animal models in vaccine development. Overall, the study provides valuable information for the development and implementation of coronavirus disease 2019 vaccines, particularly for achieving global vaccine equity and addressing emerging variants.

Polyamidoamine Dendrimers Functionalized Water-Stable Metal-Organic Frameworks for Sensitive Fluorescent Detection of Heavy Metal Ions in Aqueous Solution.

In this work, polyamidoamine (PAMAM)-functionalized water-stable Al-based metal-organic frameworks (MIL-53(Al)-NH2) were proposed with enhanced fluorescence intensity, and used for the sensitive detection of heavy metal ions in aqueous solution. The size and morphology of MIL-53(Al)-NH2 were effectively optimized by regulating the component of the reaction solvents. PAMAM dendrimers were subsequently grafted onto the surface with glutaraldehyde as a cross-linking agent. It was found that the size and morphology of MIL-53(Al)-NH2 have great influence on their fluorescence properties, and PAMAM grafting could distinctly further improve their fluorescence intensity. With higher fluorescence intensity, the PAMAM-grafted MIL-53(Al)-NH2 showed good linearity (R2 = 0.9925-0.9990) and satisfactory sensitivity (LOD = 1.1-8.6 µmol) in heavy metal ions determination. Fluorescence enhancement and heavy metal ions detection mechanisms were discussed following the experimental results. Furthermore, analogous water-stable Materials of Institute Lavoisier (MIL) metal-organic frameworks such as MIL-53(Fe)-NH2 were also proved to have similar fluorescence enhancement performance after PAMAM modification, which demonstrates the universality of the method and the great application prospects in the design of PAMAM-functionalized high-sensitivity fluorescence sensors.

19F NMR enantiodiscrimination and diastereomeric purity determination of amino acids, dipeptides, and amines.

Chiral amino-group compounds are of significance for human health, such as biogenic amino acids (AAs), dipeptides, and even various drugs. Enantiospecific discrimination of these chiral compounds is vital in diagnosing diseases, identifying pathological biomarkers and enhancing pharmaceutical chemistry research. Here, we report a simple and rapid 19F NMR-based strategy to differentiate chiral AAs, dipeptides, and amines, that were derivatized with (R)-2-(2-fluorophenyl)-2-hydroxyacetic acid ((R)-2FHA). As a result, 19 proteinogenic AAs (37 isomers) as well as Gly could be concurrently resolved. Moreover, various mirror-image dipeptides, such as Ser-His, Leu-Leu, and Ala-Ala, were commendably recognized. Intriguingly, we found that the absolute configuration of AAs in the N-terminus of dipeptides decided the relative 19F chemical shifts between two enantiomers. Besides, the ability of this method for enantiodiscrimination was further demonstrated by non-AA amines, including aromatic and aliphatic amines, and even amines having chiral centers several carbons away from the amino-group. The structurally similar antibiotics, amoxicillin and ampicillin, were well discriminated. Furthermore, this method accurately determines the de or dr values of non-racemic mixtures. Therefore, our strategy provides an effective approach for 19F NMR-based enantiodiscrimination and diastereomeric purity determination of amino-group compounds.

SARS-CoV-2 S1 Subunit Booster Vaccination Elicits Robust Humoral Immune Responses in Aged Mice.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants has raised concerns about reduced vaccine effectiveness and the increased risk of infection, and while repeated homologous booster shots are recommended for elderly and immunocompromised individuals, they cannot completely protect against breakthrough infections. In our previous study, we assessed the immunogenicity of an adenovirus-based vaccine expressing SARS-CoV-2 S1 (Ad5.S1) in mice, which induced robust humoral and cellular immune responses (E. Kim, F. J. Weisel, S. C. Balmert, M. S. Khan, et al., Eur J Immunol 51:1774-1784, 2021, https://doi.org/10.1002/eji.202149167). In this follow-up study, we found that the mice had high titers of anti-S1 antibodies 1 year after vaccination, and one booster dose of the nonadjuvanted rS1Beta (recombinant S1 protein of SARS-CoV-2 Beta [B.1.351]) subunit vaccine was effective at stimulating strong long-lived S1-specific immune responses and inducing significantly high neutralizing antibodies against Wuhan, Beta, and Delta strains, with 3.6- to 19.5-fold increases. Importantly, the booster dose also elicited cross-reactive antibodies, resulting in angiotensin-converting enzyme 2 (ACE2) binding inhibition against spikes of SARS-CoV-2, including Omicron variants, persisting for >28 weeks after booster vaccination. Interestingly, the levels of neutralizing antibodies were correlated not only with the level of S1 binding IgG but also with ACE2 inhibition. Our findings suggest that the rS1Beta subunit vaccine candidate as a booster has the potential to offer cross-neutralization against broad variants and has important implications for the vaccine control of newly emerging breakthrough SARS-CoV-2 variants in elderly individuals primed with adenovirus-based vaccines like AZD1222 and Ad26.COV2.S. IMPORTANCE Vaccines have significantly reduced the incidences of severe coronavirus disease 2019 (COVID-19) cases and deaths. However, the emergence of SARS-CoV-2 variants has raised concerns about their increased transmissibility and ability to evade neutralizing antibodies, especially among elderly individuals who are at higher risks of mortality and reductions of vaccine effectiveness. To address this, a heterologous booster vaccination strategy has been considered as a solution to protect the elderly population against breakthrough infections caused by emerging variants. This study evaluated the booster effect of an S1 subunit vaccine in aged mice that had been previously primed with adenoviral vaccines, providing valuable preclinical evidence for elderly people vaccinated with the currently approved COVID-19 vaccines. This study confirms the potential for using the S1 subunit vaccine as a booster to enhance cross-neutralizing antibodies against emerging variants of concern.

Association of estimated glomerular filtration rate and all-cause mortality in acute pancreatitis: a retrospective analysis.

BACKGROUND: Our primary objective was to explore the association between estimated glomerular filtration rate (eGFR) and all-cause mortality in acute pancreatitis (AP) admission to intensive care units. METHODS: This study is a retrospective cohort analysis based on the Medical Information Mart for Intensive Care III database. The eGFR was calculated based on Chronic Kidney Disease Epidemiology Collaboration equation. Cox models with restricted cubic spline functions were used to evaluated the association of eGFR with all-cause mortality. RESULTS: The mean eGFR was 65.93 ± 38.56 ml/min/1.73 m2 in 493 eligible patients. 28-day mortality was 11.97% (59/ 493), which decreased by 15% with every 10 ml/min/1.73 m2 increase in eGFR. The adjusted hazard ratio (95% confidence interval) was 0.85 (0.76-0.96). A non-linear association was proved between eGFR and all-cause mortality. When eGFR < 57 ml/min/1.73 m2, there was a negative correlation between eGFR and 28-day mortality, hazard ratio (95% CI) was 0.97 (0.95, 0.99). The eGFR was also negatively correlated with in-hospital and in-ICU mortality. Subgroup analysis confirmed that the association between eGFR and 28-day mortality in different characteristics was stable. CONCLUSIONS: The eGFR was negatively correlated with all-cause mortality in AP when eGFR is less than the threshold inflection point.

Tetravalent SARS-CoV-2 S1 Subunit Protein Vaccination Elicits Robust Humoral and Cellular Immune Responses in SIV-Infected Rhesus Macaque Controllers.

The COVID-19 pandemic has highlighted the need for safe and effective vaccines to be rapidly developed and distributed worldwide, especially considering the emergence of new SARS-CoV-2 variants. Protein subunit vaccines have emerged as a promising approach due to their proven safety record and ability to elicit robust immune responses. In this study, we evaluated the immunogenicity and efficacy of an adjuvanted tetravalent S1 subunit protein COVID-19 vaccine candidate composed of the Wuhan, B.1.1.7 variant, B.1.351 variant, and P.1 variant spike proteins in a nonhuman primate model with controlled SIVsab infection. The vaccine candidate induced both humoral and cellular immune responses, with T- and B cell responses mainly peaking post-boost immunization. The vaccine also elicited neutralizing and cross-reactive antibodies, ACE2 blocking antibodies, and T-cell responses, including spike specific CD4+ T cells. Importantly, the vaccine candidate was able to generate Omicron variant spike binding and ACE2 blocking antibodies without specifically vaccinating with Omicron, suggesting potential broad protection against emerging variants. The tetravalent composition of the vaccine candidate has significant implications for COVID-19 vaccine development and implementation, providing broad antibody responses against numerous SARS-CoV-2 variants.

Trivalent SARS-CoV-2 S1 Subunit Protein Vaccination Induces Broad Humoral Responses in BALB/c Mice.

This paper presents a novel approach for improving the efficacy of COVID-19 vaccines against emergent SARS-CoV-2 variants. We have evaluated the immunogenicity of unadjuvanted wild-type (WU S1-RS09cg) and variant-specific (Delta S1-RS09cg and OM S1-RS09cg) S1 subunit protein vaccines delivered either as a monovalent or a trivalent antigen in BALB/c mice. Our results show that a trivalent approach induced a broader humoral response with more coverage against antigenically distinct variants, especially when compared to monovalent Omicron-specific S1. This trivalent approach was also found to have increased or equivalent ACE2 binding inhibition, and increased S1 IgG endpoint titer at early timepoints, against SARS-CoV-2 spike variants when compared monovalent Wuhan, Delta, or Omicron S1. Our results demonstrate the utility of protein subunit vaccines against COVID-19 and provide insights into the impact of variant-specific COVID-19 vaccine approaches on the immune response in the current SARS-CoV-2 variant landscape. Particularly, our study provides insight into effects of further increasing valency of currently approved SARS-CoV-2 vaccines, a promising approach for improving protection to curtail emerging viral variants.

Solvent Effects Used for Optimal Simultaneous Analysis of Amino Acids via 19F NMR Spectroscopy.

19F NMR has been extensively used in simultaneous analysis of multicomponent due to its 100% natural isotope abundance, high NMR-sensitivity, and wide-range chemical shifts. The solvent effects are usually observed in NMR spectroscopy and cause large changes in 19F chemical shifts. Herein, we propose that the simultaneous analysis of a complex mixture can be achieved using solvent effects via 19F NMR spectroscopy, such as a mixture solution of amino acids (AAs). AAs are not only cell-signaling molecules, but are also considered as biomarkers of some diseases. Hence, the analysis of AAs is important for human health and the diagnosis of diseases. In this work, the key to the success of sensing 19 biogenic AAs is the use of 2-fluorobenzaldehyde (2FBA) as a highly sensitive derivatizing agent and solvent effects to produce distinguishable 19F NMR signals. As a result, the resolution of 19F NMR spectroscopy of multiple 2FBA-labeled AAs is obviously higher than other methods based on 19F NMR. Moreover, 14 and 18 AAs can be satisfactorily differentiated and unambiguously identified in different complicated media supporting the growth of mammalian cells. Furthermore, quantification of the concentration of AAs can be made, and the limit of detection reaches 10 µM. Our work provides new insights into the simultaneous analysis of a multicomponent mixture based on solvent effects by 19F NMR spectroscopy.

A novel in-situ strategy for enantiomeric discrimination and selective identification of multicomponent carboxylic acids in foods.

Chiral carboxylic acids are ubiquitous in nature and are of pivotal importance in practical applications in the field of food science and pharmaceuticals. Simultaneous enantiomeric analysis of carboxylic acids mixtures is a significant research goal. Herein, we demonstrate a new strategy involving the use of the highly selective chiral derivatizing agent (R)-2-amino-1,1,1-trifluoropropane ((R)-TFPA) for the enantiomeric discrimination and selective identification of carboxylic acids in mixtures, even structurally similar drugs. The key success of this sensing approach lies in the distinguishable 19F NMR signals of diastereoisomers formed via derivatization of the substrates by (R)-TFPA. The utility of this approach was demonstrated by simultaneously differentiating 20 chiral carboxylic acids in a complicated mixture with accurate determination of the enantiomeric excess (ee). Most importantly, our approach can be applied to food analysis, where the diverse carboxylic acids in real samples without separation were unambiguously identified, such as vinegar, yogurt, and grape.

Adenovirus-vectored SARS-CoV-2 vaccine expressing S1-N fusion protein.

Additional COVID-19 vaccines that are safe and immunogenic are needed for global vaccine equity. Here, we developed a recombinant type 5 adenovirus vector encoding for the SARS-CoV-2 S1 subunit antigen and nucleocapsid as a fusion protein (Ad5.SARS-CoV-2-S1N). A single subcutaneous immunization with Ad5.SARS-CoV-2-S1N induced a similar humoral response, along with a significantly higher S1-specific cellular response, as a recombinant type 5 adenovirus vector encoding for S1 alone (Ad5.SARS-CoV-2-S1). Immunogenicity was improved by homologous prime-boost vaccination, and further improved through intramuscular heterologous prime-boost vaccination using subunit recombinant S1 protein. Priming with low dose (1 × 1010 v.p.) of Ad5.SARS-CoV-2-S1N and boosting with either wild-type recombinant rS1 or B.1.351 recombinant rS1 induced a robust neutralizing response, which was sustained against Beta and Gamma SARS-CoV-2 variants. This novel Ad5-vectored SARS-CoV-2 vaccine candidate showed promising immunogenicity in mice and supports the further development of COVID-19-based vaccines incorporating the nucleoprotein as a target antigen.

Impact of backbone linkage positions on the molecular aggregation behavior of polymer photovoltaic materials.

It is imperative to advance the structural design of conjugated materials to achieve a practical impact on the performance of photovoltaic devices. However, the effect of the linkage positions (meta-, para-) of the backbone on the molecular packing has been relatively little explored. In this study, we have synthesized two wide-bandgap polymer photovoltaic materials from identical monomers with different linkage positions, using dibenzo[c,h][2,6]-naphthyridine-5,11-(6H,12H)-dione (DBND) as the building block. This study shows that the para-connected polymer exhibits an unexpected 0.2 eV higher ionization potential and a resultant higher open-circuit voltage than the meta-connected counterpart. We found that different linkage positions result in different intermolecular binding energies and molecular aggregation conformations, leading to different HOMO energy levels and photovoltaic performances. Specifically, theoretical calculations and 2D-NMR indicate that P(p-DBND-f-2T) performs a segregated stacking of f-2T and DBND units, while P(m-DBND-f-2T) films form π-overlaps between f-2T and DBND. These results show that linkage position adjustment on the polymeric backbone exerts a profound influence on the molecular aggregation of the materials. Also, the effect of isomerism on the polymer backbone is crucial in designing polymer structures for photovoltaic applications.

The Adsorption of Heavy Metal Ions by Poly (Amidoamine) Dendrimer-Functionalized Nanomaterials: A Review.

Rapid industrialization has resulted in serious heavy metal pollution. The removal of heavy metal ions from solutions is very important for environmental safety and human health. Poly (amidoamine) (PAMAM) dendrimers are artificial macromolecular materials with unique physical and chemical properties. Abundant amide bonds and amino functional groups provide them with a high affinity for heavy metal ions. Herein, PAMAM-functionalized adsorbents are reviewed in terms of different nanomaterial substrates. Approaches in which PAMAM is grafted onto the surfaces of substrates are described in detail. The adsorption isotherms and kinetics of these adsorbents are also discussed. The effects of PAMAM generation, pH, adsorbent dosage, adsorption time, thermodynamics, and ionic strength on adsorption performance are summarized. Adsorption mechanisms and the further functionalization of PAMAM-grafted adsorbents are reviewed. In addition to the positive results, existing problems are also put forward in order to provide a reference for the optimization of PAMAM-grafted adsorbents of heavy metal ions.

Simultaneous analysis of amino acids based on discriminative 19F NMR spectroscopy.

The simultaneous analysis of amino acids (AAs) is crucial for human health, diagnosis and treatment of disease, and nutritional quality evaluation in foodstuffs. Here, we establish an easy and rapid method for the simultaneous analysis of AAs using a single reagent 2-(trifluoromethyl)benzaldehyde (oTFMBA) based on spectral-separation-enabled 19F NMR spectroscopy. oTFMBA, a highly sensitive chemosensor, is capable of analyzing 19 proteinogenic AAs or non-amino acid amines (non-AAs) in a complex mixture by adjusting the pH in a toilless way. The 19F signals of oTFMBA-labeled AAs are distributed over a wide range of ∼ 0.7 ppm, demonstrating oTFMBA with higher resolution for simultaneous analysis of AAs compared to the o-phthaldialdehyde (OPA) method (<0.6 ppm). Additionally, 12 AAs were unambiguously identified in human urine, including Asp, Ser, Gly, Thr, Glu, Arg, Ala, Val, Ile, Tyr, His, and Phe. Furthermore, our method's detection limit for AAs is 5.83 µM, illustrating sensitivity with an ∼100-fold improvement over the OPA method. This work represents an approach to the analysis of AAs or non-AAs in a complicated mixture (even biofluid) using a 19F NMR probe with high sensitivity, which is of great significance for the simultaneous analysis of multiple analytes.