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1.
J Cell Physiol ; 235(1): 339-348, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31225659

RESUMO

Osteosarcoma (OS) is a type of malignancy featured with high morbidity and easy metastasis. Although past years have witnessed the great improvement in the treatments of OS, there remains a long way to go. Therefore, further research on the underlying molecular mechanism of OS progression is in imminent need. Long noncoding RNAs (lncRNA) are recognized as a cluster of transcripts over 200 bases. Increasing studies have unveiled their significant regulatory roles in cancers, including in osteosarcoma. Long intergenic non-protein coding RNA 324 (LINC00324) is a newly identified lncRNA exerting oncogenic functions in several cancers, but its role in OS is yet to be uncovered. Therefore, the present study planned to explore the role of LINC00324 in osteosarcoma. We first validated the upregulation of LINC00324 in OS tissues and cell lines and established its correlation with OS tumor progression and metastasis. Importantly, the prognostic significance of LINC00324 was identified in patients with OS. Gain- and loss-of-function assays revealed that LINC00324 accelerated cell proliferation and migration in OS. Mechanistically, we revealed that LINC00324 stabilized WD repeat-containing protein 66 (WDR66) messenger RNA through interacting with Hu antigen R. Rescue assays verified that WDR66 was required for the regulation of LINC00324 in promoting proliferation and migration of OS cells. In conclusion, the present study proved that LINC00324 accelerated the proliferation and migration of osteosarcoma cells through regulating WDR66, providing a new prognostic target for osteosarcoma.

2.
Dev Comp Immunol ; 102: 103489, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473266

RESUMO

The Canine Distemper Virus (CDV) is a high fatal virus to the giant panda (Ailuropoda melanoleuca), where CDV vaccination is a key preventative measure in captive giant pandas. However, the immune response of giant pandas to CDV vaccination has been little studied. In this study, we investigated the blood transcriptome expression profiles of five giant panda cubs after three inoculations, 21 days apart. Blood samples were collected before vaccination (0 Day), and 24 h after each of the three inoculations; defined here as 1 Day, 21  Day, and 42  Day. Compared to 0 Day, we obtained 1262 differentially expressed genes (DEGs) during inoculations. GO and KEGG pathways enrichment analysis of these DEGs found 222 GO terms and 40 pathways. The maximum immune-related terms were enriched by DEGs from comparisons of 21  Day and 0 Day. In the PPI analysis, we identified RSAD2, IL18, ISG15 immune-related hub genes from 1 Day and 21 Day comparison. Compared to 0 Day, innate immune-related genes, TLR4 and TLR8, were up-regulated at 1 Day, and the expressions of IRF1, RSAD2, MX1, and OAS2 were highest at 21  Day. Of the adaptive immune-related genes, IL15, promoting T cell differentiation into CD8+T cells, was up-regulated after the first two inoculations, IL12ß, promoting T cell differentiation into memory cells, and IL10, promoting B cell proliferation and differentiation, were down-regulated during three inoculations. Our results indicated that the immune response of five giant panda cubs was strongest after the second inoculation, most likely protected against CDV infection through innate immunity and T cells, but did not produce enough memory cells to maintain long-term immunity after CDV vaccination.

3.
Front Biosci (Landmark Ed) ; 25: 452-462, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31585896

RESUMO

Gastric cancer is the fourth most common malignancy world-wide that bears a high mortality by invasiveness and metastases. To this end, we examined the role of miR-1 in mobility and migration of gastric cancer cells. miR-1 was down-regulated and Sorcin, which supports invasion, was highly expressed in gastric cancer cell lines as compared to the control. The overexpression of miR-1 significantly inhibited the mobility and migration of gastric cancer cells, while, its knockdown exerted an oppoiste effect. In addition, while overexpression of miR-1 suppressed the expression of Sorcin, the siRNA knockdown of Sorcin significantly counteracted the effect of miR-1 inhibitor on cell invasion and migration of gastric cancer cells. A miR-1 mimic decreased while its inhibitor increased the MMP-7 and VEGF required for invasion. Taken together, the findings support the view that miR-1 controls the mobility and migration of gastric cancer cells and might be a therapeutic target for blocking gastric cancer invasion.

4.
Langmuir ; 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31592673

RESUMO

In this study, a simple, effective and versatile method was used for the exfoliation of kaolinite by high-shear mixer with graphite oxide as an amphiphilic dispersant. During the liquid phase exfoliation process, the co-exfoliation of kaolinite and graphite oxide was realized. Compared with the directly exfoliated kaolinite, when 5% graphite oxide was added to facilitate exfoliation, 95% of obtained nanosheets were distributed between 0.1-0.7 µm, in which the number of layers was less than 5 layers, and part of them were curled into nanoscrolls structure with a length of 0.2-0.9 µm. The BET surface area of the graphite oxide-assisted exfoliated kaolinite was 2.1 times that of the directly exfoliated kaolinite. Meanwhile, the graphite oxide-assisted exfoliated kaolinite exhibited excellent adsorption properties for MB, whose theoretical maximum adsorption capacity was 250 mg/g, significantly higher than that of the directly exfoliated kaolinite, which was about 111 mg/g. It has verified that the exfoliation method is efficient and facile, and can be applied extensively.

5.
Biomater Sci ; 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31576843

RESUMO

Understanding the relationship between the morphology and biological performance of nanomaterials is very important for their biomedical applications. However, most of the published research focused on spherical systems. The biological properties of the anisotropic nanomaterials have not been studied enough. In this study, we synthesized three sets of cylindrical polymer brushes (CPBs) with different lengths (∼34, 60 and 119 nm) by taking advantage of controlled radical polymerization and Cu(i)-catalyzed alkyne-azide click chemistry. These CPBs had one-dimensional wormlike morphology, the same chemical structure and diameter, desirable water solubility, abundant amino groups and narrowly distributed lengths. These characteristics encouraged us to study length effects on their in vitro and in vivo properties. We demonstrated that longer CPBs had higher cellular uptake, lower tissue permeability, shorter blood circulation time, lower tumor accumulation and rapider body clearance than their shorter counterparts. This work might provide important guidance for the design of biomedical nanomaterials.

6.
ACS Nano ; 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31566945

RESUMO

Here, a protein farnesyltransferase (PFTase)-driven plasma membrane (PM)-targeted chimeric peptide, PpIX-C6-PEG8-KKKKKKSKTKC-OMe (PCPK), was designed for PM-targeted photodynamic therapy (PM-PDT) and enhanced immunotherapy via tumor cell PM damage and fast release of damage-associated molecular patterns (DAMPs). The PM targeting ability of PCPK originates from the cellular K-Ras signaling, which occurs exclusively to drive the corresponding proteins to PM by PFTase. With the conjugation of the photosensitizer protoporphyrin IX (PpIX), PCPK could generate cytotoxic reactive oxygen species to deactivate membrane-associated proteins, initiate lipid peroxidation, and destroy PM with an extremely low concentration (1 µM) under light irradiation. The specific PM damage further induced the fast release of DAMPs (high-mobility group box 1 and ATP), resulting in antitumor immune responses stronger than those of conventional cytoplasm-localized PDT. This immune-stimulating PM-PDT strategy also exhibited the inhibition effect for distant metastatic tumors when combined with programmed cell death receptor 1 blockade therapy.

7.
Medicine (Baltimore) ; 98(40): e17244, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31577716

RESUMO

RATIONALE: Gitelman syndrome (GS) is a rare autosomal recessive hereditary salt-losing tubulopathy caused by loss-of-function mutations in the SLC12A3 gene. It is usually characterized by hypokalemia, metabolic alkalosis, hypomagnesemia, and hypocalciuria. There are only a few reports on GS combined with growth hormone deficiency (GHD). PATIENT CONCERNS: Three patients presented with weakness, spasm, and growth retardation, respectively. DIAGNOSES: GS was diagnosed based on the clinical symptoms, laboratory test results, and genetic analysis. GH stimulation tests were performed when the magnesium level returned to normal under magnesium oxide (MgO) therapy. INTERVENTIONS: Initially, all patients received oral replacement of MgO and potassium chloride, and 2 of them received simultaneous spironolactone therapy. Recombinant human growth hormone (rhGH) therapy was initiated after they were diagnosed with GHD. OUTCOMES: All 3 patients exhibited satisfactory growth velocity and normal serum magnesium level, although the potassium level was still slightly lower than normal. LESSONS: We suggest that all GS patients should undergo genetic evaluation, especially regarding SLC12A3 gene mutation. GHD should be considered if these patients have short stature. rhGH therapy is useful for stimulating the patients' growth, and it may increase the serum magnesium level.

8.
Artigo em Inglês | MEDLINE | ID: mdl-31584452

RESUMO

Shoulder pain is a common musculoskeletal disorder that has a significant impact on the patient's quality of life and functional health. Since the shoulder joint is a complex structure, the relevant symptoms of shoulder pain may not directly reflect the underlying pathology. Hence, several shoulder tests have been developed to examine shoulder problems, and their diagnostic accuracy varies. Familiarization with the performance of those physical tests and their strength and limitation is of utmost importance for physicians dealing with shoulder disorders. Therefore, the present narrative review focuses on summarizing the most commonly used tests in physical examination and their diagnostic performance on several shoulder pathologies. This article also discusses how ultrasound imaging can serve as an extension of those tests.

9.
Respir Res ; 20(1): 161, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31590675

RESUMO

BACKGROUND: There is growing literature suggesting a link between vitamin D and asthma lung function, but the results from systematic reviews are conflicting. We conducted this meta-analysis to investigate the relation between serum vitamin D and lung function in asthma patients. METHODS: Major databases, including OVID, MEDLINE, Web of Science and PUBMED, were searched until 10th October 2018. All published observational studies related to vitamin D and asthma were extracted. All meta-analyses were performed using Review Manager 5.3.5. RESULTS: This quantitative synthesis found that asthma patients with low vitamin D levels had lower forced expiratory volume In 1 s (FEV1) (mean difference (MD) = - 0.1, 95% CI = - 0.11 to - 0.08,p < 0.01;I2 = 49%, p = 0.12) and FEV1% (MD = - 10.02, 95% CI = - 11 to - 9.04, p < 0.01; I2 = 0%, p = 0.82) than those with sufficient vitamin D levels. A positive relation was found between vitamin D and FEV1 (r = 0.12, 95% CI = 0.04 to 0.2, p = 0.003; I2 = 59%,p = 0.01), FEV1% (r = 0.19, 95% CI = 0.13 to 0.26, p < 0.001; I2 = 42%, p = 0.11), forced vital capacity (FVC) (r = 0.17, 95% CI = 0.00 to 0.34, p = 0.05; I2 = 60%, p = 0.04), FEV1/FVC (r = 0.4, 95% CI = 0.3 to 0.51, p < 0.001; I2 = 48%, p = 0.07), and the asthma control test (ACT) (r = 0.33, 95% CI = 0.2 to 0.47, p < 0.001; I2 = 0%, p = 0.7). Subgroup analysis indicated that the positive correlation between vitamin D and lung function remained significant in both children and adults. CONCLUSIONS: Our meta-analysis suggested that serum vitamin D levels may be positively correlated with lung function in asthma patients. Future comprehensive studies are required to confirm these relations and to elucidate potential mechanisms.

10.
Zhongguo Zhong Yao Za Zhi ; 44(17): 3816-3824, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31602958

RESUMO

To systemically evaluate the benefits and side effects of Shensong Yangxin Capsules( SYC) in the adjuvant treatment of stable angina pectoris( SAP). Chinese and English databases( PubMed,EMbase,the Cochrane Library,CBM,CNKI,VIP,Wan Fang database) were retrieved to collect the randomized controlled trials( RCTs) about therapeutic efficacy of SYC combined with routine drug( trial group) vs routine drug( control group) in the treatment of SAP. The methodological quality of the RCTs was evaluated based on the cochrane risk of bias assessment tool. The data were extracted and Meta-analyzed by Reviewer Manager 5. 3. TSA 0. 9 software was used for trial sequential analysis( TSA) of the total effective rate of symptoms improvement. A total of 15 RCTs with 1 316 participants were included. RESULTS:: of Meta-analysis showed that the total effective rate of angina symptoms improvement( RR = 1. 15,95% CI[1. 09,1. 21],P<0. 001) of trial group were significantly higher than those of control group,with statistical significance,the total effective rate of electrocardiograms( ECG) improvement( RR = 1. 10,95% CI[0. 94,1. 29],P = 0. 25) of trial group were significantly higher than those of control group,but the difference was not statistically significant. After treatment,the improvement of the total time of 24 h general ischemia( SMD =-1. 21,95%CI[-1. 97,-0. 45],P = 0. 002),the ST-segment depression amplitude( SMD =-1. 30,95%CI [-1. 52,-1. 09],P<0. 001),the duration of angina pectoris attack( SMD =-1. 16,95% CI[-1. 36,-0. 95],P< 0. 001),the angina pectoris attack every week( SMD =-0. 80,95%CI[-1. 10,-0. 50],P<0. 001),the onsumption of nitroglycerin every week( SMD=-0. 72,95%CI[-1. 05,-0. 39],P<0. 001) in the trial group were better than that of the control group,and the difference was statistically significant. Besides,the improvement of the blood lipid and high sensitivity C reactive protein( hs-CRP) in the trial group were better than those of the control group after treatment,and the difference was statistically significant( P< 0. 001). Funnel plots and Egger's linear regression showed that there was no publication bias. By sensitivity analysis,it showed that the results of this study were stable and reliable. No obvious adverse drug reactions were observed in all studies. TSA analysis showed that the evidence of Meta-analysis was reliable. SYC combined with routine Western medicine treatment for SAP can improve the total effective rate of angina pectoris,reduce 24 h total ischemia time,ST segment depression amplitude,duration of angina pectoris attack,frequency of angina pectoris attack and nitroglycerin dosage,and also can improve blood lipid and hs-CRP levels.

11.
Drug Discov Today ; 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31593645

RESUMO

Beyond their traditional use as green solvents, new applications have become available for ionic liquids (ILs) in drug delivery. Their flexible tunability enables task-specific optimization of ILs at molecular level. Thus, ILs have been exploited to improve the solubility and permeability of drugs and relieve the polymorphic problems associated with crystalline active pharmaceutical ingredients (APIs). Controlled preparation of drug nanocarriers are also achieved by using ILs either as media or as functional agents. Here, we highlight the importance and advantages of ILs in pharmaceutics and look towards the future of IL-based drug delivery.

12.
Int J Biol Macromol ; 2019 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-31593729

RESUMO

Cationic macromolecules condense DNA into small nanoparticles and form polyplex. The composition of the polyplex determines the endocytic process, the intracellular routing and the fate of the polyplex. Previously, oligochitosan-modified vectors with different protein moieties are used as gene delivery vector and the types of protein moiety can influence the endosome escape ability and transfection efficiency. Among the modified vectors, oligochitosan-modified bovine serum albumin (BSA) showed 90% transfection efficeincy compared to the modified zein and ovalbumin. These data encouraged us to investigate the mechanism of internalization involved in the superior transfection efficiency of modified BSA/ plasmid polyplex. The effect of specific endocytic inhibitors was studied in two adherent cell lines. The caveolae-mediated and lipid-mediated pathways play a significant role in the polyplex internalization. Next, a colocation of polyplex with lysosome was investigated in the presence of LysoTracker using confocal microscopy. Up to 70% of polyplex successfully escaped the lysosome without degradation. Four non-adherent cell lines showed above than 60% transfection efficiency at an optimized vector/plasmid ratio. Moreover, no significant hemolytic effect was observed up to 500 µg/mL of cationic BSA, indicating no detectable cell membrane disruption. Overall, the hybrid biomacromolecule showed good intracellular delivery and safety in a mice model.

13.
Aging (Albany NY) ; 11(18): 7817-7829, 2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31546234

RESUMO

PRL-3, an oncogenic dual-specificity phosphatase, is overexpressed in 50% of acute myeloid leukemia patients. Stathmin has been identified as a downstream target of PRL-3 in colorectal cancer. However, the correlation between PRL-3 and stathmin in myeloid leukemia is unclear. In this study, we revealed the positive correlation between PRL-3 and stathmin in myeloid leukemia. Knockdown of the PRL-3 gene by shRNA reduced the expression of downstream stathmin, suppressed cell proliferation, induced G2/M arrest and cell apoptosis, and inhibited migration and invasion in myeloid leukemia cells. Moreover, our study was the first to provide evidence that silencing PRL-3 increased the phosphorylation level in Ser16, Ser25, Ser38, and Ser63 of stathmin, and in turn inhibited the STAT3 and STAT5 signaling in myeloid leukemia cells. This evidence points to a promoted role for PRL-3 in the progression of myeloid leukemia, and PRL-3 could be a possible new treatment target.

14.
Artigo em Inglês | MEDLINE | ID: mdl-31502223

RESUMO

This study reports a rapid and robust method for the differentiation of Asian and American ginseng samples based on differential ion mobility spectrometry-tandem mass spectrometry (DMS-MS/MS). Groups of bioactive ginsenoside/pseudo-ginsenoside isomers, including Rf/Rg1/F11, Rb2/Rb3/Rc, and Rd/Re, in the ginseng extracts were sequentially separated using DMS with stepwise changes in the gas modifier concentration prior to MS analysis. The identities of the spatially separated ginsenoside/pseudo-ginsenoside isomers were confirmed by their characteristic compensation voltages at specific modifier loading and MS/MS product ions. As expected, Asian ginseng samples contained some Rf and an insignificant amount of F11, whereas American ginseng samples had a high level of F11 but no Rf. The origin of the whole and sliced ginseng could further be confirmed using the quantitative ratios of three sets of ginsenoside markers, namely, Rg1/Re, Rb1/Rg1, and Rb2/Rc. Based on our results, new benchmark ratios of Rg1/Re < 0.15, Rb1/Rg1 > 2.15, and Rb2/Rc < 0.26 were proposed for American ginseng (as opposed to Asian ginseng).

15.
Anal Cell Pathol (Amst) ; 2019: 1598182, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31482051

RESUMO

Human hepatocellular carcinoma (HCC) is the most common and recurrent type of primary adult liver cancer without any effective therapy. Plant-derived compounds acting as anticancer agents can induce apoptosis by targeting several signaling pathways. Strigolactone (SL) is a novel class of phytohormone, whose analogues have been reported to possess anticancer properties on a panel of human cancer cell lines through inducing cell cycle arrest, destabilizing microtubular integrity, reducing damaged in the DNA repair machinery, and inducing apoptosis. In our previous study, we reported that a novel SL analogue, TIT3, reduces HepG2 cell proliferation, inhibits cell migration, and induces apoptosis. To decipher the mechanisms of TIT3-induced anticancer activity in HepG2, we performed RNA sequencing and the differential expression of genes was analyzed using different tools. RNA-Seq data showed that the genes responsible for microtubule organization such as TUBB, BUB1B, TUBG2, TUBGCP6, TPX2, and MAP7 were significantly downregulated. Several epigenetic modulators such as UHRF1, HDAC7, and DNMT1 were also considerably downregulated, and this effect was associated with significant upregulation of various proapoptotic genes including CASP3, TNF-α, CASP7, and CDKN1A (p21). Likewise, damaged DNA repair genes such as RAD51, RAD52, and DDB2 were also significantly downregulated. This study indicates that TIT3-induced antiproliferative and proapoptotic activities on HCC cells could involve several signaling pathways. Our results suggest that TIT3 might be a promising drug to treat HCC.

16.
Math Biosci Eng ; 16(5): 4846-4872, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-31499693

RESUMO

Radiofrequency ablation (RFA) and microwave ablation (MWA) have become an important means for treating liver tumors. RFA and MWA are a minimally invasive therapy which involves an ablation applicator or needle (i.e., radiofrequency electrode or microwave antenna) inserted percutaneously into a tumor under the guidance of medical imaging, so as to destroy the tumor in situ by heating-induced coagulation necrosis. Treatment planning, particularly needle trajectory planning, is crucial to RFA and MWA. In clinical procedures, however, needle trajectory planning still relies on the personal experience of clinicians. Manual needle trajectory planning is tedious and may cause inter-operator difference. Therefore, computer-assisted needle trajectory planning techniques are of clinical value and have been extensively explored. However, a literature review that focuses on computer-assisted needle trajectory planning for liver tumor RFA and MWA has not been reported. In this paper, we conducted an extensive review on computer-assisted needle trajectory planning for RFA and MWA of liver tumors. Fundamentals of needle trajectory planning are summarized. Algorithms for single-needle and multi-needle trajectory planning are analyzed. Shortcomings of current computer-assisted needle trajectory planning algorithms are discussed and future developments are suggested.

17.
Sci Total Environ ; 692: 1048-1056, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31539937

RESUMO

Elemental Ag0 is well known for its remarkable catalytic and antibacterial properties, thus the regeneration of valuable Ag0 metal from Ag+ wastewater is of great significance. In this study, a novel polyethylenimine (PEI) modified potassium tungsten oxide (N-K2W4O13) adsorbent was prepared for Ag+ removal and reduction to Ag0 using glutaraldehyde as crosslinking agent. XPS and FT-IR spectra verified PEI successfully anchored on the surface O and W atoms of K2W4O13 through aldehyde bridges. The content of PEI in N-K2W4O13 was calculated as 8.74wt% by TG curve. A heterogeneous PEI coating was observed in the SEM and TEM images. The N-K2W4O13 exhibited larger Ag+ uptake (48.25mg/g) than the raw K2W4O13 (42.50mg/g) though required a longer equilibrium time. This was due to the combined results of strong chelation and weak electrostatic repulsion that meanwhile occurring on the positive-charged surface of N-K2W4O13. The maximum Ag+ uptake on N-K2W4O13 was 72.5mg/g, which was larger than many of the reported adsorbents. Furthermore, the prepared N-K2W4O13 displayed good anti-interference toward background ions (Na+, K+) and hold a stable Ag+ removal (>95%) after five runs of recycling tests. The mechanism studies elucidated that NH/N groups from the PEI modified N-K2W4O13 mainly accounted for the Ag+ adsorption and Ag0 recovery in the adsorption-reduction process. Ion-exchange between Ag+ and K+ from the N-K2W4O13 lattice also occurred. This work provided a facile method to synthesize a promising adsorbent for Ag+ wastewater remediation and valuable Ag0 recovery.

18.
PLoS One ; 14(9): e0222091, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31509561

RESUMO

Quantitative analysis of the contribution rate of China's hydraulic science and technology and analysis of the underlying reasons behind changes provide an important foundation upon which the government can formulate water policies. This paper abandons the assumption of a scale economy and separates the changes of benefits brought about by the scale from scientific and technological progress, thus changing the C-D production function from linear to nonlinear. Based on a feedforward neural network, it calculates the coefficient of the output elasticity, the economic contribution rate of China's hydraulic science and technology and the scale economies for each year using relevant data from 1981 to 2016. The results show that (1) the average contribution rate of capital investment from 1981 to 2016 was 47.3%, and the average contribution rate of labor from 1981 to 2016 was 9.1%. It is not obvious that the significant increase in the labor force has contributed to the growth of China's water conservancy industry. (2) The average contribution rate of scale economies in 1981-2016 was 26.7%, and the contribution rate of scale economies is negatively correlated with the capital contribution rate. (3) The average contribution rate of China's hydraulic science and technology was 43.6% from 1981 to 2016, and the average contribution rate of the total factor productivity after removing scale economies from 1981 to 2016 was 16.9%. During the period of the 6th Five-Year Plan(1981~1985), the contribution rate of water conservancy science and technology was relatively high. Since that time, it has remained at 40%. In recent years, as water conservancy reforms in key areas have made positive progress, scientific and technological progress has increased the growth of water conservancy benefits annually.

20.
Artigo em Inglês | MEDLINE | ID: mdl-31476104

RESUMO

Charge-shift bonds (CSB) constitute a new class of bonds different than covalent/polar-covalent and ionic-bonds. Bonding in CSB is not contributed by either the covalent or the ionic structures of the bond, but rather by the resonance interaction between the structures. This essay describes the reasons why the CSB family was overlooked by valence-bond pioneers (Textbox 1). It then demonstrates that the unique status of CSBs is not theory-dependent. Thus, Valence-bond (VB), molecular-orbital (MO),[21,22] and Energy-Decomposition-Analysis (EDA)[23], as well as a variety of electron-density theories; Electron-Localization Function (ELF),[27] Quantum Thery of Atoms in Molecules (QTAIM),[24] and Electron-Stress Tensor (EST) approaches;[25,26] all these show the distinction of CSB vis-à-vis covalent and ionic bonds. Furthermore, the covalent-ionic resonance energy can be quantified from experiment, and hence having the same essential status as resonance energies of organic molecules, e.g., benzene. The essay then demonstrates how a variety of bond types -- dative-bonds, coordinative-bonds, and hypervalent-bonds, including 3-electron-bonds -- are CSBs. Subsequently, some experimental manifestations of CSBs are discussed, including recent experimental articulations of the concept.[78,81,82] The essay ends by arguing that the definition of CSB as a distinct family of bonding fulfills the necessary conditions for making such a claim. The distinction  between covalent-bonds and CSBs is thus fundamental, with a potential to bring about a Renaissance in the mental-map of the chemical bond, and to contribute to productive chemical diversity.

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