Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 63
Filter
1.
Front Psychol ; 15: 1408022, 2024.
Article in English | MEDLINE | ID: mdl-38840739

ABSTRACT

Introduction: Adolescence is considered a stress-sensitive developmental period, and the escalating and sustained pressure during this phase poses a significant threat to the mental and physical well-being of adolescents. Therefore, enhancing positive emotions in adolescents is crucial. This study aims to investigate the impact of physical activity on the emotional intelligence, interpersonal forgiveness, and positive emotions of adolescents. Methods: Using a cluster sampling method, data were collected from 500 adolescents in four schools across the Xiangxi Tujia and Miao Autonomous Prefecture of Hunan Province, China. A total of 428 valid questionnaires were collected and analyzed. The study employed AMOS v.23 to construct a structural equation model to validate the hypotheses. Results: The results indicate that physical activity significantly influences the emotional intelligence, interpersonal forgiveness, and positive emotions of adolescents. Furthermore, emotional intelligence and interpersonal forgiveness mediate the relationship between physical activity and positive emotions. Discussion: Based on these findings, collaborative efforts from government agencies, schools, and families are essential to provide robust support for adolescents' participation in physical activity, encouraging more adolescents to actively engage in sports.

2.
ACS Macro Lett ; 13(6): 711-718, 2024 Jun 18.
Article in English | MEDLINE | ID: mdl-38767947

ABSTRACT

Based on the characteristics of commodity polymers in large quantities and low costs, modification of existing commodity polymers emerges as the most effective approach for exploring novel materials. Nevertheless, conventional modification methods typically involve high-energy processes (e.g., high temperature, high-energy radiation), which may lead to irreversible detrimental effects on the polymers, contradicting the desired performance enhancement through modification. In this work, we propose a carbene-mediated postpolymerization modification (PPM) strategy utilizing diazo compounds. Under photochemical or thermal activation conditions, insertion of the C-H bond can be achieved without compromising the performance of polymers. These diazo compounds can be easily synthesized in just two steps and applied to all C-H-containing polymers. This practical and effective modification strategy offers new opportunities and possibilities for enhancing the value and expanding the applications of polymers.

3.
Opt Express ; 32(7): 10962-10978, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38570957

ABSTRACT

We propose a novel methane leakage rate remote sensor that combines a single-photon avalanche diode detector with a near-infrared 1653.7 nm low-power laser. The proposed M sequence and triangle wave signal modulation method simultaneously realizes the detection of methane leakage and target point clouds. Innovatively, the sensor's methane concentration and leakage rate quantification ability were simulated by combining the Gaussian plume diffusion model and the Risley prism. The effects of the prism rotation ratio, wind speed, leakage rate, atmospheric stability (AS), target reflectivity, signal averaging period, and concentration spatial interpolation method on leakage rate are discussed. When plume methane concentrations reduce from 10,000 to 500 ppm·m, the relative concentration bias rise from 1% to 30%, the absolute concentration bias is approximately 100 ppm·m. Two spatial concentration interpolation methods introduced leakage rate bias ranging from 6%-25%. For a low AS, the leakage rate bias under the cubic interpolation method was small (approximately 1.6%). In addition, when the initial leakage rate increased from 100 to 1,000 mg/s, the leakage rate bias was approximately 20% smaller.

4.
Opt Express ; 32(7): 11849-11862, 2024 Mar 25.
Article in English | MEDLINE | ID: mdl-38571023

ABSTRACT

A novel mid-infrared methane remote sensor integrated on a movable platform based on a 3.291-µm interband cascade laser (ICL) and wavelength modulation spectroscopy (WMS) is proposed. A transmitting-receiving coaxial, visualized optical layout is employed to minimize laser energy loss. Using a hollow retro-reflector remotely deployed as a cooperative target, the atmospheric average methane concentration over a 100-meter optical range is measured with high sensitivity. A deep neural network (DNN) filter is used for second harmonic (2f) signal denoising to compensate for the performance shortcomings of conventional filtering. Allan deviation analysis indicated that after applying the DNN filter, the limit of detection (LOD) of methane was 86.62 ppb with an average time of 1 s, decreasing to 12.03 ppb with an average time of 229 s, which is a significant promotion compared to similar work reported. The high sensitivity and stability of the proposed sensor are shown through a 24-hour continuous monitoring experiment of atmospheric methane conducted outdoors, providing a new solution for high-sensitivity remote sensing of atmospheric methane.

5.
Int J Pharm ; 650: 123700, 2024 Jan 25.
Article in English | MEDLINE | ID: mdl-38086493

ABSTRACT

Due to their low osmolality and high tolerability, the highly water-soluble nonionic iodinated contrast agents, such as Ioversol (IV), are widely used as clinical agents for CT imaging. However, their clinical applications still are severely limited by the rapid renal excretion, serious adverse effects especially contrast-induced nephropathy and inefficient targetability. Various nanocarriers have demonstrated tremendous potential for achieving high imaging efficiency and low side effects. However, few nanoparticulate contrast agents can simultaneously integrate the desirable functions for imaging, including high loading capacity of iodine, high structure stability for systemic circulation, high biocompatibility and high radiopacity. Herein, we designed and prepared a kind of new radiopaque liposome-camouflaged iodinated mesoporous silica nanoparticles (OIV-MSNs@Liposomes) as contrast agents in CT imaging. Their composition, structure, morphology, biocompatibility and physicochemical properties as well as in vitro radiopacity were investigated in detail. The results indicated that OIV-MSNs@Liposomes can integrate their individual advantages of liposomes and MSNs, thus exhibiting great potential for use in the CT imaging. Considering the simple preparation process and readily available starting materials as well as enhanced biosafety and high performance in X-ray attenuation, the strategy reported here offers a versatile route to efficiently deliver highly water-soluble nonionic iodinated contrast agents for enhanced CT imaging, which are unattainable by traditional means.


Subject(s)
Contrast Media , Nanoparticles , Contrast Media/chemistry , Silicon Dioxide/chemistry , Liposomes , Nanoparticles/chemistry , Water , Hemodynamics , Porosity
6.
Mol Ther Oncolytics ; 30: 132-149, 2023 Sep 21.
Article in English | MEDLINE | ID: mdl-37654973

ABSTRACT

To address CD19 loss from lymphoma after anti-CD19 chimeric antigen receptor (CAR) T cell therapy, we designed a bicistronic construct encoding an anti-CD19 CAR and an anti-CD20 CAR. We detected deletions from the expected bicistronic construct sequence in a minority of transcripts by mRNA sequencing. Loss of bicistronic construct transgene DNA was also detected. Deletions of sequence were present at much higher frequencies in transduced T cell mRNA versus gamma-retroviral vector RNA. We concluded that these deletions were caused by intramolecular template switching of the reverse transcriptase enzyme during reverse transcription of gamma-retroviral vector RNA into transgene DNA of transduced T cells. Intramolecular template switching was driven by repeated regions of highly similar nucleic acid sequence within CAR sequences. We optimized the sequence of the bicistronic CAR construct to reduce repeated regions of highly similar sequences. This optimization nearly eliminated sequence deletions. This work shows that repeated regions of highly similar nucleic acid sequence must be avoided in complex CAR constructs. We further optimized the bicistronic construct by lengthening the linker of the anti-CD20 single-chain variable fragment. This modification increased CD20-specific interleukin-2 release and reduced CD20-specific activation-induced cell death. We selected an optimized anti-CD19/CD20 bicistronic construct for clinical development.

7.
J Environ Manage ; 347: 119113, 2023 Dec 01.
Article in English | MEDLINE | ID: mdl-37769471

ABSTRACT

Insights into COVID-19 antivirals' environmental fate and ecological risk are urgently required due to their increasing concentrations in aquatic environments, which have rarely been studied. Herein, we first investigated the photochemical transformation and the resulting alterations in toxicity of arbidol, an antiviral drug with relatively higher toxicity. The photolysis of arbidol was rapid with a rate constant of 0.106 min-1 due to its superior ultraviolet light absorption, in which the direct photolysis was predominated with a contribution of 91.5%. Despite its substantial photolysis, only 14.45% of arbidol was mineralized after 100 min, implying that arbidol and its products might have a long-term impact on aquatic environment. It was inferred that arbidol was photolyzed mainly via the loss of thiophenol, bromine, and alkylamine, based on twelve photolytic products identified. Notably, the experimental results demonstrated that the photolysis process increased the acute toxicity of arbidol, and the toxicity prediction indicated that the ecotoxicity of two photolytic products was very high with LC50 values below 0.1 mg/L. Due to the co-effect of multiple constituents, the photolytic rate observed in wastewater treatment plant effluent and in river water was comparable to that in ultra-pure water, while it was slightly enhanced in lake water. The presence of dissolved organic matter suppressed arbidol photolysis, while NO3- exhibited a promotion effect. These results would be of great significance to assess the fate and risk of COVID-19 antivirals in natural aquatic environments.


Subject(s)
COVID-19 , Water Pollutants, Chemical , Humans , Sunlight , Photolysis , Water , Antiviral Agents , Water Pollutants, Chemical/analysis
8.
Front Oncol ; 13: 1175617, 2023.
Article in English | MEDLINE | ID: mdl-37228496

ABSTRACT

Background: Ovarian cancer has long been known to be the deadliest cancer associated with the female reproductive system. More than 15% of ovarian cancer patients have a defective BRCA-mediated homologous recombination repair pathway that can be therapeutically targeted with PARP inhibitors (PARPi), such as Talazoparib (TLZ). The expansion of TLZ clinical approval beyond breast cancer has been hindered due to the highly potent systemic side effects resembling chemotherapeutics. Here we report the development of a novel TLZ-loaded PLGA implant (InCeT-TLZ) that sustainedly releases TLZ directly into the peritoneal (i.p.) cavity to treat patient-mimicking BRCA-mutated metastatic ovarian cancer (mOC). Methods: InCeT-TLZ was fabricated by dissolving TLZ and PLGA in chloroform, followed by extrusion and evaporation. Drug loading and release were confirmed by HPLC. The in vivo therapeutic efficacy of InCeT-TLZ was carried out in a murine Brca2-/-p53R172H/-Pten-/- genetically engineered peritoneally mOC model. Mice with tumors were divided into four groups: PBS i.p. injection, empty implant i.p. implantation, TLZ i.p. injection, and InCeT-TLZ i.p. implantation. Body weight was recorded three times weekly as an indicator of treatment tolerance and efficacy. Mice were sacrificed when the body weight increased by 50% of the initial weight. Results: Biodegradable InCeT-TLZ administered intraperitoneally releases 66 µg of TLZ over 25 days. In vivo experimentation shows doubled survival in the InCeT-TLZ treated group compared to control, and no significant signs of toxicity were visible histologically in the surrounding peritoneal organs, indicating that the sustained and local delivery of TLZ greatly maximized therapeutic efficacy and minimized severe clinical side effects. The treated animals eventually developed resistance to PARPi therapy and were sacrificed. To explore treatments to overcome resistance, in vitro studies with TLZ sensitive and resistant ascites-derived murine cell lines were carried out and demonstrated that ATR inhibitor and PI3K inhibitor could be used in combination with the InCeT-TLZ to overcome acquired PARPi resistance. Conclusion: Compared to intraperitoneal PARPi injection, the InCeT-TLZ better inhibits tumor growth, delays the ascites formation, and prolongs the overall survival of treated mice, which could be a promising therapy option that benefits thousands of women diagnosed with ovarian cancer.

9.
J Hazard Mater ; 452: 131320, 2023 06 15.
Article in English | MEDLINE | ID: mdl-37002997

ABSTRACT

Increasing drug residues in aquatic environments have been caused by the abuse of antivirals since the global spread of the COVID-19 epidemic, whereas research on the photolytic mechanism, pathways and toxicity of these drugs is limited. The concentration of COVID-19 antivirals ribavirin in rivers has been reported to increase after the epidemic. Its photolytic behavior and environmental risk in actual waters such as wastewater treatment plant (WWTP) effluent, river water and lake water were first investigated in this study. Direct photolysis of ribavirin in these media was limited, but indirect photolysis was promoted in WWTP effluent and lake water by dissolved organic matter and NO3-. Identification of photolytic intermediates suggested that ribavirin was photolyzed mainly via C-N bond cleavage, splitting of the furan ring and oxidation of the hydroxyl group. Notably, the acute toxicity was increased after ribavirin photolysis owing to the higher toxicity of most of the products. Additionally, the overall toxicity was greater when ARB photolysis in WWTP effluent and lake water. These findings emphasize the necessity to concern about the toxicity of ribavirin transformation in natural waters, as well as to limit its usage and discharge.


Subject(s)
Antiviral Agents , COVID-19 , Ribavirin , Water Pollutants, Chemical , Humans , Angiotensin Receptor Antagonists , Angiotensin-Converting Enzyme Inhibitors , Antiviral Agents/chemistry , Photolysis , Ribavirin/chemistry , Water/chemistry , Water Pollutants, Chemical/chemistry
10.
J Ocul Pharmacol Ther ; 39(2): 175-184, 2023 03.
Article in English | MEDLINE | ID: mdl-36930765

ABSTRACT

Purpose: To investigate the efficacy and safety of pulsed ultrasound (PUS) in enhancing fluorescein sodium (NaF) transport to the rabbit eye through the transscleral and transconjunctival routes in vivo. Methods: PUS and NaF were applied onto the supratemporal sclera/conjunctiva of healthy rabbit eyes. PUS (1 MHz, 2.37 W/cm2, 30% duty cycle, 5-min application time) was performed 3 times with a 5-min interval. In the same process, NaF was administered to the eye without PUS in the control. NaF concentrations in the vitreous and retina-choroid were determined by fluorescence measurement. The safety of PUS application was assessed based on temperature and intraocular pressure measurements, clinical observations, electroretinography, histology, and Terminal Deoxynucleotidyl Transferase dUTP Nick End Labeling assay. Results: In comparison to the control, higher NaF concentrations were found in the retina-choroid following transscleral (2.45-fold) and transconjunctival (2.97-fold) PUS applications (P < 0.05). NaF concentrations in the vitreous were 3.15 and 5.86 times greater in transscleral and transconjunctival PUS applications, respectively, compared with those obtained without PUS application (P < 0.05), and NaF level in the vitreous after transconjunctival PUS application was 2.61 times that of transscleral PUS application (P < 0.05). Ocular findings were transient and mild conjunctival injection, with no other structural and functional changes in PUS-treated eyes. Conclusions: PUS treatment can improve transscleral and transconjunctival delivery of NaF efficiently and safely. Transscleral and transconjunctival PUS applications offer potential clinical benefit in increasing drug penetration to the posterior segments of the eye for the noninvasive treatment of ocular diseases.


Subject(s)
Drug Delivery Systems , Fluorescein , Animals , Rabbits , Conjunctiva , Electroretinography , Fluorescein/administration & dosage , Sclera , Ultrasonic Waves , Vitreous Body , Eye
11.
Environ Pollut ; 315: 120355, 2022 Dec 15.
Article in English | MEDLINE | ID: mdl-36243187

ABSTRACT

As the groundwater ecosystem is connected with surface, antibiotics and antibiotic resistance genes (ARGs) in aquatic environments will gradually infiltrate into the deep environment, posing a potential threat to groundwater ecosystem. However, knowledge on the environmental risk of antibiotics and ARGs in groundwater ecosystem and their ecological process still remains unexplored. In this study, lab-scale oil reservoirs under high tetracycline stress were performed to evaluate the dynamics of microbial communities, ARGs and potential functions by using 16S rRNA gene sequencing and metagenomics analysis. Although the presence of antibiotics remarkably reduced the microbial abundance and diversity in a short term, but remain stable or even increased after a long-term incubation. Antibiotic stress caused a greater diversity and abundance of ARGs, and higher numbers of ARGs-related species with the capacity to transfer ARGs to other microbes through horizontal gene transfer. Thus, a much more frequent associations of microbial community at both node- and network-level and a selective pressure on enrichment of antibiotic resistant bacteria related to "anaerobic n-alkane degradation" and "methylotrophic methanogenesis" were observed. It is important to emphasize that high antibiotic stress could also prevent some microbes related to "Sulfate reduction", "Fe(II) oxidation", "Nitrate reduction", and "Xylene and Toluene degradation". This study provides an insight into the long-term stress-responses of microbial communities and functions in oil reservoir under tetracycline exposure, which may help to elucidate the effect of antibiotic stress on biogeochemical cycling with microbial involvement in groundwater ecosystem.


Subject(s)
Microbiota , Oil and Gas Fields , Genes, Bacterial , RNA, Ribosomal, 16S , Tetracycline , Anti-Bacterial Agents/analysis
12.
Front Microbiol ; 13: 932269, 2022.
Article in English | MEDLINE | ID: mdl-35966672

ABSTRACT

Salt tolerance is one of the most important problems in the field of environmental governance and restoration. Among the various sources of factors, except temperature, salinity is a key factor that interrupts bacterial growth significantly. In this regard, constant efforts are made for the development of salt-tolerant strains, but few strains with salt tolerance, such as Terribacillus saccharophilus, were found, and there are still few relevant reports about their salt tolerance from complete genomic analysis. Furthermore, with the development of the economy, environmental pollution caused by oil exploitation has attracted much attention, so it is crucial to find the bacteria from T. saccharophilus which could degrade petroleum hydrocarbon even under high-salt conditions. Herein, one T. saccharophilus strain named ZY-1 with salt tolerance was isolated by increasing the salinity on LB medium step by step with reservoir water as the bacterial source. Its complete genome was sequenced, which was the first report of the complete genome for T. saccharophilus species with petroleum hydrocarbon degradation and emulsifying properties. In addition, its genome sequences were compared with the other five strains that are from the same genus level. The results indicated that there really exist some differences among them. In addition, some characteristics were studied. The salt-tolerant strain ZY-1 developed in this study and its emulsification and degradation performance of petroleum hydrocarbons were studied, which is expected to widely broaden the research scope of petroleum hydrocarbon-degrading bacteria in the oil field environment even in the extreme environment. The experiments verified that ZY-1 could significantly grow not only in the salt field but also in the oil field environment. It also demonstrated that the developed salt-tolerant strain can be applied in the petroleum hydrocarbon pollution field for bioremediation. In addition, we expect that the identified variants which occurred specifically in the high-salt strain will enhance the molecular biological understanding and be broadly applied to the biological engineering field.

13.
Sensors (Basel) ; 22(11)2022 May 27.
Article in English | MEDLINE | ID: mdl-35684707

ABSTRACT

This paper investigates the computation offloading problem in mobile edge computing (MEC) networks with dynamic weighted tasks. We aim to minimize the system utility of the MEC network by jointly optimizing the offloading decision and bandwidth allocation problems. The optimization of joint offloading decisions and bandwidth allocation is formulated as a mixed-integer programming (MIP) problem. In general, the problem can be efficiently generated by deep learning-based algorithms for offloading decisions and then solved by using traditional optimization methods. However, these methods are weakly adaptive to new environments and require a large number of training samples to retrain the deep learning model once the environment changes. To overcome this weakness, in this paper, we propose a deep supervised learning-based computational offloading (DSLO) algorithm for dynamic computational tasks in MEC networks. We further introduce batch normalization to speed up the model convergence process and improve the robustness of the model. Numerical results show that DSLO only requires a few training samples and can quickly adapt to new MEC scenarios. Specifically, it can achieve 99% normalized system utility by using only four training samples per MEC scenario. Therefore, DSLO enables the fast deployment of computation offloading algorithms in future MEC networks.


Subject(s)
Deep Learning , Algorithms
14.
Angiology ; 73(7): 660-667, 2022 08.
Article in English | MEDLINE | ID: mdl-35084237

ABSTRACT

Diabetes mellitus is an independent risk factor for contrast-induced nephropathy (CIN) in patients undergoing coronary arteriography/percutaneous coronary intervention (CAG/PCI). We evaluated whether preoperative fasting blood glucose (FBG) levels in diabetic and pre-diabetic patients who underwent CAG/PCI influenced the occurrence of CIN. From June 1, 2020, to February 28, 2021, 687 patients were divided into five groups based on their preoperative FBG levels. Blood samples were collected at admission and at 48 hours and 72 hours after the procedure to determine serum creatinine levels. The P value for trend was used to analyze the trend between preoperative FBG levels and the increased risk of CIN. Univariable and multivariable logistic regression analysis were used to exclude the influence of confounding factors, and some high-risk confounders were selected for subgroup analysis. The results of our cross-sectional study show that elevated preoperative FBG levels are independently associated with the risk of CIN in diabetic and pre-diabetic patients undergoing CAG/PCI. Furthermore, the incidence of CIN gradually increases with the rise in preoperative FBG levels. Patients with elevated preoperative FBG at admission should be carefully monitored and more active measures should be taken to prevent CIN.


Subject(s)
Diabetes Mellitus , Kidney Diseases , Percutaneous Coronary Intervention , Prediabetic State , Blood Glucose , Contrast Media/adverse effects , Coronary Angiography/adverse effects , Coronary Angiography/methods , Creatinine , Cross-Sectional Studies , Diabetes Mellitus/epidemiology , Fasting , Humans , Kidney Diseases/chemically induced , Percutaneous Coronary Intervention/adverse effects , Percutaneous Coronary Intervention/methods , Prediabetic State/complications , Prediabetic State/diagnosis , Risk Factors
15.
Angiology ; 73(1): 33-41, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34098771

ABSTRACT

The Mehran risk score (MRS) was used to classify patients with coronary heart disease and evaluate the preventive effect of alprostadil on contrast-induced nephropathy (CIN) after percutaneous coronary intervention. The patients (n = 1146) were randomized into an alprostadil and control group and then divided into 3 groups on the basis of the MRS: low-risk, moderate-risk, and high-risk groups. The primary end point was the occurrence of CIN (alprostadil + hydration vs simple hydration treatment); secondary end points included serum creatinine, blood urea nitrogen, creatinine clearance rate, cystatin C, interleukin-6, C-reactive protein, proteinuria, and differences in the incidence of major adverse events. In the low-risk, moderate-risk, and high-risk groups, the incidence of CIN in the control and alprostadil group was 2.9 versus 2.6% (P = .832), 11.4 versus 4.9% (P = .030), 19.1 versus 7.7% (P = .041), respectively. Multivariate logistic regression analysis showed that alprostadil treatment was a favorable protective factor for moderate-risk and high-risk CIN patients (OR = 0.343, 95% CI: 0.124-0.951, P = .040). Alprostadil can be used as a preventive treatment for moderate- and high-risk CIN patients classified by the MRS. The reduction of CIN by alprostadil may be related to an anti-inflammatory effect.


Subject(s)
Coronary Disease , Kidney Diseases , Percutaneous Coronary Intervention , Alprostadil/therapeutic use , Contrast Media/adverse effects , Coronary Angiography , Creatinine , Humans , Kidney Diseases/chemically induced , Kidney Diseases/prevention & control , Percutaneous Coronary Intervention/adverse effects , Risk Factors
16.
ACS Biomater Sci Eng ; 8(1): 32-53, 2022 01 10.
Article in English | MEDLINE | ID: mdl-34851607

ABSTRACT

X-ray computed tomography (CT), as one of the most widely used noninvasive imaging modalities, can provide three-dimensional anatomic details with high resolution, which plays a key role in disease diagnosis and treatment assessment. However, although they are the most prevalent and FDA-approved contrast agents, iodinated water-soluble molecules still face some challenges in clinical applications, such as fast clearance, serious adverse effects, nonspecific distribution, and low sensitivity. Because of their high biocompatibility, tunable designability, controllable biodegradation, facile synthesis, and modification capability, the polymers have demonstrated great potential for efficient delivery of iodinated contrast agents (ICAs). Herein, we comprehensively summarized the applications of multifunctional polymeric materials for ICA delivery in terms of increasing circulation time, decreasing nephrotoxicity, and improving the specificity and sensitivity of ICAs for CT imaging. We mainly focused on various iodinated polymers from the aspects of preparation, functionalization, and application in medical diagnosis. Future perspectives for achieving better imaging and clinical translation are also discussed to motivate new technologies and solutions.


Subject(s)
Contrast Media , Nanoparticles , Contrast Media/adverse effects , Polymers , Tomography, X-Ray Computed
17.
J Am Chem Soc ; 143(45): 19167-19177, 2021 11 17.
Article in English | MEDLINE | ID: mdl-34738793

ABSTRACT

Organosilicon compounds and polymers have found wide applications as synthetic building blocks and functional materials. Hydrosilylation is a common strategy toward the synthesis of organosilicon compounds and polymers. Although transition-metal-catalyzed hydrosilylation has achieved great advances, the metal-free hydrosilylation polymerization of dienes and bis(silane)s, especially the one suitable for both electron-rich and electron-deficient dienes, is largely lacking. Herein, we report a visible-light-driven metal-free hydrosilylation polymerization of both electron-rich and electron-deficient dienes with bis(silane)s by using the organic photocatalyst and hydrogen atom transfer (HAT) catalyst. We achieved the well-controlled step-growth hydrosilylation polymerizations of the electron-rich diene and bis(silane) monomer due to the selective activation of Si-H bonds by the organic photocatalyst (4CzIPN) and the thiol polarity reversal reagent (HAT 1). For the electron-deficient dienes, hydrosilylation polymerization and self-polymerization occurred simultaneously in the presence of 4CzIPN and aceclidine (HAT 2), providing the opportunity to produce linear, hyperbranched, and network polymers by rationally tuning the concentration of electron-deficient dienes and the ratio of bis(silane)s and dienes to alter the proportion of the two polymerizations. A wide scope of bis(silane)s and dienes furnished polycarbosilanes with high molecular weight, excellent thermal stability, and tunable architectures.

18.
Nat Commun ; 12(1): 5853, 2021 10 06.
Article in English | MEDLINE | ID: mdl-34615871

ABSTRACT

The regulation of polymer topology and the precise control over the monomer sequence is crucial and challenging in polymer science. Herein, we report an efficient solution-phase synthetic strategy to prepare regio- and sequence-controlled conjugated polymers with topological variations via the usage of methyliminodiacetic acid (MIDA) boronates. Based on the solubility of MIDA boronates and their unusual binary affinity for silica gel, the synthesized regio- and sequence-defined conjugated oligomers can be rapidly purified via precipitation or automatic liquid chromatography. These synthesized discrete oligomers can be used for iterative exponential and sequential growth to obtain linear and dendrimer-like star polymers. Moreover, different topological sequence-controlled conjugated polymers are conveniently prepared from these discrete oligomers via condensation polymerization. By investigating the structure-property relationship of these polymers, we find that the optical properties are strongly influenced by the regiochemistry, which may give inspiration to the design of optoelectronic polymeric materials.

19.
J Clin Med ; 10(7)2021 Apr 01.
Article in English | MEDLINE | ID: mdl-33916177

ABSTRACT

Cancer is the second biggest cause of death in children in the US. With the development of chemotherapy, there has been a substantial increase in the overall survival rate in the last 30 years. However, the overall mortality rate in children with cancer remains 25%, and many survivors experience a decline in overall quality of life and long-term adverse effects caused by treatments. Although cancer cells share common characteristics, pediatric cancers are different from adult cancers in their prevalence, mutation load, and drug response. Therefore, there is an urgent unmet need to develop therapeutic approaches specifically designed for children with cancer. Nanotechnology can potentially overcome the deficiencies of conventional methods of administering chemotherapy and ultimately improve clinical outcomes. The nanoparticle-based drug delivery systems can decrease the toxicity of therapy, provide a sustained or controlled drug release, improve the pharmacokinetic properties of loading contents, and achieve a targeted drug delivery with achievable modifications. Furthermore, therapeutic approaches based on combining nanoformulated drugs with novel immunotherapeutic agents are emerging. In this review, we discussed the recently developed nanotechnology-based strategies for treating blood and solid pediatric cancers.

20.
Bioresour Technol ; 333: 125203, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33901910

ABSTRACT

Water is essential in conversion of crop to bioenergy. Therefore, it is important to carefully evaluate the impact of bioenergy technology on water source. Life cycle water footprints of biobutanol from wheat straw, corn grain and corn stover are analyzed in this study according to the characteristics of crop growing and climate conditions. The results show that life cycle water footprints of biobutanol from wheat straw, corn grain and corn stover are 271, 108 and 240 L H2O/MJ biobutanol, respectively. Life cycle water footprints of the crop production stage for wheat straw, corn grain and corn stover are 269.89, 107.84 and 238.95 L H2O/MJ biobutanol, respectively. Owing to the use of fertilizer in the crop production stage, gray water footprint of wheat straw, corn grain and corn stover accounts for 91.08%, 86.65% and 86.40% of the life cycle water footprint, respectively.


Subject(s)
Triticum , Zea mays , Animals , Fertilizers , Life Cycle Stages , Water
SELECTION OF CITATIONS
SEARCH DETAIL
...