The gap report of global climate change mitigation, finance, and governance after the United States declared its withdrawal from the Paris Agreement

On 1 June 2017, the US President Donald Trump officially announced the withdrawal from the Paris Agreement, thus the study on the reasons of withdrawal, the potential impacts, and coping strategies has become a focus among policy circles and of the international community. Based on the self-developed US Policy Assessment Model, this paper systematically evaluates the three potential "major deficits" in terms of mitigation, climate finance, and global climate governance, as a result of the US withdrawal from the Paris Agreement and puts forward policy suggestions for coping with such transformations accordingly. The study shows that the United States 'withdrawal from the Paris Agreement will affect the existence and implementation of successive climate policies and result in an additional 8.8-13.4% increase in the global emissions reduction deficit.The United States' withdrawal will also deteriorate the existing climate finance mechanism. The Green Climate Fund(GCF)'s funding gap will increase by US$2 billion, while the gap of long-term climate finance will increase by about US$5 billion a year. Either the China-EU or the "BASIC plus" mechanism could fill the governance deficit caused by the United States and the lack of political momentum may continue for a while in the future.

Exosomes derived from osteoclasts under compression stress inhibit osteoblast differentiation

Orthodontic tooth movement is triggered by orthodontic force loading on the periodontal ligament and is achieved by alveolar bone remodeling,which is regulated by intimate crosstalk between osteoclastogenesis and osteoblast differentiation.Whether the communication between osteoclasts and osteoblasts is influenced by orthodontic compression stress requires further clarification.In this study,osteoclasts were differentiated for 10 days.On day 4 of differentiation,the number of pre-osteoclasts peaked,as determined by the increased expression of RANK and the number of multinucleated cells.After 24 h of compression stress loading,on day 4,the number of osteoclasts increased,and the optimal magnitude of stress to promote osteoclastogenesis was determined as 1 g/cm2.Moreover,the results of RNA-sequencing analysis showed that the miRNA expression profile changed markedly after compression loading and that many of the altered miRNAs were associated with cell communication functions.A series of indirect co-culture experiments showed an inhibitory effect of osteoclasts on osteoblast differentiation,especially after compression.Next,we added osteoclast-derived exosomes to hPDLSCs during osteoblast differentiation.Exosomes derived from osteoclasts under compression(cEXO)showed a greater inhibitory effect on osteoblast differentiation,compared to exosomes from osteoclasts without compression(EXO).Therefore,we analyzed differentially expressed miRNAs associated with bone development functions in exosomes:miR-223-5p and miR-181a-5p were downregulated,whereas miR-133a-3p,miR-203a-3p,miR-106a-5p,and miR-331-3p were upregulated;these altered expressions may explain the enhanced inhibitory effect of compression stress.

Safety Analysis of Riding at Intersection Entrance Using Video Recognition Technology

To study riding safety at intersection entrance,video recognition technology is used to build vehicle-bicycle conflict models based on the Bayesian method.It is analyzed the relationship among the width of nonmotorized lanes at the entrance lane of the intersection,the vehicle-bicycle soft isolation form of the entrance lane of intersection,the traffic volume of right-turning motor vehicles and straight-going non-motor vehicles,the speed of right-turning motor vehicles,and straight-going non-motor vehicles,and the conflict between right-turning motor vehicles and straight-going nonmotor vehicles.Due to the traditional statistical methods,to overcome the discreteness of vehicle-bicycle conflict data and the differences of influencing factors,the Bayesian random effect Poisson-log-normal model and random effect negative binomial regression model are established.The results show that the random effect Poisson-log-normal model is better than the negative binomial distribution of random effects;The width of non-motorized lanes,the form of vehicle-bicycle soft isolation,the traffic volume of right-turning motor vehicles,and the coefficients of straight traffic volume obey a normal distribution.Among them,the type of vehicle-bicycle soft isolation facilities and the vehicle-bicycle traffic volumes are significantly positively correlated with the number of vehicle-bicycle conflicts.The width of non-motorized lanes is significantly negatively correlated with the number of vehicle-bicycle conflicts.Peak periods and flat periods,the average speed of right-turning motor vehicles,and the average speed of straight-going non-motor vehicles have no significant influence on the number of vehicle-bicycle conflicts.

Evaluation of the safety and efficiency of cytotoxic T cell therapy sensitized by tumor antigens original from T-ALL-iPSC in vivo

Background:Since RNA sequencing has shown that induced pluripotent stem cells(iPSCs)share a common antigen profile with tumor cells,cancer vaccines that focus on iPSCs have made promising progress in recent years.Previously,we showed that iPSCs derived from leukemic cells of patients with primary T cell acute lymphoblastic leukemia(T-ALL)have a gene expression profile similar to that of T-ALL cell lines.Methods:Mice with T-ALL were treated with dendritic and T(DC-T)cells loaded with intact and complete antigens from T-ALL-derived iPSCs(T-ALL-iPSCs).We evaluated the safety and antitumor efficiency of autologous tumor-derived iPSC antigens by flow cytometry,cytokine release assay,acute toxicity experiments,long-term toxicity experiments,and other methods.Results:Our results indicate that complete tumor antigens from T-ALL-iPSCs could inhibit the growth of inoculated tumors in immunocompromised mice without causing acute and long-term toxicity.Conclusion:T-ALL-iPSC-based treatment is safe and can be used as a potential strategy for leukemia immunotherapy.

Atmospheric oxidizing capacity in autumn Beijing:Analysis of the O_(3) and PM_(2.5) episodes based on observation-based model

Atmospheric oxidizing capacity(AOC)is the fundamental driving factors of chemistry process(e.g.,the formation of ozone(O_(3))and secondary organic aerosols(SOA))in the troposphere.However,accurate quantification of AOC still remains uncertainty.In this study,a comprehensive field campaign was conducted during autumn 2019 in downtown of Beijing,where O_(3) and PM_(2.5) episodes had been experienced successively.The observation-based model(OBM)is used to quantify the AOC at O_(3) and PM_(2.5) episodes.The strong intensity of AOC is found at O_(3) and PM2.5 episodes,and hydroxyl radical(OH)is the dominating daytime oxidant for both episodes.The photolysis of O_(3) is main source of OH at O_(3) episode;the photolysis of nitrous acid(HONO)and formaldehyde(HCHO)plays important role in OH formation at PM_(2.5) episode.The radicals loss routines vary according to precursor pollutants,resulting in different types of air pollution.O_(3) budgets and sensitivity analysis indicates that O_(3) production is transition regime(both VOC and NOx-limited)at O3 episode.The heterogeneous reaction of hydroperoxy radicals(HO_(2))on aerosol surfaces has significant influence on OH and O_(3) production rates.The HO_(2) uptake coefficient(γHO_(2))is the determining factor and required accurate measurement in real atmospheric environment.Our findings could provide the important bases for coordinated control of PM_(2.5) and O_(3) pollution.

Sources of ambient non-methane hydrocarbon compounds and their impacts on O_(3) formation during autumn,Beijing

The field observation of 54 non-methane hydrocarbon compounds(NMHCs)was conducted from September 1 to October 20 in 2020 during autumn in Haidian District,Beijing.The mean concentration of total NMHCs was 29.81±11.39 ppbv during this period,and alkanes were the major components.There were typical festival effects of NMHCs with lower concentration during the National Day.Alkenes and aromatics were the dominant groups in ozone formation potential(OFP)and OH radical loss rate(L_(OH)).The positive matrix factorization(PMF)running results revealed that vehicular exhaust became the biggest source in urban areas,followed by liquefied petroleum gas(LPG)usage,solvent usage,and fuel evaporation.The box model coupled with master chemical mechanism(MCM)was applied to study the impacts of different NMHCs sources on ozone(O_(3))formation in an O_(3)episode.The simulation results indicated that reducing NMHCs concentration could effectively suppress O_(3)formation.Moreover,reducing traffic-related emissions of NMHCs was an effective way to control O_(3)pollution at an urban site in Beijing.

Kinetic study of the gas-phase reaction of O3 with three unsaturated alcohols

Rate constants for the reactions of ozone with 1-octen-3-ol, 1-nonen-3-ol and 1-nonen-4-ol have been determined at 298 ±1 K and atmospheric pressure for the first time. The experiments were performed in a 100-L FEP Teflon film bag using absolute rate method; the rate constants were （1.91 ± 0.19） ×10^-17, （1.89 ± 0.20） × 10^-17, and （0.83 ± 0.08） × 10^-17 cm^3/（molecule.sec） for 1-octen-3-ol, 1-nonen-3-ol, and 1-nonen-4-ol, respectively. The rate constants have been compared with those of unsaturated alcohols structural homologs, and used to estimate the reaction reactivity. The electronegativity of carbon-carbon double bond was calculated by atomic charges analysis. The calculated results show that the electronic effect of the lone pair electrons of hydroxyl oxygen is the main cause of the difference in rate coefficient. According to the obtained rate constants, the atmospheric lifetimes of studied unsaturated alcohols were also estimated, which indicates that the reaction with ozone is an important loss pathway in the atmosphere, especially in polluted areas.

Compression loading of osteoclasts attenuated micro RNA-146a-5p expression,which promotes angiogenesis by targeting adiponectin

Osteoclastogenesis in alveolar bone induced by compression stress triggers orthodontic tooth movement.Compression stress also stimulates angiogenesis,which is essential for osteoclastogenesis.However,the effects of osteoclastogenesis induced by compression on angiogenesis are poorly understood.In vivo,we found the markers of angiogenesis increased during orthodontic bone remodeling.In vitro,osteoclast-derived exosomes increased proliferation,migration,and tube formation of human umbilical vein endothelial cells(HUVECs),as well as expression of vascular endothelial growth factor and CD31.The promotive effects of exosomes derived from compressed osteoclasts were greater than those derived from osteoclasts without compression.Next,we analyzed changes in the micro RNA transcriptome after compression stress and focused on micro RNA146 a-5 p(mi R-146 a),which was significantly decreased by compression.Transfection of an inhibitor of mi R-146 a stimulated angiogenesis of HUVECs while mi R-146 a mimics repressed angiogenesis.Adiponectin(ADP)was confirmed to be a target of mi R-146 a by dual luciferase reporter assay.In HUVECs treated with exosomes,we detected increased ADP which promoted angiogenesis.Knockdown of ADP in HUVECs reduced the promotive effects of exosomes.Our results demonstrate that the decreased mi R-146 a observed in osteoclasts after compression promotes angiogenesis by targeting ADP,suggesting a novel method to interfere with bone remodeling induced by compression stress.

DNA methylation profile is associated with the osteogenic potential of three distinct human odontogenic stem cells

Among the various sources of human autologous stem cells,stem cells isolated from dental tissues exhibit excellent properties in tissue engineering and regenerative medicine.However,the distinct potential of these odontogenic cell lines remains unclear.In this study,we analyzed DNA methylation patterns to determine whether specific differences existed among three different odontogenic cell types.Using the HumanMethylation450 Beadchip,the whole genomes of human dental pulp stem cells(DPSCs),periodontal ligament stem cells(PDLSCs),and dental follicle progenitor cells(DFPCs)were compared.Then,the osteogenic potential of these cells was evaluated both in vitro and in vivo,and the methylation levels of certain genes related to bone formation differed among the three cell lines.P values less than 0.05 were considered to indicate statistical significance.The three cell types showed highly similar DNA methylation patterns,although specific differences were identified.Gene ontology analysis revealed that one of the most significantly different gene categories was related to bone formation.Thus,expression of cell surface epitopes and osteogenic-related transcription factors as well as the bone formation capacity were compared.The results showed that compared with DFPCs and DPSCs,PDLSCs had higher transcription levels of osteogenic-related factors,a higher in vitro osteogenic potential,and an increased new bone formation capacity in vivo.In conclusion,the results of this study suggested that the differential DNA methylation profiles could be related to the osteogenic potential of these human odontogenic cell populations.Additionally,the increased osteogenic potential of PDLSCs might aid researchers or clinicians in making better choices regarding tissue regeneration and clinical therapies.

Kinetic and mechanism studies of the ozonolysis of three unsaturated ketones

Reaction rate constants and products of 1-octen-3-one,3-octen-2-one and 4-hexen-3-one with ozone were studied in a 100-L fluorinated ethylene propylene(FEP) Teflon film bag using absolute rate method at 298 ± 1 K and atmospheric pressure.The rate constants were(1.09 ± 0.12) × 10-17,(3.48 ± 0.36) × 10-17 and(5.70±0.60) × 10-17 cm3/(molecule·sec),respectively.According to the obtained rate constants,the effects of carbonyl were discussed.The carbonyl group in β position has a net withdrawing effect with respect to an olefinic bond,then causing the decline of rate constants.The quantum chemical calculation was used to explain the results of rate constants.The products of ozonolysis were mainly aldehydes,which have significant influence on the formation of SOA,and hence play an important role in the atmosphere.In this work,we detected the main products of reaction and proposed the reaction mechanism by combining the results of quantum chemical calculations.Atmospheric lifetime for three unsaturated ketones reacted with ozone was 36.4,11.4 and 6.9 hr for 1-octen-3-one,3-octen-2-one and 4-hexen-3-one,respectively.

Reaction mechanism and kinetics of Criegee intermediate and hydroperoxymethyl formate

The reaction mechanism and kinetics of the simplest Criegee intermediate CH_(2)OO reaction with hydroperoxymethyl formate(HPMF)was investigated at high-level quantum chemistry calculations.HPMF has two reactive functional groups,-C(O)OH and-OOH.The calculated results of thermodynamic data and rate constants indicated that the insertion reactions of CH_(2) OO with-OOH group of HPMF were more favorable than the reactions of CH_(2)OO with-C(O)OH group.The calculated overall rate constant was 2.33×10^(−13) cm^(3)/(moleculesec)at 298 K and the rate constants decreased as the temperature increased from 200 to 480 K.In addition,we also proved the polymerization reaction mechanism between CH_(2)OO and-OOH of HPMF.This theoretical study interpreted the previous experimental results,and supplied the structures of the intermediate products that couldn’t be detected during the experiment.

Formation mechanisms of nitrous acid(HONO) during the haze and non-haze periods in Beijing,China

As an important precursor of hydroxyl radical(OH),nitrous acid(HONO)plays a significant role in atmospheric chemistry.Here,an observation of HONO and relevant air pollutants in an urban site of Beijing from 14 to 28 April,2017 was performed.Two distinct peaks of HONO concentrations occurred during the observation.In contrast,the concentration of particulate matter in the first period(periodⅠ)was significantly higher than that in the second period(periodⅡ).Comparing to HONO sources in the two periods,we found that the direct vehicle emissionwas an essential source of the ambient HONO during both periods at night,especially in periodⅡ.The heterogeneous reaction of NO_(2)was the dominant source in periodⅠ,while the homogeneous reaction of NO with OH was more critical source at night in periodⅡ.In the daytime,the heterogeneous reaction of NO_(2)was a significant source andwas confirmed by the good correlation coefficients(R^(2))between the unknown sources(P_(unknown))with NO_(2),PM_(2.5),NO_(2)×PM_(2.5)in periodⅠ.Moreover,when solar radiation and OH radicals were considered to explore unknown sources in the daytime,the enhanced correlation of P_(unknown)with photolysis rate of NO_(2)and OH(J_(NO_(2))×OH)were 0.93 in periodⅠ,0.95 in periodⅡ.These excellent correlation coefficients suggested that the unknown sources released HONO highly related to the solar radiation and the variation of OH radicals.