Controllable Synthesis of Hemoglobin-Metal Phosphate Organic-Inorganic Hybrid Nanoflowers and Their Applications in Biocatalysis.

In recent years, organic-inorganic hybrid nanoflower technology has become an effective method for enzyme immobilization. Here, seven hierarchical flower-like hemoglobin-phosphate organic-inorganic hybrid nanomaterials (Hb-M3(PO4)2·nH2O HNFs) were synthesized through an improved universal one-pot wet-chemical method, with Ca2+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+ and Zn2+ as inorganic components. In this synthesis process, the metal cations are successively involved in the coordination reaction with Hb and the metathesis reaction to generate phosphate precipitation. The coordination ability of metal cations and the generation rate of phosphate precipitations were evaluated, then the progress of the two chemical reactions was controlled synchronously by adjusting the phosphate buffer (PB) concentration, and finally a flower-like structure conducive to substrate diffusion and transport was obtained. Due to the conformational transformation of hemoglobin and the abundant Cu2+/Fe3+ active sites, the hemoglobin-Cu3(PO4)2·3H2O nanoflowers have extremely high catalytic activity, which is ∼14 times that of Hb. Importantly, this method is suitable for the monometallic-ionic, polymetallic-ionic and polyvalent metal-ion nanoflowers, which broadens the chemical composition and structural diversity of nanoflowers.

Theoretically Revealed and Experimentally Demonstrated Synergistic Electronic Interaction of CoFe Dual-Metal Sites on N-doped Carbon for Boosting Both Oxygen Reduction and Evolution Reactions.

Heteronuclear double-atom catalysts, unlike single atom catalysts, may change the charge density of active metal sites by introducing another metal single atom, thereby modifying the adsorption energies of reaction intermediates and increasing the catalytic activities. First, density functional theory calculations are used to figure out the best combination by modeling two transition-metal atoms from Fe, Co, and Ni onto N-doped graphene. Generally, Fe and Co sites are highly active for the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER), respectively. The combination of Co and Fe to form CoFe-N-C not only further improves the Fe's ORR and Co's OER activities but also greatly enhances the Co site's ORR and Fe site's OER activities. Then, we synthesize the CoFe-N-C by a two-step pyrolysis process and find that the CoFe-N-C exhibits exceptional ORR and OER electrocatalytic activities in alkaline media, significantly superior to Fe-N-C and Co-N-C and even commercial catalysts.

Site-Selective C-H Allylation of Alkanes: Facile Access to Allylic Quaternary sp3 -Carbon Centers.

The construction of allylic quaternary sp3 -carbon centers has long been a formidable challenge in transition-metal-catalyzed alkyl-allyl coupling reactions due to the severe steric hindrance. Herein, we report an effective carbene strategy that employs well-defined vinyl-N-triftosylhydrazones as a versatile allylating reagent to enable direct assembly of these medicinally desirable structural elements from low-cost alkane feedstocks. The reaction exhibited excellent site selectivity for tertiary C-H bonds, broad scope (>60 examples and >20 : 1:0 r. r.) and good efficiency, even on a gram-scale, making it a convenient alternative to the well-known Trost-Tsuji allylation reaction for the formation of alkyl-allyl bonds. Combined experimental and computational studies were employed to unravel the mechanism and origin of site- and chemoselectivity of the reaction.

Exploiting the Synergistic Electronic Interaction between Pt-Skin Wrapped Intermetallic PtCo Nanoparticles and Co-N-C Support for Efficient ORR/EOR Electrocatalysis in a Direct Ethanol Fuel Cell.

The development of low-Pt catalysts with high activity and durability is critical for fuel cells. Here, Pt-skin wrapped sub-5 nm PtCo intermetallic nanoparticles are successfully mounted on single atom Co-N-C support by exploiting the barrier effect of Co-anchor. According to a collaborative experimental and computational investigation, the increased oxygen reduction reaction activity of PtCo/Co-N-C arises from the direct electron transfer from PtCo to Co-N-C, and the resulting optimal d-band center of Pt. Owing to such unique electronic structure interaction and synergistic effect, the specific and mass activities of PtCo/Co-N-C are up to 4.20 mA cm-2 and 2.71 A mgPt-1 , respectively, with barely degraded stability after 40 000 CV cycles. The PtCo/Co-N-C also exhibits outstanding activity as an ethanol electrocatalyst. This work shows a new and effective route to boost the overall efficiency of direct ethanol fuel cells in acidic media by integrating intermetallic low-Pt alloys and single atom carbon support.

The association between the dietary pattern in abdominal obesity based on visceral fat index and dyslipidaemia in the Henan Rural Cohort Study.

The present study aimed to explore the association between dietary patterns in abdominal obesity obtained by reduced-rank regression (RRR) with visceral fat index (VFI) as a dependent variable and dyslipidemia in rural adults in Henan, China. A total of 29538 people aged 18-79 were selected from the Henan Rural Cohort Study. RRR analysis was used to identify dietary patterns; logistic regression analysis and restricted cubic spline regression models were applied to analyze the association between dietary patterns in abdominal obesity and dyslipidemia. VFI was used as a mediator to estimate the mediation effect. The dietary pattern in abdominal obesity was characterized by high carbohydrate and red meat intake and low consumption of fresh fruits, vegetables, milk, etc. After full adjustment, the highest quartile of dietary pattern scores was significantly associated with an increased risk of dyslipidemia (OR: 1·33, 95 % CI 1·23-1·44, Ptrend < 0·001), there was a non-linear dose-response relationship between them (Poverall-association < 0·001, Pnon-lin-association = 0·022). The result was similar in dose-response between the dietary pattern scores and VFI. The indirect effect partially mediated by VFI was significant (OR: 1·07, 95 % CI 1·06-1·08). VIF explained approximately 53·3 % of odds of dyslipidemia related to the dietary pattern. Abdominal obesity dietary pattern scores positively affected VFI and dyslipidemia; there was a dose-response in both relationships. Dyslipidemia progression increased with higher abdominal obesity dietary pattern scores. In addition, VFI played a partial mediating role in relationship between abdominal obesity dietary pattern and dyslipidemia.

The impact of cold spells on schizophrenia admissions and the synergistic effect with the air quality index.

OBJECTIVES: Under current global climate conditions, there are insufficient studies on the health influences of cold spells, especially on mental health. This study aimed to examine the effect of cold spells on schizophrenia admissions and to analyze the potential interaction effect with the air quality index (AQI). METHODS: Daily data on schizophrenia admissions and climatic variables in Hefei were collected from 2013 to 2019. Based on 20 definitions, the impacts of cold spells were quantified separately to find the most appropriate definition for the region, and meta-regression was used to explore the different effect sizes of the different days in a cold spell event. In addition, the potential interaction effect was tested by introducing a categorical variable, CSH, reflecting the cold spell and AQI level. RESULTS: The cold spell defined by temperature below the 6th centile while lasting for at least three days produced the optimum model fit performance. In general, the risk of schizophrenia admissions increased on cold spell days. The largest single-day effect occurred on the 12th day with RR = 1.081 (95% CI: 1.044, 1.118). In a single cold spell event, the effect of the 3rd and subsequent days of a cold spell (RR = 1.082, 95% CI: 1.036, 1.130) was higher than that on the 2nd day (RR = 1.054, 95% CI: 1.024, 1.085). Similarly, the effect of the 2nd day was also higher than that of the 1st day (RR = 1.027, 95% CI: 1.012, 1.042). We found a synergistic effect between cold spells and high AQI in the male group, and the relative excess risk due to interaction (RERI) was 0.018 (95% CI: 0.005-0.030). CONCLUSIONS: This study suggested that the impacts of cold spells should be considered based on the definition of the most appropriate for the region when formulating targeted measures of schizophrenia. The discovery of the synergistic effect was referred to help the selection of the timing of precautions for susceptible people.

MOF Structure Engineering to Synthesize CoNC Catalyst with Richer Accessible Active Sites for Enhanced Oxygen Reduction.

Single-atom cobalt-based CoNC are promising low-cost electrocatalysts for oxygen reduction reaction (ORR). However, further increasing the single cobalt-based active sites and the ORR activity remain a major challenge. Herein, an acetate (OAc) assisted metal-organic framework (MOF) structure-engineering strategy is developed to synthesize hierarchical accordion-like MOF with higher loading amount and better spatial isolation of Co and much higher yield when compared with widely reported polyhedron MOF. After pyrolysis, the accordion-structured CoNC (CoNC (A)) is loaded with denser CoN4 active sites (Co: 2.88 wt%), approximately twice that of Co in the CoNC reported. The presence of OAc in MOF also induces the generation of big pores (5-50 nm) for improving the accessibility of active sites and mass transfer during catalytic reactions. Consequently, the CoNC (A) catalyst shows an admirable ORR activity with a E1/2 of 0.89 V (40 mV better than Pt/C) in alkaline electrolytes, outstanding durability, and absolute tolerance to methanol in both alkaline and acidic media. The CoNC-based Zn-air battery exhibits a high specific capacity (976 mAh g-1 Zn ), power density (158 mW cm-2 ), rate capability, and long-term stability. This work demonstrates a reliable approach to construct single atom doped carbon catalysts with denser accessible active sites through MOF structure engineering.

A novel nonenzymatic ascorbic acid electrochemical sensor based on gold nanoparticals-chicken egg white-copper phosphate-graphene oxide hybrid nanoflowers.

Au-CEW-Cu3(PO4)2-GO nanoflowers (HNFs), which were assembled of gold nanoparticals (Au NPs), chicken egg white (CEW), copper phosphate (Cu3(PO4)2) and graphene oxide (GO) together to form a flower-like organic/inorganic hybrid nanocomposite, were synthesized through a simple and gentle one-pot co-precipitation method. The prepared samples were well characterized by scanning electron microscope, transmission electron microscope, energy dispersive x-ray spectrometer, x-ray diffraction and Raman spectrometer. The prepared Au-CEW-Cu3(PO4)2-GO HNFs was used to modify glassy carbon electrode to fabricate an electrochemical sensor for detection of ascorbic acid (AA). The electrochemical test results show that the linear range of the developed sensor is 8-300µM and the detection limit is 2.67µM (S/N = 3). While this sensor displays high sensitivity of 6.01 × 10-3µAµM-1cm-2and low detection potential of 35 mV due to the combination of the high conductivity of Au NPs, the larger specific surface area of GO and the intrinsic electrocatalytic activity of CEW-Cu3(PO4)2HNFs. Moreover, the Au-CEW-Cu3(PO4)2-GO HNFs-based sensor was successfully developed for application in electrochemical detection of AA in vitamin C tablets.

Association between cold spells and childhood asthma in Hefei, an analysis based on different definitions and characteristics.

BACKGROUND: As the global climate continues to warm, there is an increased focus on heat, but the role of low temperatures on health has been overlooked, especially for developing countries. Methods We collected the admission data of childhood asthma in 2013-2016 from Anhui Provincial Children's Hospital, as well as meteorological data from the Meteorological Bureau for the study period and collected data of pollutants from 10 monitoring stations around Hefei city. Poisson's generalized additive model (GAM) combined with a distributed lag non-linear model (DLNM) was used to estimate the short-term effects of cold spell on childhood asthma in cold seasons (November to March). 16 definitions of cold spells were clearly compared, which combining 4 temperature indexes (daily minimum and mean temperature; daily minimum and mean apparent temperature), 2 temperature thresholds (2.5th and 5th) and 3 durations of at least 2-4 days. We then have an analysis of the modifying effect of characteristics of cold spells and individuals(gender and age), with a view to discovering the susceptible population to cold spell. Results There was significant association between cold spells and admission risk for childhood asthma. And the definition, in which daily minimum apparent temperature falls below 5th percentile for at least 3 consecutive days, produced the optimum model fit performance. Based on this optimal fit we found that, for the total population, the effect of cold spell lasted approximately five days (lag1-lag5), with the largest effect occurring in lag 3 (RR = 1.110; 95% CI: 1.052-1.170). In subgroup analysis, the cumulative effect of lag0-7 was higher in males and school-age children than in females and other age groups, respectively. In addition, we found that the effect of is higher as the duration increases. Conclusion This study suggests an association between cold spell and childhood asthma, and minimum AT may be a better indicator to define the cold spells. Boys and school-age children are more vulnerable to cold spell. And one of our very interesting findings is that if a cold spell lasts for several days, the impact of the cold spell on those later days is likely to be greater than that of the previous days. In conclusion, we should pay more attention to the protection of boys and school-aged children in our future public health protection and give more attention to those cold spells that last longer. Therefore, we recommend that schools and health authorities need to take targeted measures to reduce the risk of asthma in children during the cold spell.

Efficient terahertz polarization conversion with hybrid coupling of chiral metamaterial.

We propose an ultrathin terahertz waveplate of bi-layer chiral metamaterial for cross-polarization conversion at asymmetric transmission. The chiral metamaterial is constructed with hybrid coupling plasmonic resonators of a concentric ring and a double-split ring. The terahertz metamaterial can efficiently convert the ${y}$y-polarized wave into the ${x}$x-polarized wave with the cross-polarized transmittance over 97% and the polarization conversion ratio of 99% in simulation. The asymmetric transmission parameter, defined by the difference between two opposite propagating transmittances, can be as high as 0.9. The operation frequency and efficiency are geometrically adjustable with the ring size by exploiting the hybrid coupling effect of electric and magnetic resonances. The presented metamaterial enables the functionality of the nonreciprocal terahertz waveplate with high isolation.

Super terahertz phase shifter achieving high transmission and large modulation depth.

We propose an industrial-grade liquid-crystal-based terahertz (THz) 2π-phase shifter with predictable ultra-high amplitude transmittance. The phase retardation reaches 360.5° at 1.68 THz by analyzing the birefringence of liquid crystal (LC), and the amplitude transmittance in 0.3-1.5 THz is over 83%. More than 91.5% transmittance can be reached by decreasing the scattering of the THz wave in the dynamic deflection process of LC molecules, and that is close to the transmittance limit of quartz-based devices. This millimeter-thick phase shifter reaches full phase modulation and ultra-high transmittance in a broad THz band, is easy to be integrated in a quasi-optical system with a compact size and can be utilized as a wave plate, even an element in a THz phased array.

Human adenovirus Coinfection aggravates the severity of Mycoplasma pneumoniae pneumonia in children.

BACKGROUND: Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of community-acquired pneumonia (CAP) in children. The coinfection rate of M. pneumoniae pneumonia (MPP) can reach 52% in some areas, but the effects of coinfection with different pathogens have not been clearly recognized. METHODS: The cases of MPP hospitalized in Beijing Children's Hospital from 1/1/2014 to 12/31/2016 were screened. MPP patients coinfected with Human adenovirus (HAdV) were categorized into the research group. Patients with single M. pneumoniae infection were categorized into the control group, matching the research group by age and admission time with a ratio of 1:3. Clinical manifestations, laboratory examinations, and disease severity were compared between these two groups. RESULTS: A total of 2540 hospitalized MPP cases were screened in Beijing Children's Hospital, among which thirty cases were enrolled in the research group and ninety cases were enrolled in the control group. The results indicated that patients in the research group had longer hospital stays, longer fever durations and a higher rate of dyspnea, as well as a larger proportion applications of oxygen therapy and noninvasive continuous positive airway pressure (NCPAP). No obvious differences were found in lab examinations within the two groups. Regarding disease severity, the proportions of extremely severe pneumonia and severe disease defined by the clinical score system were higher in the research group than in the control group. CONCLUSION: Compared with single M. pneumoniae infection, MPP coinfected with HAdV in children was relatively more serious.

Overexpression of CmSOS1 confers waterlogging tolerance in Chrysanthemum.

The Na+ /H+ antiporter SOS1 enhances the salinity tolerance of a number of plant species, but its involvement in the response to hypoxia is less well known. We presented chrysanthemum homologs CmSOS1 and CmRCD1 coordinately mediate waterlogging tolerance by maintaining membrane integrity and minimizing the level of reactive oxygen species.

Synthesis and coloration of highly dispersive SiO2/BiVO4 hybrid pigments with low cost and high NIR reflectance.

Highly dispersed SiO2/BiVO4 hybrid pigments with a spherical structure and high near-infrared (NIR) reflectance have been successfully fabricated by a facile sol-gel method followed by calcination. The dispersed and uniformly spherical particles of the hybrid pigments were caused by the support provided by SiO2 microspheres, and their color was adjusted via the band-gap energy, which was changed with the incorporation of SiO2 microspheres. The SiO2/BiVO4-3 hybrid pigment presented higher yellow hues (b* = 91.42) and more dispersed spherical particles than other as-prepared hybrid pigments and commercially available BiVO4-based yellow pigment. This strategy could save 72 wt% resource of BiVO4 while yielding the same amount of yellow pigment with high color performance. Therefore, the prepared hybrid pigments not only dramatically decreased the cost of expensive pigments, but also saved scarce resources and reduced environmental pollution. In addition, the SiO2/BiVO4-3 hybrid pigment also presented high NIR reflective performance, which demonstrated that it would be a favorable candidate for colorful NIR reflective pigments with wide applications in heat insulation.

Ambient concentrations of NO2 and hospital admissions for schizophrenia.

OBJECTIVES: Schizophrenia is a chronic and severe mental disorder affecting more than 21 million people worldwide. Short-term exposure to nitrogen dioxide (NO2) has been associated with hospital admissions (HAs) for mental disorders, but no study has evaluated the specific association of NO2 and schizophrenia. Additionally, the shape of the concentration-response (C-R) curve has not yet been assessed at present. This study aims to investigate the relationship between short-term exposure to NO2 and HAs for schizophrenia in Hefei, from 2014 to 2016. We also attempt to explore the C-R and the underlying effect modifiers of the association. METHODS: Daily number of HAs for schizophrenia was derived from the computerised medical record system of Anhui Mental Health Center. We used a time-series Poisson generalised linear regression combined with distributed lag non-linear models to model the NO2-schizophrenia relationship. RESULTS: A total of 11 373 HAs were identified during the study period. An increase in levels of NO2 was significantly associated with elevated schizophrenia HAs. The estimated relative risk per IQR increase in NO2 at lag 01 was 1.10 (95% CI 1.01 to 1.18). Greater association was observed in young patients (relative risk: 1.11, 95% CI 1.02 to 1.19). The modelled C-R curves of the NO2-schizophrenia relationship suggested possible threshold effects of NO2 for all ages combined, young patients, men and both seasons. CONCLUSIONS: Short-term exposure to NO2 may be associated with increased schizophrenia HAs. Findings indicated potential threshold effects of NO2, which has important implications for health-based risk assessments.

Risk effects of high and low relative humidity on allergic rhinitis: Time series study.

BACKGROUND: The relationship between environmental factors and allergic rhinitis (AR) has become a focal point recently. However, few studies have investigated the adverse effects of both high relative humidity (RH) and low relative humidity. Moreover, the laged effect and disease burden of RH on AR were also neglected. OBJECTIVES: To explore the association of both high and low RH on daily AR hospital outpatients, and to quantify the corresponding disease burden attributable to RH. METHODS: In our study, we define 95th as high RH and 5th as low RH. A distributed lag non-linear model (DLNM) combined with a Poisson generalized linear regression model were applied to analyze the relationship between RH and hospital outpatients for AR. All patients were retrieved from Anhui Provincial Children's Hospital (n = 37,221) from January 2015 to December 2016. Daily meteorological and air pollutant data were collected by Hefei Meteorological Bureau and Environmental Protection Agency. Subgroup analyses were conducted by gender and occupational groups. RESULTS: Acute adverse effects of high and low RH on AR were explored respectively, with an increase of daily AR outpatients when encountered high and low RH. The low RH presented a risk effect at current day and lasted up to the eighth day. However, high RH began to appear a risk effect on the fourth day. Notably, the fraction of hospital outpatients attributable to low RH was 5.22% (95% CI: 1.92%, 8.33%) and high RH was 4.07% (95% CI: 1.13%, 7.30%) in the backward perspective. Additionally, male and students apparent to be more sensitive to the effects of low RH. CONCLUSION: This study suggests that both high and low RH are potential trigger for AR hospital outpatients in Hefei, China. Our studies might offer valuable messages to health practitioners and useful direction to decisions-makers respectively.

Engineering phase transformation of cobalt selenide in carbon cages and the phases' bifunctional electrocatalytic activity for water splitting.

Using Co-based metal-organic frameworks as the precursor, we synthesized cobalt selenide (CoSe2) nanoparticles imbedded in carbon cages. By simply controlling the annealing conditions, phase transformation of CoSe2 from the orthorhombic phase to the cubic phase has been realized. Benefitting from the metallic character, the cubic phase CoSe2 shows greatly enhanced electrocatalytic activity for both the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). The as-prepared cubic phase CoSe2 electrode possesses onset overpotentials of 43 and 200 mV, and Tafel slopes of 51 and 83 mV dec-1 for HER and OER, respectively, which are remarkably superior to that of the orthorhombic phase CoSe2 catalyst and comparable to those of commercial noble-metal catalysts. In addition, the cubic phase CoSe2 electrode also demonstrates excellent stability after long-term operations. Our work not only provides a high performance catalyst for water splitting, but also introduces a new route to the design of a highly efficient catalyst by phase transformation.

Transcriptomic analysis of differentially expressed genes in the floral transition of the summer flowering chrysanthemum.

BACKGROUND: Chrysanthemum is a leading cut flower species. Most conventional cultivars flower during the fall, but the Chrysanthemum morifolium 'Yuuka' flowers during the summer, thereby filling a gap in the market. To date, investigations of flowering time determination have largely focused on fall-flowering types. Little is known about molecular basis of flowering time in the summer-flowering chrysanthemum. Here, the genome-wide transcriptome of 'Yuuka' was acquired using RNA-Seq technology, with a view to shedding light on the molecular basis of the shift to reproductive growth as induced by variation in the photoperiod. RESULTS: Two sequencing libraries were prepared from the apical meristem and leaves of plants exposed to short days, three from plants exposed to long days and one from plants sampled before any photoperiod treatment was imposed. From the ~316 million clean reads obtained, 115,300 Unigenes were assembled. In total 70,860 annotated sequences were identified by reference to various databases. A number of transcription factors and genes involved in flowering pathways were found to be differentially transcribed. Under short days, genes acting in the photoperiod and gibberellin pathways might accelerate flowering, while under long days, the trehalose-6-phosphate and sugar signaling pathways might be promoted, while the phytochrome B pathway might block flowering. The differential transcription of eight of the differentially transcribed genes was successfully validated using quantitative real time PCR. CONCLUSIONS: A transcriptome analysis of the summer-flowering cultivar 'Yuuka' has been described, along with a global analysis of floral transition under various daylengths. The large number of differentially transcribed genes identified confirmed the complexity of the regulatory machinery underlying floral transition.

Variation in tissue Na(+) content and the activity of SOS1 genes among two species and two related genera of Chrysanthemum.

BACKGROUND: Chrysanthemum, a leading ornamental species, does not tolerate salinity stress, although some of its related species do. The current level of understanding regarding the mechanisms underlying salinity tolerance in this botanical group is still limited. RESULTS: A comparison of the physiological responses to salinity stress was made between Chrysanthemum morifolium 'Jinba' and its more tolerant relatives Crossostephium chinense, Artemisia japonica and Chrysanthemum crassum. The stress induced a higher accumulation of Na(+) and more reduction of K(+) in C. morifolium than in C. chinense, C. crassum and A. japonica, which also showed higher K(+)/Na(+) ratio. Homologs of an Na(+)/H(+) antiporter (SOS1) were isolated from each species. The gene carried by the tolerant plants were more strongly induced by salt stress than those carried by the non-tolerant ones. When expressed heterologously, they also conferred a greater degree of tolerance to a yeast mutant lacking Na(+)-pumping ATPase and plasma membrane Na(+)/H(+) antiporter activity. The data suggested that the products of AjSOS1, CrcSOS1 and CcSOS1 functioned more effectively as Na (+) excluders than those of CmSOS1. Over expression of four SOS1s improves the salinity tolerance of transgenic plants and the overexpressing plants of SOS1s from salt tolerant plants were more tolerant than that from salt sensitive plants. In addition, the importance of certain AjSOS1 residues for effective ion transport activity and salinity tolerance was established by site-directed mutagenesis and heterologous expression in yeast. CONCLUSIONS: AjSOS1, CrcSOS1 and CcSOS1 have potential as transgenes for enhancing salinity tolerance. Some of the mutations identified here may offer opportunities to better understand the mechanistic basis of salinity tolerance in the chrysanthemum complex.

A transcriptomic analysis of Chrysanthemum nankingense provides insights into the basis of low temperature tolerance.

BACKGROUND: A major constraint affecting the quality and productivity of chrysanthemum is the unusual period of low temperature occurring during early spring, late autumn, and winter. Yet, there has been no systematic investigation on the genes underlying the response to low temperature in chrysanthemum. Herein, we used RNA-Seq platform to characterize the transcriptomic response to low temperature by comparing different transcriptome of Chrysanthemum nankingense plants and subjecting them to a period of sub-zero temperature, with or without a prior low temperature acclimation. RESULTS: Six separate RNA-Seq libraries were generated from the RNA samples of leaves and stems from six different temperature treatments, including one cold acclimation (CA), two freezing treatments without prior CA, two freezing treatments with prior CA and the control. At least seven million clean reads were obtained from each library. Over 77% of the reads could be mapped to sets of C. nankingense unigenes established previously. The differentially transcribed genes (DTGs) were identified as low temperature sensing and signalling genes, transcription factors, functional proteins associated with the abiotic response, and low temperature-responsive genes involved in post-transcriptional regulation. The differential transcription of 15 DTGs was validated using quantitative RT-PCR. CONCLUSIONS: The large number of DTGs identified in this study, confirmed the complexity of the regulatory machinery involved in the processes of low temperature acclimation and low temperature/freezing tolerance.