Determination of Aromatic Components of Rosa davurica Pall. by Headspace Solid Phase Microextraction Combined with GC-MS

[Objectives] To determine the aromatic components of Rosa davurica Pall. [Methods] 42 kinds of aromatic components were identified from the flowers of R. davurica by headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS). The main compounds were alcohols( 54. 88%) and aldehydes( 19. 55%). [Results] The top five components with the highest relative content were phenylethyl alcohol( 12. 69%),geraniol( 9. 85%),citronellol( 8. 80%),nerol( 7. 84%) and 2-n-pentylfuran( 7. 45%). [Conclusions] Headspace solid phase microextraction( HS-SPME) combined with gas chromatography-mass spectrometry( GC-MS) can provide basis for further development and utilization of R. davurica.

Gas sensors based on TiO_(2) nanostructured materials for the detection of hazardous gases: A review

Hazardous gases have been strongly associated with being a detriment to human life within the environment The development of a reliable gas sensor with high response and selectivity is of great signifcance for detecting different hazardous gases.TiO_(2) nanomaterials are promising candidates with great potential and excellent per-formance in gas sensor applications,such as hydrogen,acetone,ammonia,and ethanol detection.This review begins with a detailed discussion of the di ferent dimensional morphologies of TiO_(2),whitch affect the gas sensing performance of TiO_(2) sensors.The diverse morphologies of TiO_(2) can easily be tuned by regulating the manufacturing conditions.Meanwhile,they exhibit unique characteristics for detecting gases,including large specific suface area,superior elecron tr ansport rates,extraordinary pemmeability,and active reaction sites,which offer new opportunities to improve the gas sensing properties.In addition,a variety of efforts have been made to functional TiO_(2) nanomaterials to further enhance sensing properties,including TiO_(2)-based composites and light-assisted gas sensors.The enhanced gas sensing mechanisms of multi-component composite nano-materials based on TiO_(2) include loaded noble metals,doped elements,constructed heterojunctions,and com-pounded with other functional materials.Finally,several studies have been summarized to demonstate the compar ative sensing properties of TiO_(2)-based gas sensors.

SnO_(2)nanostructured materials used as gas sensors for the detection of hazardous and flammable gases:A review

SnO_(2)has been extensively used in the detection of various gases.As a gas sensing material,SnO_(2)has excellent physical-chemical properties,high reliability,and short adsorption-desorption time.The application of the traditional SnO_(2)gas sensor is limited due to its higher work-temperature,low gas response,and poor selectivity.Nanomaterials can significantly impact gas-sensitive properties due to the quantum size,surface,and small size effects of nanomaterials.By applying nanotechnology to the preparation of SnO_(2),the SnO_(2)nanomaterial-based sensors could show better performance,which greatly expands the application of SnO_(2)gas sensors.In this review,the preparation method of the SnO_(2)nanostructure,the types of gas detected,and the improvements of SnO_(2)gas-sensing performances via elemental modification are introduced as well as the future development of SnO_(2)is discussed.

Effects of Different Seedling Raising Methods on Seedling Growth of Two Kinds of Fritillaria

[Objectives] To reveal the effects of film mulching and open ground seedling raising on the differences between Fritillaria przewalskii Maxim. and Fritillaria pallidiflora Schrenkf., find the optimal seedling raising method, and provide scientific basis for standard seedling raising technique and protecting wild resources of Fritillaria. [Methods] This experiment counted the seedling emergence number and calculated the seedling emergence indicator and the yield. [Results] The results showed that under the condition of film mulching and open ground seedling raising, the changes of Fritillaria seedlings showed an "S" curve, conforming to the Logistic equation, and the rapid growth period appeared 5-13 d after seedling emergence. Compared with the open ground seedling raising, the seedlings of F. przewalskii Maxim. and F. pallidiflora Schrenkf. raised through film mulching emerged 2-4 d earlier, and the yield increased by 56.8% and 21.71%, respectively, and the individual quality was excellent. [Conclusions] The film mulching of F. przewalskii Maxim. and F. pallidiflora Schrenkf. has great significance to protect the wild resources of Fritillaria in Eryin Mountain Area. It is recommended to adopt the film mulching method for Fritillaria seedling raising, to reduce the yield decline due to lodging, and adopt sun-shading net covering after sowing.

Preparation and Photocatalytic Properties of LnBaCo<SUB>2</SUB>O<SUB>5+δ</SUB>(Ln = Eu, Gd, and Sm)

A new type of photocatalytic material, double-perovskite oxides, LnBaCo2O5+δ (Ln = Eu, Gd, and Sm) was synthesized via a conventional solid-state reaction process using Ln2O3, BaCO3 and Co2O3 as raw materials. X-ray diffraction results show that the crystalline structures are a pure orthorhombic lattice and are consistent with LnBaCo2O5+δ microparticles. The photocatalytic activity of the LnBaCo2O5+δ (Ln = Eu, Gd, and Sm) powders was further demonstrated in the degradation of Congo red (CR) under ultraviolet light irradiation with the dye solution concentration of 25 or 50 mg·L-1. The double-perovskite oxides LnBaCo2O5+δ show a certain photocatalytic activity during the degradation of CR under ultraviolet light, which means that they are one kind of the promising photocatalytic materials for the degradation of the azo dyes.

Further evidence for paternal DNA transmission in gynogenetic grass carp

Gynogenesis is an important breeding method in aquaculture and has been widely applied to many fish species.If gynogenetic progenies are to inherit paternal partial genomic DNA,this will increase genetic variation and will provide a useful outcome for breeding.In this study,we investigated the genetic variation in homeobox(Hox)gene clusters(Hox A4 a,Hox A9 a,Hox A11 b,Hox B1 b,Hox C4 a,Hox C6 b,and Hox D10 a)among koi carp(Cyprinus carpio haematopterus,KOC;the stimulation sperm source),grass carp(Ctenopharyngodon idellus),and gynogenetic grass carp(GGC).We found paternal DNA(a special DNA fragment and Hox C6 b)derived from KOC and a recombinant gene belonging to Hox C6 b in GGC.We are the first to report the recombinant Hox C6 b in GGC.Our study provides further evidence for paternal DNA transmission to gynogenetic progenies,which is a finding with great significance for the genetic breeding of fish.

An improved hybrid bream derived from a hybrid lineage of Megalobrama amblycephala(♀)×Culter alburnus(♂)

Distant hybridization is an important technique in fish genetic breeding.In this study,based on the establishment of an allodiploid fish lineage(BT,2n=48,F_(1)–F_(6))derived from distant hybridization between female Megalobrama amblycephala(BSB,2n=48)and male Culter alburnus(TC,2n=48),and the backcross progeny(BTB,2n=48)derived by backcrossing female F_(1) of BT to male BSB,an improved hybrid bream(BTBB,2n=48)was obtained by backcrossing BTB(♀)to BSB(♂).Moreover,the morphological and genetic characteristics of BTBB individuals were investigated;BTBB was similar to BSB in appearance but had a higher body height than BSB.The study results regarding chromosome numbers and DNA content indicated that BTBB is a diploid hybrid fish.The 5S rDNA and Hox gene of BTBB were inherited from the original parents.Gonadal development in BTBB was normal.On the other hand,BTBB had a faster growth rate,higher muscle protein level,and lower muscle carbohydrate level than BSB.Hence,bisexual fertile BTBB is promoted and can be applied as a high-quality fish,and it can also be used as a new fish germplasm resource to develop high-quality fish further.Thus,this study is of great significance for fish genetic breeding.