High adsorption selectivity of activated carbon and carbon molecular sieve boosting CO_(2)/N_(2) and CH_(4)/N_(2) separation

Flue gas and coal bed methane are two important sources of greenhouse gases.Pressure swing adsorption process has a wide range of application in the field of gas separation,and the selection of adsorbent is crucial.In this regard,in order to assess the better adsorbent for separating CO_(2) from flue gas and CH_(4) from coal bed methane,adsorption isotherms of CO_(2),CH_(4) and N_(2) on activated carbon and carbon molecular sieve are measured at 303.15,318.15 and 333.15 K,and up to 250 kPa.The experimental data fit better with Langmuir 2 compared to Langmuir 3 and Langmuir-Freundlich models,and Clausius-Clapeyron equation was used to calculate the isosteric heat.Both the order of the adsorbed amount and the adsorption heat on the two adsorbents are CO_(2)>CH_(4)>N_(2).The adsorption kinetics are calculated by the pseudo-first kinetic model,and the order of adsorption rates on activated carbon is N_(2)-CH_(4)>CO_(2),while on carbon molecular sieve,it is CO_(2)-N_(2)>CH_(4).It is shown that relative molecular mass and adsorption heat are the primary effect on kinetics for activated carbon,while kinetic diameter is the main resistance factor for carbon molecular sieve.Moreover,the adsorption selectivity of CH_(4)/N_(2) and CO_(2)/N_(2) were estimated with the ideal adsorption solution theory,and carbon molecular sieve performed best at 318.15 K for both CO_(2) and CH_(4) separation.The study suggested that activated carbon is a better choice for separating flue gas and carbon molecular sieve can be a strong candidate for separating coal bed methane.

Influence of alkali metal doping on surface properties and catalytic activity/selectivity of CaO catalysts in oxidative coupling of methane

Surface properties （viz. surface area, basicity/base strength distribution, and crystal phases） of alkali metal doped CaO （alkali metal/Ca= 0.1 and 0.4） catalysts and their catalytic activity/selectivity in oxidative coupling of methane （OCM） to higher hydrocarbons at different reaction conditions （viz. temperature, 700 and 750 ℃; CH4/O2 ratio, 4.0 and 8.0 and space velocity, 5140-20550 cm^3 ·g^-1·h^-1） have been investigated. The influence of catalyst calcination temperature on the activity/selectivity has also been investigated. The surface properties （viz. surface area, basicity/base strength distribution） and catalytic activity/selectivity of the alkali metal doped CaO catalysts are strongly influenced by the alkali metal promoter and its concentration in the alkali metal doped CaO catalysts. An addition of alkali metal promoter to CaO results in a large decrease in the surface area but a large increase in the surface basicity （strong basic sites） and the C2＋ selectivity and yield of the catalysts in the OCM process. The activity and selectivity are strongly influenced by the catalyst calcination temperature. No direct relationship between surface basicity and catalytic activity/selectivity has been observed. Among the alkali metal doped CaO catalysts, Na-CaO （Na/Ca = 0.1, before calcination） catalyst （calcined at 750 ℃）, showed best performance （C2＋ selectivity of 68.8% with 24.7% methane conversion）, whereas the poorest performance was shown by the Rb-CaO catalyst in the OCM process.

Enhancement of bimetallic Fe-Mn/CNTs nano catalyst activity and product selectivity using microemulsion technique

Bimetallic Fe-Mn nano catalysts supported on carbon nanotubes(CNTs) were prepared using microemulsion technique with water-to-surfactant ratios of 0.4-1.6. The nano catalysts were extensively characterized by different methods and their activity and selectivity in Fischer-Tropsch synthesis(FTS) have been assessed in a fixed-bed microreactor. The physicochemical properties and performance of the nanocatalysts were compared with the catalyst prepared by impregnation method. Very narrow particle size distribution has been produced by the microemulsion technique at relatively high loading of active metal. TEM images showed that small metal nano particles in the range of 3–7 nm were not only confined inside the CNTs but also located on the outer surface of the CNTs. Using microemulsion technique with water to surfactant ratio of0.4 decreased the average iron particle sizes to 5.1 nm. The reduction percentage and dispersion percentage were almost doubled. Activity and selectivity were found to be dependent on the catalyst preparation method and average iron particle size. CO conversion and FTS rate increased from 49.1% to 71.0% and 0.144 to 0.289 gHC/(gcat h), respectively. While the WGS rate decreased from 0.097 to 0.056 gCO2/(gcat h). C5+liquid hydrocarbons selectivity decreased slightly and olefins selectivity almost doubled.

Developmental Lead Exposure Alters the Distribution of Protein Kinase C Activity in the Rat Hippocampus

Chronic low-level lead (Pb) exposure in children is known to cause a deficit in learning and memory. In vitro studies have demonstrated that Pb altered protein kinase C (PKC) activityt Especially, hippocampal PKC has been correlated with performance in several learning tasks. The effects of Pb exposure on hippocampal PKC were investigated during development at various postnatal ages: postnatal day (PN) 7, 14, 28, and 56. Two-tenth % Pb acetate was administered to pregnant and lactating dams and then administered to weanling rats in drinking water. PKC activity was measured in both membrane and cytosolic fractions from the hippocampi of the controls and Pb-exposed animals. Pb-induced increase in PKC activity in the cytosolic fraction was obsereved in the PN56 rats. In contrast, PKC activity was decreased by Pb at PN7 in the membrane fraction. Furthermore, a significant decrease in the ratio of membrane to cytosolic PKC activity which is representative of PKC distribution was observed in the PN28 and PN56 Pb-exposed rats relative to the same-age controls. This study indicates that chronic Pb exposure during development influences hippocampal PKC activity and distribution. These changes may be involved in the subclinical neurotoxicity of chronic Pb exposure in young children.

Carbon‐based metal‐free catalysts for electrochemical CO2 reduction: Activity, selectivity, and stability

Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 reduction(eCO2R)to value‐added fuels and chemicals by using renewable electricity provides a cleaner and more sustainable route with economic benefits,in which the key is to develop clean and economical electrocatalysts.Carbon‐based catalyst materials possess desirable properties such as high offset potential for H2 evolution and chemical stability at the negative applied potential.Although it is still challenging to achieve highly efficient carbon‐based catalysts,considerable efforts have been devoted to overcoming the low selectivity,activity,and stability.Here,we summarize and discuss the recent progress in carbon‐based metal‐free catalysts including carbon nanotubes,carbon nanofibers,carbon nanoribbons,graphene,carbon nitride,and diamonds with an emphasis on their activity,product selectivity,and stability.In addition,the key challenges and future potential approaches for efficient eCO2R to low carbon‐based fuels are highlighted.For a good understanding of the whole history of the development of eCO2R,the CO2 reduction reactions,principles,and techniques including the role of electrolytes,electrochemical cell design and evaluation,product selectivity,and structural composition are also discussed.The metal/metal oxides decorated with carbon‐based electrocatalysts are also summarized.We aim to provide insights for further development of carbon‐based metal‐free electrocatalysts for CO2 reduction from the perspective of both fundamental understanding and technological applications in the future.

Influence of surface strain on activity and selectivity of Pd-based catalysts for the hydrogenation of acetylene: A DFT study

The effects of surface strain and subsurface promoters, which are both important factors in heterogeneous catalysis, on catalytic selectivity and activity of Pd are examined in this study by considering the selective hydrogenation of acetylene as an example. Combined density functional theory calculations and microkinetic modeling reveal that the selectivity and activity of the Pd catalyst for acetylene hydrogenation can both be substantially influenced by the effects of Pd lattice strain variation and subsurface carbon species formation on the adsorption properties of the reactants and products. It is found that the adsorption energies of the reactants and products are, in general, linearly scaled with the lattice strain for both pristine and subsurface carbon atom-modified Pd（111） surfaces, except for the adsorption of C_2H_2 over Pd（111）-C. The activity for ethylene formation typically corresponds to the region of strong reactants adsorption in the volcano curve; such an effect of lattice strain and the presence of subsurface promoters can improve the activity of the catalyst through the weakening of the adsorption of reactants. The activity and selectivity for Pd（111）-C are always higher than those for the pristine Pd（111） surfaces with respect to ethylene formation. Based on the results obtained, Pd-based catalysts with shrinking lattice constants are suggested as good candidates for the selective hydrogenation of acetylene. A similar approach can be used to facilitate the future design of novel heterogeneous catalysts.

The Measurement of Membrane Potential and NO3 Activity in Root Cells Using Ion-Selective Microelectrodes

Remobilisation of nitrate in plants, especially in vacuole of plant, is mostly related to the qua- lity of agricultural products and the high nitrogen use efficiency in plants. Ion-selective microelectrodes offer a non-destructive and non-interruptive method to measure NO 3 gradients and electric potential differences across both the plasma membrane and tonoplast. Thus, a double-barrelled microelectrode backfilled with a membrane sensor for NO 3 embedded in poly vinyl chloride (PVC) can record the NO 3 activity in cytoplasm and vacuole of a cell. This paper presented how to make this kind of microelectrode and how to do the intracellular measurements on intact plants. Our result showed that nitrate activity was about 2.7 mmol L 1 in cytoplasm while 70 mmol L 1 in vacuole, which implicated that vacuole was a pool of nitrate in plants.

Chronic Immune Activation and Sexual Exposure among HIV Serodiscordant Couples in Senegal

Purpose: In Sub-Saharan Africa, an important proportion of incident HIV cases occur among heterosexual serodiscordant couples (HSDC) but the majority of HIV negative partners can remain seronegative. These are called HIV-exposed seronegative (HESN). We aimed to compare immune activation (IA) levels between HESN, their HIV infected counterparts (HIV+ partners) and HIV unexposed uninfected individuals (HIV-neg Controls) and to evaluate the association between sexual exposure to HIV (SEHIV) and IA. Methods: We conducted a cross-sectional study in Dakar, Senegal on 148 participants recruited between November 2013 and February 2014: 40 HIV-neg Controls, 54 HESN and 54 HIV+ Partners. SEHIV was evaluated individually using questionnaires. IA level was measured by plasma level of β2-microglobulin (β2m). Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for the different associations. Results: The median levels of β2m were 1.57 mg/l (IQR: 1.37 - 1.77), 2.14 mg/l (IQR: 1.76 - 2.43) and 2.24 mg/l (IQR: 1.80 - 3.17) for HIV-neg Controls, HESN and HIV+ partners, respectively. After adjustment, HESN had similar levels of IA with HIV+ partners but significantly higher than that of HIV-neg Controls (adjusted OR = 6.28;95% CI: [2.19 - 18.00]). The association between IA and SEHIV was evaluated in the HIV negative individuals. High frequency of SEHIV was associated with a β2m > 2.2 mg/l (OR = 6.56;95% CI: [1.71 - 25.21]);significantly more than median cut off value of >1.81 mg/l. Conclusions: Our study shows that, despite being uninfected with HIV, HESN individuals show a high level of IA, which was depended on the level of SEHIV.

Effect of N+ Beam Exposure on Superoxide Dismutase and Catalase Activities and Induction of Mn-SOD in Deinococcus Radiodurans

Though bacteria of the radiation-resistant Deinococcus radiodurans have a high resistance to the lethal and mutagenic effects of many DNA-damaging agents, the mechanisms involved in the response of these bacteria to oxidative stress are poorly understood. In this report, the superoxide dismutase (SOD) and catalase (CAT) activities produced by these bacteria were measured, and the change of SOD and CAT activities by 20 keV N+ beam exposure was examined. Their activities were increased by N+ beam exposure from 8x 1014 ions/cm2 to 6x1015 ions/cm2.The treatment of H2O2 and [ CHC13 +CH3 CH2OH ] and the measurement of absorption spectrum showed that the increase in SOD activity was resulted from inducible activities of MnSOD in D. radiodurans AS1.633 by N+ beam exposure . These results suggested that this bacteria possess inducible defense mechanisms against the deleterious effects of oxidization.

Hemoglobin Adducts as Biomarkers of Exposure to and metabolic Activation of Carcinogenic Tobacco-Specific Nitrosamines

The carcinogenic tobacco-specific nitrosamines N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-l-(3-pyridyl)-l-butanone (NNK) form hemoglobin adducts in laboratory animals and humans. These adducts release 4-hydroxy-l-(3-pyridyl)-l-butanone (HPB) upon mild base hydrolysis. HPB released from human hemoglobin can be quantified by gas chromatography-mass spectrometry. It is the only available biochemical marker for determination of exposure to, and metabolic activation of, carcinogens present only in tobacco. Levels of HPB were highest in snuff-dippers, followed by smokers and nonsmokers. Large interindividual variations in adduct levels were observed. The relationship between HPB levels in globin and DNA of rats treated with NNK has been investigated in order to aid in interpretation of the data from humans. These studies have provided the initial database for understanding the metabolic activation of tobacco-specific nitrosamines in humans.

Environmental correlates of sedentary behaviors and physical activity in Chinese preschool children:A cross-sectional study

Objective:This cross-sectional study examined environmental correlates of sedentary behavior(SB) and physical activity(PA) in preschool children in the urban area of Tianjin,China.Methods:Data were collected from the Physical Activity and Health in Tianjin Chinese Children study,involving healthy children 3-6 years old and their families.In all children(n=980),leisure-time SB(LTSB) and leisure-time PA(LTPA) were reported in min/day by parents.In a subgroup(n=134),overall sedentary time,light PA,and moderate-to-vigorous PA(MVP A) were objectively measured using ActiGraph accelerometry(>3 days,>10 h/day).Environmental correlates were collected using a questionnaire that included home and neighborhood characteristics(e.g.,traffic safety,presence of physical activity facilities) and children’s behaviors.Potential correlates were identified using linear regression analysis.Results:Multiple linear regression analysis showed that "having grandparents as primary caregivers"(βs and 95% confidence intervals(95%CIs)for overall sedentary time:29.7(2.1-57.2);LTSB(In):0.19(0.11-0.28)) and "having a television(for LTSB(In):0.13(0.00-0.25)) or computer(for LTSB(ln):0.13(0.03-0.23) in the child’ s bedroom" were both associated with higher SB.Furthermore, "having grandparents as primary caregivers" was associated with less MVPA(β(95%CI):-7.6(-14.1 to-1.2)),and "active commuting to school by walking" correlated with more MVPA(β(95%CI):9.8(2.2-17.4)).The path model showed that "more neighborhood PA facilities close to home" was indirectly related to higher LTPA(In),which was partly mediated by "outdoor play"(path coefficients(95%CI):0.005(0.002-0.008)) and "going to these facilities more often"(path coefficients(95%CI):0.013(0.008-0.01 8)).Traffic safety was not a correlate.Conclusion:Family structure and media exposure in the home maybe important factors in shaping preschoolers’ PA patterns.Built environmental correlates could indirectly influence preschoolers’ LTPA through parental help with engaging in active behaviors.

Effects of surface physicochemical properties on NH_3-SCR activity of MnO_2 catalysts with different crystal structures

α‐,β‐,δ‐,andγ‐MnO2nanocrystals are successfully prepared.We then evaluated the NH3selective catalytic reduction(SCR)performance of the MnO2catalysts with different phases.The NOx conversion efficiency decreased in the order:γ‐MnO2>α‐MnO2>δ‐MnO2>β‐MnO2.The NOx conversion with the use ofγ‐MnO2andα‐MnO2catalysts reached90%in the temperature range of140–200°C,while that based onβ‐MnO2reached only40%at200°C.Theγ‐MnO2andα‐MnO2nanowire crystal morphologies enabled good dispersion of the catalysts and resulted in a relatively high specific surface area.We found thatγ‐MnO2andα‐MnO2possessed stronger reducing abilities and more and stronger acidic sites than the other catalysts.In addition,more chemisorbed oxygen existed on the surface of theγ‐MnO2andα‐MnO2catalysts.Theγ‐MnO2andα‐MnO2catalysts showed excellent performance in the low‐temperature SCR of NO to N2with NH3.

Biochemical Changes Associated with Long Term Exposure to Pesticide among Farmers in the Gaza Strip

The study characterized the biochemical changes associated with long term exposure to pesticides. Practical parameters of pesticides were collected using 500 questionnaires. Farmers having 10 years working period were invited to a private clinic for blood sampling and enzyme analysis. All participants were male farmers of different age groups, and education levels. Occupational parameters indicated that majority of farmers used manual methods for pesticide works. About 130 pesticides are currently used in Gaza. Toxicological symptoms indicated that dizziness, headache, and nausea were dominant among farmers, whereas vomiting abdominal colic and tearing were less dominant. Acetyl Cholinesterase (ACHE) cumulatively inhibited among farmers after work whereas Alanine Aminotransferase (ALT), Aspartate Aminotransferase (AST) and Alkaline Phosphatase (ALP) activities were above range after long term exposure. It can be concluded that long term exposure to pesticides may damage liver and kidney cells resulting in hepatic-toxicity and/or nephrotoxicity.

Effective exposure of nitrogen heteroatoms in 3D porous graphene framework for oxygen reduction reaction and lithium–sulfur batteries

The introduction of nitrogen heteroatoms into carbon materials is a facile and efficient strategy to regulate their reactivities and facilitate their potential applications in energy conversion and storage. However,most of nitrogen heteroatoms are doped into the bulk phase of carbon without site selectivity, which significantly reduces the contacts of feedstocks with the active dopants in a conductive scaffold. Herein we proposed the chemical vapor deposition of a nitrogen-doped graphene skin on the 3D porous graphene framework and donated the carbon/carbon composite as surface N-doped grapheme（SNG）. In contrast with routine N-doped graphene framework（NGF） with bulk distribution of N heteroatoms, the SNG renders a high surface N content of 1.81 at%, enhanced electrical conductivity of 31 S cm^（-1）, a large surface area of 1531 m^2 g^（-1）, a low defect density with a low I_D/I_G ratio of 1.55 calculated from Raman spectrum, and a high oxidation peak of 532.7 ℃ in oxygen atmosphere. The selective distribution of N heteroatoms on the surface of SNG affords the effective exposure of active sites at the interfaces of the electrode/electrolyte, so that more N heteroatoms are able to contact with oxygen feedstocks in oxygen reduction reaction or serve as polysulfide anchoring sites to retard the shuttle of polysulfides in a lithium–sulfur battery. This work opens a fresh viewpoint on the manipulation of active site distribution in a conductive scaffolds for multi-electron redox reaction based energy conversion and storage.

Effects of Vanadium Oxidation Number on Light Olefins Selectivity of FCC Catalyst

Effects of vanadium on light olefins selectivity of FCC catalysts were investigated with vanadium having different oxidation numbers （hereinafter abbreviated as Oxnum）. Molecular modeling studies showed that vanadium with low Oxnum could affect the chemical conversion of large-size hydrocarbon molecules. However, the vanadium deposited on equilibrium catalyst bad high Oxnum because of the oxidation reaction taking place in the regenerator, so an activation method to reduce vanadium Oxnum named ＂selective activation＂ was introduced. It was proved by means of Electron Paramagnetic Resonance （EPR） and Temperature-Programmed Reduction （TPR） methods that the vanadium Oxnum was decreased, when the catalyst was activated. The molecular modeling studies are consistent well with the lab evaluation results. The light olefins selectivity of activated equilibrium catalysts was better than that achieved by the inactivated catalysts. Similar results were observed with the lab vanadium-contaminated catalyst. The light olefins selectivity of the catalyst was optimized when the vanadium Oxnum was close to 2 （VO）.

Comparison of the Activity Differences in Two Terminal Oxidases between Upland Cotton and Sea-island Cotton

[Objective] This study was to reveal the differences in two terminal oxdiases,so as to provide theoretical basis for the selection of upland and sea-land hybrid materials. [Methods] Using 7 shares of upland cotton cultivars and 4 shares of sea-land cultivars as experimental materials,the change differences in AAO and PPO activities during whole growth period of the materials tested were studied. [Results] Two terminal oxdiases both in upland and sea-land cotton cultivars assumed similar change laws during whole growth period. AAO activity assumed a low-high trend,and there is a peak at the early stage. PPO activity presented two peaks,and that at the early stage was higher than at the late stage; the first peak is obviously higher than the second for sea-land cultivars,and two peaks are not remarkably different for upland cultivars. [Conclusion] The differences in AAO and PPO activities of sea-land and upland cotton cultivars observed on Jul.4th and Aug.6th,may provide guidance for the selection of upland and sea-land hybrids.

Engineering Geological Assessment for Route Selection of Railway Line in Geologically Active Area:A Case Study in China

The Cheng-Lan railway links Chengdu, a central city in Southwestern China, and Lanzhou, a central city in Northwestern China. The railway passes through the Longmenshan fault zone (Wenchuan earthquake happened there on May 12, 2008), Minjiang fault zone, and Dongkunlun fault zone, which are all active. It runs over the Yangtze River and the Yellow River, and crosses high mountains and deep valleys. There exists, along the railway's alignment, different kinds of strata of hard granite and soft, weak metamorphic rocks such as carbonaceous slate, schist, and phyllite. It is, therefore, a key issue for such an infrastructure construction to assess the engineering geological conditions and risks, so as to mitigate or avoid possible georisks and to offer optional designs. Geological survey and georisk assessment along the railway corridor are carried out. Special attention is given to active faults, earthquakes and seismic zones. Based on these, discussions about geological aspects for route selection of the railway are conducted and countermeasures for georisk control are proposed accordingly. Main conclusions are achieved as follows: (1) Geohazards such as landslides, rockfalls and debries flows dominate both the route selection of the railway and the engineering structures (e.g., tunnels or bridges) adopted; (2) Tunnel has been proved to be an excellent structure for linear engineering in geologically active area; and (3) In the case where avoiding is impractical, necessary protection measures should be taken to engineering slopes in high earthquake intensity areas, especially the area with earthquake of Ms. 8 or greater.

Low-Temperature Denitrification Performance of Cu2O/Activated Carbon Catalysts for Selective Catalytic Reduction of NOx by CO

To improve the denitrification performance of carbon-based materials for sintering flue gas,we prepared a composite catalyst comprising coconut shell activated carbon(AC)modified by thermal oxidation air.The microstructure,the specific surface area,the pore volume,the crystal structure,and functional groups presented in the prepared Cu2O/AC catalysts were thoroughly characterized.By using scanning electron microscopy(SEM),nitrogen adsorption/desorption isotherms,Fourier-transform infrared(FTIR)spectroscopy and X-ray diffractometry(XRD),the effects of Cu2O loading and calcination temperature on Cu2O/AC catalysts were investigated at low temperature(150℃).The research shows that Cu on the Cu2O/AC catalyst is in the form of Cu2O with good crystalline performance and is spherical and uniformly dispersed on the AC surface.The loading of Cu2O increases the active sites and the specific surface area of the reaction gas contact,which is conducive to the rapid progress of the carbon monoxide selective catalytic reduction(CO-SCR)reaction.When the loading of Cu2O was 8%and the calcination temperature was 500℃,the removal rate of NOx facilitated by the Cu2O/AC catalyst reached 97.9%.These findings provide a theoretical basis for understanding the denitrification of sintering flue gas.

Effects of an immunosuppressive active component of Periplocae Cortex (Periploca sepium Bge.) on positive selection of thymocytes in vitro

Objective:To determine the effect of an immunosuppressive active component (periploside A) isolated from the stem bark of Periplocae Cortex (Periploca sepium Bge.),a Chinese medicinal herb used in the treatment of rheumatoid arthritis for centuries in China,on positive selection of thymocytes in vitro.Methods:Female C57BL/6 mice at 6 weeks of age were housed in specific pathogen-free conditions.Double-positive thymocytes from C57BL/6 mice were induced into positive selection in vitro with or without periploside A treatment.Cell viability and expression of CD69,CD4,and CD8 were analyzed by flow cytometry.Results:Flow cytometric examination of thymocyte populations revealed that the percentage of CD8+ single-positive thymocytes was decreased by periploside A upon differentiation induced by an anti-CD3 antibody.However,the percentage of CD4+ single-positive thymocytes was decreased by periploside A upon differentiation induced by phorbol 12-myristate 13-acetate/ionomycin.Expression of CD69 plays a major role in prohibiting differentiation of thymocytes.Treatment with periploside A decreased CD69 expression in thymocytes.Conclusion:These results demonstrate that periploside A influences positive selection of thymocytes in vitro.

Neurotoxicity of prenatal alcohol exposure on medullary pre-B?tzinger complex neurons in neonatal rats

Prenatal alcohol exposure disrupts the development of normal fetal respiratory function, but whether it perturbs respiratory rhythmical discharge activity is unclear. Furthermore, it is unknown whether the 5-hydroxytryptamine 2A receptor（5-HT2AR） is involved in the effects of prenatal alcohol exposure. In the present study, pregnant female rats received drinking water containing alcohol at concentrations of 0%, 1%, 2%, 4%, 8% or 10%（v/v） throughout the gestation period. Slices of the medulla from 2-day-old neonatal rats were obtained to record respiratory rhythmical discharge activity. 5-HT2 AR protein and m RNA levels in the pre-B？tzinger complex of the respiratory center were measured by western blot analysis and quantitative RT-PCR, respectively. Compared with the 0% alcohol group, respiratory rhythmical discharge activity in medullary slices in the 4%, 8% and 10% alcohol groups was decreased, and the reduction was greatest in the 8% alcohol group. Respiratory rhythmical discharge activity in the 10% alcohol group was irregular. Thus, 8% was the most effective alcohol concentration at attenuating respiratory rhythmical discharge activity. These findings suggest that prenatal alcohol exposure attenuates respiratory rhythmical discharge activity in neonatal rats by downregulating 5-HT2 AR protein and m RNA levels.