花椰菜雄性不育系组培快繁及无糖培养技术

以花椰菜雄性不育亲本的花球为外植体,进行组培快繁及无糖生产技术的研究。结果表明：在MS＋BA 1.0 mg/L＋NAA 0.3 mg/L的培养基上诱导,25 d时不定芽的分化率达到96%,继代增殖在MS＋BA 0.6 mg/L＋NAA 0.1 mg/L的培养基效果最好,增殖率可达4.25倍。无糖组织培养的培养基为MS无机成分＋NAA 0.1,光照4 000 lx,CO2浓度1 000 mL/L,11 d可大量生根。通过上述方法,1个花球,在4个月可生产上万株组培苗,是一种高效快速的方法。     

SD5切丝机烟叶切丝工艺的优化

[目的]探索SD5切丝机最佳烟叶切丝加工参数,为提高烟叶切丝质量提供科学依据.[方法]分别对SD5切丝机的刀门压力、刀辊转速、修正系数、排链比速等因素进行优化,探讨其对烟叶切丝合格率的影响.[结果]刀门压力与切丝合格率相关,且呈—元线性关系;刀辊转速与切丝合格率关系显著,且呈一元二次关系;修正系数明显影响切丝合格率;排链比速与切丝合格率关系显著,呈一元二次关系;切丝合格率影响因素的主次顺序为：刀辊转速＞刀门压力＞排链比速＞修正系数.当刀辊转速为289 r/min、刀门压力为0.252 MPa、排链比速为0.9、修正系数为1.01时,切丝合格率达96.3％,可满足工艺要求.[结论]SD5切丝机设置不同参数,对切丝合格率有明显的影响.烟叶在切丝加工时对切丝机的各关键设备参数进行合理设置、有效控制,可达到稳定和提高切丝合格率的目的.     

二甲硝咪唑及其代谢物在猪体内的消除规律

建立了应用HPLC法测定二甲硝咪唑（DMZ）在猪组织中残留的方法。在猪肌肉、肝脏、肾脏、脂肪等组织中添加高、中、低不同量的二甲硝咪唑，HPLC测定的回收率均在80％以上，变异系数在10％以内。肌肉、肝脏、肾脏的最低检测限为10μg/kg，脂肪为50μg/kg。同时研究了二甲硝咪唑在猪组织中残留的消除规律。试验结果认为，二甲硝咪唑在猪体内很快地转变为2－羟甲基硝基咪唑（DMZOH），DMZOH是其主要代谢物。以300、600mg/kg的剂量连续内服5d，停药48h后各组织中均检测不到DMZ及DMZOH。     

Antioxidant properties of carnosine re-evaluated in a ferrylmyoglobin model system and in cooked pork patties

The antioxidative effect of purified carnosine (i.e., separated from the common contaminant hydrazine) has been evaluated in two systems: (i) Carnosine was found to possess poor reducing properties toward the prooxidant ferrylmyoglobin; at pH approximately 5 the presence of carnosine did not increase the rate of reduction of MbFe(IV)=O compared to autoreduction, whereas at pH 7.4 the rate constant for reduction by carnosine was 0.010 +/- 0.002 M(-1).s(-1) (I = 0.16; 25.0 degrees C). (ii) In cooked pork patties prepared from meat (longissimus dorsi and masseter) with purified or nonpurified carnosine added, the effect of purified carnosine was insignificant when compared to control patties, whereas patties with carnosine contaminated with hydrazine had a lower oxidation level than patties with purified carnosine. Carnosine is concluded not to deactivate the prooxidant ferrylmyoglobin and not to have any antioxidative effect in cooked pork.     

Protein binding in deactivation of ferrylmyoglobin by chlorogenate and ascorbate

Kinetics of reduction of iron(IV) in ferrylmyoglobin by chlorogenate in neutral or moderately acidic aqueous solutions (0.16 M NaCl) to yield metmyoglobin was studied using stopped flow absorption spectroscopy. The reaction occurs by direct bimolecular electron transfer with (2.7 +/- 0.3) x 10(3) M(-)(1).s(-)(1) at 25.0 degrees C (DeltaH( )(#) = 59 +/- 6 kJ.mol(-)(1), DeltaS(#) = 15 +/- 22 J. mol(-)(1).K(-)(1)) for protonated ferrylmyoglobin (pK(a) = 4.95) and with 216 +/- 50 M(-)(1).s(-)(1) (DeltaH( )(#) = 73 +/- 8 kJ. mol(-)(1), DeltaS( )(#) = 41 +/- 30 J.mol(-)(1).K(-)(1)) for nonprotonated ferrylmyoglobin in parallel with reduction of a chlorogenate/ferrylmyoglobin complex by a second chlorogenate molecule with (8.6 +/- 1.1) x 10(2) M(-)(1).s(-)(1) (DeltaH( )(#) = 74 +/- 8 kJ.mol(-)(1), DeltaS( )(#) = 59 +/- 28 J.mol(-)(1).K(-)(1)) for protonated ferrylmyoglobin and with 61 +/- 9 M(-)(1).s(-)(1) (DeltaH( )(#) = 82 +/- 12 kJ.mol(-)(1), DeltaS( )(#) = 63 +/- 41 J. mol(-)(1).K(-)(1)) for nonprotonated ferrylmyoglobin. Previously published data on ascorbate reduction of ferrylmyoglobin are reevaluated according to a similar mechanism. For both protonated and nonprotonated ferrylmyoglobin the binding constant of chlorogenate is approximately 300 M(-)(1), and the modulation of ferrylmyoglobin as an oxidant by chlorogenate (or ascorbate) leads to a novel antioxidant interaction for reduction of ferrylmyoglobin by ascorbate in mixtures with chlorogenate.     

Penny ice cap cores, baffin island, canada, and the wisconsinan foxe dome connection: two states of hudson bay ice cover

Ice cores from Penny Ice Cap, Baffin Island, Canada, provide continuous Holocene records of oxygen isotopic composition (delta18O, proxy for temperature) and atmospheric impurities. A time scale was established with the use of altered seasonal variations, some volcanic horizons, and the age for the end of the Wisconsin ice age determined from the GRIP and GISP2 ice cores. There is pre-Holocene ice near the bed. The change in delta18O since the last glacial maximum (LGM) is at least 12.5 per mil, compared with an expected value of 7 per mil, suggesting that LGM ice originated at the much higher elevations of the then existing Foxe Dome and Foxe Ridge of the Laurentide Ice Sheet. The LGM delta18O values suggest thick ice frozen to the bed of Hudson Bay.     

Synchronized Terrestrial-Atmospheric Deglacial Records Around the North Atlantic

On the basis of synchronization of three carbon-14 (14C)-dated lacustrine sequences from Sweden with tree ring and ice core records, the absolute age of the Younger Dryas-Preboreal climatic shift was determined to be 11,450 to 11,390 +/- 80 years before the present. A 150-year-long cooling in the early Preboreal, associated with rising Delta14C values, is evident in all records and indicates an ocean ventilation change. This cooling is similar to earlier deglacial coolings, and box-model calculations suggest that they all may have been the result of increased freshwater forcing that inhibited the strength of the North Atlantic heat conveyor, although the Younger Dryas may have begun as an anomalous meltwater event.     

Effect of information on attitudes towards offshore marine finfish aquaculture development in northern New England

Abstract

Social science can make important contributions to understanding the prospects for offshore marine aquaculture development because many of the potential barriers that may restrict its development are social and institutional rather than biological or technical. This study collects baseline data on attitudes towards offshore marine aquaculture held by a key stakeholder group. It also investigates the influence of information on attitudes towards marine aquaculture. Data reported in this study were collected from visitors to a seafood festival in coastal New Hampshire. The formal objectives of this research were to determine what effect, if any, two‐sided information on the potential advantages and disadvantages of marine aquaculture has on attitudes towards marine aquaculture and how prior familiarity with aquaculture moderates the effect of information. The findings from this study indicate that two‐sided information has a negative effect on attitudes, especially among individuals who are unsure of their level of familiarity with the issue.     

商服用地及其细分用途基准地价评估研究

随着中国城镇土地使用制度改革的不断深化和土地市场的不断发展,基准地价精细化管理已是客观现实需求。在分析了商服用地用途细分必要性的基础上,提出了商服用地及其细分用途用地区片价及级别基准地价评估的总体思路与方法。通过具体案例,系统地研究了商服用地用途细分、细分用途基准地价评估的具体过程,以期为细分用途基准地价体系建设提供思路,满足当前土地市场管理及评估的需要。