Prediction of watermelon quality based on vibration spectrum

Judging watermelon quality based on its apparent properties such as size or skin color is difficult. A non-destructive method is employed here, based on vibrational response spectrum, to determine the quality indices of watermelon (Charleston gray). The responses of samples to vibration excitation were recorded by laser Doppler vibrometry (LDV). The phase shift between input and output signals were extracted over a wide frequency range. The total soluble solids (TSS), titratable acidity (TA) and TSS/TA ratio also measured as watermelon quality characters. Stepwise multiple linear regression (SMLR) as well as partial least square regression (PLS) was applied to extracted vibration spectrums to construct prediction models of watermelon quality. The results showed that performance of SMLR models were better than PLS. The determination coefficients (R²) of SMLR validation models were 0.9976, 0.9985 and 0.9542 for TSS, TA and TSS/TA respectively. It is likely that reduction of cell wall materials to soluble solids during ripening process changes viscoelastic properties of watermelon reflected by vibrational response. This study demonstrated the feasibility of mentioned method for predicting the quality of watermelons in an industrial grading system.     

Experimental osteoarthritis in the rabbit. III. Acute osteoarthritis: subchondral P02 and oxygen consumption and diffusion capacity in the synovial membrane

The earliest sign of osteoarthritis is acute synovitis with joint effusion and elevated intraarticular pressure, which causes compression of the intracapsular vein segments draining the epiphyseal bone compartment. The increased outflow resistance may cause a fall in the regional blood flow and thereby lead to a state of tissue hypoxia. The acute osteoarthritis may also affect the transfer of oxygen to the cartilage across synovial membrane because of the extensive inflammation with hypercellularity and edema.In the present study we have investigated the subchondral P₀₂ and P_c02 in acute osteoarthritis. There was no significant difference between these gas tensions in the normal and osteoarthritic bone. We have also investigated the oxygen consumption and diffusion capacity in the synovial membrane. The latter was decreased by a factor of 4 in the osteoarthritic joints whilst the oxygen consumption was increased by a factor of 3.     

QuEChERS-超高效液相色谱-质谱联用法测定熊胆粉中9种苯二氮䓬类药物残留量

建立了超高效液相色谱-质谱联用法(UPLC-MS/MS)快速测定中药材熊胆粉中9种苯二氮?类药物残留的方法。样品以乙腈为提取溶剂,经萃取盐包除杂提取,采用分散式固相萃取管 (EMR-Lipid dSPE) 净化,ACQUITY BEH C18色谱柱(1.7 μm,2.1×100 mm)分离,多反应监测模式(MRM)采集数据,外标法定量。在优化的条件下,虽9种药物存在不同程度的基质效应,但不影响检测结果的准确性。方法学考察结果显示,9种苯二氮?类药物在对应的浓度范围内线性关系良好,决定系数(R²)≥0.9961,方法检出限(LOD,S/N =3)在0.06～0.71 μg/kg范围内,定量限(LOQ,S/N =10)在0.20～2.60 μg/kg范围内,3个加标水平的平均回收率在69.1%～108.0%范围内,日内RSD为1.8%～9.0%,日间RSD为2.6%～9.3%。该方法前处理操作简便、重现性好,准确度高,为熊胆粉中苯二氮?类药物残留的风险监控提供了一种有效的检测技术。     

广东康禾自然保护区植物区系研究

根据对保护区的植被调查,分析了该保护区的植物区系、生活型谱和植被类型,结果显示该保护区植物区系组成以泛热带和热带亚洲成分最为丰富,各占30.5%和13.8%;生活型谱以高位芽植物占绝对优势,但比例略低于近纬度带的阴那山等地区;植被类型主要为亚热带常绿阔叶林,但因人为破坏较严重,现有植被主要为次生性较强的常绿阔叶林和针阔叶混交林。     

山地植物群落生物多样性与生物生产力海拔梯度变化研究进展

文中从生物学谱中群落和生态系统尺度，根据国内外的野外观测文献，总结了山地植被在群落生物多样性和生物生产力2方面的海拔梯度变化特征，以及群落生物生产力与生物多样性的关系，并提出目前该领域研究的几个热点问题。     

超早强大体积混凝土的温控防裂

论述了对大体积混凝土的原材料,通过优化配合比设计、提高混凝土设计等级、选用适当外加剂、增设导流管等技术措施和先进的施工工艺,并结合测温加强养护,可以解决大体积混凝土施工中的温度裂缝问题。     

红树植物地面反射光谱特征研究

结合使用野外便携式光谱仪对九龙江口红树林保护区白骨壤、秋茄、桐花树3种红树植物的叶冠表观光谱的测量结果,系统分析比较了红树植物叶冠反射光谱特征及其差异;并在一个潮间带底质遥感信息处理平台上对研究地点进行基于表观光谱特征的白骨壤和秋茄的SPOT卫星遥感图像分类;最后讨论了红树光谱研究中存在的问题。     

三羟鹅膏毒肽的反相高效液相色谱分离纯化

用反相高效液相色谱法,以0.02mol醋酸铵-乙腈为流动相和梯度洗脱模式,从灰花纹鹅膏菌中分离纯化出三羟鹅膏毒肽(amanin),产品纯度达96%以上,三羟鹅膏毒肽的分子量为903.3.     

Slash pine (Pinus elliottii Engelm.) somatic embryogenesis I. Initiation of embryogenic cultures from immature zygotic embryos

Immature female gametophytes and enclosed zygotic embryos of slash pine (Pinus elliottii Engelm.) collected at various developmental stages were cultured either on eight initiation media supplemented with different plant growth regulator (PGR) combinations or on LPM medium solidified with two brands of agar. Embryonal-suspensor cell masses extruded from gametophyte explants infrequently produced white or translucent mucilaginous embryogenic cultures. Variation in extrusion frequency was observed across seed sources (families), explant collection dates, agar types and culture media. Increased explant maturity (as related to collection dates) reduced cell extrusion rates. Four types of extrusions were grouped according to their morphology. One type of extrusion produced the greatest number of established and long-surviving embryogenic cultures. This extrusion type (type I) was associated with an extrusion condition termed empty in which the entirety of the embryonal-suspensor mass was extruded out of the gametophyte. Three other extrusion types (types II, III and IV) showed less culture establishment and survival.     

基于标准森林单位的中国乔木林资源物量核算方法与应用

森林资源核算是森林资源管理的基础，森林资源是数量与质量的统一体，全面的森林资源实物量核算应该综合考虑数量和质量2个方面。文中提出森林资源物量这一概念作为森林资源数量与质量的融合，进一步提出以“标准森林单位”为核算森林资源物量的基本单位，通过将质量参差不齐的各种森林折算为标准森林单位来核算森林资源物量；最后，基于中国第7和第8次全国森林资源连续清查乔木林省域汇总数据进行了试算。结果显示:乔木林资源物量最高的省份为黑龙江、内蒙古、云南等，最低的省份为上海、天津、宁夏等；第7和第8次森林资源清查间隔期间乔木林资源物量增幅最高的省份为江苏、天津、北京等，物量出现下降的为湖南和江西；根据森林资源清查各省份汇总数据计算的乔木林资源物量之和与根据全国汇总数据计算的乔木林资源物量相差不大，表明我们所建立的乔木林资源物量核算体系具有较强的一致性与稳定性。