Log sawing position optimization using computed tomography scanning

When disjoining a log, several factors affect the value of the sawn timber. There are log features, such as outer shape, knots, rot, and so on. There are also sawing parameters, such as sawing pattern, log position, and so on. If full information about log features is available, sawing parameters can be adapted in order to maximize product value in sawmills. This is soon possible, since computed tomography (CT) scanners for the sawmill industry are being realized. This study aimed at investigating how CT data can be used to choose rotational position, parallel displacement, and skew of sawlogs, to maximize the value of the sawn products. The study was made by sawing simulation of 269 CT scanned logs of Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies [L.] H. Karst.). The results showed that value recovery could be improved by 13% in average, compared to a sawing position based on log outer shape, and 21% compared to sawing logs centered and horns down. It can be concluded that a CT scanner, used in a sawline to optimize sawing parameters, has a large potential for increasing value recovery and thus profit.     

Moisture-related adjustment factor to obtain a reference ultrasonic velocity in structural lumber of plantation hardwood

Wave propagation techniques based on ultrasound for timber grading are influenced by the moisture content (MC) of wood. The ultrasound velocities at an equilibrium MC (V₁₂) and above saturation point (V_sat) were used to calculate moisture-related adjustment factors (k_H). Tests were conducted using plantation hardwoods (Corymbia citriodora, Eucalyptus grandis and Eucalyptus pellita) grown in Brazil. Below the fiber saturation point (FSP), k_H values were between 0.66% and 0.83%, which concurred with intervals proposed in existing literature for softwoods. However, the k_H inferred from the velocities obtained at MCs above the FSP increased (from 10% to 30%) with increasing density. The sound velocity under saturated conditions (V_sat) obtained by adjustment equations was 2–9% lower than the actual V_sat obtained from the tests. The obtained adjustment factors may be useful for the standardization of nondestructive timber grading based on ultrasound propagation.     

叶面喷施有机硅对草地早熟禾幼苗生长的影响

为明确有机硅对草地早熟禾幼苗生长的影响,以草地早熟禾(Poa pratensis L.)品种"午夜"为参试材料,设置7个有机硅肥梯度(0、1、2、2.5、3、4、5 mmol·L~(-1))进行叶面喷施,研究了不同浓度的有机硅对草地早熟禾苗长、苗干重、根长、根干重、根系总长、根系总表面积、根头数、叶片相对电导率及地上部硅含量的影响。结果表明,添加一定浓度的有机硅可以增加草地早熟禾的苗长、苗干重、根长、根干重、根系总长、根系总表面积和根头数,其中施有机硅2.5 mmol·L~(-1)处理表现最佳,显著高于对照,对根系平均直径有促进作用,但不显著;干旱胁迫下喷施有机硅能够减少叶片细胞电解质的渗漏,保持叶片细胞膜的完整性,提高草地早熟禾抗逆性;喷施不同浓度的有机硅均能显著提高草地早熟禾地上部含硅量,其中喷施3 mmol·L~(-1)有机硅制剂含硅量最高。可见,适宜浓度的有机硅显著促进了草地早熟禾的生长。     

西瓜雄性不育两用系雄蕊电镜扫描观察

以雄性不育两用系DT2-3为试材,对其雄蕊发育过程进行了电镜扫描观察。结果表明:不育株和可育株的雄蕊从蕾期开始就表现不同,不育株雄蕊萎缩变小,进一步畸形,横切剖面无花粉粒;可育株雄蕊发育正常,剖面有发育成熟的花粉粒。该研究进一步揭示了雄性不育两用系DT2-3不育株败育的机制。     

DIAGNOSTIC ACCURACY OF GRAY‐SCALE ULTRASONOGRAPHY FOR THE DETECTION OF HEPATIC AND SPLENIC LYMPHOMA IN DOGS

Gray‐scale ultrasonography is often used to screen for involvement of the liver and spleen in canine lymphoma patients but the utility of sonography for staging lymphoma has not been evaluated quantitatively. We performed abdominal sonography in 28 dogs with a confirmed diagnosis of lymphoma. Needle aspirates were obtained for cytology from three separate sites in the liver and three sites in the spleen and the sonographic appearance was noted at each site. Our hypothesis was that in dogs newly diagnosed with lymphoma, abnormal appearance of the liver or spleen on ultrasound examination is an indication that lymphoma is present in that organ. Cytologic evaluation was used as the gold standard. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of hepatic and splenic abnormalities seen on ultrasound for diagnosis of lymphoma were 72.7%, 80.6%, 77.4%, 76.3%, and 76.8% for the liver, respectively, and 100%, 23.3%, 64.6%, 100%, and 68.1% for the spleen, respectively. Based on these results, we recommend that aspirates be performed for detection of lymphoma in the spleen of dogs only when the spleen appears abnormal ultrasonographically and that cytology of the liver be performed, regardless of ultrasonographic appearance, to determine the presence or absence of lymphoma.     

RELATIONSHIP OF PANCREATIC DUCT DILATION TO AGE AND CLINICAL FINDINGS IN CATS

Dilation of the pancreatic duct has been described as an ultrasonographic feature of pancreatitis in cats. The purpose of this study was to determine normal pancreatic duct width in healthy older cats and assess the significance of pancreatic duct dilation observed in a clinical population. In a prospective study, pancreatic ultrasound was performed in 15 healthy cats (mean age 13 +/- 3 years). Mean pancreatic width of left lobe, body, and right lobe was 0.65 +/- 0.16 cm (0.46-1.03 cm), 0.64 +/- 0.14 cm (0.46-0.9 cm), and 0.43 +/- 0.09 cm (0.3-0.57 cm), respectively. Mean pancreatic duct width was 0.13 +/- 0.04 cm (0.06-0.24 cm), which was significantly larger than previously reported for younger cats (0.08 +/- 0.025 cm) (P < 0.001). One hundred and four of 1445 clinical patients (7.2%) were diagnosed with a dilated pancreatic duct and were reviewed in a retrospective study. Incidence of pancreatic duct dilation was significantly higher in older than in younger cats (2.7% in cats < 1-5 years vs. 18.1% in cats 15 years or older; P < 0.001). Mean pancreatic duct width was 0.23 +/- 0.07 cm (0.14-0.52 cm), and there was a significant correlation between age and pancreatic duct width (P = 0.01). There was also a significant relationship between the mean ratio of pancreatic duct width and pancreatic thickness (n = 98) (0.29 +/- 0.09; 0.09-0.58; P = 0.041). There was no significant difference in age between cats with and without pancreatic disease. There was no association between pancreatic disease and pancreatic duct width or pancreatic duct width/pancreatic thickness ratio. Pancreatic duct width and pancreatic duct width/pancreatic thickness ratio in cats are significantly associated with age.     

Histopathological Observations in Guava Root during Wilting caused by Fusarium Species: A Scanning Electron Microscopy Study

Fusarium oxysporum and Fusarium solani are the two most destructive pathogens causing wilt disease in guava (Psidium guajava L.) commonly known as ‘super fruits’. These pathogens attack mainly on the root region of the plant and cause severe infection. In the present investigation the infection process was studied with scanning electron microscopy (SEM) and it was observed that the root region of the guava plant showed disintegration and necrosis in the epidermal layer, cortex tissue, and in vascular bundles, while the root region of a healthy sapling showed no such changes. The rupturing of the epidermal layer may show the entry of pathogens in the host tissue through the secretion of toxic enzymes/metabolites. These toxins have great potential to cause wilting symptoms in guava plants in the form of necrosis. Wilt disease causes huge losses in guava production in both tropical and subtropical countries. Therefore, there is a need to find the responsible factors. The present study is an attempt to understand the interaction mechanism of phyto-pathogens causing wilt disease.     

莲种质花粉形态特征研究

利用扫描电镜对不同来源的31份莲种质的花粉形态进行了观察。研究结果表明:花粉外部形态均呈近球形,赤道面观均为椭圆形,极面观大部分呈三裂圆形,少量种质有近圆形。所有莲种质除都具3条萌发沟外,在5个种质中还首次发现具有散沟的花粉(六沟花粉)。不同种质间花粉形态特征具有差异,尤其是萌发器官和外壁纹饰细部特征的差别,体现了不同莲种质的遗传多样性和遗传分化,可为种质间亲缘关系及系统发育研究提供有价值的依据。     

用显微光度计对不同细胞DNA含量的测定

显微光度计可以直接测量单细胞内核酸、蛋白质和酶的含量,每条染色体的 DNA 量和带数以及免疫反应中结合抗体的定量等。我们用 Univar 显微光度计比较了吸收扫描法和荧光法的效果。实验测定了小麦和大麦根尖细胞、鸡血细胞,镰刀菌孢子和酵母菌不同生长阶段的细胞。结果表明吸收扫描法测定小麦六倍体、四倍体和二倍体 DNA 含量,其比值为3.2:2.1:1。荧光测定酵母菌子囊孢子 DNA 含量(任意值)为462.61,营养细胞为914.38,两个子囊孢子核结合后为925.08。对大细胞(植物)两种方法效果都好。对小细胞(微生物)荧光法较吸收扫描法更为稳定。