Coordination strategies used in stone knapping

Stone tool‐use and manufacture is seen as an important skill during the evolution of our species and recently there has been increased interest in the understanding of perceptual‐motor abilities underlying this skill. This study provides further information with respect to the motor strategies used during stone knapping. Kinematics of the striking arm were recorded in expert and novice knappers while producing flakes of two different sizes. Using Uncontrolled Manifold Analysis, the results showed that knappers structure joint angle movements such that the hammer trajectory variability is minimized across trials, with experts displaying significantly smaller variability compared with novices. Principal component analysis further revealed that a single component captures the complexity of the strike and that the strike is governed by movements of the elbow and the wrist. Analysis of movement velocities indicated that both groups adjusted movement velocities according to flake size although experts used smaller hammer, wrist, and elbow velocities in both flake conditions compared with novices. The results suggest that while the gross striking movement is easy to replicate for a novice knapper, it requires prolonged training before a knapper becomes attuned to the finer details necessary for controlled flaking. © 2013 Wiley Periodicals, Inc.     

Heat denaturation increases the sensitivity of the cytomegalovirus loop‐mediated isothermal amplification method

A new protocol for CMV LAMP with an additional heat denaturation step was developed. While the sensitivity of the original CMV LAMP method was 500 copies/tube, sensitivity was increased by up to 100 copies/tube by additional heat denaturation. CMV DNA was detected in 103 of 350 samples (29.4%) by the original CMV LAMP procedure and 148 of 350 samples (42.3%) by the new CMV LAMP protocol. When the pp65 antigenemia assay was used as the standard method, the sensitivity, specificity, PPV, and NPV of the new protocol were 92.9%, 77.7%, 62.2%, and 96.5%, respectively.     

Cation exchange chromatography performed in overloaded mode is effective in removing viruses during the manufacturing of monoclonal antibodies

Viral safety is a critical concern with regard to monoclonal antibody (mAb) products produced in mammalian cells such as Chinese hamster ovary cells. Manufacturers are required to ensure the safety of such products by validating the clearance of viruses in downstream purification steps. Cation exchange (CEX) chromatography is widely used in bind/elute mode as a polishing step in mAb purification. However, bind/elute modes require a large volume of expensive resin. To reduce the production cost, the use of CEX chromatography in overloaded mode has recently been investigated. The viral clearance ability in overloaded mode was evaluated using murine leukemia virus (MLV). Even under high-load conditions such as 2,000 g mAb/L resin, MLV was removed from mAb solutions. This viral clearance ability was not significantly affected by resin type or mAb type. The overloaded mode can also remove other types of viruses such as pseudorabies virus and reovirus Type 3 from mAb solutions. Based on these results, this cost-effective overloaded mode is comparable to the bind-elute mode in terms of viral removal.     

Marriage season, promptness of successful pregnancy and first-born sex ratio in a historical natural fertility population – evidence for sex-dependent early pregnancy loss?

 We investigated population-based vital records of the seventeenth and eighteenth century French Canadian population to assess the effects of marriage season on the outcome of the first births under natural fertility conditions (n=21,698 marriages). Promptness of the first successful conception after marriage differed according to marriage season; the proportion of marriages with a marriage-first birth interval of 8.0–10.0 months was lowest (34%) for marriages in August–October (P=0.001). Although the male/female sex ratio of the babies born with an interval of 8.0–10.0 months was generally higher (1.10) than those with an interval of 10.0–24.0 months (1.05), the marriages in August–October resulted in a significantly reduced sex ratio (0.96) among only the prompt conceptions (P=0.026). We discuss whether this seasonal reduction of the sex ratio could be partly explained by a clustered pregnancy loss of male zygotes in early pregnancy. Received: 5 January 1998 / Accepted: 9 September 1998     

Light-sheet microscopy-based 3D single-cell tracking reveals a correlation between cell cycle and the start of endoderm cell internalization in early zebrafish development

Controlling the initiation of cell migration plays a fundamental role in shaping the tissue during embryonic development. During gastrulation in zebrafish, some mesendoderm cells migrate inward to form the endoderm as the innermost germ layer along the yolk syncytial layer. However, how the initiation of inward migration is regulated is poorly understood. In this study, we performed light-sheet microscopy-based 3D single-cell tracking consisting of (a) whole-embryo time-lapse imaging with light-sheet microscopy and (b) three-dimensional single cell tracking in the zebrafish gastrula in which cells are marked with histone H2A-mCherry (nuclei) and the sox17:EGFP transgene (expressed in endoderm cells). We analyzed the correlation between the timing of cell internalization and cell division. Most cells that differentiated into endoderm cells began to internalize during the first half of the cell cycle, where the length of a cell cycle was defined by the period between two successive cell divisions. By contrast, the timing of other internalized cells was not correlated with a certain phase of the cell cycle. These results suggest the possibility that cell differentiation is associated with the relationship between cell cycle progression and the start of internalization. Moreover, the 3D single-cell tracking approach is useful for further investigating how cell migration is integrated with cell proliferation to shape tissues in zebrafish embryos.     

The prevention of an anomalous chromatographic behavior and the resulting successful removal of viruses from monoclonal antibody with an asymmetric charge distribution by using a membrane adsorber in highly efficient,anion-exchange chromatography in flow-through mode

Anion exchange (AEX) chromatography in the flow-through mode is a widely employed purification process for removal of process/product-related impurities and exogenous/endogenous viruses from monoclonal antibodies (mAbs). The pH of the mobile phase for AEX chromatography is typically set at half a unit below the isoelectric point (pI) of each mAb (i.e., pI − 0.5) or lower and, in combination with a low ionic strength, these conditions are usually satisfactory for both the recovery of the mAb and removal of impurities. However, we have recently encountered a tight binding of mAb1 to AEX resins under these standard chromatographic conditions. This anomalous adsorption behavior appears to be an effect of the asymmetric charge distribution on the surface of the mAb1. We found that mAb1 did not bind to the AEX resins if the mobile phase has a much lower pH and higher ionic strength, but those conditions would not allow adequate virus removal. We predicted that the use of membrane adsorbers might provide effective mAb1 purification, since the supporting matrix has a network structure that would be less susceptible to interactions with the asymmetric charge distribution on the protein surface. We tested the Natriflo HD-Q AEX membrane adsorber under standard chromatographic conditions and found that mAb1 flowed through the membrane adsorber, resulting in successful separation from murine leukemia virus. This AEX membrane adsorber is expected to be useful for process development because mAbs can be purified under similar standard chromatographic conditions regardless of their charge distributions.     

Genetic study on the mandibular molar size of rats

Tooth size is determined by genetic and environmental factors like other quantitative characters such as body weight and body height. However, the degree of the relative contribution of both factors to the determination of tooth size has not been well clarified. In order to study the genetic and environmental factors affecting tooth size, we carried out a diallel cross mating by the cohabitation of pairs of males and females among 10 strains of rats. The bucco-lingual widths of the first, second, and third molars of the right mandible were measured in each offspring of F1 population. The body weight was also measured as a parameter that might indicate systemic growth factor in connection with tooth development. The quantitative genetic analysis was performed based on Wearden's model (Heredity 19:669-680, 1964). As a result, the size of the first and the second molars was more significantly controlled by genetic effect than maternal effect, while maternal effect could not be ignored for the size of the third molar in addition to genetic effect. The genetic effect on body weight became greater with age, while the maternal effect showed its maximum influence upon the body weight around the weaning. It is concluded that the size of the molar teeth beginning to develop in the uterus and to be calcified just after birth was mainly controlled by genetic factor, and that the size of the molar teeth beginning to develop approximately after birth was mainly controlled by maternal effect affecting body weight at the same period.