213 research outputs found
AN INVENTORY CONTROL POLICY WITH TRACKING INFORMATION FOR DUAL-CHANNEL SUPPLY CHAINS
Recently, many products have been sold through retail stores and direct sales via the Internet. For dual-channel supply chains, Chiang and Monahan (2010) and Chiang (2010) have proposed an inventory control policy; however, they assumed one-for-one replenishment and short replenishment lead times. For single-channel supply chains with long and uncertain replenishment lead times, Liu et al. (2009) have introduced tracking information into inventory control. However, they did not consider the cost of tracking information. Therefore, in this paper, a Markov chain model for dual-channel supply chains with long and uncertain replenishment lead times is developed, and an inventory control policy is proposed that considers tracking information and its cost. The performance of the proposed policy is evaluated and compared with two policies, one without tracking information and the other without reduplicated normal replenishment. The results show the effectiveness of the proposed policy
Spatially resolved metabolic distribution for unraveling the physiological change and responses in tomato fruit using matrix-assisted laser desorption/ionizationāmass spectrometry imaging (MALDIāMSI)
Information on spatiotemporal metabolic behavior is indispensable for a precise understanding of physiological changes and responses, including those of ripening processes and wounding stress, in fruit, but such information is still limited. Here, we visualized the spatial distribution of metabolites within tissue sections of tomato (Solanum lycopersicum L.) fruit using a matrix-assisted laser desorption/ionizationāmass spectrometry imaging (MALDIāMSI) technique combined with a matrix sublimation/recrystallization method. This technique elucidated the unique distribution patterns of more than 30 metabolite-derived ions, including primary and secondary metabolites, simultaneously. To investigate spatiotemporal metabolic alterations during physiological changes at the whole-tissue level, MALDIāMSI was performed using the different ripening phenotypes of mature green and mature red tomato fruits. Although apparent alterations in the localization and intensity of many detected metabolites were not observed between the two tomatoes, the amounts of glutamate and adenosine monophosphate, umami compounds, increased in both mesocarp and locule regions during the ripening process. In contrast, malate, a sour compound, decreased in both regions. MALDIāMSI was also applied to evaluate more local metabolic responses to wounding stress. Accumulations of a glycoalkaloid, tomatine, and a low level of its glycosylated metabolite, esculeoside A, were found in the wound region where cell death had been induced. Their inverse levels were observed in non-wounded regions. Furthermore, the amounts of both compounds differed in the developmental stages. Thus, our MALDIāMSI technique increased the understanding of the physiological changes and responses of tomato fruit through the determination of spatiotemporally resolved metabolic alterations
Topological melting of the metastable skyrmion lattice in the chiral magnet CoZnMn
In a -Mn-type chiral magnet CoZnMn, we demonstrate that
the magnetic field-driven collapse of a room temperature metastable topological
skyrmion lattice passes through a regime described by a partial topological
charge inversion. Using Lorentz transmission electron microscopy, the
magnetization distribution was observed directly as the magnetic field was
swept antiparallel to the original skyrmion core magnetization, i.e. negative
magnetic fields. Due to the topological stability of skyrmions, a direct
transition of the metastable skyrmion lattice to the equilibrium helical state
is avoided for increasingly negative fields. Instead, the metastable skyrmion
lattice gradually transforms into giant magnetic bubbles separated by
domain walls. Eventually these large structures give way to form a
near-homogeneously magnetized medium that unexpectedly hosts a low density of
isolated skyrmions with inverted core magnetization, and thus a total
topological charge of reduced size and opposite sign compared with the initial
state. A similar phenomenon has been observed previously in systems hosting
ordered lattices of magnetic bubbles stabilized by the dipolar interaction and
called "topological melting". With support from numerical calculations, we
argue that the observed regime of partial topological charge inversion has its
origin in the topological protection of the starting metastable skyrmion state.Comment: 9 pages, 4 figure
Purified Mesenchymal Stem Cells Are an Efficient Source for iPS Cell Induction
Induced pluripotent stem (iPS) cells are generated from mouse and human somatic cells by the forced expression of defined transcription factors. Although most somatic cells are capable of acquiring pluripotency with minimal gene transduction, the poor efficiency of cell reprogramming and the uneven quality of iPS cells are still important problems. In particular, the choice of cell type most suitable for inducing high-quality iPS cells remains unclear.Here, we generated iPS cells from PDGFRĪ±+ Sca-1+ (PĪ±S) adult mouse mesenchymal stem cells (MSCs) and PDGFRĪ±ā» Sca-1ā» osteo-progenitors (OP cells), and compared the induction efficiency and quality of individual iPS clones. MSCs had a higher reprogramming efficiency compared with OP cells and Tail Tip Fibroblasts (TTFs). The iPS cells induced from MSCs by Oct3/4, Sox2, and Klf4 appeared to be the closest equivalent to ES cells by DNA microarray gene profile and germline-transmission efficiency.Our findings suggest that a purified source of undifferentiated cells from adult tissue can produce high-quality iPS cells. In this context, prospectively enriched MSCs are a promising candidate for the efficient generation of high-quality iPS cells
Calaxin is required for cilia-driven determination of vertebrate laterality
Sasaki, K., Shiba, K., Nakamura, A. et al. Calaxin is required for cilia-driven determination of vertebrate laterality. Commun Biol 2, 226 (2019). https://doi.org/10.1038/s42003-019-0462-
CNVs in Three Psychiatric Disorders
BACKGROUND: We aimed to determine the similarities and differences in the roles of genic and regulatory copy number variations (CNVs) in bipolar disorder (BD), schizophrenia (SCZ), and autism spectrum disorder (ASD).
METHODS: Based on high-resolution CNV data from 8708 Japanese samples, we performed to our knowledge the largest cross-disorder analysis of genic and regulatory CNVs in BD, SCZ, and ASD.
RESULTS: In genic CNVs, we found an increased burden of smaller (500 kb) exonic CNVs in SCZ/ASD. Pathogenic CNVs linked to neurodevelopmental disorders were significantly associated with the risk for each disorder, but BD and SCZ/ASD differed in terms of the effect size (smaller in BD) and subtype distribution of CNVs linked to neurodevelopmental disorders. We identified 3 synaptic genes (DLG2, PCDH15, and ASTN2) as risk factors for BD. Whereas gene set analysis showed that BD-associated pathways were restricted to chromatin biology, SCZ and ASD involved more extensive and similar pathways. Nevertheless, a correlation analysis of gene set results indicated weak but significant pathway similarities between BD and SCZ or ASD (r = 0.25ā0.31). In SCZ and ASD, but not BD, CNVs were significantly enriched in enhancers and promoters in brain tissue.
CONCLUSIONS: BD and SCZ/ASD differ in terms of CNV burden, characteristics of CNVs linked to neurodevelopmental disorders, and regulatory CNVs. On the other hand, they have shared molecular mechanisms, including chromatin biology. The BD risk genes identified here could provide insight into the pathogenesis of BD
- ā¦