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Although a substantial number of hormones and drugs increase cellular cAMP levels, the global impact of cAMP and its major effector mechanism, protein kinase A (PKA), on gene expression is not known. Here we show that treatment of murine wild-type S49 lymphoma cells for 24 h with 8-(4-chlorophenylthio)-cAMP (8-CPT-cAMP), a PKA-selective cAMP analog, alters the expression of approximate to 4,500 of approximate to 13,600 unique genes. By contrast, gene expression was unaltered in Kin(-) S49 cells (that lack PKA) incubated with 8-CPT-cAMP. Changes in mRNA and protein expression of several cell-cycle regulators accompanied cAMP-induced G(1)-phase cell-cycle arrest of wild-type S49 cells. Within 2 h, 8-CPT-cAMP altered expression of 152 genes that contain evolutionarily conserved cAMP-response elements within 5 kb of transcriptional start sites, including the circadian clock gene Per1. Thus, cAMP through its activation of PKA produces extensive transcriptional regulation in eukaryotic cells. These transcriptional networks include a primary group of cAMP-response element-containing genes and secondary networks that include the circadian clock.

AlSi10Mg porous alloy was prepared by selective laser melting (SLM) with a Nd:YAG laser beam, and the compression properties were studied using both experiments and the finite element method (FEM). The results illustrate that the porous alloy undergoes elastic deformation, plastic deformation and densification stage. The joints of the porous alloy are preferentially fractured, and the Si content at the bottom position of the dimple is higher than the dimple edge. During the compression process of the porous AlSi10Mg alloy, the stress and strain distribution at the joint are concentrated, resulting in joint fracture. The inherent elasticity, shear stress and forced contact of supporting plates or chips are the causes of these compression stages. The distribution of Si element in the fracture is caused by the dimples that are easily formed at the a-Al/Si interface, eventually resulting in the Si content at the bottom of the dimple being higher than the dimple edge. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aims to explore the expression pattern and clinical significance of circ_001680 in gastric carcinoma (GC) process. PATIENTS AND METHODS: Circ_001680 levels in 40 pairs of GC and paracancerous ones were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The relationship between circ_001680 and GC clinicopathological parameters was analyzed. AGS and SGC-7901 cells were used for constructing circ_001680 knockdown models by shRNA transfection. Proliferative and metastatic abilities in GC cells with circ_001680 knockdown were examined by cell counting kit-8 (CCK-8) and transwell assay, respectively. Dual-Luciferase reporter assay was conducted to clarify the interaction between circ_001680 and MAP2. Their co-regulation on GC process was detected through rescue experiments. RESULTS: Circ_001680 was highly expressed in GC tissues and cell lines. High level of circ_001680 predicted high incidences of lymphatic and distant metastasis, and poor prognosis in GC patients. Knockdown of circ_001680 suppressed proliferative and metastatic abilities in AGS and SGC-7901 cells. MAP2 was the target gene binding circ_001680, which was lowly expressed in GC. In addition, MAP2 was negatively correlated to circ_001680. Knockdown of MAP2 could abolish the suppressed proliferative and metastatic abilities in GC cells with circ_001680 knockdown. CONCLUSIONS: Circ_001680 is highly expressed in GC tissues and closely related to metastasis and prognosis in GC patients, which promotes the proliferative and metastatic abilities in GC cells by negatively interacting with MAP2. [ABSTRACT FROM AUTHOR]

Intermittent adsorption cycles, driven by low temperature heat, like solar heat, instead of electricity or natural gas, can achieve substantial fossil energy savings. In this paper, the mathematical model for the coupled heat and mass transfer in the adsorber of an intermittent adsorption cooling system is set up. The model includes four submodels: heat transfer in heating/cooling fluids, heat transfer in the metal tube, heat transfer in the fins, and heat and mass transfer in the adsorbent. The model for the heat and mass transfer in the adsorbent is a three-dimensional non-equilibrium model which takes into account both the internal and the external mass transfer resistance in the adsorbent. An experiment has been done to validate the model. With some modifications, the model can be used in system optimization and design of adsorption cycles driven by solar energy or waste heat. [C] 2000 Elsevier Science Ltd. All rights reserved.

The polyandrous mating behaviour of the honeybee queen increases the genetic variability amongst her worker offspring and the genetic variability within the honeybee colony can affect their polyethism. In this study, we intend to understand whether there is genetic variability in the task of the queen retinue. MicrosatelliteDNAanalyses revealed a total of 13 and 12 subfamilies in two colonies, respectively. It shows that the subfamily proportion of the queen retinue workers significantly deviated from random distribution, which suggests that they might have a genetic preference in the task of the queen retinue. [ABSTRACT FROM AUTHOR]

Presents information on a study which characterized stain etched porous silicon layers using photoluminescence, electron paramagnetic resonance and infrared absorption spectroscopy. Methods; Results; Discussion.

Presents a study which measured room-temperature photoluminescence spectra using a two-band structure from porous silicon (PS) as a function of excitation wavelengths. Details of experimental techniques used; Assumption of the quantum confinement/luminescence centers model.