No abstract

No abstract

Human dental pulp stem cells (hDPSCs) show significant potential for exploitation in novel regeneration strategies, although lack of understanding of their responses to bacterial challenge constrains their application. The present study aimed to investigate whether lipopolysaccharide (LPS), the major pathogenic factor of Gram-negative bacteria, regulates the differentiation of hDPSCs and which intracellular signaling pathways may be involved. LPS treatment significantly promoted the differentiation of hDPSCs demonstrable by increased mineralized nodule formation and mRNA expression of several odontoblastic markers in a dose-dependent manner. While inhibition of TLR4, p38, and ERK signaling markedly antagonized LPS-mediated differentiation of hDPSCs. The inhibition of JNK and NF-κB signaling had no detectable effect on LPS activation of hDPSCs. LPS stimulation resulted in phosphorylation of NF-κB p65, IκB-α, extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (MAPK) in DPSCs in a time-dependent manner, which was markedly suppressed by their specific inhibitors, respectively. Data demonstrated that LPS promoted odontoblastic differentiation of hDPSCs via TLR4, ERK, and P38 MAPK signaling pathways, but not NF-κB signaling.

No abstract

Sensitive and accurate rotation sensing is a critical requirement for applications such as inertial navigation [1], north-finding [2], geophysical analysis [3], and tests of general relativity [4]. One effective technique used for rotation sensing is Sagnac interferometry, in which a wave is split, traverses two paths that enclose an area, and then recombined. The resulting interference signal depends on the rotation rate of the system and the area enclosed by the paths [5]. Optical Sagnac interferometers are an important component in present-day navigation systems [6], but suffer from limited sensitivity and stability. Interferometers using matter waves are intrinsically more sensitive and have demonstrated superior gyroscope performance [7-9], but the benefits have not been large enough to offset the substantial increase in apparatus size and complexity that atomic systems require. It has long been hoped that these problems might be overcome using atoms confined in a guiding potential or trap, as opposed to atoms falling in free space [10][11][12]. This allows the atoms to be supported against gravity, so a long measurement time can be achieved without requiring a large drop distance. The guiding potential can also be used to control the trajectory of the atoms, causing them to move in a circular loop that provides the optimum enclosed area for a given linear size [13]. Here we use such an approach to demonstrate a rotation measurement with Earth-rate sensitivity.A small number of trapped-atom Sagnac interferometers have been demonstrated in the past [14-18], but none have been used to make a quantitative rotation measurement. The largest enclosed areas have been achieved using a linear interferometer that is translated along a direction perpendicular to the interferometer axis [19], but this approach may not be well-suited for inertial measurements in a moving vehicle. Here, we demonstrate a true two-dimensional interferometer configuration in which atoms travel in circular trajectories through a static confining potential. We obtain an effective enclosed area of 0.50 mm 2 , compared to areas of 0.20 mm 2 reported by Wu et al.[15] and 0.35 mm 2 recently obtained by the Los Alamos group [18]. Our approach is readily scalable to weaker traps and multiple orbits by the atoms, making larger areas feasible.Another key advance is the use of dual counterpropagating interferometer measurements. Here, two Sagnac interferometers are implemented at the same time in the same trap, with atoms travelling at opposite velocities over the same paths. This technique was developed for free space interferometers [8], and allows the common-mode rejection of interferometric phases from accelerations, laser noise, background fields, and other effects that can mask the rotation signal. The Sagnac effect itself is differential and can be extracted by comparing the two individual measurements. This technique is likely to be essential for any practical rotation-sensing system, but has not previously been demonstrated in a trapped-atom s...