Organic-walled microfossils offer important information on the biospheric evolution in pre-Cryogenian and provide biostratigraphic implications for many Proterozoic fossiliferous sequences that are poorly age constrained for the lack of reliable radiometric date. Recently, macroscopic carbonaceous compression fossils have been reported for the first time from the Tonian Shiwangzhuang Formation of the Tumen Group in western Shandong, North China. However, organic-walled microfossils have never been discovered from this formation up till now. To improve our knowledge about Proterozoic biodiversity in North China, we conducted a micropaleontological survey on the argillaceous limestone samples of the Shiwangzhuang Formation, which also contain macroscopic carbonaceous compression fossils, from the Baishicun section in Anqiu, western Shandong, North China. Our investigation shows that the Shiwangzhuang microfossil assemblage is dominated by smooth-walled sphaeromorphic acritarchs and cyanobacterium-like filaments and relatively low abundance of other acritarchs, including 16 taxa, such as Polysphaeroides filliformis, Ostiana microcystis, Simia annulare, ?Jacutianema sp., Arctacellularia tetragonala, Pellicularia tenera, Polythrichoides lineatus, and Navifusa actinomorpha. The Shiwangzhuang organic-walled microfossil assemblage, although consisting of long-ranging and not age diagnostic taxa, is consistent with a Tonian age suggested by macroscopic carbonaceous compression fossils, including the Chuaria-Tawuia and Sinosabellidites-Protoarenicola-Pararenicola assemblages, revealed from the same fossiliferous horizon of the Shiwangzhuang Formation and by organic-walled microfossil assemblage, including the late Mesoproterozoic to Tonian index fossil Trachyhystrichosphaera aimika, from the underlying Tongjiazhuang Formation. However, it is also worth noting that a Cryogenian or Ediacaran age cannot be completely excluded based just on the Shiwangzhuang microfossils because of their limited biostratigraphic utility. 相似文献
The organic non-crystalline medium of 5,6-dichloro-2-[[5,6-dichloro-1-ethyl-3-(4-sulfobutyl)-benzimidazol-2-ylidene]-propenyl]-1-ethyl-3-(4-sulfobutyl)-benzimidazolium hydroxide (TDBC) is emerging as possible alternative plasmonic material for noble metal in visible region. In this paper, a novel long-range surface exciton-polariton (LRSEP) sensor based on TDBC film covered with graphene is reported. To enhance the imaging sensitivity, the thickness of TDBC film and the number of graphene layers are optimized. The result shows that the optimized imaging sensitivity is enhanced to 3243 RIU−1 when ns = 1.34. Compared with the traditional noble metal film-based sensor, the proposed LRSEP sensor demonstrates that the imaging sensitivity has been greatly improved. This is the first study of the TDBC film-based LRSEP sensor, which we hope to support the potential development of chemical sensing and bio-sensing.
Caenorhabditis elegans is a leading model organism for studying the basic mechanisms of aging. Progress has been limited, however, by the lack of an automated system for quantitative analysis of longevity and mean lifespan. To address this barrier, we developed ‘WormFarm’, an integrated microfluidic device for culturing nematodes. Cohorts of 30–50 animals are maintained throughout their lifespan in each of eight separate chambers on a single WormFarm polydimethylsiloxane chip. Design features allow for automated removal of progeny and efficient control of environmental conditions. In addition, we have developed computational algorithms for automated analysis of video footage to quantitate survival and other phenotypes, such as body size and motility. As proof‐of‐principle, we show here that WormFarm successfully recapitulates survival data obtained from a standard plate‐based assay for both RNAi‐mediated and dietary‐induced changes in lifespan. Further, using a fluorescent reporter in conjunction with WormFarm, we report an age‐associated decrease in fluorescent intensity of GFP in transgenic worms expressing GFP tagged with a mitochondrial import signal under the control of the myo‐3 promoter. This marker may therefore serve as a useful biomarker of biological age and aging rate. 相似文献
We evaluated the associations between bone marrow lesion (BML) volume change and changes in periarticular bone mineral density (paBMD) as well as subchondral sclerosis to determine whether BML change is associated with other local bone changes.
Methods
The convenience sample comprised participants in the Osteoarthritis Initiative (OAI) with weight-bearing posterior-anterior knee radiographs and magnetic resonance images (MRIs) at the 24- and 48-month visits and dual-energy x-ray absorptiometry (DXA) at the 30-/36-month and 48-month visits. The right knee was assessed unless contraindicated for MRI. We used knee DXA scans to measure medial tibia paBMD and medial/lateral paBMD ratio (M:L paBMD). Knee radiographs were scored for sclerosis (grades 0 to 3) in the medial tibia. Two raters determined BML volume on sagittal fat-suppressed MRI by using a semiautomated segmentation method. To focus on knees with only medial tibia BML changes, knees with lateral tibial BMLs were excluded. Medial tibial BML volume change was classified into three groups: BML regression (lowest quartile of medial tibial BML volume change), no-to-minimal change (middle two quartiles), and BML progression (highest quartile). We used proportional odds logistic regression models to evaluate the association between quartiles of changes in medial paBMD or M:L paBMD ratio, as outcomes, and BML volume change.
Results
The sample (n = 308) included 163 (53%) female subjects, 212 (69%) knees with radiographic osteoarthritis, and participants with a mean age of 63.8 ± 9.3 years and mean body mass index of 29.8 ± 4.7 kg/m2. We found an association between greater increases in medial tibia paBMD and BML regression (OR = 1.7 (95% confidence interval (CI) = 1.1 to 2.8)) and a similar trend for BML progression (OR = 1.6 (95% CI = 1.0 to 2.6]). We also detected associations between greater increase in M:L paBMD and BML regression (OR = 1.6 (95% CI = 1.0 to 2.7]) and BML progression (OR = 1.8 (95% CI = 1.1 to 3.0)), although BML regression had borderline statistical significance. The frequency of sclerosis progression in the medial tibia (n = 14) was greater among knees with BML progression or regression compared with knees without BML change (P = 0.01 and P = 0.04, respectively).
Conclusion
BML regression and BML progression are characterized by concurrent increases in paBMD and sclerosis, which are characteristic of increased radiographic osteoarthritis severity. At least during 24 months, BML regression is not representative of improvement in other periarticular bone measures. 相似文献
Background aimsToll-like receptors (TLRs) play an important role in innate and adaptive immunity by recognizing pathogen-associated molecular patterns (PAMPs).MethodsIn the present study, we investigated the expression and role of TLRs on human umbilical cord mesenchymal stromal cells (UC-MSCs). The proliferation, differentiation and immunoregulatory activity of UC-MSCs primed with or without TLR ligands were determined.ResultsAt the RNA level, the expression of TLR2, 4, 6 and 9 was relatively higher than that of other TLRs. However, TLR3 and TLR4 expression were relatively higher at the protein level. UC-MSCs expressed functional TLRs by nuclear factor-κB activation and cytokine expression assay. Poly-inosinic acid:cytidylic acid [Poly(I:C)] stimulation inhibited the proliferation of UC-MSCs, but the ligand of other TLRs had no significant effect. Poly(I:C) stimulation enhanced the adipogenic differentiation capability of UC-MSCs, but lipopolysaccharide inhibited the adipogenic differentiation. Poly(I:C) and CpG-oligonucleotide promoted the immunosuppressive potentiality of UC-MSCs, accompanied with the phosphorylation of interferon regulatory factor 3 (IRF3) and increased expression of indoleamine 2,3-dioxygenase and interferon β, whereas activation of other TLR ligands (synthetic analog fibroblast-stimulating lipopeptide-1 and lipopolysaccharide) failed to affect the immunoregulatory activity of UC-MSCs.ConclusionsTaken together, our data demonstrated that TLR activation influenced the function of UC-MSCs, which might have important implications in future efforts to explore the clinical potentials of UC-MSCs. 相似文献
The neural ganglioside GD2 has recently been reported to be a novel surface marker that is only expressed on human bone marrow mesenchymal stem cells within normal marrow. In this study, an MRI-visible, targeted, non-viral vector for effective gene delivery to human bone marrow mesenchymal stem cells was first synthesized by attaching a targeting ligand, the GD2 single chain antibody (scAbGD2), to the distal ends of PEG-g-PEI-SPION. The targeted vector was then used to condense plasmid DNA to form nanoparticles showing stable small size, low cytotoxicity, and good biocompatibility. Based on a reporter gene assay, the transfection efficiency of targeting complex reached the highest value at 59.6% ± 4.5% in human bone marrow mesenchymal stem cells, which was higher than those obtained using nontargeting complex and lipofectamine/pDNA (17.7% ± 2.9% and 34.9% ± 3.6%, respectively) (P<0.01). Consequently, compared with the nontargeting group, more in vivo gene expression was observed in the fibrotic rat livers of the targeting group. Furthermore, the targeting capacity of scAbGD2-PEG-g-PEI-SPION was successfully verified in vitro by confocal laser scanning microscopy, Prussian blue staining, and magnetic resonance imaging. Our results indicate that scAbGD2-PEG-g-PEI-SPION is a promising MRI-visible non-viral vector for targeted gene delivery to human bone marrow mesenchymal stem cells. 相似文献
The fruit of Schisandra chinensis has been used in the traditional Chinese medicine for thousands of years. Accumulating evidence suggests that Schisandrin B (Sch B) has cardioprotection effect on myocardial ischemia invitro. However, it is unclear whether Sch B has beneficial effects on continuous myocardial ischemia in vivo. The aim of the present study was to investigate whether Sch B could improve cardiac function and attenuate myocardial remodeling after myocardial infarction (MI) in mice. Mice model of MI was established by permanent ligation of the left anterior descending (LAD) coronary artery. Then the MI mice were randomly treated with Sch B or vehicle alone. After treatment for 3 weeks, Sch B could increase survival rate, improve heart function and decrease infarct size compared with vehicle. Moreover, Sch B could down-regulate some inflammatory cytokines, activate eNOS pathway, inhibit cell apoptosis, and enhance cell proliferation. Further in vitro study on H9c2 cells showed similar effects of Sch B on prevention of hypoxia-induced inflammation and cell apoptosis. Taken together, our results demonstrate that Sch B can reduce inflammation, inhibit apoptosis, and improve cardiac function after ischemic injury. It represents a potential novel therapeutic approach for treatment of ischemic heart disease. 相似文献