Anomalous Evolution of the Near-Side Jet Peak Shape in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

The measurement of two-particle angular correlations is a powerful tool to study jet quenching in a p_{T} region inaccessible by direct jet identification. In these measurements pseudorapidity (Δη) and azimuthal (Δφ) differences are used to extract the shape of the near-side peak formed by particles associated with a higher p_{T} trigger particle (1<p_{T,trig}<8  GeV/c). A combined fit of the near-side peak and long-range correlations is applied to the data allowing the extraction of the centrality evolution of the peak shape in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV. A significant broadening of the peak in the Δη direction at low p_{T} is found from peripheral to central collisions, which vanishes above 4  GeV/c, while in the Δφ direction the peak is almost independent of centrality. For the 10% most central collisions and 1<p_{T,assoc}<2  GeV/c, 1<p_{T,trig}<3  GeV/c a novel feature is observed: a depletion develops around the center of the peak. The results are compared to pp collisions at the same center of mass energy and ampt model simulations. The comparison to the investigated models suggests that the broadening and the development of the depletion is connected to the strength of radial and longitudinal flow.

Associations between proximal tibiofibular joint (PTFJ) types and knee osteoarthritic changes in older adults

PURPOSE

To describe the cross-sectional associations between proximal tibiofibular joint (PTFJ) type configurations and knee joint structural abnormalities in older adults.

METHODS

A total of 967 community-based participants were studied. T1-weighted fat-suppressed magnetic resonance image (MRI) with spoiled gradient recalled echo sequence was utilized to assess the PTFJ type configurations. Knee cartilage volume, cartilage defects, bone marrow lesions and osteophytes were measured. Linear regression and binary logistic regression analyses were used to examine the associations between PTFJ type configurations and knee joint cartilage volume as well as knee structural abnormalities, respectively, after adjustment for potential confounders.

RESULTS

Seven PTFJ types including plane (49.4%), trochoid (31.9%), double trochoid (4.3%), saddle (5.4%), condylar (5.3%), trochlear (3.5%) and ball & socket (0.2%) were observed. Plane type was used as the comparator. In multivariable analyses, irregular joint types (comprising the five uncommon joint types) were associated negatively with cartilage volume, and positively with knee cartilage defects, bone marrow lesions and osteophytes in the lateral (but not medial) compartments. In contrast, trochoid type was only associated with reduced femoral cartilage volume, but not with knee cartilage defects, bone marrow lesions and osteophytes.

CONCLUSIONS

Irregular PTFJ joint shapes are associated with osteoarthritic changes in the lateral, but not medial, tibiofemoral compartment in older adults. The causal relationship needs to be examined in future longitudinal studies.

Tissue-engineered trachea regeneration using decellularized trachea matrix treated with laser micropore technique

Tissue-engineered trachea provides a promising approach for reconstruction of long segmental tracheal defects. However, a lack of ideal biodegradable scaffolds greatly restricts its clinical translation. Decellularized trachea matrix (DTM) is considered a proper scaffold for trachea cartilage regeneration owing to natural tubular structure, cartilage matrix components, and biodegradability. However, cell residual and low porosity of DTM easily result in immunogenicity and incomplete cartilage regeneration. To address these problems, a laser micropore technique (LMT) was applied in the current study to modify trachea sample porosity to facilitate decellular treatment and cell ingrowth. Decellularization processing demonstrated that cells in LMT treated samples were more easily removed compared with untreated native trachea. Furthermore, after optimizing the protocols of LMT and decellular treatments, the LMT-treated DTM (LDTM) could retain their original tubular shape with only mild extracellular matrix damage. After seeding with chondrocytes and culture in vitro for 8 weeks, the cell-LDTM constructs formed tubular cartilage with relatively homogenous cell distribution in both micropores and bilateral surfaces. In vivo results further confirmed that the constructs could form mature tubular cartilage with increased DNA and cartilage matrix contents, as well as enhanced mechanical strength, compared with native trachea. Collectively, these results indicate that LDTM is an ideal scaffold for tubular cartilage regeneration and, thus, provides a promising strategy for functional reconstruction of trachea cartilage.

STATEMENT OF SIGNIFICANCE

Lacking ideal biodegradable scaffolds greatly restricts development of tissue-engineered trachea. Decellularized trachea matrix (DTM) is considered a proper scaffold for trachea cartilage regeneration. However, cell residual and low porosity of DTM easily result in immunogenicity and incomplete cartilage regeneration. By laser micropore technique (LMT), the current study efficiently enhanced the porosity and decellularized efficacy of DTM. The LMT-treated DTM basically retained the original tubular shape with mild matrix damage. After chondrocyte seeding followed by in vitro culture and in vivo implantation, the constructs formed mature tubular cartilage with matrix content and mechanical strength similar to native trachea. The current study provides an ideal scaffold and a promising strategy for cartilage regeneration and functional reconstruction of trachea.

Energy dependence of forward-rapidity [Formula: see text] and [Formula: see text] production in pp collisions at the LHC

We present results on transverse momentum ([Formula: see text]) and rapidity ([Formula: see text]) differential production cross sections, mean transverse momentum and mean transverse momentum square of inclusive [Formula: see text] and [Formula: see text] at forward rapidity ([Formula: see text]) as well as [Formula: see text]-to-[Formula: see text] cross section ratios. These quantities are measured in pp collisions at center of mass energies [Formula: see text] and 13 TeV with the ALICE detector. Both charmonium states are reconstructed in the dimuon decay channel, using the muon spectrometer. A comprehensive comparison to inclusive charmonium cross sections measured at [Formula: see text], 7 and 8 TeV is performed. A comparison to non-relativistic quantum chromodynamics and fixed-order next-to-leading logarithm calculations, which describe prompt and non-prompt charmonium production respectively, is also presented. A good description of the data is obtained over the full [Formula: see text] range, provided that both contributions are summed. In particular, it is found that for [Formula: see text] GeV/c the non-prompt contribution reaches up to 50% of the total charmonium yield.

Production of Σ(1385)± and Ξ(1530)0 in p-Pb collisions at sNN=5.02 TeV

The transverse momentum distributions of the strange and double-strange hyperon resonances (Σ ( 1385 ) ± , Ξ ( 1530 ) 0 ) produced in p-Pb collisions at s NN = 5.02 TeV were measured in the rapidity range - 0.5 < y CMS < 0 for event classes corresponding to different charged-particle multiplicity densities, ⟨ dN ch /dη lab ⟩ . The mean transverse momentum values are presented as a function of ⟨ dN ch /dη lab ⟩ , as well as a function of the particle masses and compared with previous results on hyperon production. The integrated yield ratios of excited to ground-state hyperons are constant as a function of ⟨ dN ch /dη lab ⟩ . The equivalent ratios to pions exhibit an increase with ⟨ dN ch /dη lab ⟩ , depending on their strangeness content.

Production of [Formula: see text] and [Formula: see text] mesons up to high transverse momentum in pp collisions at 2.76 TeV

The invariant differential cross sections for inclusive [Formula: see text] and [Formula: see text] mesons at midrapidity were measured in pp collisions at [Formula: see text] TeV for transverse momenta [Formula: see text] GeV/c and [Formula: see text] GeV/c, respectively, using the ALICE detector. This large range in [Formula: see text] was achieved by combining various analysis techniques and different triggers involving the electromagnetic calorimeter (EMCal). In particular, a new single-cluster, shower-shape based method was developed for the identification of high-[Formula: see text] neutral pions, which exploits that the showers originating from their decay photons overlap in the EMCal. Above 4 GeV/[Formula: see text], the measured cross sections are found to exhibit a similar power-law behavior with an exponent of about 6.3. Next-to-leading-order perturbative QCD calculations differ from the measured cross sections by about 30% for the [Formula: see text], and between 30-50% for the [Formula: see text] meson, while generator-level simulations with PYTHIA 8.2 describe the data to better than 10-30%, except at [Formula: see text] GeV/[Formula: see text]. The new data can therefore be used to further improve the theoretical description of [Formula: see text] and [Formula: see text] meson production.

Stable subcutaneous cartilage regeneration of bone marrow stromal cells directed by chondrocyte sheet

In vivo niche plays an important role in regulating differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. This study explored the feasibility that chondrocyte sheet created chondrogenic niche retained chondrogenic phenotype of BMSC engineered cartilage (BEC) in subcutaneous environments. Porcine BMSCs were seeded into biodegradable scaffolds followed by 4weeks of chondrogenic induction in vitro to form BEC, which were wrapped with chondrocyte sheets (Sheet group), acellular small intestinal submucosa (SIS, SIS group), or nothing (Blank group) respectively and then implanted subcutaneously into nude mice to trace the maintenance of chondrogenic phenotype. The results showed that all the constructs in Sheet group displayed typical cartilaginous features with abundant lacunae and cartilage specific matrices deposition. These samples became more mature with prolonged in vivo implantation, and few signs of ossification were observed at all time points except for one sample that had not been wrapped completely. Cell labeling results in Sheet group further revealed that the implanted BEC directly participated in cartilage formation. Samples in both SIS and Blank groups mainly showed ossified tissue at all time points with partial fibrogenesis in a few samples. These results suggested that chondrocyte sheet could create a chondrogenic niche for retaining chondrogenic phenotype of BEC in subcutaneous environment and thus provide a novel research model for stable ectopic cartilage regeneration based on stem cells.

STATEMENT OF SIGNIFICANCE

In vivo niche plays an important role in directing differentiation fate of stem cells. Due to lack of proper chondrogenic niche, stable cartilage regeneration of bone marrow stromal cells (BMSCs) in subcutaneous environments is always a great challenge. The current study demonstrated that chondrocyte sheet generated by high-density culture of chondrocytes in vitro could cearte a chondrogenic niche in subcutaneous environment and efficiently retain the chondrogenic phenotype of in vitro BMSC engineered cartilage (vitro-BEC). Furthermore, cell tracing results revealed that the regenerated cartilage mainly derived from the implanted vitro-BEC. The current study not only proposes a novel research model for microenvironment simulation but also provides a useful strategy for stable ectopic cartilage regeneration of stem cells.

Flow Dominance and Factorization of Transverse Momentum Correlations in Pb-Pb Collisions at the LHC

We present the first measurement of the two-particle transverse momentum differential correlation function, P_{2}≡⟨Δp_{T}Δp_{T}⟩/⟨p_{T}⟩^{2}, in Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV. Results for P_{2} are reported as a function of the relative pseudorapidity (Δη) and azimuthal angle (Δφ) between two particles for different collision centralities. The Δϕ dependence is found to be largely independent of Δη for |Δη|≥0.9. In the 5% most central Pb-Pb collisions, the two-particle transverse momentum correlation function exhibits a clear double-hump structure around Δφ=π (i.e., on the away side), which is not observed in number correlations in the same centrality range, and thus provides an indication of the dominance of triangular flow in this collision centrality. Fourier decompositions of P_{2}, studied as a function of the collision centrality, show that correlations at |Δη|≥0.9 can be well reproduced by a flow ansatz based on the notion that measured transverse momentum correlations are strictly determined by the collective motion of the system.

Measurement of azimuthal correlations of D mesons with charged particles in pp collisions at [Formula: see text] TeV and p-Pb collisions at [Formula: see text] TeV

The azimuthal correlations of D mesons with charged particles were measured with the ALICE apparatus in pp collisions at [Formula: see text] and p-Pb collisions at [Formula: see text] at the Large Hadron Collider. [Formula: see text], [Formula: see text], and [Formula: see text] mesons and their charge conjugates with transverse momentum [Formula: see text] and rapidity in the nucleon-nucleon centre-of-mass system [Formula: see text] (pp collisions) and [Formula: see text] (p-Pb collisions) were correlated to charged particles with [Formula: see text]. The yield of charged particles in the correlation peak induced by the jet containing the D meson and the peak width are compatible within uncertainties in the two collision systems. The data are described within uncertainties by Monte-Carlo simulations based on PYTHIA, POWHEG, and EPOS 3 event generators.

Critical roles of conventional dendritic cells in promoting T cell-dependent hepatitis through regulating natural killer T cells

Dendritic cells (DCs) play critical roles in initiating and regulating innate immunity as well as adaptive immune responses. However, the role of conventional dendritic cells (cDCs) in concanavalin A (ConA)-induced fulminant hepatitis is unknown. In this study, we demonstrated that depletion of cDCs using either CD11c-diphtheria toxin receptor transgenic mice (DTR Tg) mice or anti-CD11c antibody reduced the severity of liver injury significantly, indicating a detrimental role of cDCs in ConA-induced hepatitis. We elucidated further the pathological role of cDCs as being the critical source of interleukin (IL)-12, which induced the secretion of interferon (IFN)-γ by natural killer (NK) T cells. Reconstitution of cDCs-depleted mice with IL-12 restored ConA-induced hepatitis significantly. Furthermore, we determined that NK T cells were the target of DC-derived IL-12, and NK T cells contributed to liver inflammation and injury through production of IFN-γ. In summary, our study demonstrated a novel function of cDCs in mediating ConA-induced hepatitis through regulating IFN-γ secretion of NK T cells in an IL-12-dependent fashion. Targeting cDCs might provide potentially therapeutic applications in treating autoimmune related liver diseases.

Dietary Diversity and Cognitive Function among Elderly People: A Population-Based Study

OBJECTIVES

To explore associations of dietary diversity with cognitive function among Chinese elderly.

DESIGN

This cross-sectional study was conducted in 2011-2012, data were analyzed using multiple linear regression and logistic regression models.

SETTING

community-based setting in the 23 provinces in China.

SUBJECTS

8,571 elderly participants, including 2984 younger elderly aged 65-79 and 5587 oldest old aged 80+ participated in this study.

MEASUREMENT

Intake frequencies of food groups was collected and dietary diversity (DD) was assessed based on the mean of DD score. Cognitive function was assessed using the Chinese version of Mini-Mental State Examination (MMSE), and cognitive impairment was defined using education-based cutoffs. Information about socio-demographics, lifestyles, resilience and health status was also collected.

RESULTS

Poor dietary diversity was significantly associated with cognitive function, with β (95% CI) of -0.11(-0.14, -0.08) for -log (31-MMSE score) and odds ratio (95% CI) of 1.29 (1.14, 1.47) for cognitive impairment. Interaction effect of age with DD was observed on cognitive impairment (P interaction=0.018), but not on -log (31-MMSE score) (P interaction=0.08). Further separate analysis showed that poor DD was significantly associated with increased risk of cognitive impairment in the oldest old (p<0.01), with odds ratio (95% CI) of 1.34 (1.17, 1.54), while not in the younger elderly (p>0.05), with OR (95% CI) being 1.09 (0.80, 1.47) in the fully adjusted model. Similar results were obtained when DD was categorized into four groups.

CONCLUSIONS

Poor dietary diversity was associated with worse global cognitive function among Chinese elderly, and particularly for the oldest old. This finding would be very meaningful for prevention of cognitive impairment.

Remodeling of the gut microbiota and structural shifts in Preeclampsia patients in South China

Preeclampsia (PE) is one of the pregnancy metabolic diseases. Since Gut microbiota play important roles in the hosts' metabolism, it is necessary to investigate the gut microbiota in PE patients, so that some intestinal dysbiosis might be detected as a biomarker for PE early diagnosis or as a target for intervention. One hundred subjects were categorized into four groups: 26 PE patients in late pregnancy, healthy individuals in early, middle, and late pregnancy (26/24/24 women). Gut microbiota were analyzed by sequencing the V4 region of the 16S rDNA gene using Illuminal MiSeq. Data were analyzed by multivariate statistics. Bacteroidetes was the dominant bacterium (47.57-52.35%) in the pregnant women in South China. Tenericutes increased while Verrucomicrobia almost disappeared in late pregnancy. In the PE patients, there was an overall increase in pathogenic bacteria, Clostridium perfringens (p = 0.03) and Bulleidia moorei (p = 0.00) but a reduction in probiotic bacteria Coprococcus catus (p = 0.03). Our research suggests that there is a significant structural shift of the gut microbiota in PE patients, which might be associated with the occurrence and development of the disease. However, further studies are required to understand the underlying mechanisms.

Prolonged in vitro precultivation alleviates post-implantation inflammation and promotes stable subcutaneous cartilage formation in a goat model

Synthetic biodegradable scaffolds such as polylactic acid coated polyglycolic acid (PLA-PGA) are especially suitable for engineering shaped cartilage such as auricle, but they induce a serious inflammatory reaction particularly in the immunologically aggressive subcutaneous site, leading to resorption of the engineered autologous cartilage. Our previous study in a rabbit model has demonstrated 2 weeks of in vitro precultivation could significantly alleviate the post-implantation inflammation induced by PLA-PGA engineered cartilaginous grafts, but reproduction of this result failed in a preclinical goat model. The aims of the current study were to investigate whether prolonged in vitro precultivation could form a mature cartilaginous graft to resist the acute host response and promote stable subcutaneous cartilage formation in a preclinical goat model. Goat chondrocytes were seeded onto PLA-PGA scaffolds, in vitro precultivated for 2, 4, 8, and 12 weeks, and then implanted subcutaneously in autologous goats for 1 and 8 weeks. The in vitro engineered cartilage (vitro-EC) was examined histologically (hematoxylin and eosin, safranin-O, collagen II). The 1 week explants were examined histologically and stained for CD3, CD68, collagen I, and apoptosis. The 8 week explants were evaluated by histology, wet weight, volume, glycosaminoglycan (GAG) quantification and Young's modulus. With prolonged in vitro time, the quality of vitro-EC improved and the amount of scaffold residue decreased; more pronounced cartilage formation with fewer immune cells (CD3 and CD68 positive), apoptotic cells, and less collagen I expression were observed in explants that had been in vitro precultivated for a longer period. The subcutaneously regenerated neocartilage became more mature after prolonged implantation. These results suggested that prolonged in vitro precultivation allowed formation of a mature cartilaginous graft to resist the acute host response and promoted stable subcutaneous cartilage formation in autologous goats. These findings may provide useful reference for engineering auricle, trachea, nose, and eyelid shaped cartilage, for example.

Correlated Event-by-Event Fluctuations of Flow Harmonics in Pb-Pb Collisions at sqrt[s_{NN}]=2.76 TeV

We report the measurements of correlations between event-by-event fluctuations of amplitudes of anisotropic flow harmonics in nucleus-nucleus collisions, obtained for the first time using a new analysis method based on multiparticle cumulants in mixed harmonics. This novel method is robust against systematic biases originating from nonflow effects and by construction any dependence on symmetry planes is eliminated. We demonstrate that correlations of flow harmonics exhibit a better sensitivity to medium properties than the individual flow harmonics. The new measurements are performed in Pb-Pb collisions at the center-of-mass energy per nucleon pair of sqrt[s_{NN}]=2.76  TeV by the ALICE experiment at the Large Hadron Collider. The centrality dependence of correlation between event-by-event fluctuations of the elliptic v_{2} and quadrangular v_{4} flow harmonics, as well as of anticorrelation between v_{2} and triangular v_{3} flow harmonics are presented. The results cover two different regimes of the initial state configurations: geometry dominated (in midcentral collisions) and fluctuation dominated (in the most central collisions). Comparisons are made to predictions from Monte Carlo Glauber, viscous hydrodynamics, ampt, and hijing models. Together with the existing measurements of the individual flow harmonics the presented results provide further constraints on the initial conditions and the transport properties of the system produced in heavy-ion collisions.

The promoter polymorphisms of receptor for advanced glycation end products were associated with the susceptibility and progression of sepsis

Receptor for advanced glycation end products (RAGE) is considered a major pattern recognition receptor, which plays an important role in the development of sepsis. Increasing evidence showed an association between RAGE polymorphisms and the susceptibility to several inflammatory-related diseases. However, little is known about the clinical relationship between RAGE polymorphisms and sepsis. In this study, we analyzed the association of sepsis with three functional RAGE gene polymorphisms (rs1800624, rs1800625 and rs2070600) in a Chinese Han population (372 sepsis cases and 400 healthy controls). Significant differences were observed in the rs1800624 and rs1800625 genotype/allele distributions between the sepsis and controls, but no significant difference was observed in the rs2070600 genotype/allele. Moreover, our results also revealed a significant difference in the genotype/allele frequencies of the rs1800624 and rs1800625 polymorphisms between the sepsis and severe sepsis subtypes, the rs1800624 TT or rs1800625 TT genotype carriers exhibited a significant increase in RAGE mRNA, sRAGE, TNF-α and IL-6 expression compared with the rs1800624 AT/AA or rs1800625 CT/CC carriers in sepsis patients. Overall, this study might provide valuable clinical evidence between the RAGE gene polymorphisms and the risk or the development of sepsis.

Centrality Dependence of the Charged-Particle Multiplicity Density at Midrapidity in Pb-Pb Collisions at sqrt[s_{NN}]=5.02 TeV

The pseudorapidity density of charged particles, dN_{ch}/dη, at midrapidity in Pb-Pb collisions has been measured at a center-of-mass energy per nucleon pair of sqrt[s_{NN}]=5.02  TeV. For the 5% most central collisions, we measure a value of 1943±54. The rise in dN_{ch}/dη as a function of sqrt[s_{NN}] is steeper than that observed in proton-proton collisions and follows the trend established by measurements at lower energy. The increase of dN_{ch}/dη as a function of the average number of participant nucleons, ⟨N_{part}⟩, calculated in a Glauber model, is compared with the previous measurement at sqrt[s_{NN}]=2.76  TeV. A constant factor of about 1.2 describes the increase in dN_{ch}/dη from sqrt[s_{NN}]=2.76 to 5.02 TeV for all centrality classes, within the measured range of 0%-80% centrality. The results are also compared to models based on different mechanisms for particle production in nuclear collisions.

Measurement of an Excess in the Yield of J/ψ at Very Low p_{T} in Pb-Pb Collisions at sqrt[s]_{NN}=2.76 TeV

We report on the first measurement of an excess in the yield of J/ψ at very low transverse momentum (p_{T}<0.3  GeV/c) in peripheral hadronic Pb-Pb collisions at sqrt[s_{NN}]=2.76  TeV, performed by ALICE at the CERN LHC. Remarkably, the measured nuclear modification factor of J/ψ in the rapidity range 2.5<y<4 reaches about 7 (2) in the p_{T} range 0-0.3  GeV/c in the 70%-90% (50%-70%) centrality class. The J/ψ production cross section associated with the observed excess is obtained under the hypothesis that coherent photoproduction of J/ψ is the underlying physics mechanism. If confirmed, the observation of J/ψ coherent photoproduction in Pb-Pb collisions at impact parameters smaller than twice the nuclear radius opens new theoretical and experimental challenges and opportunities. In particular, coherent photoproduction accompanying hadronic collisions may provide insight into the dynamics of photoproduction and nuclear reactions, as well as become a novel probe of the quark-gluon plasma.