Purpose
Obesity is the main driving factor for comorbidities in Prader–Willi syndrome (PWS) patients due to overeating behaviors. The gut microbiota has been implicated in the etiology of obesity and ...associated comorbidities. The purpose of the present study was to characterize the fecal microbiota in Chinese patients with PWS and compare it to that of patients with obesity as well as healthy controls.
Methods
We conducted a cross-sectional study with 35 PWS patients (PWS), 35 patients with obesity (OB), and 35 healthy controls (HC). Metagenomic sequencing was performed in stool samples.
Results
The composition of the fecal microbiota in PWS patients differed from that of participants in the OB and HC groups. It was characterized by increased
Akkermansia Eubacterium, Eubacterium rectale
, and
Roseburia intestinalis
and decreased
Parabacteroides
and
Phascolarctobacterium
. Additionally, the homeostatic model assessment of insulin resistance (HOMA-IR) was lower in PWS patients than in patients with obesity. Spearman rank correlation analysis showed that
Achromobacter
,
Acidiphilium
,
Xylophilus
, and
Frisingicoccus
were significantly negatively correlated with HOMA-IR.
Conclusion
The composition of the gut microbiota in Chinese PWS patients differed from that in patients with obesity, which might contribute to higher insulin sensitivity in PWS patients.
Summary An inverse relationship between osteoarthritis and osteoporosis has been debated over years. The microstructure of the femoral heads from postmenopausal osteoarthritic and osteoporotic women ...was evaluated with micro-CT. Significant differences were observed in microstructural parameters between them. Different microstructure might relate to the opposite bone defects in osteoarthritis and osteoporosis. Introduction This study was undertaken to verify the inverse relationship between osteoarthritis (OA) and osteoporosis (OP) by comparing the structural and mechanical indices. Methods Femoral head specimens were obtained from 17 postmenopausal women (OA, n = 8; OP, n = 9) during hip surgery. The microstructural parameters were measured with micro-CT. Mechanical test was performed after bone cube scanning. Results Significant difference in bone volume fraction (BV/TV) and trabecular thickness was noted between OA and OP groups. Structure model index decreased in OA, and increased in OP. The higher apparent density (AD) and lower material density (MD) were also shown in OA. Different from OP, positive correlation were noted between connectivity density and mechanical indices in OA. In OA group, BV/TV was associated with Young's modulus and AD, while trabecular number was the only parameter that correlated with MD. However, in OP group, only BV/TV correlated with yield strength, AD, and MD. Conclusions We observed the difference in microstructure between postmenopausal women with OA and OP, which might relate to the opposite bone defects in OA and OP. BV/TV might play an important role in mechanical properties of the subchondral bone in either OA or OP.
Vertically aligned single‐walled carbon nanotube (VA‐SWNT) arrays synthesized by a combined plasma‐enhanced chemical vapor deposition and fast heating method show a maximum achievable macroscopic ...adhesive force of 29 N cm–2, which is the highest among all synthetic and natural gecko feet (10 N cm–2). This, together with the unique thermal and electric properties of SWNTs, represents a significant advance in developing new dry adhesives of electrical/thermal management capabilities for diverse potential applications, ranging from smart packaging to advanced electronic integration.
To uncover the physical origin of shear-banding instability in metallic glass (MG), a theoretical description of thermo-mechanical deformation of MG undergoing one-dimensional simple shearing is ...presented. The coupled thermo-mechanical model takes into account the momentum balance, the energy balance and the dynamics of free volume. The interplay between free-volume production and temperature increase being two potential causes for shear-banding instability is examined on the basis of the homogeneous solution. It is found that the free-volume production facilitates the sudden increase in the temperature before instability and vice versa. A rigorous linear perturbation analysis is used to examine the inhomogeneous deformation, during which the onset criteria and the internal length and time scales for three types of instabilities, namely free-volume softening, thermal softening and coupling softening, are clearly revealed. The shear-banding instability originating from sole free-volume softening takes place
easier and faster than that due to sole thermal softening, and dominates in the coupling softening. Furthermore, the coupled thermo-mechanical shear-band analysis does show that an initial slight distribution of local free volume can incur significant strain localization, producing a shear band. During such a localization process, the local free-volume creation occurs indeed
prior to the increase in local temperature, indicating that the former is the cause of shear localization, whereas the latter is its consequence. Finally, extension of the above model to include the shear-induced dilatation shows that such dilatation facilitates the shear instability in metallic glasses.
Aims/hypothesis
Arctigenin is a natural compound that had never been previously demonstrated to have a glucose-lowering effect. Here it was found to activate AMP-activated protein kinase (AMPK), and ...the mechanism by which this occurred, as well as the effects on glucose and lipid metabolism were investigated.
Methods
2-Deoxyglucose uptake and AMPK phosphorylation were examined in L6 myotubes and isolated skeletal muscle. Gluconeogenesis and lipid synthesis were evaluated in rat primary hepatocytes. The acute and chronic effects of arctigenin on metabolic abnormalities were observed in C57BL/6J and
ob
/
ob
mice. Changes in mitochondrial membrane potential were measured using the J-aggregate-forming dye, JC-1. Analysis of respiration of L6 myotubes or isolated mitochondria was conducted in a channel oxygen system.
Results
Arctigenin increased AMPK phosphorylation and stimulated glucose uptake in L6 myotubes and isolated skeletal muscles. In primary hepatocytes, it decreased gluconeogenesis and lipid synthesis. The enhancement of glucose uptake and suppression of hepatic gluconeogenesis and lipid synthesis by arctigenin were prevented by blockade of AMPK activation. The respiration of L6 myotubes or isolated mitochondria was inhibited by arctigenin with a specific effect on respiratory complex I. A single oral dose of arctigenin reduced gluconeogenesis in C57BL/6J mice. Chronic oral administration of arctigenin lowered blood glucose and improved lipid metabolism in
ob
/
ob
mice.
Conclusions/interpretation
This study demonstrates a new role for arctigenin as a potent indirect activator of AMPK via inhibition of respiratory complex I, with beneficial effects on metabolic disorders in
ob
/
ob
mice. This highlights the potential value of arctigenin as a possible treatment of type 2 diabetes.
Obesity is a well-known primary risk factor for osteoarthritis (OA). In recent decades, the biomechanics-based theoretical paradigm for the pathogenesis of obesity-associated OA has been gradually ...but fundamentally modified. This modification is a result of accumulating evidence that biological factors also contribute to the etiology of the disease. The gut microbiota is a complicated ecosystem that profoundly influences the health of the host and can be modulated by the combined effects of environmental stimuli and genetic factors. Recently, enteric dysbacteriosis has been identified as a causal factor in the initiation and propagation of obesity-associated OA in animal models. Gut microbes and their components, microbe-associated lipid metabolites, and OA interact at both systemic and local levels through mechanisms that involve interplay with the innate immune system. However, the demonstration of causality in humans will require further studies. Nonetheless, probiotics, prebiotics, dietary habits and exercise, which aid the restoration of a healthy microbial community, are potential therapeutic approaches in the treatment of obesity-associated OA.
ABSTRACT
The Venusian clouds originate from the binary condensation of H2SO4 and H2O. The two components strongly interact with each other via chemistry and cloud formation. Previous works adopted ...sophisticated microphysical approaches to understand the clouds. Here, we show that the observed vapour and cloud distributions on Venus can be well explained by a semi-analytical model. Our model assumes local thermodynamical equilibrium for water vapour but not for sulphuric acid vapour, and includes the feedback of cloud condensation and acidity to vapour distributions. The model predicts strong supersaturation of the H2SO4 vapour above 60 km, consistent with our recent cloud condensation model. The semi-analytical model is 100 times faster than the condensation model and 1000 times faster than the microphysical models. This allows us to quickly explore a large parameter space of the sulphuric acid gas-cloud system. We found that the cloud mass loading in the upper clouds has an opposite response of that in the lower clouds to the vapour mixing ratios in the lower atmosphere. The transport of water vapour influences the cloud acidity in all cloud layers, while the transport of sulphuric acid vapour only dominates in the lower clouds. This cloud model is fast enough to be coupled with the climate models and chemistry models to understand the cloudy atmospheres of Venus and Venus-like extra-solar planets.
We study for the first time the
p
Σ
-
→
K
-
d
and
K
-
d
→
p
Σ
-
reactions close to threshold and show that they are driven by a triangle mechanism, with the
Λ
(
1405
)
, a proton and a neutron as ...intermediate states, which develops a triangle singularity close to the
K
¯
d
threshold. We find that a mechanism involving virtual pion exchange and the
K
-
p
→
π
+
Σ
-
amplitude dominates over another one involving kaon exchange and the
K
-
p
→
K
-
p
amplitude. Moreover, of the two
Λ
(
1405
)
states, the one with higher mass around 1420 MeV, gives the largest contribution to the process. We show that the cross section, well within measurable range, is very sensitive to different models that, while reproducing
K
¯
N
observables above threshold, provide different extrapolations of the
K
¯
N
amplitudes below threshold. The observables of this reaction will provide new constraints on the theoretical models, leading to more reliable extrapolations of the
K
¯
N
amplitudes below threshold and to more accurate predictions of the
Λ
(
1405
)
state of lower mass.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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