Background and purpose
Recent studies have demonstrated that Alzheimer's disease (AD) and subcortical vascular dementia (SVaD) have white matter (WM) microstructural changes. However, previous ...studies on AD and SVaD rarely eliminated the confounding effects of patients with mixed Alzheimer's and cerebrovascular disease pathologies. Therefore, our aim was to evaluate the divergent topography of WM microstructural changes in patients with pure AD and SVaD.
Methods
Patients who were clinically diagnosed with AD and SVaD were prospectively recruited. Forty AD patients who were Pittsburgh compound B (PiB) positive PiB(+) AD without WM hyperintensities and 32 SVaD patients who were PiB negative PiB(−) SVaD were chosen. Fifty‐six cognitively normal individuals were also recruited (NC). Tract‐based spatial statistics of diffuse tensor imaging were used to compare patterns of fractional anisotropy (FA) and mean diffusivity (MD).
Results
Compared with the NC group, the PiB(+) AD group showed decreased FA in the bilateral frontal, temporal and parietal WM regions and the genu and splenium of the corpus callosum as well as increased MD in the left frontal and temporal WM region. PiB(−) SVaD patients showed decreased FA and increased MD in all WM regions. Direct comparison between PiB(+) AD and PiB(−) SVaD groups showed that the PiB(−) SVaD group had decreased FA across all WM regions and increased MD in all WM regions except occipital regions.
Conclusion
Our findings suggest that pure AD and pure SVaD have divergent topography of WM microstructural changes including normal appearing WM.
•Systematic studies of reinforced concrete (RC) structures under progressive collapse, starting from RC skeletal frames and culminating in RC frame-slab systems under corner and exterior column ...removal scenarios.•Tests on 3D RC skeletal frame identified the subsequent developments of flexure and catenary action in the double-span beams, and the development of cantilever mechanism in the single-span beam (inadequate lateral restraint).•In the RC frame-slab substructure tests, the slab flexural capacity under corner column removal scenarios, and combination of the slab flexural and tensile membrane action capacities under exterior column removal scenarios contributed 55% and 40% additional capacity on top of their corresponding frame capacities, respectively.•Under corner and exterior column removal scenarios, the lack of restraint at the middle joint hindered the development of plastic hinge at the middle joint, catenary action of single-span beam. However, the lack of restraint at the same time generated a small compatibility torsion, which prevented significant damage or weakening to the load-carrying capacity.
In a cast in-situ reinforced concrete (RC) beam-slab system, concurrent development of secondary mechanisms, i.e. catenary action in beams and tensile membrane action in slabs, may significantly increase load-carrying and deformation capacities of structures under missing column scenarios. Previous researches mainly focused on structural behaviour of individual RC beams, slabs or beam-slab systems, without clearly defining structural interactions among slabs, beams and columns. To obtain a better understanding of these complex interactions, a systematic study starting from RC skeletal frames and culminating in frame-slab systems is conducted under corner and exterior column removal scenarios, which are among the most critical scenarios for analysis of structural resistance towards progressive collapse. Four specimens were included in this programme, i.e. under corner column loss event, one skeletal frame (COR) and one frame-slab (S-COR) specimens were tested to failure, while one skeletal frame (EXT) and one frame-slab (S-EXT) specimens were loaded to collapse under exterior column loss scenario. In 3D beam-slab tests, it is very challenging to design a test setup with complete measurements of all support reactions due to a great number of statical indeterminacies. The novelty of the paper is to address this aspect. Through the proper test setup and instrumentation of structural behaviour of RC 3-D skeletal frames under corner and exterior column loss scenarios, interactions between the columns and beams could be elucidated. In turn, the slab contributions could be isolated and quantified through direct comparisons between skeletal frame and frame-slab specimens for both scenarios.
The trapping of hydrogen at a variety of sites in multiphase transformation-induced plasticity (TRIP) steels has been characterized using thermal desorption spectroscopy and the results have been ...modelled using diffusion theory. It is discovered that austenite serves as a reversible trapping site which is more potent than grain boundaries or dislocations in ferrite. Plastic deformation which leads to the partial martensitic transformation of the austenite results in an alteration in the trapping condition of the inherited hydrogen. It is demonstrated that these phenomena can be incorporated into a mathematical model which permits the desorption of hydrogen to be predicted quantitatively as a function of, for example, the heating rate, phase fractions and phase transformation. An interesting outcome is that the mechanical degradation of the steel by hydrogen is more pronounced in TRIP steel containing austenite which is relatively less stable to martensitic transformation during deformation. This is because the phase transformation causes a reduction in the trap binding energy, thus enhancing the apparent mobility of the hydrogen.
ABSTRACT
The atmospheres of brown dwarfs have been long observed to exhibit a multitude of non-equilibrium chemical signatures and spectral variability across the L, T, and Y spectral types. We aim ...to investigate the link between the large-scale 3D atmospheric dynamics and time-dependent chemistry in the brown dwarf regime, and to assess its impact on spectral variability. We couple the miniature kinetic chemistry module ‘mini-chem’ to the Exo-FMS general circulation model (GCM). We then perform a series of idealized brown dwarf regime atmospheric models to investigate the dynamical 3D chemical structures produced by our simulations. The GCM output is post-processed using a 3D radiative transfer model to investigate hemisphere-dependent spectral signatures and rotational variability. Our results show the expected strong non-equilibrium chemical behaviour brought on by vertical mixing and global spatial variations due to zonal flows. Chemical species are generally globally homogenized, showing variations of ±10 per cent or less, dependent on pressure level, and follow the dynamical structures present in the atmosphere. However, we find localized storm regions and eddies can show higher contrasts, up to ±100 per cent, in mixing ratio compared to the background global mean. This initial study represents another step in understanding the connection between 3D atmospheric flows in brown dwarfs and their rich chemical inventories.
Abstract Objectives Metabolic syndrome (MS), as a precursor of diabetes mellitus (DM) and cardiovascular disease, is increasing steadily worldwide. We examined the preventive effects of lifestyle ...intervention on the occurrence of DM and acute myocardial infarction (AMI) in MS. Study design Observational study on disease occurrence after lifestyle intervention. Methods The lifestyle intervention was administered to subjects with MS participating in a metropolitan lifestyle intervention program for 1 year. The same numbers of non-participating age- and sex-matched subjects with MS were randomly extracted from national health examination data. After intervention or examination, new occurrences of hypertension, DM, and AMI were identified through the national health insurance claims data during 1 year. For DM and AMI, multivariate logistic regression analysis for the factors affecting each disease was performed. Results In the intervention group and the control group (14,918 in each group), the occurrence of hypertension was 555 (6.07%) and 751 (8.33%), the occurrence of DM was 324 (2.55%) and 488 (3.89%), the occurrence of dyslipidemia was 321 (2.59%) and 373 (2.72%), and the occurrence of AMI was 13 (0.09%) and 26 (0.17%), respectively. In multivariate logistic regression analysis, adjusted odds ratios for intervention were 0.752 (95% confidence interval CI: 0.644–0.879) and 0.499 (95% CI: 0.251–0.992) for DM and AMI, respectively, indicating that lifestyle intervention has a preventive effect. Conclusions Lifestyle intervention in MS has preventive effects on the occurrence of DM and AMI, and long-term follow-up is needed to evaluate these preventive effects in more detail.
Background
Neoadjuvant chemotherapy has been shown to improve the rate of complete (R0) resection and downstaging in patients with localized gastric cancer. There are few reports, however, regarding ...its impact on postoperative morbidity and mortality. The aims of this study were to analyse complication and mortality rates after neoadjuvant chemotherapy using a modified regimen of folinic acid, 5‐fluorouracil and oxaliplatin (mFOLFOX6) for locally advanced gastric cancer (AGC), compared with rates in patients who underwent surgery without neoadjuvant chemotherapy.
Methods
Data were collected from patients with AGC enrolled in a phase II trial of four cycles of neoadjuvant mFOLFOX6 followed by surgery, between January 2005 and June 2008 at two of three institutions, and compared with those from a cohort of patients with AGC who underwent surgery alone at one of the institutions in 2006.
Results
Among 51 patients who received neoadjuvant chemotherapy, there were no deaths and a morbidity rate of 24 per cent after surgery. Comparison of 48 patients in one institution who received neoadjuvant chemotherapy with 92 patients who had surgery alone in the same institution showed no increase in postoperative morbidity (23 versus 29 per cent; P = 0·417). Combined resection was the only risk factor for postoperative morbidity after neoadjuvant chemotherapy.
Conclusion
Neoadjuvant chemotherapy with mFOLFOX is a safe treatment for patients with localized AGC, and does not increase postoperative morbidity or mortality.
Safe and well tolerated
In the past decade, the characterisation of the microbial community in anaerobic digestion was primarily done by using high-throughput short-read amplicon sequencing. However, the short-read approach ...has inherent primer bias and low phylogenetic resolution. Our previous study using Illumina MiSeq suggested that the heterogeneity of AD microbiome was operation-driven. To advance our knowledge towards the complexity of the AD microbiome, we performed full-length 16S rRNA gene amplicon sequencing using PacBio Sequel for a more accurate phylogenetic identification. To this end, purified DNA samples from 19 global anaerobic digesters were sequenced. Sixteen methanogenic archaea were identified at the species level. Among them, Methanosarcina horonobensis and Methanosarcina flavescens had significant presence under specific operating conditions. Methanothrix concilii presented in all digesters sequenced. Unexpectedly, over 90% of the Smithella detected were closely related to alkane-degrading Smithella strains D17 and M82, not Smithella propionica. Using LEfSe and network analysis, the interspecies relationship between the fermentative and syntrophic bacteria was addressed. Comparison of the short- and long-read sequencing results were performed and discussed. From sample preparation to data analysis, this work characterised the digester microbiomes in a superior resolution.
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•Digester microbiomes were characterised with full-length 16S rRNA gene sequencing.•Species-level identification of methanogens and syntrophs were achieved.•Alkane-degrading Smithella strain D17 and M82 were predominant.•Interactions with the uncultivated fermentative bacteria was revealed.
We experimentally investigate the charge (isospin) frustration induced by a geometrical symmetry in a triangular triple quantum dot. We observe the ground-state charge configurations of sixfold ...degeneracy, the manifestation of the frustration. The frustration results in omnidirectional charge transport, and it is accompanied by nearby nontrivial triple degenerate states in the charge stability diagram. The findings agree with a capacitive interaction model. We also observe unusual transport by the frustration, which might be related to elastic cotunneling and the interference of trajectories through the dot. This work demonstrates a unique way of studying geometrical frustration in a controllable way.
To prospectively use hydrogen 1 (1H) magnetic resonance (MR) spectroscopy and dynamic contrast material-enhanced MR imaging to measure vertebral body marrow fat content and bone marrow perfusion in ...older men with varying bone mineral densities as documented with dual x-ray absorptiometry (DXA).
This study had institutional review board approval, and all participants provided informed consent. DXA, 1H MR spectroscopy, and dynamic contrast-enhanced MR imaging of the lumbar spine were performed in 90 men (mean age, 73 years; range, 67-101 years). Vertebral marrow fat content and perfusion (maximum enhancement and enhancement slope) were compared for subject groups with differing bone densities (normal, osteopenic, and osteoporotic). The t test was used for comparisons between groups, and the Pearson test was used to determine correlation between marrow fat content and perfusion indexes.
Eight subjects were excluded, yielding a final cohort of 82 subjects (mean age, 73 years; range, 67-101 years) that included 42 subjects with normal bone density (mean T score, 0.8 +/- 1.1 standard deviation), 23 subjects with osteopenia (mean T score, -1.6 +/- 0.4), and 17 subjects with osteoporosis (mean T score, -3.2 +/- 0.5). Vertebral marrow fat content was significantly increased in subjects with osteoporosis (mean fat content, 58.23% +/- 7.8) (P = .002) or osteopenia (mean fat content, 55.68% +/- 10.2) (P = .034) compared with that in subjects with normal bone density (50.45% +/- 8.7). Vertebral marrow perfusion indexes were significantly decreased in osteoporotic subjects (mean enhancement slope, 0.78%/sec +/- 0.3) compared with those in osteopenic subjects (mean enhancement slope, 1.15%/sec +/- 0.6) (P = .007) and those in subjects with normal bone density (mean enhancement slope, 1.48%/sec +/- 0.7) (P < .001).
Subjects with osteoporosis have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with osteopenia. Similarly, subjects with osteopenia have decreased vertebral marrow perfusion and increased marrow fat compared with these parameters in subjects with normal bone density.
This study evaluated the capability of a MALDI Biotyper system equipped with the newly introduced MBT STAR-BL module to simultaneously perform species identification and β-lactamase-mediated ...resistance detection in bacteremia -causing bacteria isolated from cultured isolates and patient-derived blood cultures (BCs).
Two hundred retrospective cultured isolates and 153 prospective BCs containing Gram-negative rods (GNR) were collected and subjected to direct bacterial identification, followed by the measurement of β-lactamase activities against ampicillin, piperacillin, cefotaxime, ceftazidime, and meropenem using the MBT STAR-BL module. The results and turnaround times were compared with those of routine microbiological processing. All strains were also characterized by beta-lactamase PCR and sequencing.
Using the saponin-based extraction method, MALDI-TOF MS correctly identified bacteria in 116/134 (86.6%) monomicrobial BCs. The detection sensitivities for β-lactamase activities against ampicillin, piperacillin, third-generation cephalosporin and meropenem were 91.3, 100, 97.9, and 100% for cultured isolates, and 80.4, 100, 68.8, and 40% for monomicrobial BCs (
= 134) respectively. The overall specificities ranged from 91.5 to 100%. Furthermore, the MBT STAR-BL and conventional drug susceptibility test results were concordant in 14/19 (73.7%) polymicrobial cultures. Reducing the logRQ cut-off value from 0.4 to 0.2 increased the direct detection sensitivities for β-lactamase activities against ampicillin, cefotaxime and meropenem in BCs to 85.7, 87.5, and 100% respectively. The MBT STAR-BL test enabled the reporting of β-lactamase-producing GNR at 14.16 and 47.64 h before the interim and final reports of routine BCs processing, respectively, were available.
The MALDI Biotyper system equipped with the MBT STAR-BL module enables the simultaneous rapid identification of bacterial species and β-lactamase-mediated resistance from BCs and cultured isolates. Adjustment of the logRQ cut-off value to 0.2 significantly increased the detection sensitivities for clinically important drug-resistant pathogens.
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