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The resonance properties, frequency and half-band-half-width, of a quartz crystal microbalance (QCM) immersed in concentrated suspensions of 16.2 vol% TiO2 are shown to be a function ...of pH. The overall QCM response is dependent on the complex interactions between the QCM sensor and overlying particle suspension. Atomic force microscopy confirms pH dependent interaction forces between the QCM sensor (gold-coated) and a TiO2 particle: a strong attraction is measured between pH 4–4.5, and the interaction becomes increasingly repulsive at all pH > 6.5. Yield stress measurements of the concentrated TiO2 suspensions also confirm the changing particle-particle interaction strength as the pH is adjusted from acidic to basic conditions. For the chosen system, the total potential energy of interaction (VT) between the sensor-suspension (Au-TiO2) is comparatively stronger than the particle-particle (TiO2-TiO2) interaction; hence the QCM responds to changes in VT sensor-suspension, as verified by the calculated interaction energy between two dissimilar surfaces (Hogg-Healy-Fuerstenau (HHF) theory), and not the suspension yield stress. Slight deviation between the measured QCM responses and the theoretical sphere-plate interaction strength is shown over a narrow pH range and likely corresponds to strengthening particle-particle interactions. Although the suspensions exhibit significant yield strengths, the QCM response can be suitably described by the sensor-suspension contact mechanics of inertial loading. Combined with our previous study 1, the current study confirms the suspension yield strength can only be measured when VT sensor-suspension is attractive and comparatively weaker than VT particle-particle.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Along-strike variation in scarp morphology reflects differences in a fault's geomorphic and structural development and can thus indicate fault rupture history and mechanical segmentation. Parameters ...that define scarp morphology (height, width, slope) are typically measured or calculated manually. The time-consuming manual approach reduces the density and objectivity of measurements and can lead to oversight of small-scale morphological variations that occur at a resolution impractical to capture. Furthermore, inconsistencies in the manual approach may also lead to unknown discrepancies and uncertainties between, and also within, individual fault scarp studies. Here, we aim to improve the efficiency, transparency and uniformity of calculating scarp morphological parameters by developing a semi-automated Scarp PARameTer Algorithm (SPARTA). We compare our findings against a traditional, manual analysis and assess the performance of the algorithm using a range of digital elevation model (DEM) resolutions. We then apply our new algorithm to a 12 m resolution TanDEM-X DEM for four southern Malawi fault scarps, located at the southern end of the East African Rift system: the Bilila–Mtakataka fault (BMF) and three previously unreported scarps – Thyolo, Muona and Malombe. All but Muona exhibit first-order structural segmentation at their surface. By using a 5 m resolution DEM derived from high-resolution (50 cm pixel−1) Pleiades stereo-satellite imagery for the Bilila–Mtakataka fault scarp, we quantify secondary structural segmentation. Our scarp height calculations from all four fault scarps suggest that if each scarp was formed by a single, complete rupture, the slip–length ratio for each earthquake exceeds the maximum typical value observed in historical normal faulting earthquakes around the world. The high slip–length ratios therefore imply that the Malawi fault scarps likely formed in multiple earthquakes. The scarp height distribution implies the structural segments of both the BMF and Thyolo fault have merged via rupture of discrete faults (hard links) through several earthquake cycles, and the segments of the Malombe fault have connected via distributed deformation zones (soft links). For all faults studied here, the length of earthquake ruptures may therefore exceed the length of each segment. Thus, our findings shed new light on the seismic hazard in southern Malawi, indicating evidence for a number of large (Mw 7–8) prehistoric earthquakes, as well as providing a new semi-automated methodology (SPARTA) for calculating scarp morphological parameters, which can be used on other fault scarps to infer structural development.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Premature atrial contractions (PACs) are frequently observed on electrocardiograms and are associated with increased risks of atrial fibrillation (AF), stroke, and mortality. In this study, we aimed ...to identify genetic susceptibility loci for PAC frequency. We performed a genome-wide association study meta-analysis with PAC frequency obtained from ambulatory cardiac monitoring in 4,831 individuals of European ancestry. We identified a genome-wide significant locus at the SCN5A gene. The lead variant, rs7373862, located in an intron of SCN5A, was associated with an increase of 0.12 95% CI 0.08–0.16 standard deviations of the normalized PAC frequency per risk allele. Among genetic variants previously associated with AF, there was a significant enrichment in concordance of effect for PAC frequency (n = 73/106, p = 5.1 × 10−5). However, several AF risk loci, including PITX2, were not associated with PAC frequency. These findings suggest the existence of both shared and distinct genetic mechanisms for PAC frequency and AF.
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•Variants in SCN5A are associated with premature atrial contractions (PAC) frequency•Other atrial fibrillation (AF) risk variants are also associated with PAC frequency•Both shared and distinct genetic mechanisms exist for PAC frequency and AF
Clinical genetics; Cardiovascular medicine; Human genetics; Genomics
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Abstract only
Introduction:
Type 2 diabetes (T2D) is a cardiovascular disease risk equivalent and likely results from broad metabolic changes, which high throughput proteomics have helped to unravel. ...Prior studies are limited by proteomic coverage, cross sectional design, and lack of physiologic phenotyping.
Hypothesis:
Complementary proteomic studies of incident T2D and physiologic responses to an intravenous glucose tolerance test (IVGTT) will identify novel proteins with roles in glucose homeostasis and future risk of T2D.
Methods:
Cardiovascular Health Study (CHS) and HERITAGE study participants without diabetes underwent SomaScan
®
profiling of 4,776 plasma proteins. HERITAGE participants underwent IVGTT, from which insulin sensitivity index (S
I
), acute insulin response to glucose (AIR
G
), and glucose effectiveness (S
G
) were derived. We used Cox regression to test protein associations with 18-year incident T2D in CHS, and multivariable linear regression to test protein associations with IVGTT measures in HERITAGE.
Results:
In CHS (N = 2631, 74 ± 5 years, 62% female, 14% Black), 57 proteins were significantly associated with incident T2D after comprehensive covariate and multiple testing adjustment. Of these, 44, 9, and 8 were associated with S
I
, AIR
G
, and S
G
respectively in HERITAGE (N = 752, 35 ± 14 years, 55% female, 38% Black) (Figure). Notable findings include beta-glucuronidase, which associated with increased T2D risk (HR 1.46 per SD increase in log
2
protein level) and lower S
G
, suggesting a role in insulin-independent glucose disposal, and thrombospondin-2, which associated with increased T2D risk (HR 1.26 per SD), lower AIR
G
, and not with S
I
, indicating that it may be a marker of pancreatic dysfunction.
Conclusions:
By integrating proteomics from two complementary prospective cohorts using different but related outcomes, we identified 34 novel protein-T2D associations, and characterized their relationship with physiologic axes of glucose metabolism.
Conservation Science Education Online (CSEO) is a new online resource that shares strategies for teaching science in art conservation and related cultural heritage fields. An overview will be given ...of how undergraduate chemistry curricula in the United States have used examples from cultural heritage. The field of art conservation will then be described with an emphasis on the science curricula taught in art conservation programs around the world. Challenges include relating theoretical learning to real-world applications and teaching scientific terminology and concepts to students who may have limited science backgrounds; as well, there is a lack of textbooks and resources with appropriate case studies. The newly launched CSEO online resource offers freely available, effective teaching methods in the form of modules developed by international educators in the field. The inaugural CSEO Conference 2022 served as an introduction to the online resource for a global audience and was the first dedicated conference to bring together heritage science educators to discuss challenges and teaching strategies with the goal of building such a resource. The conference facilitated discussions among participants about teaching strategies, with the intention that these topics would become modules for the online resource, available to all science educators.
Inflammation is believed to play a role in prostate cancer (PCa) etiology, but it is unclear whether inflammatory markers C-reactive protein (CRP) and interleukin-6 (IL-6) associate with PCa risk in ...older men. Using Cox regression, we assessed the relationship between baseline concentrations of CRP and IL-6 and the subsequent PCa risk in the Cardiovascular Health Study, a population-based cohort study of mostly European American men of ages >64years (n=2,234; mean follow-up=8.7years; 215 incident PCa cases). We also tested associations between CRP and IL-6 tagSNPs and PCa risk, focusing on SNPs that are known to associate with circulating CRP and/or IL-6. Neither CRP nor IL-6 blood concentrations was associated with PCa risk. The C allele of IL-6 SNP rs1800795 (-174), a known functional variant, was associated with increased risk in a dominant model (HR=1.44; 95% CI=1.03-2.01; p=0.03), but was not statistically significant after accounting for multiple tests (permutation p=0.21). Our results suggest that circulating CRP and IL-6 do not influence PCa risk. SNPs at the CRP locus are not associated with PCa risk in this cohort, while the association between rs1800795 and PCa risk warrants further investigation.
This paper presents a numerical model for the closure of a two-dimensional island polynya, assuming that the pile-up depth
H of consolidated new ice at the polynya edge (during opening) and at the ...coast (during closing) is constant. The polynya closing time
T is found to be relatively insensitive to ice drift orientation, and the quotient
|
U
|/|
u
|
, where
u
and
U
are the frazil and consolidated ice velocities, respectively. Also,
T is weakly dependent on the island length
D, except when both the onset of closure occurs significantly before the opening polynya steady-state is reached, and also
D≲
L
a, the alongshore adjustment length scale. However,
T is found to be sensitive to
F/
F
o, where
F and
F
o are the constant frazil ice production rates during polynya closing and opening, respectively. We exploit the parameter dependence of
T as a function of
F,
F
o,
D,
u
,
U
and
H to derive an approximate expression for the closing time that is accurate to within ∼8%, assuming that the polynya closes from an initial area that is close to its steady-state area.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Phantoms provide valuable platforms for testing of medical devices including microwave diagnostic systems. This work describes a 3D printable solid tissue-mimicking material (TMM) for the production ...of such phantoms. The TMM is fabricated from ABS, SEBS and Carbon Black. The polymers ABS and SEBS produce a material that is 3D printable, robust and mechanically stable. Adjustment of the percentage of Carbon Black in a mixture alters the dielectric properties of the mixture. A variety of such mixtures were fabricated into 3D printable spools and the dielectric properties were measured across the 0.5 - 8.5 GHz band. The dielectric properties of a wide biological range are covered with the ability to emulate tissues within the range. The material hence can be used to print anatomically realistic and dielectrically accurate phantoms that can be multi-layered and as complex as desired depending on the study.
19 cases of malignant melanoma (MM) were observed during 1972-77 among approximately 5100 employees of the Lawrence Livermore National Laboratory, where high energy physics research is conducted. ...This number was significantly higher (p less than 2 X 10(-6)) than that expected in a comparable age/race/sex/geographical segment of the population of the San Francisco Bay Area. The excess seemed to occur only among laboratory employees and not among the surrounding community, which suggests that an occupational factor is responsible. Preliminary case-comparison findings suggest that MM risk is not associated with length of employment at the laboratory nor with type of monitored radiation exposure. Although the data did not support an association between MM incidence and all scientific job classifications combined, an excess relative risk was observed among chemists. The reasons for the MM excess have not been identified.
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