Microbeads find widespread usage in personal care items and cosmetics, serving as exfoliants or scrubbing agents. Their micro-scale size poses challenges in effective drainage capture and given their ...origin from non-biodegradable oil-based plastics, this contributes substantially to marine pollution. In this study, microbeads were prepared by a simple yet scalable melt homogenization method using four types of polyhydroxyalkanoates (PHA), namely poly(R)-3-hydroxybutyrate (P(3HB)), poly(R)-3-hydroxybutyrate-co-(R)-3-hydroxyvalerate (P(3HB-co-3HV)), poly(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate (P(3HB-co-3HHx)) and poly(R)-3-hydroxybutyrate-co-(R)-4-hydroxyvalerate (P(3HB-co-4HB)). Microbeads with different surface smoothness, compressive strength (6.2-13.3 MPa) and diameter (from 1 ~ 150 μm) could be produced. The microbeads were subjected to a comprehensive degradation analysis using three techniques: enzymatic, Biochemical Oxygen Demand (BOD) evaluations, and in situ degradation tests in the deep-sea off Misaki Port in the northern Pacific Ocean (depth of 757 m). Qualitatively, results from enzymatic and in situ degradation demonstrated significant degradation within one week and five months, respectively. Quantitatively, BOD findings indicated that all PHA microbeads degraded similarly to cellulose (~ 85% biodegradability in 25 days). In conclusion, PHA microbeads from this study exhibit promising potential as alternatives to conventional non-biodegradable microbeads.
A survey conducted by Abiomed, Inc. revealed that 10 of 60 patients who received ventricular assistance via the AB5000 ventricular assist device (VAD) experienced hemolysis. The present study was ...conducted to investigate which factors influence hemolysis under pulsatile-flow VADs such as the AB5000. We compared the specificity of the AB5000 and its driving console with those of the NIPRO-VAD and VCT50χ under severe heart failure conditions using a mock circulatory system with a glycerol water solution. We used the mock circuit with bovine blood to confirm which pump conditions were most likely to cause hemolysis. In addition, we measured the shear velocity using particle image velocimetry by analyzing the seeding particle motion for both the AB5000 and NIPRO-VAD under the same conditions as those indicated in the initial experiment. Finally, we analyzed the correlation between negative pressure, exposure time, and hemolysis by continuously exposing fixed vacuum pressures for fixed times in a sealed device injected with bovine blood. Applying higher vacuum pressure to the AB5000 pump yielded a larger minimum inlet pressure and a longer exposure time when the negative pressure was under − 10 mmHg. The plasma-free hemoglobin increased as more negative pressure was driven into the AB5000 pump. Moreover, the negative pressure interacted with the exposure time, inducing hemolysis. This study revealed that negative pressure and exposure time were both associated with hemolysis.
Abstract
Background
Body temperature (BT) is thought to have associations with oxygen consumption (VO
2
). However, there have been few studies in which the association between systemic VO
2
and BT ...in humans was investigated in a wide range of BTs. The aims of this study were 1) to determine the association between VO
2
and age and 2) to determine the association between VO
2
and BT.
Methods
This study was a retrospective study of patients who underwent surgery under general anesthesia at a tertiary teaching hospital. VO
2
was measured by the Dräger Perseus A500 anesthesia workstation (Dräger Medical, Lubeck, Germany). The associations of VO
2
with age and BT were examined using spline regression and multivariable regression analysis with a random effect.
Results
A total of 7,567 cases were included in this study. A linear spline with one knot shows that VO
2
was reduced by 2.1 ml/kg/min with one year of age (
p
< 0.001) among patients less than 18 years of age and that there was no significant change in VO
2
among patients 18 years of age or older (estimate: 0.014 ml/kg/min, p = 0.08). VO
2
in all bands of BT < 36.0 °C was not significantly different from VO
2
in BT > = 36 °C and < 36.5 °C. Multivariable linear regression analysis showed that compared with VO
2
in BT > = 36 °C and < 36.5 °C as a reference, VO
2
levels were significantly higher by 0.57 ml/kg/min in BT > = 36.5 °C and < 37 °C (
p
< 0.001), by 1.8 ml/kg/min in BT > = 37 °C and < 37.5 °C (
p
< 0.001), by 3.6 ml/kg/min in BT > = 37.5 °C and < 38 °C (
p
< 0.001), by 4.9 ml/kg/min in BT > = 38 °C and < 38.5 °C (
p
< 0.001), and by 5.7 ml/kg/min in BT > = 38.5 °C (
p
< 0.001). The associations between VO
2
and BT were significantly different among categorized age groups (
p
= 0.03).
Conclusions
VO
2
increases in parallel with increase in body temperature in a hyperthermic state but remains constant in a hypothermic state. Neonates and infants, who have high VO
2
, may have a large systemic organ response in VO
2
to change in BT.
Phylogenetic evidence suggests a shared ancestry between mitochondria and modern Proteobacteria, a phylum including several genera of intracellular pathogens. Studying these diverse pathogens, ...particularly during intracellular infection of their hosts, can reveal characteristics potentially representative of the mitochondrial-Proteobacterial ancestor by identifying traits shared with mitochondria. While transcriptomic approaches can provide global insights into intracellular acclimatization by pathogens, they are often limited by excess host RNAs in extracts. Here, we developed a method employing magnetic nanoparticles to enrich RNA from an intracellular Gammaproteobacterium,
, within zebrafish,
, fin fibroblasts, enabling comprehensive exploration of the bacterial transcriptome. Our findings revealed that the intracellular
transcriptome reflects a mitochondrion-like energy generation program characterized by the suppression of glycolysis and sugar transport, coupled with upregulation of the tricarboxylic acid (TCA) cycle and alternative import of simple organic acids that directly flux into TCA cycle intermediates or electron transport chain donors. Additionally, genes predicted to be members of excludons, loci of gene pairs antagonistically co-regulated by overlapping antisense transcription, are significantly enriched in the set of all genes with perturbed sense and antisense transcription, suggesting a general but important involvement of excludons with intracellular acclimatization. Notably, genes involved with the activation of the mitochondrion-like energy generation program, specifically with metabolite import and glycolysis, are also members of predicted excludons. Other intracellular Proteobacterial pathogens appear to employ a similar mitochondrion-like energy generation program, suggesting a potentially conserved mechanism for optimized energy acquisition from hosts centered around the TCA cycle.IMPORTANCEPhylogenetic evidence suggests that mitochondria and Proteobacteria, a phylum encompassing various intracellular pathogens, share a common ancestral lineage. In this study, we developed a novel method employing magnetic nanoparticles to explore the transcriptome of an aquatic Gammaproteobacterium,
, during intracellular infection of host cells. We show that the strategy
uses to generate energy strikingly mirrors the function of mitochondria-energy generators devoid of glycolytic processes. Notably, several implicated genes are members of excludons-gene pairs antagonistically co-regulated by overlapping antisense transcription. Other intracellular Proteobacterial pathogens appear to adopt a similar mitochondrion-like energy generation program, indicating a possibly conserved strategy for optimized energy acquisition from hosts centered around the tricarboxylic acid cycle.
Freshwater produced by the surface melting of ice sheets is commonly discharged into ocean fjords from the bottom of deep fjord-terminating glaciers. The discharge of the freshwater forms upwelling ...plumes in front of the glacier calving face. This study simulates the meltwater plumes emanated into an unstratified environment using a nonhydrostatic ocean model with an unstructured mesh and subgrid-scale mixing calibrated by comparison to established plume theory. The presence of an ice face reduces the entrainment of seawater into the meltwater plumes, so the plumes remain attached to the ice front, in contrast to previous simple models. Ice melting increases with height above the discharge, also in contrast to some simple models, and the authors speculate that this "overcutting" may contribute to the tendency of icebergs to topple inwards toward the ice face upon calving. The overall melt rate is found to increase with discharge flux only up to a critical value, which depends on the channel size. The melt rate is not a simple function of the subglacial discharge flux, as assumed by many previous studies. For a given discharge flux, the geometry of the plume source also significantly affects the melting, with higher melt rates obtained for a thinner, wider source. In a wider channel, two plumes are emanated near the source and these plumes eventually coalesce. Such merged meltwater plumes ascend faster and increase the maximum melt rate near the center of the channel. The melt rate per unit discharge decreases as the subglacial system becomes more channelized.
Abstract
Diffusive convection–favorable thermohaline staircases are observed directly beneath George VI Ice Shelf, Antarctica. A thermohaline staircase is one of the most pronounced manifestations of ...double-diffusive convection. Cooling and freshening of the ocean by melting ice produces cool, freshwater above the warmer, saltier water, the water mass distribution favorable to a type of double-diffusive convection known as diffusive convection. While the vertical distribution of water masses can be susceptible to diffusive convection, none of the observations beneath ice shelves so far have shown signals of this process and its effect on melting ice shelves is uncertain. The melt rate of ice shelves is commonly estimated using a parameterization based on a three-equation model, which assumes a fully developed, unstratified turbulent flow over hydraulically smooth surfaces. These prerequisites are clearly not met in the presence of a thermohaline staircase. The basal melt rate is estimated by applying an existing heat flux parameterization for diffusive convection in conjunction with the measurements of oceanic conditions at one site beneath George VI Ice Shelf. These estimates yield a possible range of melt rates between 0.1 and 1.3 m yr
−1
, where the observed melt rate of this site is ~1.4 m yr
−1
. Limitations of the formulation and implications of diffusive convection beneath ice shelves are discussed.
Microbes can decompose biodegradable plastics on land, rivers and seashore. However, it is unclear whether deep-sea microbes can degrade biodegradable plastics in the extreme environmental conditions ...of the seafloor. Here, we report microbial decomposition of representative biodegradable plastics (polyhydroxyalkanoates, biodegradable polyesters, and polysaccharide esters) at diverse deep-sea floor locations ranging in depth from 757 to 5552 m. The degradation of samples was evaluated in terms of weight loss, reduction in material thickness, and surface morphological changes. Poly(L-lactic acid) did not degrade at either shore or deep-sea sites, while other biodegradable polyesters, polyhydroxyalkanoates, and polysaccharide esters were degraded. The rate of degradation slowed with water depth. We analysed the plastic-associated microbial communities by 16S rRNA gene amplicon sequencing and metagenomics. Several dominant microorganisms carried genes potentially encoding plastic-degrading enzymes such as polyhydroxyalkanoate depolymerases and cutinases/polyesterases. Analysis of available metagenomic datasets indicated that these microorganisms are present in other deep-sea locations. Our results confirm that biodegradable plastics can be degraded by the action of microorganisms on the deep-sea floor, although with much less efficiency than in coastal settings.
Ice shelves in the Amundsen Sea Embayment have thinned, accelerating the seaward flow of ice sheets upstream over recent decades. This imbalance is caused by an increase in the ocean‐driven melting ...of the ice shelves. Observations and models show that the ocean heat content reaching the ice shelves is sensitive to the depth of thermocline, which separates the cool, fresh surface waters from warm, salty waters. Yet the processes controlling the variability of thermocline depth remain poorly constrained. Here we quantify the oceanic conditions and ocean‐driven melting of Cosgrove, Pine Island Glacier (PIG), Thwaites, Crosson, and Dotson ice shelves in the Amundsen Sea Embayment from 1991 to 2014 using a general circulation model. Ice‐shelf melting is coupled to variability in the wind field and the sea‐ice motions over the continental shelf break and associated onshore advection of warm waters in deep troughs. The layer of warm, salty waters at the calving front of PIG and Thwaites is thicker in austral spring (June–October) than in austral summer (December–March), whereas the seasonal cycle at the calving front of Dotson is reversed. Furthermore, the ocean‐driven melting in PIG is enhanced by an asymmetric response to changes in ocean heat transport anomalies at the continental shelf break: melting responds more rapidly to increases in ocean heat transport than to decreases. This asymmetry is caused by the inland deepening of bathymetry and the glacial meltwater circulation around the ice shelf.
Key Points
The onshore heat transport is coupled to the offshore zonal wind stress
The seasonal cycle of ice‐shelf melting depends on its thickness distribution
Asymmetric response to change in ocean heat transport enhances ice‐shelf melting
Acquired von Willebrand syndrome (aVWS) develops with various underlying diseases. We herein report an individual with aVWS associated with mucosa-associated lymphoid tissue lymphoma in the lungs ...complicated by hyperviscosity syndrome, Sjögren's syndrome, and hypothyroidism. This patient developed life-threatening hemorrhaging during a lung biopsy despite transfusion of concentrate of plasma-derived VWF/factor VIII. The use of rituximab caused remission of the lymphoma and hyperviscosity syndrome in parallel with the resolution of aVWS. Thus, lymphoma and hyperviscosity might result in aVWS. Invasive procedures with a risk of bleeding should be avoided in individuals with aVWS.
Cellulose–chitosan gels were prepared using a LiOH/urea aqueous solution for a co-dissolution. After cellulose and chitosan were dissolved by a freeze–thaw process, the hydrogels were prepared via ...regeneration in methanol and washing with water. Finally, freeze-dried cellulose–chitosan gels were obtained via solvent exchange (water → ethanol →
t
-butyl alcohol) followed by freeze-drying. The chitosan contents of the gels were determined by the amino and nitrogen contents, confirming formation at the blend ratio of cellulose and chitosan. Structural and thermal analyses showed that the data profiles were proportional to the content of each component. Although all gels exhibited a three-dimensional porous structure, the introduction of chitosan remarkably increased pore size, resulting in lower transmittance of the hydrogels. The surface area of the cellulose–chitosan gels increased from 247 to 337 m
2
/g, and the swelling ratio gradually improved with an increase in chitosan content, especially up to 22.9 g/g at pH 5 due to protonation of amino groups. The increase in chitosan content significantly reduced the mechanical strength, while the adsorption capacity of anionic dye was greatly enhanced.
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