We assess the measurement of hyperspectral reflectance for outdoor monitoring of green algae and cyanobacteria cultures with a multichannel, fiber-coupled spectroradiometer. Reflectance data acquired ...over a 4-week period are interpreted via numerical inversion of a reflectance model, in which the above-water reflectance is expressed as a quadratic function of the single backscattering albedo, which is dependent on the absorption and backscatter coefficients. The absorption coefficient is treated as the sum of component spectra consisting of the cultured species (green algae or cyanobacteria), dissolved organic matter, and water (including the temperature dependence of the water absorption spectrum). The backscatter coefficient is approximated as the scaled Hilbert transform of the culture absorption spectrum with a wavelength-independent vertical offset. Additional terms in the reflectance model account for the pigment fluorescence features and the water-surface reflection of sunlight and skylight. For the green algae and cyanobacteria, the wavelength-independent vertical offset of the backscatter coefficient is found to scale linearly with daily dry weight measurements, providing the capability for a nonsampling measurement of biomass in outdoor ponds. Other fitting parameters in the reflectance model are compared with auxiliary measurements and physics-based calculations. The model-derived magnitudes of sunlight and skylight water-surface reflections compare favorably with Fresnel reflectance calculations, while the model-derived quantum efficiency of Chl-a fluorescence is found to be in agreement with literature values. Finally, the water temperatures derived from the reflectance model exhibit excellent agreement with thermocouple measurements during the morning hours but correspond to significantly elevated temperatures in the afternoon hours.
Emission spectra from multiply-charged Sn5+-Sn10+ ions are recorded from an electron beam ion trap (EBIT) and from laser-produced plasma (LPP) in the extreme ultraviolet range relevant for ...nanolithographic applications. Features in the wavelength regime between 12.6 and 20.8 nm are studied. Using the Cowan code, emission line features of the charge-state-resolved Sn ion spectra obtained from the EBIT are identified. Emission features from tin LPP either from a liquid micro-droplet or planar solid target are subsequently identified and assigned to specific charge states using the EBIT data. For the planar solid tin target, the 4d-5p transitions of Sn8+-Sn10+ ions are shown to dominate the long-wavelength part of the measured spectrum and transitions of type 4d-4f + 4p-4d are visible in absorption. For the droplet target case, a clear increase in the charge state distribution with increasing laser intensity is observed. This qualitatively demonstrates the potential of using long-wavelength out-of-band emission features to probe the charge states contributing to the strong unresolved transition array at 13.5 nm relevant for nanolithography.
Objective:To determine whether the phosphorescent probe Oxyphor R2 (a palladium porphyrin dendrimer) becomes extravasated within normotensive skeletal muscle, R2 perfusion and washout studies were ...performed using a perfused rat hindlimb preparation. Methods:Phosphorescence signals were monitored in tibialis anterior muscles after 35 min of R2 blood perfusion and across a subsequent washout period that included vasodilation (sodium nitroprusside, SNP, ∼3 × 10−2M). Results:Two responses were evident: Group 1(n= 4)-Inflowing blood pressure and vascular conductance remained stable close to initial values and subsequently a marked vasodilation was evident with SNP (vascular conductance; R2 blood perfusion, 0.096 ± 0.005; washout, pre-SNP, 0.085 ± 0.005, post-SNP, 0.110 ± 0.005 mL/min/mmHg, p< .05, for pre- vs. post-SNP). Baseline phosphorescence signals could be monitored up to 99 ± 36 s post-SNP when the phosphorescence signal disappeared. For these muscles, palladium content was undetectable. Group 2(n= 3)-Inflowing blood pressure increased 112% and vascular conductance fell ∼50%. These hindlimbs were unresponsive to SNP, phosphorescence signal was undiminished by washout and SNP, and muscles became edematous. Conclusions:These results suggest that in normotensive muscle (i.e., Group 1 above), extravasation of phosphorescent probe R2 over 35 min of perfusion is insufficient to yield a detectable phosphorescence signal in skeletal muscle. Microcirculation(2004) 11,317-326. doi:10.1080/10739680490437487
Abstract only
The cardinal symptom in heart failure with preserved ejection fraction (HFpEF) is severe exercise intolerance. Limited understanding of HFpEF pathophysiology has precluded the ...development of effective therapies. We examined the effects of HFpEF on nitric oxide (NO)‐mediated regulation of skeletal muscle capillary hemodynamics. The hypothesis was tested that HFpEF would reduce the proportion of capillaries supporting continuous red blood cell (RBC) flow and impair microvascular hemodynamics in perfused capillaries partly via deteriorations in NO‐mediated function.
METHODS
Intravital microscopy was used to evaluate the resting spinotrapezius muscle in old male Spontaneously Hypertensive Rats (SHR; n=7) and healthy normotensive Wistar‐Kyoto rats (WKY; n=5). Presence of HFpEF in SHR rats was determined using
in vivo
(echocardiography and micromanometer) and
post‐mortem
evaluation of cardiac structure and function. Capillary lumen diameter (
d
cap
), %RBC‐perfused capillaries, and RBC flux (
f
RBC
), velocity (
V
RBC
) and hematocrit (Hct
cap
) were assessed at physiological sarcomere lengths (2.8±0.1 μm) under control (CON) and non‐selective NO synthase blockade (L‐NAME; 1.5 mM) superfusion conditions.
RESULTS
Compared to WKY, SHR had elevated left ventricular end‐diastolic pressure (LVEDP; SHR: 11.3±1.3, WKY: 6.9±1.1 mmHg;
P
<0.05), preserved LV ejection fraction (EF; 76±3 and 81±4%;
P
>0.05) and fractional shortening (FS; 41±3 and 46±4%;
P
>0.05), and increased LV mass/body mass (2.54±0.09 and 2.01±0.04 mg/g;
P
<0.05). As expected, mean arterial pressure was higher in SHR compared to WKY under CON (139±14 and 93±5 mmHg, respectively;
P
<0.05) with no changes produced by L‐NAME (
P
>0.05). There were no differences in the %RBC‐flowing capillaries between SHR and WKY under CON (88±2 and 92±2%;
P
>0.05) or L‐NAME (
P
>0.05). In RBC‐flowing capillaries under CON, SHR had lower
f
RBC
(10.9±1.3 and 13.7±1.4 cells/s) and
V
RBC
(142±14 and 185±11 μm/s) than WKY (
P
<0.05 for both). L‐NAME reduced
f
RBC
in WKY (7.6±0.6;
P
<0.05) but not SHR (10.0±1.0 cells/s;
P
>0.05). Moreover, L‐NAME induced a greater magnitude of
V
RBC
reduction in WKY (42±3%) than SHR (12±5%;
P
<0.05). No differences in Hct
cap
were observed between SHR and WKY under CON (0.25±0.01 and 0.23±0.02) or L‐NAME (
P
>0.05 for all). Similarly, no differences in
d
cap
were seen between SHR and WKY under CON (4.9±0.1 and 5.1±0.1 μm) or L‐NAME (
P
>0.05 for all).
CONCLUSIONS
SHR displayed several cardiovascular alterations consistent with HFpEF, including elevated LVEDP, preserved EF and FS, and increased LV mass/body mass. Although not impacting
d
cap
or Hct
cap
, SHR showed marked reductions in
f
RBC
and
V
RBC
resulting partly from impaired NO‐mediated function. These alterations in microvascular O
2
perfusion likely contribute to exercise intolerance in HFpEF. These data thus reveal important mechanistic clues into muscle dysfunction in this disease and identify the skeletal muscle capillary network as a potential therapeutic target in HFpEF.
Support or Funding Information
NIH HL‐2‐108328
The liver has an extraordinary capacity to regenerate through activation of key molecular pathways. However, central regulators controlling liver regeneration remain insufficiently studied. Here, we ...show that B cell–deficient animals failed to induce sufficient liver regeneration after partial hepatectomy (PHx). Consistently, adoptive transfer of B cells could rescue defective liver regeneration. B cell–mediated lymphotoxin beta production promoted recovery from PHx. Absence of B cells coincided with loss of splenic cluster of differentiation 169–positive (CD169+) macrophages. Moreover, depletion of CD169+ cells resulted in defective liver regeneration and decreased survival, which was associated with reduced hepatocyte proliferation. Mechanistically, CD169+ cells contributed to liver regeneration by inducing hepatic interleukin‐6 (IL‐6) production and signal transducer and activator of transcription 3 activation. Accordingly, treatment of CD169+ cell–depleted animals with IL‐6/IL‐6 receptor rescued liver regeneration and severe pathology following PHx. Conclusion: We identified CD169+ cells to be a central trigger for liver regeneration, by inducing key signaling pathways important for liver regeneration.
Abstract Several theoretical and empirical studies have suggested that immunocompetence may act as a constraint on learning, due to a trade-off in investment in the two processes. Here we tested ...whether experimentally depressing immune responsiveness of male BKW mice using antithymocyte serum (ATS) would lead to reduced learning performance in a radial maze task. Correct choices in the maze were indicated by the presence of familiar odours, incorrect choices by unfamiliar odours. We showed that temporarily depressing cellular immunity led to a reduction in performance in terms of a reduced proportion of correct choices. We also found a positive relationship between the proportion of correct entries over the period of testing and haemagglutination titre, indicating that mice showing greater immune responsiveness performed better in the maze. We conclude that depressing the immune system reduces learning performance in a combined odour/spatial learning task, and that some individuals are better able to compensate for the experimental immunodepression. In contrast to previous studies, there was no evidence that the effect of ATS was mediated by associated changes in corticosterone or testosterone secretion. There were no significant effects of the presence of female odour on learning performance, and therefore no evidence that the down regulation of learning in relation to immune depression was influenced by apparent reproductive opportunity.
Introduction
Mechanical ventilation (MV) is a life‐saving intervention and is employed in Intensive Care Units across the world. Previous work has shown a substantial time‐dependent reduction in ...diaphragmatic blood flow and O2 delivery with MV that may contribute to ventilator‐induced diaphragm dysfunction. However, the precise mechanism responsible for these alterations in blood flow are unknown. Given the reduction in diaphragm blood flow with prolonged MV, we tested the hypothesis that prolonged MV (e.g. 6 hours) enhances diaphragm arteriole contractile responses to alpha‐adrenergic agonists.
Methods
Female Sprague Dawley rats (5–8 mo) were divided into spontaneous breathing (SPB; n= 10) and MV (n= 3). Following SPB and 6 hours of MV, diaphragm arterioles (~200mm diameter, ~2mm in length) were isolated, cannulated, and pressurized to develop spontaneous tone. Thereafter, contractile responses to cumulative doses of norepinephrine (NE) and phenylephrine (PE) (10−9 to 10−4M) were determined.
Results and Conclusion
From this preliminary data, vasoconstrictor responses to NE, and PE in diaphragm arterioles were not different after prolonged MV (% max constriction, NE=23.3± 20.47, PE=16.8± 16.41 compared to SPB (% max constriction, NE= 37.5± 16.71 (P = 0.27); PE= 38.03± 21.76 (P =0.098). Between SPB and MV % max constriction with NE, there was mean difference of 14.2%, and 21.2% with PE. Additional studies are under way to increase the sample size herein. These investigations will seek to resolve the impact of prolonged MV on the diaphragm resistance vasculature and responsiveness to these (i.e. NE, PE) and other vasoactive mediators such as Angiotensin‐II and Endothelin‐1 that may be upregulated with MV as well as potential structural alterations.
Support or Funding Information
NIH (1 R15 HL137156‐01A1)
This is from the Experimental Biology 2019 Meeting. There is no full text article associated with this published in The FASEB Journal.
We analysed 3 independently collected datasets of fully censused helminth burdens in wood mice, Apodemus sylvaticus, testing the a priori hypothesis of Behnke et al. (2005) that the presence of the ...intestinal nematode Heligmosomoides polygyrus predisposes wood mice to carrying other species of helminths. In Portugal, mice carrying H. polygyrus showed a higher prevalence of other helminths but the magnitude of the effect was seasonal. In Egham, mice with H. polygyrus showed a higher prevalence of other helminth species, not confounded by other factors. In Malham Tarn, mice carrying H. polygyrus were more likely to be infected with other species, but only among older mice. Allowing for other factors, heavy residual H. polygyrus infections carried more species of other helminths in both the Portugal and Egham data; species richness in Malham was too low to conduct a similar analysis, but as H. polygyrus worm burdens increased, so the prevalence of other helminths also increased. Our results support those of Behnke et al. (2005), providing firm evidence that at the level of species richness a highly predictable element of co-infections in wood mice has now been defined: infection with H. polygyrus has detectable consequences for the susceptibility of wood mice to other intestinal helminth species.
Assessment of vancomycin-resistant Enterococcus faecium (VREfm) prevalence upon hospital admission and analysis of risk factors for colonization.
From 2014 to 2018, patients were recruited within ...72 hours of admission to seven participating German university hospitals, screened for VREfm and questioned for potential risk factors (prior multidrug-resistant organism detection, current/prior antibiotic consumption, prior hospital, rehabilitation or long-term care facility stay, international travel, animal contact and proton pump inhibitor PPI/antacid therapy). Genotype analysis was done using cgMLST typing. Multivariable analysis was performed.
In 5 years, 265 of 17,349 included patients were colonized with VREfm (a prevalence of 1.5%). Risk factors for VREfm colonization were age (adjusted OR aOR, 1.02; 95% CI, 1.01–1.03), previous (aOR, 2.71; 95% CI, 1.87–3.92) or current (aOR, 2.91; 95% CI, 2.60–3.24) antibiotic treatment, prior multidrug-resistant organism detection (aOR, 2.83; 95% CI, 2.21–3.63), prior stay in a long-term care facility (aOR, 2.19; 95% CI, 1.62–2.97), prior stay in a hospital (aOR, 2.91; 95% CI, 2.05–4.13) and prior consumption of PPI/antacids (aOR, 1.29; 95% CI, 1.18–1.41). Overall, the VREfm admission prevalence increased by 33% each year and 2% each year of life. 250 of 265 isolates were genotyped and 141 (53.2%) of the VREfm were the emerging ST117. Multivariable analysis showed that ST117 and non-ST117 VREfm colonized patients differed with respect to admission year and prior multidrug-resistant organism detection.
Age, healthcare contacts and antibiotic and PPI/antacid consumption increase the individual risk of VREfm colonization. The VREfm admission prevalence increase in Germany is mainly driven by the emergence of ST117.
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