Since the end of 19th century, the Vistula has entered the Gulf of Gdańsk directly through an artificial channel. This direct inflow without a transitional estuary causes the water masses to mix in the gulf. Depending Selleckchem GKT137831 on the wind and the currents, the two water

bodies can mix vigorously, creating dynamic water fronts or broken off portions of riverine waters moving into the gulf as freshwater plumes. Conveyed by rivers, terrestrial organic matter may be a very important source of energy for the Baltic’s trophic levels (Rolff & Elmgren 2000). In recent years, the structure and activity of bacterial communities have been investigated in several estuaries along salinity gradients (Langenheder et al. 2004, Kirchman et al. 2005, Campbell & Kirchman 2013). In the Skagerrak-Kattegat water front area, along salinity gradients ranging from 21 to 30, differences in bacterioplankton composition were due to qualitative differences in bacterial growth conditions, as documented by changes in phytoplankton biomass, dissolved organic carbon and bacterial production (Pinhassi et al. 2003). The Landsort Deep surface waters (salinity between 5.9 and 6.7) were dominated by Bacteroidetes and a mixture of typical

freshwater bacteria like Actinobacteria, Verrucomicrobia and Betaproteobacteria. Marine taxa were not found ( Riemann et al. 2008). In the coastal zone of the Gulf of Gdańsk (salinity ca 7), Piwosz et al. (2013) recorded the activity of freshwater lineages of acI Actinobacteria, LD12 Alphaproteobacteria and the betaproteobacterial genus Limnohabitans (R-BT), while the marine lineage SAR11 was thought to have originated from a passive inflow from the selleck chemical Baltic Proper. Studies performed along the 2000 km salinity gradient of the Baltic Sea showed that marine SAR11 and Rhodobacteriaceae were noted mainly in the marine part of the Baltic Sea or below 50 m depth in the Baltic Proper ( Herlemann et al. 2011). Roseobacter, which are very abundant in marine environments and also culturable, have been broadly TCL studied from different aspects ( Buchan et al. 2005, Wagner-Döbler & Biebl

2006, Dang et al. 2008). They are often associated with diatoms in cultures ( Allgaier et al. 2003) and frequently observed in the phytoplankton-attached fraction of bacterioplankton in environmental samples ( Rooney-Varga et al. 2005). In a previous study, a significantly higher bacterial production to primary production ratio was observed in the inner part of the Gulf of Gdańsk (Ameryk et al. 2005). The aim of this study was to investigate changes along the salinity gradient, as well as other environmental parameters, with the focus on the abundance and composition of bacterioplankton populations. Bacterial interactions with some phytoplankton organisms, especially Coscinodiscus sp. were noted by chance. Based on a wide range of methods, this study gave a precise snapshot of the microbial system observed during one sampling day.

As the composition and relative

proportion of PCB congeners are comparable among stations and throughout time, the flux of PCBs to the western Barents Sea has remained relatively constant over time. Skotvold & Savinov (2003) evaluated several chemicals as potential sources of Bleomycin PCBs to this region of the Arctic. These included Clophens produced in Germany, Aroclor (USA), Kanechlors (Japan) and Sovol (Russia). They found that the dominance of CB 101, CB 138 and CB 153, particularly at the northern stations, points to global emission sources, namely of Clophen A60 and Aroclor 1260, as the main sources. On the basis of contaminant burial fluxes, inventories and congener composition, we conclude that the western Barents Sea is a sink for PCBs supplied by long-range atmospheric transport from lower latitude sources (Breivik et al. 2002), but other sources may Quizartinib mouse also be important, e.g. sea ice melting. For

PAHs, proximity to combustion sources is the major factor controlling both the distribution and composition patterns in sediments. The levels of both groups of volatile organic compounds are relatively low compared to areas adjacent to industrial activities. For the heavily industrialized Guba Pechenga area of north-west Russia, Savinov et al. (2003) report ∑11 PCB levels in surface sediments reaching 38 ng g−1 d.w−1 (∑11 PCBs = congeners measured in the present study + CB31, CB 105, CB 156 and CB209). The PCB compositions in sediments from the SE Barents Sea and Kara Sea Vitamin B12 have also been shown to reflect the predominant influence of local PCB sources (Savinov et al. 2003, Skotvold & Savinov 2003).

The levels of PAHs in sediments reported in the present investigation are well below pollution levels that would raise concerns for marine organisms or human health. BKF, together with BAA, BAP, IND and DBA, are known carcinogenic compounds; the sum of these is designated as CPAH (Savinov et al. 2003). In the present study, maximum CPAH concentrations are 61 ng g−1 d.w−1 (station I, layer 0–1 cm), a value consistent with surface sediment levels from other areas in the region, e.g. the White Sea (< 150 ng g−1 d.w−1 – Savinov et al. 2000), Kara Sea (< 110 ng g−1 d.w−1 – Dahle et al. 2003) and the coastal Barents Sea (< 240 ng g−1 d.w−1Savinov et al. 2003). In contrast, CPAH levels in several Norwegian fjords affected by direct discharges from aluminium and manganese-alloy smelters are considerably higher (~800 × 103 ng g −1 d.w -1) (Næs & Oug 1998). Higher concentrations have also been detected in the vicinity of Guba Pechenga (up to ~ 2500 ng g−1 d.w−1) (Savinov et al. 2003). The combined influences of sediment mixing (< 0.1 cm2 yr−1) and low sedimentation velocities (< 0.1 mm yr−1) in the western Barents Sea (Carroll et al. 2008b, Zaborska et al. 2008), restrict the temporal resolution of down-core changes in contaminant concentrations.

Specifically, cadmium, lead and arsenic smoke deliveries for this cigarette under ISO smoking regime were 34.6 ± 3.2, 12.3 ± 1.1 and 3.05 ± 0.35 ng/cigarette respectively, in line with a recently organized ring trial results [38]. Dabrafenib concentration In one Korean brand, nicotine was reported as below limit of quantification (LOQ) in analyses under the ISO machine-smoking regime. This sample

was removed from the data set since the assessment of nicotine transfer was part of the data analysis. Only 267 data points were thus available for the smoke yields obtained under the ISO machine-smoking regime, while 567 data points were considered for the analysis of smoke yields obtained under the HCI machine-smoking regime. Data below the limits

of quantification were reported as Z-VAD-FMK in vitro sample. All measured values were above LOQ. Descriptive statistics for the results are presented in Table 2, together with a range of typical mean values reported in previously published surveys. Nicotine levels were also measured since nicotine transfer was required for the assessment of the elements transfer. Smoke yields of arsenic, cadmium, lead and nicotine were measured for each sample under

HCI machine-smoking regime. In addition, the yields under ISO machine smoking regime were also obtained from a subset of the samples (267 retained for the study). Unlike the filler levels, these smoke yields were below the analytical limit of quantification for many samples, Chloroambucil especially when the samples were smoked under ISO. The numbers of samples with levels determined below the limit of quantification are highlighted alongside the descriptive statistics in Table 3 (ISO yields) and Table 4 (HCI yields). Because samples with yields below LOQ were attributed the LOQ value in the calculation of medians and quartiles, some of the statistical data in Table 3 and Table 4 are reported as

In contrast, other investigators have shown a loss of T-cell response to antigenic stimulation [31], while cryopreservation has been shown to induce apoptosis [16]. In addition, sample storage at −30 °C, or temperature rises mimicking sample transport conditions, have been shown to lead to a reduction in T-cell functionality [40] and cell damage [13]. Despite such investigations, there is a lack of data about the influence of temperature rises during sample storage,

sorting and removal, if specimens are cryopreserved in conventional liquid nitrogen tanks without a protective hood system to guard against temperature fluctuations. Our studies provide additional information that the quality of sample storage

and handling is critical for maintaining PBMC viability, selleck PBMC recovery and T-cell functionality. Exposure of cryopreserved PBMC to suboptimal sample storage with repeated temperature fluctuations can lead to a reduction in sample quality. We have demonstrated that temperature shifts during storage reduce cell recovery and viability as measured by trypan blue dye exclusion and could resulted in significant cell death, especially after overnight culture. Other groups have also reported a reduction in cell viability after culture compared to immediately post thaw, suggesting that a population of cells still undergoes DAPT mw apoptosis or necrosis following thawing [21] and [31]. Smith et al. (2007) showed an increase in the percentage of apoptotic cells after cyclical temperature rises and programmed cell death can be induced by physiological signals or by a number of physical events like

heat shock, free radicals, UV light and gamma radiation [43]. Cells can also receive signals that make them predisposed to apoptosis but they do not actually undergo cell death until the final signal is received [7], [8] and [17]. Suboptimal cryopreservation may prime the cells for the apoptotic pathway, without initiating the process. Overnight culture of the cryopreserved cells in the presence of mitogens, that are known 17-DMAG (Alvespimycin) HCl to exist in fetal calf serum, could trigger the primed cells into the death cascade [13], [51] and [52]. We have also demonstrated that cyclical temperature rises during the storage process decrease T-cell functionality after stimulation with CEF and CMV peptide pools. Mimicking sample storage, sample sorting and sample removal processes that use a protective hood system increased the T-cell response by about 23% in comparison to the same procedures without protective hood system. The degree of reduction in T-cell functionality ranged from 0% to 74% and was donor-dependent and not predictable. For that reason it was not possible to apply a correction factor to the results received from the immune assays.

Each electrode chip was fabricated by a semiconducting processes including a photoresist coating, patterning, lift off, and passivation. As can be seen in Fig. 1(a), approximately 250 chips on a 4 in glass wafer were fabricated for each process. A central circle shaped Au electrode with an area of π mm2 was utilized as the working electrode ( Fig 1(b)). An Au-electrode printed circuit board Fulvestrant manufacturer (PCB) chip was fabricated by an electroplating method and two types of PCB chips were made for use in other applications ( Fig 1(c and d)). Functionalization of GO nanosheets with MPHs was achieved by following a previous

study Veerapandian et al. Briefly, 200 μL of MPHs and 40 μL of 3-APTES were added to a tube containing anhydrous C2H5OH and kept for 10 h. After completion of the reaction process, FGO was drop-cast onto the oxygen plasma cleaned Au electrode PCB chip and allowed to evaporate at room temperature for 1 h. After modification of each Au electrode on the wafer, multiple layers were spin coated on the wafer. These layers were composed of a silane coupling layer on top of the FGO-Au electrode

followed by GOX composites, nafion, a silane coupling layer, and a restricted permeable polymer layer to form the multilayer-FGO-Au electrode. A customized reading platform was designed and built for the experiment. Fig. 2(a) shows the layout of the read out main board, the capable analog signal range of the system is between +5 and −5 V. As can be seen in Fig. 2(b), indicated with arrow, five different chips can be placed into the slots Selleckchem GDC-0199 for performing simultaneous measurements of different concentrations of glucose in TES and urine and between-run tests in same

concentration of glucose. All experiments were performed at room temperature in a 5 mL of collected urine samples and TES buffer for characterization. All amperometric measurements were performed at a working electrode potential of +0.6 V. The concentration of glucose in the TES buffer was examined by the fabricated Au-PCBs and the customized platform and the resultant images are displayed in Fig. 3. As can be seen in Fig. 3(a), the amperometric response with Molecular motor glucose concentration has strong proportionality to the concentration as it increases. Fig. 3(b) shows the amperometric responses measured 7 s after the immersion of five different chips with their variations from the mean values on each concentration. The between-run results show that their variations are within 6% from their mean values. Such materials including Ag/AgCl and Pt were not used as reference and auxiliary electrodes in this study despite these being the conventionally used materials in most electrochemical systems. Instead, we used an Au substrate as reference and auxiliary to reduce cost of chip production and increase stability during the field measurements.

2013). Here

we present for the first time data on (1) the occurrence, distribution and density of R. harrisii in the Gulf of Gdańsk, (2) the structure of the benthic communities of which it is a component, and (3) preliminary characteristics of the individuals with regard GSK-3 inhibitor to sex and size. Based on material collected in 2006–2010, this study provides new information on this non-native species. Together with other ecological data (e.g. on food preferences and consumption rate), the results may find application, e.g. in ecological models, or be useful in the development of management strategies for the species. Samples were taken with a bottom dredge (33 × 66 cm, mesh size 0.5 × 0.5 cm) from r/v ‘Oceanograf 2’ at 129 randomly

chosen sampling points located at depths from 5 to 60 m. The dredging time of 5 min as well as the vessel’s speed of 1.5 knots were recorded to estimate the abundance of R. harrisii. In order to obtain information TSA HDAC clinical trial on seasonal variations in Harris mud crab abundance, material was also collected monthly from January to September (excluding May 2009) from two depth profiles located in Gdynia (G) and Sopot (S). Three sampling points were fixed at each profile. The same dredging procedure was repeated three times at each sampling point ( Table 1). At each sampling point temperature (± 0.1°) and salinity (± 0.1 PSU) were determined with a Multi340i multimeter (WTW, Germany). The macrobenthic taxa found in the sample were identified as accurately

as possible, based on Stańczykowska (1986), Żmudziński (1999), Kołodziejczyk & Koperski (2000) and Barnes (2005). The frequency of co-occurring taxa was determined at 46 random sampling points in Puck Bay (n = 17) and in the Gdynia and Sopot area (n = 29). Additional information on the occurrence of R. harrisii in shallow Sclareol waters (< 5 m) was obtained from divers and the local community. After collection, the animals were immediately frozen at − 20 °C. In the laboratory the crabs were sexed on the basis of their abdominal structure and pleopod shape (De Man 1892), and their carapace width was measured (± 0.01 mm) with slide calipers (ECOTONE, Poland). In accordance with Turoboyski (1973), specimens with a carapace width under 4.4 mm were classified as juveniles. The results were expressed as mean plus standard deviation (mean ± SD). The maps were prepared in the ArcGIS 8.x. program. In 2006–2010 Rhithropanopeus harrisii was recorded at 69 out of 129 sampling points, at depths from 0 to 20 m ( Figure 1a). In the samples from Puck Bay, which has a muddy bottom, gammarids were dominant among the organisms co-occurring with R. harrisii. Crangon crangon and Cerastoderma glaucum were recorded in more than 50% of samples containing the Harris mud crab ( Figure 2a).

That is, using ζ=0ζ=0, setting k   and m   according to the grid spacing and holding M2,f,νhM2,f,νh, and νvνv constant, the growth rates can be plotted purely as a function of N2N2. Furthermore, beginning with an initial state where Ri=0.25Ri=0.25, it is known a priori   that N2N2 must increase by a factor of 4 to reach the stable state of Ri=1Ri=1. Then the growth rates can be calculated for a discrete set of values of N2N2 between N02 and

4N02 to predict the SI-stable value of N2N2 that will be reached, and by extension the stable value of Ri  . Note that (23) and (24) require both M2M2 and N2N2 to be constant in space and time and GSI-IX in vitro the perturbations to be small in amplitude, and are approximations to the instantaneous growth rate found by holding N2N2 fixed at each instant in time. The grid spacing ΔxΔx is varied from simulation to simulation to test the hypothesis that the amount of restratification depends on how well the SI modes are resolved. The pseudo-spectral numerical solver uses a IWR1 Two-Thirds Rule de-aliasing (Orszag, 1971) to prevent aliasing of high-wavenumber modes, making the shortest resolved wavelength in the model λ=3Δxλ=3Δx. The higher-resolution

simulations (subscripts 1 through 5) are meant to demonstrate that the restratification can be limited by the stratification and viscosity, not necessarily the model resolution. The lowest-resolution simulations do not resolve the most-restratifying mode, and demonstrate restratification that is limited (subscript 6) and completely negated (subscript 7) due to the model resolution. The dimensional width of the domain varies according to the choice of ΔxΔx for each individual simulation, but the depth of the mixed layer is set to be 300 m in all cases. A uniform grid of size (Ny,Nz)=(128,80)(Ny,Nz)=(128,80) points is used, with the vertical grid spacing set to a constant Δz=5Δz=5 m. Using this number of points in the horizontal ensures that the domain is wide

enough to resolve Immune system multiple SI overturning cells in all cases, and that the largest SI modes will not be excluded even in the finest-resolution runs. The vertical diffusivity κv=1×10-6κv=1×10-6 m2 s−1 was set to be very small to prevent highly stratified fluid from diffusing up from the thermocline, and for simplicity in the stability analysis (Appendix A) the vertical viscosity was set to match this value. At higher values (i.e. κv⩾1×10-4κv⩾1×10-4 m2 s−1), diffusion caused the lowest parts of the mixed layer to become stabilized to SI before the instability became nonlinear. This effectively reduced the lengthscale of the gravest vertical mode and reduced the amount of restratification that could occur.

5 and 7.5 (Figures S3-5). This may account for lower docking scores for prohexadione and trinexapac stereoisomers, compared to N-oxalylglycine,

at both pH 5.5 and 7.5 ( Table 1). The docking scores of all the ligands were lower at pH 7.5 compared to pH 5.5. This could be due to the electrostatic award which was more favorable when the ligands were docked to the Jmjd2a protein prepared at pH 5.5. In general, docking scores and ligand efficiency (i. e. docking score/number of heavy atoms) were best for N-oxalylglycine followed by prohexadione (R-prohexadione–10.1 kcal/mol and–8.2 kcal/mol at pH 5.5 and 7.5, respectively; S-prohexadione–10.3 kcal/mol and–9.3 kcal/mol at pH 5.5 and 7.5, respectively) and then by trinexapac (R-trinexapac–10.2 kcal/mol and–8.3 kcal/mol at pH 5.5 and 7.5, respectively; S-trinexapac–9.4 kcal/mol and–7.6 kcal/mol at pH 5.5 and 7.5, respectively), ( Table 1). Our docking BGB324 in vivo experiments suggest that prohexadione and trinexapac, to a lesser extent, Gefitinib molecular weight may inhibit Jmjd2a, and possibly other KDMs, by directly binding at the 2OG binding site in the active site of KDMs. Jmjd2a demethylates

tri-methylated H3-K9 (H3-K9me3), H3-K9me2, and H3-K36me3 [11]. In order to test our hypothesis that prohexadione and trinexapac act as general inhibitors of recently identified KDMs, Jmjd2a was purified to homogeneity and assayed for the ability of different chemicals e.g. N-oxalylglycine, prohexadione, and trinexapac to inhibit the demethylation of H3-K9me3 into the dimethylated product, H3-K9me2. The results showed that in the absence of N-oxalylglycine and PGRs, Jmjd2a efficiently converted H3-K9me3 peptide into H3-K9me2 ( Figure 1a). However, in the presence of 1 mM N-oxalylglycine, a known inhibitor of iron (II), 2OG-dependent KDMs, no product formation was detected ( Figure 1b).

These results suggest that our assay conditions are suitable for inhibition studies using prohexadione and trinexapac. The presence of 1 mM prohexadione in the reaction mixture completely abrogated the conversion of H3-K9me3 peptide substrate into H3-K9me2 product ( Figure 1c). However, under the same assay condition Inositol monophosphatase 1 only a partial inhibition of Jmjd2a catalytic activity was observed by trinexapac ( Figure 1d). Although our studies were performed with the racemic mixture of trinexapac, which contains both R/S-stereoisomers, a limited inhibition by trinexapac could be due to poor the docking score, especially for the S-trinexapac (–7.6 kcal/mol) at pH 7.5, at which the enzymatic assays were performed. These results demonstrate that prohexadione, and trinexapac to some extent, directly inhibit the catalytic activity of Jmjd2a demethylase. Next, the effects of prohexadione and trinexapac on KDMs were evaluated using neurosphere cultures.

The Ibrutinib latter may serve to “fine tune” their actions in vivo (Schwartz-Albiez, 2012). These results also indicate that this IgG class-dependent cross-reactivity can be reduced by the introduction of PEGs, and this is considered important for the accurate detection of analytes in particular in an artificial array system as the SGA. In order to determine the contribution of non-target binding we assayed P1-, PEG23-, and PEG60-P1 modified beads with fetal calf serum-derived and presumably heterophilic antibodies. The results (Fig. 6B) demonstrate that no substantial binding to all three types of beads was observed for IgM (MFI of around

20) whereas some binding (MFI of around 500) was detected for IgG for the regular P1-beads. This observation is in concordance to the previous experiments (Figs. 5B

and 6A). These IgG signals were reduced for the PEG60-P1 beads to about 100 MFI and for the PEG23-P1 beads to 15 MFI. In summary, unspecific binding was observed almost exclusively when IgGs, but not IgMs were applied as glycan-binding antibodies or as secondary detection antibodies. These data seem to be consistent with existing evidence regarding anti-glycan antibodies. It is known that naturally occurring anti-glycan antibodies are predominantly of IgM class and are produced by CD5 positive B1 cells expressing a distinct pattern of surface markers, but not conventional B cells (Viau and Zouali, 2005, Vollmers and Brandlein, 2009, Griffin et al., 2011 and Bovin, 2013). Despite their polyreactive nature anti-glycan IgMs appear to be highly specific in terms of affinity distinctions. Specific recognition of certain glycan structure strongly selleck compound depends on its natural molecular context (Bovin, 2013). Pentameric IgMs have ten Fab regions and therefore possess a theoretical valency of 10. Multivalent recognition is very important for glycan–protein interaction, providing stable and affine binding to multiple oligosaccharide structures. On the contrary, IgGs are only divalent, their interactions with glycans

may be weaker that is why this antibody class is typically not ascribed to recognize glycans in nature. Due to the same reasons IgGs may be more predisposed to unspecific binding than IgMs upon profiling with glycoarrays. To further exploit the possibility to reduce anti-glycan ADAM7 antibody cross-reactivity by using heterobifunctional PEGs, we linked PEG23 and PEG60 to the bead surface, coupled Pk trisaccharide to these beads, and compared the binding of monoclonal human anti-P1 IgM either to P1-coupled beads or to Pk-coupled beads (without or with heterofunctional PEGs) as a function of the antibody dilution (Fig. 7). The results showed that the binding of the anti-P1 IgM antibodies, regardless of the dilution, to Pk-beads was several-fold lower than to P1-beads, indicating that indeed anti-P1 antibodies bind to Pk trisaccharide with much lower affinity than P1 trisaccharide.

9) in the Wiley Library (Ver. 7) or comparison

with literature mass spectra; for 4-OPA (Fruekilde et al., 1998, Hutton et al., 2003 and Molander and Cameron, 1993) and IPOH (Calogirou et al., 1999a). The purity was based on GC peak area integration in full scan mode and averaged (n = 2). Inbred BALB/cA male mice were purchased from Taconic, Denmark. At the initiation of the study, the mean weight and SD of the mice was 25.8 ± 1.3 g. Mice were housed in polypropylene cages (380 mm × 220 mm × 150 mm) with pinewood sawdust bedding (Lignocel S8, Brogaarden, selleckchem Denmark). The photoperiod was from 6 a.m. to 6 p.m., and the temperature and relative humidity in the animal room were 22 ± 2 °C and 50 ± 5%, respectively. The cages were sanitized twice weekly. Food (Altromin no. 1324, Altromin, Lage, Germany) and tap water were available ad libitum. Treatment of the animals adhered to procedures approved by The Animal Experiment Inspectorate, Denmark with Permission numbers 2006/561-1123 and 2011/561-1990. The terpene reaction products were PS-341 research buy evaporated in Pitt No. 1 VOC generator (Wong and Alarie, 1982), diluted with medical dry air, and fed into a 24 L exposure chamber (Larsen and Nielsen, 2012). The airflow rates in

the chamber were set between 18.8 and 23.2 L/min. The chamber exposure concentrations were monitored every fourth minute by 15 sequential 1.0 mL air samples on Tenax TA steel tubes (PerkinElmer), taken by syringe (size: 2.0 mL) suction, followed by thermal desorption within 12 h, and GC/FID analysis, as described previously (Wolkoff, 1998). Six-point calibration of the weighed compound in methanol (0.08–2.5 μg/mL) was applied for determination of air concentrations (R2 ≥ 0.98), except for 4-OPA that was dissolved in pentane. Initially, a starting concentration was selected on the basis of the relation for non-reactive compounds according to Alarie et al. (1996). However, for reactive compounds, i.e. with an aldehyde group, a lower starting concentration was decided. Other exposure concentrations were decided upon the first observation of a bioresponse. The resulting exposure concentrations

are shown in Table 2. The respiratory effects were studied in a head out mouse bioassay (Alarie, 1998). The bioassay allows detection of respiratory effects on the upper airways (sensory irritation), effects on the conducting Metalloexopeptidase airways, and at the alveolar level by continuous computerized monitoring of the breathing pattern. The inhalation effects are investigated by analyses of the breathing patterns in mice (Alarie, 1973 and Nielsen et al., 1999). Briefly, the breathing pattern analysis recognizes and quantifies specific deviations from the normal breathing pattern (for terms and definitions, see Fig. 1 in Nielsen et al. (1999)). Thus, after end of inhalation, a short brake occurs before the exhalation is initiated, termed time of brake (TB, ms). An increase in TB leads to a decrease in the respiratory frequency (f, breaths/min).