Effects Of Limitation Research Articles

Operando characterisation of the products of Fischer-Tropsch synthesis in a fixed-bed reactor studied by magnetic resonance

Operando measurement of catalyst performance presents many difficulties as it is necessary to obtain measurements at reaction temperature and pressure and also at relevant length scales of multiple pellets to replicate the pellet-scale mass transport. Non-invasive measurement under such conditions is challenging. In this study we have developed an NMR/MRI compatible reactor that is of industrially-relevant scale and can operate at typical conditions for Fischer-Tropsch synthesis (FTS). The pilot-scale fixed-bed reactor (20 mm i.d.) used for FTS is operated at 220 °C and 37 bar and is packed with 1 wt % Ru/TiO2 catalyst pellets. Multiple magnetic resonance techniques have been developed and applied to achieve quantitative characterisation of product species including hydrocarbons, water, oxygenates and branched alkanes in pores. In addition to spatially-resolved measurements of molecular diffusion coefficients of the product species from which the carbon chain length of the saturated hydrocarbons can be determined, preliminary estimates of the relative amount of oxygenate and water species and branched saturated hydrocarbons present within the pore space of the catalyst are also determined using non spatially-resolved two-dimensional 1H T1-chemical shift and two-dimensional 1H double quantum filtered correlated spectroscopy (DQF-COSY), respectively. The concentrations of water and oxygenates detected inside the pores of catalyst pellets decrease when the feed H2/CO ratio decreases. The amount and extent of branching of saturated hydrocarbon species is observed to be higher than for the effluent wax product, most likely due to the effect of mass transfer limitation within the reactor. This work demonstrates that a toolbox of operando magnetic resonance techniques is available to characterise different product species of FTS from within catalyst pellets. The information provided by these techniques can give insight into how both catalyst and reactor can be optimised.

A study on association of obstructive airway disease in previously treated pulmonary tuberculosis patients

Pulmonary tuberculosis (TB) and obstructive airway disease are of growing concern in a developing country akin to India. A considerable number of TB patients develop post-tubercular respiratory disease. There are few Indian studies assessing the relationship between antecedents of PTB and COPD. PTB has a considerable impact on quality of life. To evaluate the prevalence of obstructive airway disease in previously treated pulmonary tuberculosis patients and to evaluate the impact of post TB obstructive airway disease on QOL using SGRQ-C. A prospective, observational cross-sectional study was conducted in a tertiary care health centre over six months, enrolling 116 study subjects who met the inclusion criteria included after acquiring Informed consent. Study subjects had been categorized primarily based on prior history of PTB. Therefore, this study involved two groups of study subjects, PTB associated COPD and COPD. Subjects were assessed for PFT through the aid of MIR Spirobank smart App and QOL using SGRQ-C scale. Of 116 patients, 19(22.6%) women and 65(77.4%) men and 5(15.6%) women and 27(84.4%) men were diagnosed as PTB associated COPD and COPD respectively. Dyspnea and cough with sputum were the most common symptoms presented by 76(94.04%) and 62(71.42%) patients respectively. The effect of airflow limitation (FEV1) was slightly increased in PTB associated COPD patients (25.65%) compared to COPD patients (26.4%) and study endpoint showed noteworthy decrease in QOL of PTB associated COPD(72%) patients compared to COPD(66.4%). PTB-associated COPD constitutes a significant proportion of COPD within clinical setting. It is an independent risk factor for OAD in extensive TB burden countries. The results indicated that early diagnosis, appropriate management and control of TB are as critical as smoking cessation for reducing OAD. Early identification of Post tubercular COPD and early initiation of treatment in these patients improve the QOL and reduces morbidity and mortality.

Effect of anode material and dispersal limitation on the performance and biofilm community in microbial electrolysis cells

In a microbial electrolysis cell (MEC), the oxidization of organic compounds is facilitated by an electrogenic biofilm on the anode surface. The biofilm community composition determines the function of the system. Both deterministic and stochastic factors affect the community, but the relative importance of different factors is poorly understood. Anode material is a deterministic factor as materials with different properties may select for different microorganisms. Ecological drift is a stochastic factor, which is amplified by dispersal limitation between communities. Here, we compared the effects of three anode materials (graphene, carbon cloth, and nickel) with the effect of dispersal limitation on the function and biofilm community assembly. Twelve MECs were operated for 56 days in four hydraulically connected loops and shotgun metagenomic sequencing was used to analyse the microbial community composition on the anode surfaces at the end of the experiment. The anode material was the most important factor affecting the performance of the MECs, explaining 54–80 % of the variance observed in peak current density, total electric charge generation, and start-up lag time, while dispersal limitation explained 10–16 % of the variance. Carbon cloth anodes had the highest current generation and shortest lag time. However, dispersal limitation was the most important factor affecting microbial community structure, explaining 61–98 % of the variance in community diversity, evenness, and the relative abundance of the most abundant taxa, while anode material explained 0–20 % of the variance. The biofilms contained nine Desulfobacterota metagenome-assembled genomes (MAGs), which made up 64–89 % of the communities and were likely responsible for electricity generation in the MECs. Different MAGs dominated in different MECs. Particularly two different genotypes related to Geobacter benzoatilyticus competed for dominance on the anodes and reached relative abundances up to 83 %. The winning genotype was the same in all MECs that were hydraulically connected irrespective of anode material used.

Nitrogen limitation affects carbon and nitrogen metabolism in mung bean (Vigna radiata L.)

Studying the effects of nitrogen limitation on carbon, nitrogen metabolism, and nutrient uptake of mung bean is a scientific issue. In this study, urea (CO(NH2)2, 125 kg hm−2) was applied at the V2, V6, R1, R2, and R4 stages, respectively, to ensure sufficient N resources during the growth process of mung beans. This study found that nitrogen limitation inhibited mung bean photosynthesis and reduced photosynthetic efficiency, which was manifested by reducing Pn (net photosynthetic rate), Gs (stomatal conductance), Tr (transpiration rate), and Ci (intercellular carbon dioxide concentration). Second, nitrogen limitation reduced N metabolism-related enzyme activity, such as NR (nitrate reductase), GOGAT (glutamate synthase), and GDH (glutamate dehydrogenase), indicating that nitrogen limitation inhibited the process of nitrogen metabolism, reducing nitrogen assimilation. Meanwhile, topdressing N fertilizer can promote the P and K uptake, and improve the partial factor productivity of P and K, which suggests that nitrogen limitation reduced P and K use efficiency. In addition, this study found that Lvfeng5 responded more significantly to nitrogen fertilizers, and had higher nitrogen use efficiency or better adaptability compared with Lvfeng2. This study provided valuable insights into the physiological and metabolic responses of mung beans to nutrient deficiency.

Metformin Administration to Glucose-restricted Cells Attenuates PKA Signaling in S. cerevisiae

Recent research in cancer treatment points to metformin, a drug for type 2 diabetes, as a potential anti-cancer therapeutic, as well as carbon limitation as a dietary measure. A new study, investigating effects of metformin treatment on colorectal cancer cells, pointed to the fact that response to metformin treatment depended on extracellular glucose concentration. That is why in the current study, effects of both carbon limitation and metformin treatment are explored via transcriptomics analyses. It is demonstrated that cells grown in glucose-limited and metformin treated medium had the highest variance according to transcriptional profiles, compared to individual treatments. Metformin administration, when combined with glucose restriction, downregulates proliferative pathways such as transcription initiation and ribosome biogenesis while upregulates energy derivation and autophagic mechanisms. Enrichment analyses point to an attenuated cAMP-PKA signaling pathway in the cells grown in combined treatment medium. It is proposed that combined treatment exerts its beneficial effect on this pathway, since cAMP-PKA signaling may be a potential target for pharmacological treatment of tumors.

Acclimation to medium-level non-lethal iron limitation: Adjustment of electron flow around the PSII and metalloprotein expression in Trichodesmium erythraeum IMS101

The aim of this study was to investigate how acclimation to medium-level, long-term, non-lethal iron limitation changes the electron flux around the Photosystem II of the oceanic diazotroph Trichodesmium erythraeum IMS101. Fe availability of about 5× and 100× lower than a replete level, i.e. conditions common in the natural environment of this cyanobacterium, were applied in chemostats. The response of the cells was studied not only in terms of growth, but also mechanistically, measuring the chlorophyll fluorescence of dark-adapted filaments via imaging fluorescence kinetic microscopy (FKM) with 0.3 ms time resolution. Combining these measurements with those of metal binding to proteins via online coupling of metal-free HPLC (size exclusion chromatography SEC) to sector-field ICP-MS allowed to track the fate of the photosystems, together with other metalloproteins. General increase of fluorescence has been observed, with the consequent decrease in the quantum yields φ of the PSII, while the efficiency ψ of the electron flux between PSII and the PSI remained surprisingly unchanged. This indicates the ability of Trichodesmium to cope with a situation that makes assembling the many iron clusters in Photosystem I a particular challenge, as shown by decreasing ratios of Fe to Mg in these proteins. The negative effect of Fe limitation on PSII may also be due to its fast turnover. A broader view was obtained from metalloproteomics via HPLC-ICP-MS, revealing a differential protein expression pattern under iron limitation with a drastic down-regulation especially of iron-containing proteins and some increase in low MW metal-binding complexes.

Mechanisms of cardiac collapse at high temperature in a marine teleost (Girella nigrians)

Heat-induced mortality in ectotherms may be attributed to impaired cardiac performance, specifically a collapse in maximum heart rate (fHmax), although the physiological mechanisms driving this phenomenon are still unknown. Here, we tested two proposed factors which may restrict cardiac upper thermal limits: noxious venous blood conditions and oxygen limitation. We hypothesized elevated blood [K+] (hyperkalemia) and low oxygen (hypoxia) would reduce cardiac upper thermal limits in a marine teleost (Girella nigricans), while high oxygen (hyperoxia) would increase thermal limits. We also hypothesized higher acclimation temperatures would exacerbate the harmful effects of an oxygen limitation. Using the Arrhenius breakpoint temperature test, we measured fHmax in acutely warmed fish under control (saline injected) and hyperkalemic conditions (elevated plasma [K+]) while exposed to hyperoxia (200% air saturation), normoxia (100% air saturation), or hypoxia (20% air saturation). We also measured ventricle lactate content and venous blood oxygen partial pressure (PO2) to determine if there were universal thresholds in either metric driving cardiac collapse. Elevated [K+] was not significantly correlated with any cardiac thermal tolerance metric. Hypoxia significantly reduced cardiac upper thermal limits (Arrhenius breakpoint temperature [TAB], peak fHmax, temperature of peak heart rate [TPeak], and temperature at arrhythmia [TARR]). Hyperoxia did not alter cardiac thermal limits compared to normoxia. There was no evidence of a species-wide threshold in ventricular [lactate] or venous PO2. Here, we demonstrate that oxygen limits cardiac thermal tolerance only in instances of hypoxia, but that other physiological processes are responsible for causing temperature-induced heart failure when oxygen is not limited.

Effect of phosphorus limitation on the anammox process under different nitrogen concentrations

The effect of phosphorus limitation on the nitrogen removal performance of the anammox process was investigated using continuous feeding reactors. When the phosphorus supply was stopped under an influent nitrogen concentration of 256 mg-N L−1, a high nitrogen conversion rate of 1.88 kg-N m−3 d−1 was maintained for 17 days. However, during the next 25 days, the nitrogen conversion rate decreased by 16.5%. Subsequently, nitrogen removal activity was recovered entirely by re-adding 0.1 mg-P L−1 of phosphorus. Similar tests were performed at different influent nitrogen concentrations. The results showed that the minimum phosphorus concentrations (MPC) in the influent required to maintain anammox activity at influent nitrogen concentrations of 379 and 502 mg-N L−1 were 0.2 and 0.3 mg L−1, respectively. These results indicate that the MPC increased with N concentration, with an MPC/N of 0.0005. A microbial community analysis based on the 16S rRNA gene amplicon sequencing revealed that two genera of anammox bacteria (Candidatus Kuenenia and Candidatus Jettenia) were presented. The dominant anammox bacteria changed from Candidatus Kuenenia to Candidatus Jettenia after the phosphorus-limitation tests.

An Exploration of Graphene-Water Interface Electrochemical Circuit Model

Graphene has been considered a good candidate for sensor material due to its large surface-to-volume ratio and high conductivity. For instance, high-sensitivity solvent sensors can be achieved through liquid-gated graphene field effect transistors (GFET). In such kind of sensors, ions and other molecules in the test solution will be chemically adsorbed by the graphene sheet. It results in changes of the channel surface potential and conductance. However, the measured potential difference are affected by electrical double-layer capacitance in solution, and quantum capacitance in graphene. Studies have reported the quantum capacitance of graphene in an ionic or aqueous liquid, while the interface between graphene and deionized (DI) water hasn’t been fully explored yet. To address this point, in this work, we measured the electrochemical impedance spectroscopy (EIS) of graphene electrodes in deionized water and proposed an electrical circuit model for the electrochemical cell. The meaning of each element of the circuit model was also discussed.In our experiment, single-layer graphene was grown by chemical vapor deposition (CVD) on copper foil and transferred to Si/SiO2 substrate with gold contacts. Our test solution, DI water, was confined on the graphene sensing layer by polydimethylsiloxane (PDMS). This electrochemical cell was measured with BioLogic SP-150 potentiostat by 2-probe EIS method, with graphene as working electrode (WE) and Ag/AgCl electrode placed in DI water as counter electrode (CE). Another electrochemical cell with gold pad WE was also prepared as the control group.The electrochemical impedance of the water-graphene cell was plotted in a Nyquist plot and showed two semicircles. This observation is different from a regular electrochemical cell, whose impedance shows a semicircle, corresponding to the interface RC impedance, and a low-frequency 45° straight line, corresponding to molecular mass transport limitation. The two semicircles in our water-graphene cell impedance indicate that the equivalent circuit model is based on two parallel RC circuits, corresponding to the interface and solution impedance. By modifying the biasing potential and adding supporting electrolyte, we observed the response of the impedance and identified that the high-frequency semicircle is related to solution impedance, and the low-frequency semicircle is related to interface impedance, which is consistent with the reaction rate of both parts. To make more precise fittings, an additional Warburg element was introduced into the circuit model for the effect of mass-transfer limitation. We proposed a model based on an RC parallel circuit in series with a Randles circuit. Comparing with the 2-RC model, the fitting residual of the proposed model improved by 13%. The RWC parallel circuit was fitted to the high-frequency semicircle, which corresponds to the solution impedance. This is different from the commonly used Randles model, where the Warburg element is included in interface impedance. This difference arises from the lack of supporting electrolytes. When there are supporting electrolytes in an electrochemical cell, the double-layer capacitor at the electrode-solution interface is mainly contributed by supporting electrolytes. While using DI water as the solution in our case, the charged species contributes to both faradic current and non-faradic current, which means that the mass-transport limitation affects both the charge transfer resistor and the double-layer capacitor. Hence, the Warburg element for mass-transport limitation can be extracted from the interface RC parallel circuit and put into the solution impedance when there is no supporting electrolyte.After the circuit model was decided and the elements were identified, we fit the electrochemical impedance curves of both the water-graphene cell and the control group, whose WE was replaced by a gold pad. The fitting result shows that the bulk resistor and capacitor, Rb and Cb, values are unrelated to the WE material, which again supports our circuit model. While the WE surface capacitance Cs of the graphene-water electrochemical cell is 0.0606 F/m2, which is 1/65 of that of the control group. To verify the reason for the capacitance difference, we considered the effect of the graphene quantum capacitance. The theoretic value of the quantum capacitance in single-layer graphene was found to be 0.0752 F/m2 under our setup, which is only 18.8% smaller than our experimental value. Hence, we concluded that SLG surface capacitance was dominated by quantum capacitance. Figure 1

Diagnosing evapotranspiration responses to water deficit across biomes using deep learning.

Accounting for water limitation is key to determining vegetation sensitivity to drought. Quantifying water limitation effects on evapotranspiration (ET) is challenged by the heterogeneity of vegetation types, climate zones and vertically along the rooting zone. Here, we train deep neural networks using flux measurements to study ET responses to progressing drought conditions. We determine a water stress factor (fET) that isolates ET reductions from effects of atmospheric aridity and other covarying drivers. We regress fET against the cumulative water deficit, which reveals the control of whole-column moisture availability. We find a variety of ET responses to water stress. Responses range from rapid declines of fET to 10% of its water-unlimited rate at several savannah and grassland sites, to mild fET reductions in most forests, despite substantial water deficits. Most sensitive responses are found at the most arid and warm sites. A combination of regulation of stomatal and hydraulic conductance and access to belowground water reservoirs, whether in groundwater or deep soil moisture, could explain the different behaviors observed across sites. This variety of responses is not captured by a standard land surface model, likely reflecting simplifications in its representation of belowground water storage.

URLLC-eMBB hierarchical network slicing for Internet of Vehicles: An AoI-sensitive approach

Network slicing has been considered as a promising candidate to meet the heterogeneous Quality of Service (QoS) requirements of various vehicular applications. In this paper, network slicing is utilized on the Road Side Unit (RSU) side for the heterogeneous data freshness requirements in Internet of Vehicles (IoV). The services in enhanced Mobile BroadBand (eMBB) slice are usually bandwidth-consuming, thus the performance can be characterized by throughput. Unlike eMBB slice, the services in Ultra-Reliable Low-Latency Communications (URLLC) slice are usually time-critical, calling for fresh content delivery within short delay, in this case, the trade-off can be made between Age of Information (AoI) and delay in URLLC slice. The resource limitation and coupling effect at both the inter-slice and the intra-slice level have brought challenges to the resource allocation of vehicular network slice. To this end, this paper models the inter- and intra-slice resource allocation problem as a Stackelberg game, in which the RSU acts as the leader and the two slices act as followers. To minimize the weighted sum of AoI and delay in URLLC slice while ensuring the throughput of eMBB slice, this paper proposes a multi-win Stackelberg game resource allocation (MWRA) algorithm. The proposed algorithm can achieve Stackelberg equilibrium (SE) and the SE point is taken as the optimal resource allocation strategy of inter- and intra-slice. Simulation shows the trade-off of inter- and intra-slice resource allocation, and further reveals the interaction of performance between different slices. Numerical results show that compared with the traditional hard slicing, the proposed algorithm can improve the AoI and delay performance of URLLC slice by about 30% under the premise of ensuring the throughput of eMBB slicing.

Investigating the effect of carbohydrate buildup and sink limitation to photosynthetic rate: A review

Investigating the effect of carbohydrate buildup and sink limitation to photosynthetic rate: A review

Testing for age-dependent effects of dietary restriction on the strength of condition dependence in ejaculate traits in the guppy (Poecilia reticulata).

Ejaculates can be costly to produce and depend on an individual's condition, defined as the pool of resources allocated to fitness. A method for assessing condition dependence is to manipulate resource availability and test for a reduction in trait expression. Here, we assess the effects of dietary restriction on two determinants of reproductive fitness in the guppy Poecilia reticulata-sperm production and sperm motility. Importantly, we administered dietary restriction at distinct developmental stages to test: (1) whether dietary restriction, when applied exclusively to juveniles, compromised the ejaculates of newly mature males; (2) whether any observed effects of dietary restriction seen in (1) were reversible when fish returned to an unrestricted diet; and (3) whether dietary restriction applied exclusively to adults influenced ejaculates. We found detrimental effects of resource limitation on both traits, and these were consistent across the three developmental stages tested. Furthermore, dietary restriction reduced male body weight, but this was partially reversed when diet-stressed juveniles (i.e. group 2) returned to unrestricted diets. This latter result suggests that diet-stressed males may sacrifice growth in order to maintain their investment in ejaculates. Together these findings underscore the importance of resource acquisition in determining the expression of ejaculate traits.

Nanometer resolution of 2D single-shot low-coherence & comb-based profilometry based on the effect of discrete height of spatial phase modulator surface

A 2D single-shot comb-based interferometer is well known as a powerful tool for inline inspection owing to its high speed, extensive measurement range, and anti-vibration. However, nanometer resolution is still a milestone that has not been achieved in comb-based interferometers owing to the precision limitation caused by the discrete profile of the spatial phase modulator (SPM) device, typically in the range of several micrometers. Therefore, this study confirms 2D single-shot comb-based profilometry at sub-micron and nanometer-scale resolutions. The system first investigates the effect of the discrete limitation of the SPM surface profile and then verifies the submicron detection ability of the optical frequency comb-based setup. It was quantitatively shown that the highest resolution can be obtained by properly setting the step size of the spatial phase modulator and the SPM surface resolution of the imaging optics. The highest profilometry resolution was recorded at 26.4 nm in a short measurement range, while the setup using the optical comb source with millimeters measurement range for industrial application also can achieve a resolution of approximately 259.2 nm. The results demonstrate the system feasibility in overcoming the discrete limitations of the SPM profile. It also demonstrates for the first time that the so-called 2D single-shot comb-based interferometer can achieve nanometer-scale profilometry resolution covering the measurement range from tens of millimeters to sub-micrometer detection.

Effects of light environments within Cinnamomum camphora canopy on leaf functional traits and photosynthetic characteristics.

To explore the adaptive mechanism of leaf photosynthetic capacity in different light environments within Cinnamomum camphora canopy and enhance carbon sequestration, we investigated morphological structures, nutritional and physiological traits and photosynthetic characteristics of leaves in different orientations of C. camphora canopy, southern side in the outer layer (100% full light), southern side in the inner layer (34% full light) and northern side (21% full light). We analyzed the main limitation resulting in down-regulation of photosynthetic capacity in low light environments. Results showed that specific leaf weight, the thickness of lower and upper epidermal cuticle, lower epidermis, palisade tissue as well as cell number and width of palisade tissue, the thickness ratio of palisade to spongy tissue, cell structure closely degree significantly decreased with decreasing light intensity within canopy, opposite to the responses of spongy tissue thickness, cell length-width ratio of palisade tissue, and cell structure loose degree. The contents of leaf carbon, soluble protein, soluble sugar and starch were significantly lower in two low light environments compared with full light, whereas nitrogen content was markedly higher in north side. Low light prominently reduced gas exchange parameters, i.e., net photosynthetic rate (Pn), dark respiration rate, stomatal conductance to CO2(gsc), mesophyll conductance to CO2(gm), total conductance to CO2(gtot), intercellular CO2 concentration (Ci), CO2 concentration at the chloroplast (Cc). Pn was positively correlated with gsc, gm, gtot and Cc. There were no differences in maximum quantum photochemical efficiency, actual quantum photochemical efficiency, photochemical quenching coefficient, maximum rate of Rubisco carboxylation (Vc max) and maximum rate of electron transport (Jmax) among light environments. Vc max and Jmax were positively correlated to Pn. Of the shading-induced limitations to photosynthesis, gm limitation was the most important, and gsc limitation was enhanced with further weakened light intensity while biochemical limitation was rather limited. In summary, the results suggested that full light could improve leaf photosynthetic potential in C. camphora canopy leaves, reduce the effects of gm and gsc limitation on photosynthesis, and consequently enhance carbon assimilation capacity.

Non-Newtonian Casson Fluid Behaviour in the Presence of Nanofluid Particles During MHD Flow Through a Vertical Cone Filled With Porous Material

The flow of nanofluids around a vertical cone with porous media and Casson fluid characteristics is being looked at in this study. Thermophoresis, Brownian motion, and chemical reactions are also looked at. There are some ways to change the connected partial differential equations into a set of third-order ordinary differential equation with variable coefficients. This is called a similarity transformation. The Runge-Kutta method is used to solve third-order boundary layer equations. Physical processes, such as Epidermis slippage, velocity, temperature, but instead fluid density, mass transfer, heat transference coefficients, besides rate of heat handover coefficients, may be studied in this research. These processes may be looked at in this study. There are graphs that show a lot of different physical processes. Current numerical results are compared to results that have been published in the past to make sure computer programmes work. The resultant velocity profiles are decreasing utilising an increasing trendy captivating field as a result of Lorentz potency. Species concentration of Casson-When the oxidizing agent factor is increased, the microspheres decrease. Temperature profile areas a result of the rise in Thermo Scattering movements but instead heat conduction and Brownian motion parameters. Also, roles about increasing values of Biot number and this same criterion of radiant heat would be to surge the room’s temperature hybrid Nanofluid flow as well as rate of heat flows so at exterior. Concentration profiles remain rising with increasing the morals of Thermo migration limitation and contrary effect occurs as a consequence of Brownian motion parameter.

Effect of joint limitation and balance control on gait changes in diabetic peripheral neuropathy.

This study analyzed the gait patterns of diabetic peripheral neuropathy (DPN) patients and changes in the center of mass sway to prevent the formation and recurrence of foot ulcers. Forty-two subjects were divided into the diabetes mellitus (DM), DPN, and diabetic foot ulcer (DFU) groups. We measured the range of motion (ROM) of the lower limb joints in the resting position and the center of mass sway in the standing position. Joint angles, ROM during walking, and distance factors were evaluated. In the DFU group, ROM limitation during walking was detected at the knee joint, and functional and ROM limitations were found at the ankle joint. The step length ratio and step width in the DFU group were significantly lower and higher than those in the DM group, respectively. The sway distances in the DFU group were greater than those in the DM and DPN groups. Functional joint limitations and gait changes due to the decreased ability to maintain the center of gravity were observed in the DFU group. As DPN progressed, the patients' gait became small, wide, and shuffled. Thus, supporting joint movement during walking may help reduce the incidence and recurrence of foot ulcers. The online version contains supplementary material available at 10.1007/s13340-023-00647-9.

Intra-particle diffusion limitation for steam methane reforming over a Ni-based catalyst

This work aims to evaluate the diffusion limitation for the steam methane reforming process over spherical catalyst particles (Ni/α-Al2O). Numerical calculations based on a CFD model were conducted to determine the intrinsic and actual reaction rates. The CFD model was validated using experimental results, and good agreement was achieved. The effectiveness factor for the reaction rates was used to express the effect of diffusion limitation within the porous catalyst particle. The effectiveness factor was determined for a wide range of operational parameters, including a temperature range of 800–1300 K and a steam-to-methane ratio of 1–5. The analysis was performed for spherical catalyst particles with diameters up to 3.42 mm, and the effectiveness factor as a function of catalyst particle diameter, temperature, and steam-to-methane ratio was established. The results show that the effectiveness factor is inversely proportional to the diameter of the catalyst particle and that an increase in reaction temperature and steam-to-methane ratio leads to an increase in diffusion limitation. The limitations of the analysis are discussed and justified. The final expression for the effectiveness factor can be used in a pseudo-homogeneous steam methane reformer model where the effectiveness factor varies depending on the position in the packed bed.

Analysis of Bandwidth Narrowing in Wavelength Selective Switch Enabled DP-64QAM Systems With Transceiver Noise

The impact of filtering impairments resulting from cascaded, wavelength selective switches is investigated for 32 Gbaud dual-polarization 64-ary quadrature amplitude modulation in the presence of transceiver noise. Training-sequence based adaptive equalization and pilot-aided carrier phase estimation are employed to cope with the combined effects of the transceiver-imposed limitation in achievable signal-to-noise ratio and the filtering-induced signal distortion. For a given level of amplified spontaneous emission noise, transceiver noise reduces the total signal-to-noise ratio resulting in an increased dependence of the bit-wise achievable information rate on filtering-induced bandwidth narrowing. The implications of statistical variations in the overall filter frequency response are also assessed by considering randomly selected responses for each of the individual filters in a cascade. Further, the impact of the frequency response of the demultiplexing filter at the receiver is investigated by considering a 3-channel 32 Gbaud wavelength division multiplexed system with a channel spacing of 37.5 GHz.

Co-Limitation of Phytoplankton by N and P in a Shallow Coastal Lagoon (Ria Formosa): Implications for Eutrophication Evaluation

AbstractThe Ria Formosa coastal lagoon is a highly productive shallow ecosystem in southern Portugal, subjected to nutrient inputs from anthropogenic and natural sources. Nutrients are major abiotic drivers of phytoplankton in this system, but their effects on phytoplankton assemblages and the occurrence of nutrient limitation are still poorly understood. The main goal of this study was, thus, to evaluate the occurrence, type, and effects of nutrient limitation on phytoplankton community and specific functional groups in the Ria Formosa coastal lagoon. We conducted nutrient enrichment experiments with factorial additions of nitrogen (N) and phosphorus (P) using natural phytoplankton assemblages from distinct locations in the Ria Formosa, throughout a yearly cycle. Phytoplankton composition and abundance were evaluated using inverted and epifluorescence microscopies, and spectrophotometric methods were used for biomass. Limitation was defined as higher phytoplankton growth following enrichment with a particular nutrient in relation to the non-enriched control. The most common type of phytoplankton limitation was simultaneous co-limitation by N and P; diatoms, as r-strategists, were the most frequently limited group. Single N and P limitation, and serial P limitation were also observed, as well as negative responses to nutrient enrichment. Group-specific responses to nutrient enrichment were not reflected in the relative abundance of phytoplankton groups within the whole assemblage, due to the numerical dominance of pico-sized groups (cyanobacteria and eukaryotic picophytoplankton). Ambient nutrient ratios and concentrations did not predict phytoplankton nutrient limitation, given the different nutrient utilisation traits among phytoplankton functional groups. Therefore, nutrient ratios should not be used as indicators of nutrient limitation in eutrophication assessment.