Spatial variation in sapwood area to leaf area ratio and specific leaf area within a crown of silver birch

Spatial variation in sapwood area to leaf area ratio (Huber value, HV) and specific leaf area (SLA) was examined in branches of closed-canopy trees of silver birch (Betula pendula Roth). HV increased basipetally within a crown and decreased with increasing branch order, but exhibited no significant radial trend along a primary branch. HV was primarily determined by branch position in a crown and branch diameter at the sampling point, being independent of the size of the tree and branch. Greater HV in the lower-crown branches is considered a means to mitigate differences in hydraulic transport capacity between the branches located in different canopy layers. Beside branch position and sampling location on a branch, SLA depended significantly on several other variables characterising tree and branch size. SLA increased basipetally within a crown and along a primary branch, but exhibited no significant trend with branch orders. Because height caused leaf area (A_L) to diminish more rapidly than leaf dry weight, A_L primarily determined the vertical variation in SLA.     

Surface area‐to‐volume ratio,not cellular viscoelasticity,is the major determinant of red blood cell traversal through small channels

The remarkable deformability of red blood cells (RBCs) depends on the viscoelasticity of the plasma membrane and cell contents and the surface area to volume (SA:V) ratio; however, it remains unclear which of these factors is the key determinant for passage through small capillaries. We used a microfluidic device to examine the traversal of normal, stiffened, swollen, parasitised and immature RBCs. We show that dramatic stiffening of RBCs had no measurable effect on their ability to traverse small channels. By contrast, a moderate decrease in the SA:V ratio had a marked effect on the equivalent cylinder diameter that is traversable by RBCs of similar cellular viscoelasticity. We developed a finite element model that provides a coherent rationale for the experimental observations, based on the nonlinear mechanical behaviour of the RBC membrane skeleton. We conclude that the SA:V ratio should be given more prominence in studies of RBC pathologies.     

Static allometry of unicellular green algae: scaling of cellular surface area and volume in the genus Micrasterias (Desmidiales)

The surface area‐to‐volume ratio of cells is one of the key factors affecting fundamental biological processes and, thus, fitness of unicellular organisms. One of the general models for allometric increase in surface‐to‐volume scaling involves fractal‐like elaboration of cellular surfaces. However, specific data illustrating this pattern in natural populations of the unicellular organisms have not previously been available. This study shows that unicellular green algae of the genus Micrasterias (Desmidiales) have positive allometric surface‐to‐volume scaling caused by changes in morphology of individual species, especially in the degree of cell lobulation. This allometric pattern was also detected within most of the cultured and natural populations analysed. Values of the allometric S:V scaling within individual populations were closely correlated to the phylogenetic structure of the clade. In addition, they were related to species‐specific cellular morphology. Individual populations differed in their allometric patterns, and their position in the allometric space was strongly correlated with the degree of allometric S:V scaling. This result illustrates that allometric shape patterns are an important correlate of the capacity of individual populations to compensate for increases in their cell volumes by increasing the surface area. However, variation in allometric patterns was not associated with phylogenetic structure. This indicates that the position of the populations in the allometric space was not evolutionarily conserved and might be influenced by environmental factors.     

Measurement of body surface area in children with liver disease by a novel three-dimensional body scanning device

Body surface area (BSA) is used in paediatrics to assess fluid requirement, drug doses, cardiac output and glomerular filtration rate. The aim of this study was to examine, in children with liver disease, the relationship between BSA determined by a traditional nomogram and BSA measured by a novel three-dimensional technique — Loughborough Anthropometric Shadow Scanner (LASS). Subjects were 16 children, mean age 8.1 (range 3.6–14.9) years, with a variety of liver diseases. Twenty-eight controls had a mean age of 7.1 (3.1–10.5) years. All had LASS scans performed as well as 21 anthropometric measurements taken by a single observer. There was a significant relationship between BSA (LASS) and BSA nomogram for liver-diseased children (r=0.99) and controls (r=0.96). The BSA nomogram values were significantly greater (P < 0.05) than BSA (LASS) for liver-diseased subjects by 10.1% (–0.35 to + 20.6; 95% confidence interval), and for controls by 9.6% (4.1–23.2). Best prediction of BSA (LASS) for liver-disease subjects used height, body weight and gluteal furrow circumference [r ²=0.997; standard estimated error (SEE) = 0.015 m²] and for controls used body weight alone (r ²=0.907; SEE=0.048 m²). BSA nomogram has no additional error in children with liver disease, but may overestimate BSA by 10% compared with a novel three-dimensional body surface scanning technique.     

Moisture adsorption capacity and surface area as deduced from vapour pressure isotherms in relation to hygroscopic water of soils

Six calcareous and alluvial soil profiles differing in their texture, CaCO₃ and salinity were chosen from west and middle Nile Delta for the present study. The 1^st and 2^nd profiles from Borg El-Arab area were sandy loam in texture and > 30% CaCO₃, while the 3^rd and 4^th profiles (from Nubaria area) were sandy clay loam and < 30% CaCO₃. The 2^nd and 4^th profiles were taken from cultivated area with maize. The 5^th profile from Epshan area was non-saline clay alluvial soil and the 6^th from El-Khamsen was saline clay alluvial soil. The relation between soil moisture content (W%) and water vapour pressure (P/P _o) was established for the mentioned soils. Data showed that the specific surface area (S) values were 34–53 and 44–60 m²/g for calcareous soils of Borg El-Arab and Nubaria areas, 206–219 and 206–249 m²/g for non-saline and saline clay alluvial soils of Epshan and El-Khamsen areas, respectively. The corresponding values of the external specific surface area (S _e) were 16–21, 14–22, 72–86 and 92–112 m²/g. Submitting W _m+W _me as an adsorption boundary of moisture films (W _c) (where W _m is mono-adsorbed layer of water vapour on soil particles and W _me is the external mono-adsorbed layer), the maximum water adsorption capacity (W _a) was found to be W _c + W _me or W _m + 2W _me. It was ranged from 1.88 to 2.70%, 1.97 to 2.95%, 9.70–10.70% and 10.80 to 13.12% while the maximum hygroscopic water (M _H) values were 2.43–3.78%, 2.91–4.65%, 16–17% and 18.30–21.9% for the studied soil profiles respectively. The residual moisture content (θ _r) at pF 7 and P/P _o = 0 was ranged from 0.0005–0.0010%, 0.0007–0.0019% and 0.0043–0.0048% in Borg El-Arab, Nubaria and Epshan soil profiles, respectively. The inter-relations between the surface area and the hygroscopic moisture parameters of the soils under investigation were as follows Calcareous soils; W _m = 0.40 M _H, W _c = 0.55 M _H, W _a = 0.70 M _H, S = 14 M _H Non-saline soil; W _m = 0.35 M _H, W _c = 0.49 M _H, W _a = 0.63 M _H, S = 13 M _H Saline soil; W _m = 031 M _H, W _c = 0.45 M _H, W _a = 0.59 M _H, S = 12 M _H These relations give possibility to deduce the soil moisture adsorption capacities and specific surface area via maximum hygroscopic water, which can be obtained through the experimental determination of water vapor adsorption isotherms.     

Bacterial abundance in relation to surface area and organic content of marine sediments

Based on direct measurements on surface sediments collected from an intertidal salt marsh, a positive relationship was demonstrated between bacterial abundance and specific surface area of sediment. While this relationship has been postulated previously, this is the first direct confirmation that it holds over a wide range of sediment types. A laboratory experiment was conducted to determine the effects of specific surface area, distribution of surface area, and organic loading on bacterial colonization. Model sediments included angular silica particles, kaolin, and spherical glass beads, used singly or in mixtures. Organic loading resulted in substantial enhancement of bacterial colonization. Distribution of surface area controlled by textural, shape, and sorting, had a complex effect, with glass bead sediments generally supporting better colonization than silica particles or kaolin. The effect of specific surface area was noted only in restricted comparisons of similarly shaped glass beads.     

The relationship between the solvent-accessible surface area of a protein and the number of native contacts in its structure

The degree of protein folding is characterized either by the solvent-accessible surface area (S _ASA ) or the actual number of native contacts (N _cont). Evidently, these values should correlate with each other, as a decrease in S _ASA caused by the change in protein conformation during its folding must be accompanied by the corresponding increase in the number of native contacts. It is shown that this correlation does exist and is very strong (the correlation coefficient exceeds 99%), which can be used for an accurate and rapid estimation of the protein surface area from the number of native contacts. Among the methods commonly used for calculating the native contacts, the atom-atom approach gives the best fit if hydrogen atoms are taken into account and the cutoff value for the distance between the centers of atoms is taken to be 8 Å. The latter means that two layers of surface atoms are required to shield the protein core from the solvent.     

The loss in hydrophobic surface area resulting from a Leu to Val mutation at the N-terminus of the aldehyde dehydrogenase presequence prevents import of the protein into mitochondria

An apparent conservative mutation, Leu to Val, at the second residue of the rat liver mitochondrial aldehyde dehydrogenase (ALDH) presequence resulted in a precursor protein that was not imported into mitochondria. Additional mutants were made to substitute various amino acids with nonpolar side chains for Leu2. The Ile, Phe, and Trp mutants were imported to an extent similar to that of the native precursor, but the Ala mutant was imported only about one-fourth as well. It was shown that the N-terminal methionine was removed from the L2V mutant in a reaction catalyzed by methionine aminopeptidase. The N-terminal methionine of native pALDH and the other mutant presequences was blocked, presumably by acetylation. Because of the difference in co-translational modification, the L2V mutant sustained a significant loss in the available hydrophobic surface of the presequence. Import competence was restored to the L2V mutant when it was translated using a system that did not remove Met1. The removal of an Arg-Gly-Pro helix linker segment (residues 11-14) from the L2V mutant, which shifted three leucine residues toward the N-terminus, also restored import competence. These results lead to the conclusion that a minimum amount of hydrophobic surface area near the N-termini of mitochondrial presequences is an essential property to determine their ability to be imported. As a result, both electrostatic and hydrophobic components must be considered when trying to understand the interactions between precursor proteins and proteins of the mitochondrial import apparatus.     

Monocyte-to-albumin ratio as a novel predictor of long-term adverse outcomes in patients after percutaneous coronary intervention

Background: Monocyte count and serum albumin (Alb) have been proven to be involved in the process of systemic inflammation. Therefore, we investigated the prognostic value of monocyte-to-albumin ratio (MAR) in patients who underwent percutaneous coronary intervention (PCI).Methods: We enrolled a total of 3561 patients in the present study from January 2013 to December 2017. They were divided into two groups according to MAR cut-off value (MAR < 0.014, n=2220; MAR ≥ 0.014, n=1119) as evaluated by receiver operating characteristic (ROC) curve. The average follow-up time was 37.59 ± 22.24 months.Results: The two groups differed significantly in the incidences of all-cause mortality (ACM; P<0.001), cardiac mortality (CM; P<0.001), major adverse cardiovascular events (MACEs; P=0.038), and major adverse cardiovascular and cerebrovascular events (MACCEs; P=0.037). Multivariate Cox regression analyses revealed MAR as an independent prognostic factor for ACM and CM. The incidence of ACM increased by 56.5% (hazard ratio [HR] = 1.565; 95% confidence interval [CI], 1.086–2.256; P=0.016) and that of CM increased by 76.3% (HR = 1.763; 95% CI, 1.106–2.810; P=0.017) in patients in the higher-MAR group. Kaplan–Meier survival analysis suggested that patients with higher MAR tended to have an increased accumulated risk of ACM (Log-rank P<0.001) and CM (Log-rank P<0.001).Conclusion: The findings of the present study suggested that MAR was a novel independent predictor of long-term mortality in patients who underwent PCI.     

Determination of bilayer thickness and lipid surface area in unilamellar dimyristoylphosphatidylcholine vesicles from small-angle neutron scattering curves: a comparison of evaluation methods

Small-angle neutron scattering (SANS) experiments were performed on unilamellar 1,2-dimyristoylphosphatidylcholine (DMPC) vesicles prepared in heavy water by extrusion through polycarbonate filters with 500 Å pores. The data obtained at 30±0.1 °C were evaluated using a five-strip function model of the bilayer coherent neutron scattering length density, three different approximate form factors describing scattering from vesicles, and different methods of evaluation of the experimental data. It is shown that the results obtained from the SANS data in the range of scattering vector values 0.0316 Å^–1<q<0.0775 Å^–1 are not sensitive to the vesicle form factor, nor to the evaluation method. Using the hollow sphere model of vesicles convoluted with the Gaussian distribution of their sizes, a constrained bilayer polar region thickness of 9 Å and a DMPC headgroup volume of 325.5 ų, it was possible to obtain from the experimental data the DMPC surface area as 58.9±0.8 Ų, the bilayer thickness as 44.5±0.3 Å and the number of water molecules as 6.8±0.2 per DMPC located in the bilayer polar region.     

黄土丘陵区表层土壤有机碳沿降水梯度的分布

沿368～591 mm降水量梯度选取7个调查地点、共63个调查样点,在每个样点选择恢复年限相近的林地、草地和农地,调查表层（0～30 cm）土壤有机碳的分布特征,分析气候、土层深度和土地利用类型等因素对土壤有机碳分布的影响.结果表明： 在黄土丘陵区368～591 mm的降水量范围内,表层土壤有机碳含量表现为草地（8.70 g·kg^-1）>林地（7.88 g·kg^-1）>农地（7.73 g·kg^-1）,土壤有机碳密度表现为草地（20.28 kg·m^-2）>农地（19.34 kg·m^-2）>林地（17.14 kg·m^-2）.林地、草地、农地的土壤有机碳含量无显著差异,综合3种土地利用类型的数据分析表明,不同降雨梯度下土壤有机碳含量差异显著（P<0.001）,土壤有机碳含量（r=0.838,P<0.001）与年均降水量间存在显著线性正相关关系;由北向南（以最北端鄂尔多斯为起点）,土壤有机碳含量沿着368～591 mm的年均降水量梯度的递增速率为0.04 g·kg^-1·mm^-1,土壤有机碳密度的递增速率为0.08 kg·m^-2·mm^-1.年均降水量、土壤黏粒含量、林下枯落物蓄积量和农作物根系密度可较好地模拟表层土壤有机碳分布.     

青杨人工林根系生物量、表面积和根长密度变化

在植物生长季节,采用钻取土芯法对秦岭北坡50年生青杨人工林根径≤2 mm和2～5 mm根系的生物量、表面积和根长密度进行测定.结果表明：在青杨人工林根系(＜5 mm)中,根径≤2 mm根系占总生物量的77.8%,2～5 mm根系仅占22.2%;根径≤2 mm根系表面积和根长密度占根系总量的97%以上,而根径2～5 mm根系不足3%.随着土层的加深,根径≤2 mm根系生物量、表面积和根长密度数量减少,根径2～5 mm根系生物量、表面积和根长密度最小值均分布在20～30 cm土层.≤2 mm根系生物量、表面积和根长密度与土壤有机质、有效氮呈极显著相关,而根径2～5 mm根系的相关性不显著.     

Age estimation from the auricular surface of the ilium: a revised method

A revised method for estimating adult age at death using the auricular surface of the ilium has been developed. It is based on the existing auricular surface aging method of Lovejoy et al. ([1985] Am. J. Phys. Anthropol. 68:15-28), but the revised technique is easier to apply, and has low levels of inter- and intraobserver error. The new method records age-related stages for different features of the auricular surface, which are then combined to provide a composite score from which an estimate of age at death is obtained. Blind tests of the method were carried out on a known-age skeletal collection from Christ Church, Spitalfields, London. These tests showed that the dispersion of age at death for a given morphological stage was large, particularly after the first decade of adult life. Statistical analysis showed that the age-related changes in auricular surface are not significantly different for males and females. The scores from the revised method have a slightly higher correlation with age than do the Suchey-Brooks pubic symphysis stages. Considering the higher survival rates of the auricular surface compared with the pubic symphysis, this method promises to be useful for biological anthropology and forensic science.     

Application of the functional-form model to the culture of seaweeds

Selecting the most appropriate species or strains is an important first step in the development of most algal cultivation systems and is usually a tedious, time-consuming, and expensive step. The functional-form model, first developed to synthesize the adaptive significance of easily assessed thallus-form attributes relative to the productivity and survival of benthic macroalgae, is applicable to the culture of seaweeds and can expedite species or strain selection. The production ecology aspects of the model are useful particularly for applications where the desired product is not species-specific, e.g., systems in which the emphasis is on algal production, such as algal biomass farms and wastewater treatment. A thallus-form with a high surface area: volume ratio is more suited for rapid production and nutrient uptake. The utility of this model to strain selection is demonstrated with the red alga Gracilaria tikvahiae, a species that has been considered a maricultural candidate for a number of utilizations. A continuum of surface area: volume ratios for eight clones of G. tikvahiae showed that this ratio decreased as morphological complexity increased and was a good predictor of both short-term photosynthesis and long-term growth rate. Clones near opposite ends of the surface area: volume ratio spectrum had significant differences for both photosynthesis and growth. Each clone of G. tikvahiae possesses concomitant combinations of benefits as well as costs, which should be carefully evaluated for the cultivation application of interest. Knowledge of functional-form relationships in seaweeds can significantly expedite their successful cultivation.     

Alkaline phosphatase-to-albumin ratio as a novel predictor of long-term adverse outcomes in coronary artery disease patients who underwent PCI

Background: Alkaline phosphatase (ALP) and albumin (ALB) have been shown to be associated with coronary artery disease (CAD), and it has been reported that alkaline phosphatase-to-albumin ratio (AAR) is associated with the liver damage and poorer prognosis of patients with digestive system malignancy. Moreover, several previous studies showed that there was a higher incidence of malignancy in CAD patients. However, to our knowledge, the relationship between AAR and long-term adverse outcomes in CAD patients after undergoing percutaneous coronary intervention (PCI) has not been investigated. Therefore, we aim to access the relation between AAR and long-term adverse outcomes in post-PCI patients with CAD.Methods: A total of 3378 post-PCI patients with CAD were enrolled in the retrospective Clinical Outcomes and Risk Factors of Patients with Coronary Heart Disease after PCI (CORFCHD-ZZ) study from January 2013 to December 2017. The median duration of follow-up was 37.59 ± 22.24 months. The primary end point was long-term mortality including all-cause mortality (ACM) and cardiac mortality (CM). The secondary end points were major adverse cardiac events (MACEs) and major adverse cardiac and cerebrovascular events (MACCEs).Results: Kaplan–Meier analyses showed that an increased AAR was positively correlated with incidences of long-term ACM (log-rank, P=0.014), CM (log-rank, P=0.011), MACEs (log-rank, P=0.013) and MACCEs (log-rank, P=0.006). Multivariate Cox regression analyses showed that the elevated AAR was an independent predictor of long-term ACM (adjusted HR = 1.488 [1.031–2.149], P=0.034), CM (adjusted HR = 1.837 [1.141–2.959], P=0.012), MACEs (adjusted HR = 1.257 [1.018–1.551], P=0.033) and MACCEs (adjusted HR = 1.237 [1.029–1.486], P=0.024).Conclusion: An elevated AAR is a novel independent predictor of long-term adverse outcomes in CAD patients following PCI.     

Responses of root length/leaf area ratio and specific root length of an understory herb, Pteridophyllum racemosum, to increases in irradiance

The understory evergreen perennial Pteridophyllum racemosum Sieb. et Zucc. (Papaveraceae) has the ability to increase root mass per unit transpiring leaf area (RMA) if irradiance increases gradually over several years. In this study, we examined how P. racemosum changes its root length/leaf area ratio and specific root length when the species encounters abrupt increases in irradiance, such as sudden and unexpected canopy openings. Plants were transplanted from a low light condition in a subalpine wave-regenerating forest (photon flux density on the forest floor relative to the full sun (RPFD) was 2.7%) to a high light condition in a glasshouse (30% RPFD) (LH treatment). Transplantation from the low light condition in the forest to a low light condition in the glasshouse (LL) and transplantation from a high light condition in the forest (33% RPFD) to a high light condition in the glasshouse (HH) were also conducted as controls. Compared to the LL plants, the LH plants exhibited significant increases in RMA and root length/leaf area ratio from 30 to 70 days after transplantation. On the other hand, the effect of increased irradiance on specific root length (SRL) was weak, and both the LL and LH plants showed increased SRL from 30 to 70 days after transplantation. Increased SRL results from longer root length per unit construction cost. We concluded that increased root length/leaf area ratio of P. racemosum in response to abrupt increases in irradiance was caused by a combination of enhanced carbon allocation to roots with increased SRL.