Diameter Increment Research Articles

Effect of Chemical Fertilizer and Humic Acid on the Growth and Development of Paulownia tomentosa Seedlings.

Silvicultural treatments were applied in forest nursery to produce high quality and quantity seedlings. Fertilizer application is one of the most important treatments that were used to improve seedling morphological and physiological traits. The study investigated the influence of NPK fertilizer levels viz. 0, 0.5, 1, and 1.5 g pot-1, Humic acid levels viz. 0, 5, 10 and 15 g pot-1 and their interactions on growth and physiological properties of Paulownia tomentosa. Morphological growth parameters (the increment in the stem height, stem diameter and leaf number) and physiological parameters (leaf area, chlorophyll content and protein percent, and N, P, K content) were measured. The results indicate that the highest values of stem height and stem diameter increment were (52.70 cm and 10.69mm) at (1.5g) of NPK fertilizers. The maximum values of both traits were (51.40 cm and 10.33mm) recorded at (15g) of Humic acid. The highest mean value of nitrogen (2.90 and 2.53 %) reported from application of (1.5 g NPK and15g Humic acid), respectively. Among physiological parameters chlorophyll content recorded the highest value which were (56.97 and 56.04) at (1.5g NPK and 10g Humic acid,) respectively. From interaction between (1g NPK x 15g Humic acid) recorded the highest value of potassium which was (3.74%). The results will help will improve nursery practices to produce healthy and a high quality of P. tomentosa seedlings to meet the plantation programs.

Age-independent diameter increment models for mixed mountain forests

Mixed mountain forests with an uneven-aged structure are characterized by a high tree-growth variability making traditional age-dependent growth models inapplicable. Estimating site productivity is yet another impediment for modelling tree growth in such forests. Uneven-aged mixed-stand forests are known for their high resilience, resistance and productivity, and are being promoted as a suitable alternative to even-aged, pure plantations for climate change adaptation and mitigation. However, their growth must be accurately measured and predicted, but diameter at the breast height (dbh) increment models specifically designed for uneven-aged mixed mountain forests are still rare. Using permanent sampling network data and 465 increment cores, we built two age-independent dbh increment ({i}_{d}) models for the main species of the study area, namely Norway spruce (Picea abies (L.) Karst.), silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.). Mixed effects models and the algebraic difference approach were employed to develop {i}_{d} models based on empirical and commonly used theoretical growth functions. A past growth index was further developed and introduced in the model in order to explain the {i}_{d} variability. Several mixed effects calibration strategies were assessed in order to obtain the most accurate localized curve for new plots. Tree size, competition and biogeoclimatic variables were found to explain the {i}_{d} through the empirical growth function, while the growth index significantly improved the theoretical growth function for Norway spruce. The optimization of the calibration strategy for the mixed effects modelling framework enables the growth index implementation in forest practice as an accurate method for estimating site productivity. The accuracy of the two {i}_{d} models was similar: the root mean squared error of the empirical growth function varied between 0.940 and 1.042 cm for spruce, beech and fir, while the root mean squared error obtained through the theoretical growth function for spruce only was 1.105 cm. The basal area increment prediction at the plot level based on the theoretical growth function reached a root mean squared error of 0.043 m2 while using the empirical growth function the root mean squared error is 0.047 m2. The high accuracy obtained using age-independent models underlines their suitability for predicting growth in mixed uneven-aged forests. The developed models can be easily integrated into forest practice to accurately obtain {i}_{d} estimates.

Individual tree growth responses to coinciding thinning and drought events in mixed stands of Norway spruce and Scots pine

Both thinning and drought can strongly affect individual tree diameter growth. Effects of thinning on individual tree growth responses to drought have been studied extensively, but the interaction between the thinning response and the drought response, and their dynamics is often overlooked.Diameter growth responses were studied using a dataset containing individual tree data from six mixed Norway spruce - Scots pine stands thinned between one year before and two years after a drought event in 2006. In four sample plots per stand, all trees with a diameter at breast height larger than 5 cm were analyzed for diameter increment, covering the full range of social status for both species. Growth reductions during the drought event were quantified using a new method accounting for the strong growth trends following the thinning. A new metric was developed to describe the growth response in first phase of the thinning response during which the diameter growth gradually increases, considering both the duration and the dynamics of the growth response.In the majority of the stands, thinning had no effect on the growth reduction during the drought event. The growth reduction during the drought event did not significantly delay thinning response. For spruce, the growth reduction during the drought event was not independent of the growth rate across the full range of social status. Neither the growth reduction during the drought event nor growth response in the first phase of the thinning response was significantly affected by the neighborhood species composition.

Thinning Effects on Changes in Crown Length and the Increment in Diameter at Breast Height of Japanese Cedar Trees in Overcrowded Mature Plantations

Thinning Effects on Changes in Crown Length and the Increment in Diameter at Breast Height of Japanese Cedar Trees in Overcrowded Mature Plantations

Unele aspecte privind studiul creșterilor în diametru la goruneturile de provenienţă vegetativă (lăstari) din Republica Moldova

It is known that the growth rate of a tree, respectively, a stand, during its life differs from one period of life to another. Thus, the growth rate is more accelerated at the beginning of life, so that, achieving the peak of growth in volume, this rate gradually decreases, becoming more and more weak in old age, until the tree stand passes into a state of decrepitude. This variation in the process of accumulation of wood biomass makes the economic efficiency of the tree, respectively, the stand, which varies depending on the development phase, i.e. its age. This increase in volume, usually expressed by the current annual growth of the tree, respectively, the stand at the level of measurement unit and transferred to total yield, ultimately defines its economic efficiency, which in turn varies according to the amplitude of the variation of the growth index. In this context, the purpose of this aper was to evaluate the diameter increments of sessile oak stands (Quercus petraea Liebl.) of vegetative origin from shoots in the Republic of Moldova in relation to the yield class, age and generation originating from shoots, as well as in relation to the composition and consistency of the stand at the level of physical-geographical areas and phytoclimatic levels.

Effect of density on Mediterranean pine seedlings using the Nelder wheel design: analysis of survival and early growth

Abstract There is growing interest in mixed-species forests but also a lack of studies that analyse them at the regeneration phases or any stage other than mature stands. Information is particularly scarce about relatively unproductive species such as Pinus pinaster and Pinus halepensis in Mediterranean ecosystems. The objective of this study was to investigate inter- and intra-specific interactions of both species at different tree densities during the first years of establishment. Five Nelder wheel plots were planted to test densities ranging from 1000 to 80 000 seedlings/ha and simulate establishment sub-processes at high densities. Further, P. pinaster and P. halepensis were mixed along the spokes, to obtain three mixture levels in which 100, 80 or 60 per cent of the seedlings were of the same species. Cox proportional-hazards models and binomial logistic regressions were fitted to analyse seedling survival. Early growth (basal diameter and height at one and four years after plantation) was analysed by fitting linear mixed-effects models. In this regard, P. halepensis showed higher survival rates and basal diameter increments but more time is needed to know how P. pinaster responds to density and mixture. Both competitive and facilitating seedling interactions were observed at higher densities, which fostered seedling survival but decreased early growth.

The effect of white mistletoe (Viscum album subsp. abietis (Wiesb.) Abromerit) on diameter increment in Kazdağı fir stands

In this study, the effects of white mistletoe (Viscum album subsp. abietis (Wiesb.) Abromerit) on diameter increment in Kazdağı fir (Abies nordmanniana subsp. equi-trojani (Asc. & Sint. ex Boiss.) Coode & Cullen) stands distributed in Kastamonu region of Turkey were investigated. For this purpose, a total of 183 sample trees (77 healthy (uninfected) and 106 infected) were selected from mistletoe-infected stands. Mistletoe infected sample trees were classified according to the mistletoe intensity groups as lightly-, moderately- and heavily-infection levels. Increment cores were taken from the sampled trees, and annual ring widths were measured for evaluation period which is the last 30 years of sample trees. Underbark diameter increments were determined for the last 10, 20 and 30 years and for also last three 10-year periods. Mistletoe infected trees were compared to healthy trees according to the mean diameter increments. As a result, it was determined that there were statistically significant differences between underbark diameter increments of infected and uninfected trees. Increment losses of infected trees compared to uninfected trees were calculated as 21%, 28% and 33% for the last 30, 20 and 10 years, respectively. Similarly, significant differences were also observed for the last three 10-year periods and it was revealed that the underbark diameter increment losses were 11%, 24% and 33%, respectively. The results show that increment losses increase gradually with infection and the presence of white mistletoe negatively affects diameter increments with an increasing acceleration from the past to the present.

P-440 Impact of electrospun scaffold topology on the performance of in-vitro Folliculogenesis applied to preantral ovine follicles

Abstract Study question How to improve in-vitro Folliculogenesis (ivF) protocols to address the enlarged demand of fertility preservation? Summary answer Tissue engineering-based approach opens new frontiers for ivF improving 3D-technologies addressed to support immature-ovarian-follicle-growth to obtain an increased number of competent oocytes enrolled in Assisted-Reproductive-Technology. What is known already ivF is a promising Assisted-Reproductive-Technology (ART) for preserving and restoring fertility. This technology potentially reproduces the early stages of folliculogenesis and oogenesis in-vitro allowing to move a large amount of oocyte on individual basis towards the validated protocol of in-vitro maturation/in-vitro fertilization (IVM/IVF). The current availability of biocompatible-supporting materials offers the challenging opportunity to mimic the native organ stroma in order to better reproduce the 3D environmental conditions leading to synergic follicles-oocyte development in-vitro with the aim to improve the performance of ivF in translational large sized mammal models. Study design, size, duration The present research aimed to compare preantral (PA) follicles culture on two different typologies of scaffolds fabricated using PCL(poly(epsilon caprolactone)), respectively made with patterned and randomly aligned fibers (PCL-Patterned/PCL-Randomic) with a standardized-single-follicle scaffold-free-method (3D-oil), widely validated on ovine model (Cecconi et al., 2004). The culture outcomes are compared analyzing follicle/oocyte growth, percentage of antrum differentiation and the incidence of meiotic competence, by exposing ivF growing oocytes to IVM protocol. Participants/materials, setting, methods PA follicles (mean size diameter: 250±4μm), mechanically isolated from slaughterhoused lamb ovaries, were individually cultured on electrospun PCL scaffolds (patterned vs randomic) or using the 3D-oil method. ivF were cultured alphaMEM-Fetal Bovine Serum free medium (5% Knockout Serum Replacement) supplemented with 4 IU/mL of equine Chorionic Gonadotropin (Di Berardino et al., 2021). At the end of ivF (14-days) the fully-grown oocytes isolated from early-antral follicles were tested on IVM. Main results and the role of chance PCL-Patterned electrospun scaffolds were able to strongly support a synergic oocyte and follicular growth. The 3D culture on Patterned electrospun scaffold supported the highest viability of follicles (87.5% vs 63% under 3D-oil conditions). On the contrary, the highest incidence of degenerated follicles was observed in cultures performed using PCL-Randomic materials (55 vs 37% vs 12.5% for PCL-Randomic vs 3D-oil vs PCL-Patterned, respectively; p <0.0004). The greatest follicle diameter increment (74.7±1 vs 70±0.4 vs 60.9±2%, for PCL-Patterned vs 3D-oil vs PCL-Randomic, respectively p <0.0007) and rate of antrum differentiation (87.5% vs 45% and vs 63%, for PCL-Patterned vs 3D-oil vs PCL-Randomic, for both p <0.0001) were observed in PA ovine follicles cultured on PCL-Patterned scaffolds. Furthermore, PCL-Patterned electrospun scaffolds supported a complete functional development of the oocyte compartment. More in detail, the majority of fully grown oocytes isolated from early- antral follicles grown on PCL-Patterned materials reached the metaphase-II stage (MII 80%) at the end of IVM in comparison to the significant lower percentage in 3D-oil (MII 68%, p =0.04) and PCL-Randomic (MII 18%, p <0.0001) protocols, respectively. Limitations, reasons for caution - Wider implications of the findings Tissue engineering scaffold-based approach represents a valid strategy generating a multi-organ in-vitro system, where different compartments may cooperate generating the complexity of paracrine-mechanism controlling early-follicles outcomes. Scaffold topology is essential to control early-follicles development. Indeed, exclusively PCL-Patterned can preserve long-term follicle 3D-microarchitecture supporting in-vitro oogenesis up to a complete meiotic-competence-acquisition. Trial registration number not applicable

Tree Growth, Foliar Nutrition, and Soil Properties in Mixtures of Lodgepole Pine and Sitka Alder in the Central Interior of British Columbia, Canada: 25-Year Results

Densities of naturally regenerated mixtures of lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) and Sitka alder [Alnus viridis subsp. sinuata (Regel) Á. Löve & D. Löve] were manipulated in 1995 at a site logged in 1987 in the central interior of British Columbia, Canada. Four levels of alder retention (0, 500, 1,000, and 2,000 clumps/ha) were combined with a uniform lodgepole pine density of 1,000 stems/ha across all treatments. After 25 years, effects of alder retention on lodgepole pine growth consisted of modest reductions in height and diameter increment, and treatment effects on soil nitrogen were confined to the forest floor organic horizons. Nutritional benefits of alder retention for lodgepole pine were not detected after year 6. The operational silvicultural implication of these findings is that only limited intervention to control Sitka alder in similar stands can be justified.

Современное состояние лиственницы ольгинской (Larix olgensis A. Henry) на Борисовском плато (Приморский край)

The modern literature on dendrology recognizes and describes 3 species of larch: Gmelin (Daurian) larch (L. gmelinii (Rupr) Rupr), Kayander larch (L. cajanderi Mayr.) and Olginsky larch (Larix olgensis A. Henry). However, Far Eastern foresters-researchers believe that the Lyubarsky larch, described in 1931 by V.N. Sukachev, grows on the territory of Primorsky Krai. The article presents research data on the current state of the Olginskaya larch (Lyubarsky larch) biogroups on the territory of the Borisov Plateau in Primorsky Krai. The Olginsky larch vegetation area and the grass cover of the territory is described in detail. The characteristics of the stand are given according to taxation indicators: origin, composition divided into stories (by weight and number of trees), age, forest density, average height and diameter, bonus, sum of cross-sectional areas, stock. The measurement results of 100 larch trees (diameter and height) were processed in the Exel STATISTIKA program. The age of the stand was determined, the influence of the average annual temperature and the annual amount of precipitation on the growth of larch in diameter was analyzed. The dynamics of the growth of model trees in diameter is analyzed. It has been established that the Olginskaya larch under the conditions of the Borisov Plateau shows negative growth rates in diameter with a lack and excess of moisture, and also at high temperatures the growth rates decrease. The analysis showed that in the conditions of the Borisov plateau there is a general dependence of the increments in diameter on climatic factors. Larch trees growing in the same micro-conditions showed completely different growth rates, which is obviously explained by genetic differences.

Rehabilitation of degraded forest area using dipterocarp species in Merlimau Forest Reserve, Melaka

The rehabilitation of degraded sites is now recognized as major issue globally. One of the means in rehabilitating degraded areas is through replanting. In this study, a variety of dipterocarp species were planted in a 1.5 hectare degraded forest area in Merlimau Forest Reserve, Melaka. The main objective of this study is to rehabilitate degraded site with commercial timber species. Combinations of slow-release fertilizer and organic fertilizers as well as big planting hole were applied as a part of the improved planting technique. In order to sustain the flora biodiversity of the site, line clearing for planting was adopted. Suitable species were matched to the topography of the site to increase the survival and growth. Growth and survival of saplings planted were monitored and data obtained were analyzed using SPSS program. After 62 months of planting, the survival rate recorded was very high which was 78% in average with Merawan siput jantan exhibiting the highest increment in both height and diameter throughout planting measurements.

Plastic Flow Characteristics of Micro Single-Crystal Copper

In order to study the plastic flow characteristics of micro single-crystal Cu, an in-situ uniaxial loading test was carried out. The slip direction of the test is determined by the Schmidt factor, which is at 1μm~4μm. Within the micropillar size range, the sample has an obvious size effect. This is essentially due to the continuous proliferation of dislocations in the micropillar flowing out of the surface. The smaller the size, the more difficult it is to store dislocations, and the easier dislocations flow out. Therefore, the yield stress significantly increases with the increment of sample diameter. This study provides guidance for the reliability evaluation of microscale components based on the single-crystal Cu.

Diametric Increment Patterns of Open-Grown and Under Competition Pinus taeda L. Trees in Southern Brazil

Diametric Increment Patterns of Open-Grown and Under Competition Pinus taeda L. Trees in Southern Brazil

Experimental investigation to study the effect of reinforcement on strength behavior of fly ash

Stabilization of the subgrade soil is a primary and significant phase in highway construction. In constructing a flexible pavement subgrade, soil investigation is an important parameter, as the load is transferred to it under a repetitive vehicle load. Subgrade soils with low strength of bearing are incapable of bearing heavy loads and are considered unsuitable for construction. The author proposed a solution for the weak subgrade of flexible pavements in this paper. This study aims to address weak subgrade issues by using fly ash reinforced with reinforcement. The California bearing ratio test (CBR) unsoaked was performed on the fly ash positioning with square and circular reinforcement patterns in the center of the loaded area. The test was performed using different reinforcement of diameters 1 and 2 and twisted 2 mm (1 mm diameter reinforcement overlap, then it was twisted over each other to make a 2 mm diameter twisted reinforcement). The CBR value for plain fly ash is found to be 14.64%, and the maximum CBR value for square and circular reinforcement is 34.89% and 24.23%, respectively. The percentage increase in the CBR value for square and circular reinforcement is to be 138.31% and 65.50%, respectively. The study found that the reinforcement spacing pattern affects the subgrade bearing capacity. As the reinforcement spacing decreases, the bearing capacity of the fly ash increases with the increment of reinforcement diameter. This study is important for subgrade soil strengthening since this fine reinforcement has increased the bearing capacity of poor soils.

Genetic Variability and Combining Abilities for Earliness to Nut Yield and Nut Weight in Selected Cashew (Anacardium Occidentale L.) Clones

ABSTRACT Introduction of exotic clones into the pedigree of commercial cashew clones could constitute a viable strategy to overcome the current low early nut yield and nut weight of the crop in West Africa. The aim of this study was to assess the combining abilities of Beninese, Brazilian and Ghanaian clones for early nut yield and nut weight. Twelve F1 hybrids were evaluated in the field for five traits such as stem diameter increment, canopy spread, nut yield, nut weight and cropping efficiency. Significant difference (p ≤ .01) was observed for most of the traits. Nut weight varied from 5.3 to 10.1 g/year, whilst nut yield ranged from 666.1 to 872.8 kg/ha/year among the top five crosses in the third to fifth year after planting. The Beninese (BE) progenies were comparable to the Ghanaian (SG) progenies for early nut yield but inferior to the Ghanaian and Brazilian (A) progenies for nut weight. Pearson correlation coefficient estimate (r = 0.74; p ≤ .01) suggest that, selecting for canopy spread in the north-south direction might improve early nut yield. GCA effects were more important than SCA effects. Narrow-sense heritability was moderate and exceeded 50% for all the traits. BE203 and SG224 showed positive GCA for early nut yield, whereas A2 and SG273 showed positive GCA for nut weight. Our study suggest that the Brazilian, Beninese and Ghanaian clones had different merits as potential parents for early nut yield and nut weight and could constitute a suitable genetic resource for improving cashew productivity.

Is it necessary to apply chemical weed control in short-rotation poplar plantations on deep soil sites?

Chemical weed control has been widely applied in plantation forests around the world. However, understanding the long-term influence of weed control on stand growth and its underlying mechanisms is still limited. We conducted a six-year (2016–2021; an entire rotation) weed control study in Chinese white poplar (Populus tomentosa Carr.) plantations established using tall planting stock on a deep soil site, which is a typical afforestation mode for poplars in north China. Three treatments of chemical weed control degree were implemented: no weeding (W0), removing weeds within 50 cm distance from the tree row (W50) and removing all weeds on the ground (W150). Different tree growth indicators, soil water content (θ), tree root distribution, and soil physical properties were measured. There was no weed control degree effect on θ in 2017 (P = 0.4408) but significant θ difference (P = 0.0140) among treatments existed in 0–30 cm soil in 2021. Different degrees of weed control did not change soil physical properties (P > 0.05) after the long-term application of chemical weeding. There were no differences (P > 0.05) in all growth indicators. But the cumulative increments of tree diameter, height, stand volume index, and biomass at the end of the rotation in W150 were numerically 2–27% lower than W0 and 11–26% lower than W50. The total fine roots biomass increased with decreasing weed control degree, although the difference was non-significant (P > 0.05). The fine root distribution pattern indicated that there might be many fine roots below 200 cm depth. The tree growth response to weed control may be attributed to tall planting stock that avoids light competition from weeds and deep soil resource exploration by tree roots that alleviate competition by shallow weed roots. Consequently, it may be unnecessary to apply chemical weed control in poplar plantations established using tall planting stock on deep soil sites. Our findings provide guidance for the sustainable management of industrial plantation forests.

ROOT PENETRATION INDEX 3, a major quantitative trait locus associated with root system penetrability in Arabidopsis.

Soil mechanical impedance precludes root penetration, confining root system development to shallow soil horizons where mobile nutrients are scarce. Using a two-phase-agar system, we characterized Arabidopsis responses to low and high mechanical impedance at three root penetration stages. We found that seedlings whose roots fail to penetrate agar barriers show a significant reduction in leaf area, root length, and elongation zone and an increment in root diameter, while those capable of penetrating show only minor morphological effects. Analyses using different auxin-responsive reporter lines, exogenous auxins, and inhibitor treatments suggest that auxin responsiveness and PIN-mediated auxin distribution play an important role in regulating root responses to mechanical impedance. The assessment of 21 Arabidopsis accessions revealed that primary root penetrability varies widely among accessions. To search for quantitative trait loci (QTLs) associated to root system penetrability, we evaluated a recombinant inbred population derived from Landsberg erecta (Ler-0, with a high primary root penetrability) and Shahdara (Sha, with a low primary root penetrability) accessions. QTL analysis revealed a major-effect QTL localized in chromosome 3, ROOT PENETRATION INDEX 3 (q-RPI3), which accounted for 29.98% (logarithm of odds=8.82) of the total phenotypic variation. Employing an introgression line (IL-321) with a homozygous q-RPI3 region from Sha in the Ler-0 genetic background, we demonstrated that q-RPI3 plays a crucial role in root penetrability. This multiscale study reveals new insights into root plasticity during the penetration process in hard agar layers, natural variation, and genetic architecture behind primary root penetrability in Arabidopsis.

Protocolo eficiente para aumentar el porcentaje de prendimiento en injertos de Pinus greggii Engelm. var. australis Donahue et López

Introduction: Grafted plants of conifers are used in the establishment of clonal seed orchards, but with the methodology currently used, unsatisfactory results are reported. Objective: To compare grafting and growth of Pinus greggii var. australis scion from nursery and field stock plants grafted on four rootstocks. Materials and methods: Scions of P. greggii Engelm. var. australis Donahue et López, collected from nursery stock plants (NSSP) and field trees (FSSP), were divided into terminal bud and basal segment, and grafted onto P. greggii var. australis, P. patula Schiede ex Schltdl. et Cham., P. teocote Schiede ex Schltdl. et Cham. and P. leiophylla Schiede ex Schltdl. et Cham. Percentage of grafting, height increment, diameter, scion-rootstock ratio and number of shoots (NS) were evaluated. Height and diameter increment data were subjected to an ANOVA and NS was analyzed with Poisson regression. Results and discussion: Grafting ranged from 93 to 100 %. The greatest increase in height was reported for P. teocote (14 cm) with scion from the terminal shoot of the nursery plant, while the combination P. greggii / P. leiophylla had the best scion-rootstock ratio with a value of 1. The highest NS was recorded with scion from the basal segment of NSSP. Getting two types of scions from one scion made the use of vegetative material more efficient. Conclusions: The use of nursery stock plants, 15-month-old rootstock, and two types of scions allowed having grafted plants in three months. The methodology developed was efficient, cost-effective and fast.

Hydrodynamics of gas-liquid bubble columns under bubbling, transient, and jetting flow regimes using volume of fluid computational fluid dynamics

A volume of fluid computational fluid dynamics (VOF-CFD) model was used to investigate hydrodynamics of air-water bubble columns in the gas distributor region under bubbling, transient, and jetting flow regimes. The Reynolds-averaged Navier-Stokes (RANS) and large eddy simulation (LES) turbulence equations were coupled with the VOF-CFisms@2015D model. A novel bubble detection algorithm was developed to calculate the bubble size, where a gas fraction of 0.5 was adopted to detect bubbles in the gas-liquid mixture. The CFD results for all three flow regimes were compared to the experimental data in terms of the bubble size distribution (BSD) and mean bubble size. In the framework of VOF, the LES turbulence model captured bubble behaviors in the three flow regimes more accurately than the RANS approach by taking computational time 20% more. Increasing the surface tension from 0.025 to 0.0719 N/m resulted in the increment of the Sauter mean diameter from 4.0 to 5.4 mm. The VOF-CFD model coupled with LES yielded the initial BSD near the gas distributor, which is necessary for Eulerian CFD often applied to an entire column.

Influence of particle size on the SARS-CoV-2 spike protein detection using IgG-capped gold nanoparticles and dynamic light scattering

Due to the unprecedented and ongoing nature of the coronavirus outbreak, the development of rapid immunoassays to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its highly contagious variants is an important and challenging task. Here, we report the development of polyclonal antibody-functionalized spherical gold nanoparticle biosensors as well as the influence of the nanoparticle sizes on the immunoassay response to detect the SARS-CoV-2 spike protein by dynamic light scattering. By monitoring the increment in the hydrodynamic diameter (ΔDH) by dynamic light scattering measurements in the antigen–antibody interaction, SARS-CoV-2 S-protein can be detected in only 5 min. The larger the nanoparticles, the larger ΔDH in the presence of spike protein. From adsorption isotherm, the calculated binding constant (KD) was 83 nM and the estimated limit of detection was 13 ng/mL (30 pM). The biosensor was stable up to 90 days at 4 °C. Therefore, the biosensor developed in this work could be potentially applied as a fast and sensible immunoassay to detect SARS-CoV-2 infection in patient samples.