Entire Stem Research Articles

Indian Grasses and Their Potential for Sustainability

Global researcher and consumer prioritize protecting the atmosphere and biodiversity by promoting eco-friendly products, favoring natural fibers over synthetic materials for their bio-renewable properties and sustainability benefits. The main aim of the review paper was to study the different grasses and their utilization. The author focused on Grass fibres, their sources, properties, and application and their scope for sustainable development ins textile industry. Grasses are somewhat unique in that they frequently succeed in displacing other plants from wide areas of land. Grass fibers are another group of monocotyledonous fibers, where the entire stem together with the leaves are pulped and used in papermaking. Such pulps are composed not only of fibers, but of other cellular elements as well. However, very few individuals recognise the value of grasses. While several plant families provide for human needs, the grass family out performs all others in terms of the quantity and quality of its output. Not much of the work has been done on grass fibres. Hence the need of the hour was felt to explore the potential application of Golden grass (sabai grass fibre), Nettle grass, Vetvier grass, Nappier grass and Gajar grass so as to find sustainable solutions for textile sector.

The cemented stem in hip arthroplasty - state of the art technique and recommendations.

The indication for femoral stem cementation should be made on a patient-specific basis, taking physical activity, femoral geometry, and bone tissue quality into account. Age alone should not be the sole justification for cementation. The Dorr classification can serve as decision support for whether a cemented fixation should be used. Femoral neck fractures should generally be cemented. Familiarize yourself with the applied stem philosophy. Force-closed stems typically have a polished surface that allows for subsidence, especially in the first 2 years postoperatively. Stems following the shape-closed philosophy have rougher surfaces and do not allow subsidence. There are various types of cement that differ in viscosity and can be categorized accordingly. These cement types go through four temperature-dependent phases: mixing phase, waiting phase, working phase, and curing phase. Rough implants should be implanted quickly, using wetter cement. For a polished stem, the cement should be slightly firmer. To avoid complications like bone cement implantation syndrome, it is essential to adhere to the state-of-the-art retrograde cementation technique, which recommends pulsatile lavage and vacuum mixing of the cement. Additionally, cement restrictors and pressurizers are used. A thorough understanding of cementation techniques is crucial to ensure a favorable outcome with a uniformly thick cement mantle that encompasses the entire stem. Incorrect cementing can lead to the premature failure of the endoprosthesis.

Evaluation of taper measurement schemes for modeling stem profiles: A case study of two conifer species

Taper models have been widely used and treated as the primary means of calculating tree volume. However, constructing taper models is challenging in practice due to the high cost and time involved in measuring stem diameters. Therefore, we designed twenty new taper measurement schemes that increase the stem diameter measurement interval (diameter above breast height) by two to five times. The taper models were evaluated by predicting stem diameter, volume, and merchantable height of two conifer species (Pinus sylvestris var. mongolica and Larix gmelinii) in Northeastern China. Results showed that the variable-exponent taper model of Kozak (2004) performed best for both species, while diameters can be measured every 2 m above 4 m. In addition, for both species, reducing the diameter measurement required for modeling by one-third to one-half does not increase the error in predicting the entire stem profile. This study will provide additional insights for collecting taper measurement data through traditional destructive sampling.

Directed Evolution of a Bacterial Leucyl tRNA in Mammalian Cells for Enhanced Noncanonical Amino Acid Mutagenesis.

The Escherichia coli leucyl-tRNA synthetase (EcLeuRS)/tRNAEcLeu pair has been engineered to genetically encode a structurally diverse group of enabling noncanonical amino acids (ncAAs) in eukaryotes, including those with bioconjugation handles, environment-sensitive fluorophores, photocaged amino acids, and native post-translational modifications. However, the scope of this toolbox in mammalian cells is limited by the poor activity of tRNAEcLeu. Here, we overcome this limitation by evolving tRNAEcLeu directly in mammalian cells by using a virus-assisted selection scheme. This directed evolution platform was optimized for higher throughput such that the entire acceptor stem of tRNAEcLeu could be simultaneously engineered, which resulted in the identification of several variants with remarkably improved efficiency for incorporating a wide range of ncAAs. The advantage of the evolved leucyl tRNAs was demonstrated by expressing ncAA mutants in mammalian cells that were challenging to express before using the wild-type tRNAEcLeu, by creating viral vectors that facilitated ncAA mutagenesis at a significantly lower dose and by creating more efficient mammalian cell lines stably expressing the ncAA-incorporation machinery.

Whole-Tree Green Density Equations for Loblolly and Slash Pine Trees

Abstract Using extensive legacy and new datasets, two equations of whole-tree green density, defined as the ratio of the green weight of stem wood with bark (GWob) divided either by the stem outside-bark volume (Vob) or by the stem inside-bark volume (Vib), were developed along with individual tree Vob, Vib, and GWob equations for loblolly and slash pines. The green density equations indicated that the GWob/Vob ratio increases while the GWob/Vib ratio decreases with an increase in tree size for both species. The transition from low-intensity management to intensive management has a notable impact on tree green weight characteristics. Generally, trees from older established plantations exhibited a higher GWob/Vob ratio compared with trees from more recently established plantations, spanning both loblolly and slash pines. Study Implications: Derived whole-tree green density equations, alongside updated stem green weight and volume equations, are valuable tools for estimating the volume and green weight of entire stem boles, facilitating volume-to-green-weight conversion for specific sections for loblolly and slash pines, the primary commercial timber species in the southern United States.

Enhanced Directed Evolution in Mammalian Cells Yields a Hyperefficient Pyrrolysyl tRNA for Noncanonical Amino Acid Mutagenesis.

Heterologous tRNAs used for noncanonical amino acid (ncAA) mutagenesis in mammalian cells typically show poor activity. We recently introduced a virus-assisted directed evolution strategy (VADER) that can enrich improved tRNA mutants from naïve libraries in mammalian cells. However, VADER was limited to processing only a few thousand mutants; the inability to screen a larger sequence space precluded the identification of highly active variants with distal synergistic mutations. Here, we report VADER2.0, which can process significantly larger mutant libraries. It also employs a novel library design, which maintains base-pairing between distant residues in the stem regions, allowing us to pack a higher density of functional mutants within a fixed sequence space. VADER2.0 enabled simultaneous engineering of the entire acceptor stem of M. mazei pyrrolysyl tRNA (tRNAPyl ), leading to a remarkably improved variant, which facilitates more efficient incorporation of a wider range of ncAAs, and enables facile development of viral vectors and stable cell-lines for ncAA mutagenesis.

Enhanced Directed Evolution in Mammalian Cells Yields a Hyperefficient Pyrrolysyl tRNA for Noncanonical Amino Acid Mutagenesis

AbstractHeterologous tRNAs used for noncanonical amino acid (ncAA) mutagenesis in mammalian cells typically show poor activity. We recently introduced a virus‐assisted directed evolution strategy (VADER) that can enrich improved tRNA mutants from naïve libraries in mammalian cells. However, VADER was limited to processing only a few thousand mutants; the inability to screen a larger sequence space precluded the identification of highly active variants with distal synergistic mutations. Here, we report VADER2.0, which can process significantly larger mutant libraries. It also employs a novel library design, which maintains base‐pairing between distant residues in the stem regions, allowing us to pack a higher density of functional mutants within a fixed sequence space. VADER2.0 enabled simultaneous engineering of the entire acceptor stem of M. mazei pyrrolysyl tRNA (tRNAPyl), leading to a remarkably improved variant, which facilitates more efficient incorporation of a wider range of ncAAs, and enables facile development of viral vectors and stable cell‐lines for ncAA mutagenesis.

Abnormal Winter Drought-Induced Transient Dieback of Korean Fir in the Montane Forests of Mt. Jirisan, South Korea

Although climate change-related concerns have long been raised regarding the sudden dieback of Korean fir (Abies koreana), the event’s etiology and subsequent ecosystem processes must be explained. Our study aims to clarify the continuity or transience of mass mortality events within the coarse woody debris (CWD) structure and, if transient, to identify the climatic conditions (1974–2021) that could be responsible for the massive dying phenomena in Korean fir populations. On average, precipitation during the non-growing season (November–April as winter) constituted 18.5% relative to the growth period; in the winter of 1999, it was 4.8% due to an abnormal drought event. The dead stems occurred evenly across all size classes. In the CWD structure, the density and biomass of the dead fir individuals peaked in decay classes II or III. The size distribution of the retained fir was inverse-J shaped across the entire altitudinal range. The abnormal winter drought event, causing root damage by soil frost and heaving, may be one of the factors that increased Korean fir mortality across the entire stem size range. Despite transient cohort senescence, the retained Korean fir individuals transmitted drought-resistant traits into the regional pool following the drought event.

Characterization of mango hybrids and their parents for vigor, flowering, yield components and biochemical traits

The vigour, blooming, yield, and biochemical features of seventy mango hybrids, including their parents,‘Amrapali’ and ‘Sensation’, were evaluated. The hybrid ‘H-13-5’ had the greatest plant height (10.11m), wherestem girth was maximum in ‘H-1-6’ (132.21cm), and ‘H-13-1’ had the largest canopy spread (9.77 m). The hybrid‘H-13-4’ exhibited the highest bark-wood ratio (7.59), signifying a higher percentage of mature wood surroundingthe entire stem. Hybrid ‘H-1-9’ had the highest stomatal density (797 stomata/mm2) as a dwarfing trait. Regardingreproductive characteristics, hybrid ‘H-11-4’ produced the maximum number of fruits (2.51) per panicle. Witha more significant fruit retention percentage of 62%, the hybrid ‘H-11-1’ showed improved fruit retention onthe tree. The tree with the higher fruit output, hybrid ‘H-1-8’, produced 43 kg of fruit per tree. The hybrid ‘H-1-5’ produced the maximum size of fruits (317 g/ per fruit). These signify that the resultant hybrids have a lotof potential for future breeding and commercial exploitation be cause of their advantageous economic traits

Structural characterization of SLYM—a 4th meningeal membrane

Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4th meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1–3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.

Employing entire stem might underestimate the amount of carbohydrate remobilization in wheat

Employing entire stem might underestimate the amount of carbohydrate remobilization in wheat

Tree-ring dating of the common trees in Wadi Allaqi Biosphere Reserve, South-East Egypt

Twenty-five increment cores and tree discs were sampled for four common trees in Wadi Allaqi, an extremely arid region in South-East Egypt (19 for Acacia tortilis subsp. raddiana (Savi) Brenan and 2 for each of Balanites aegyptiaca (L.) Delile, Acacia ehrenbergiana Hayne, and Tamarix nilotica (Ehrenb.) Bunge). The main aim of the current study is to achieve a longer temporal perspective on growth, longevity, and marginal parenchyma of the wood samples. The growth ring boundaries of the acacias are differentiated by thin parenchyma bands, which run around the entire stem discs. Samples of Acacia tortilis subsp. raddiana were located along this Wadi from its upstream to downstream parts; based on the mean distance between the bands of marginal parenchyma, longevity, based on the marginal parenchyma bands, indicated that Acacia tortilis subsp. raddiana grew slowly and some of its studied individuals reflected 2 age scenarios in the downstream part, while the measurement interval reflected an established date of around 1884 or 1886. Both scenarios grew fast over a long period of time, and so the chiefly recent growth was dated back to 1885. Approximate dates for the midstream part dated back to 1648, while the overall growth for the upstream part dated back to 1482. Samples of Balanites aegyptiaca may be established between 1608 and 1715, while those of Acacia ehrenbergiana may be established between 1945 and 1975. Tamarix nilotica swiftly established itself, and a new ecosystem replaced the severe arid habitat after the dropping of the water level in 1980s.Two scenarios of age are probably true for the downstream part, implying a date of establishment between 1884 and 1886. It was also discovered that the outdated scenario for B. aegyptiaca and A. ehrenbergiana is more in line with asymptotic value and current growth, indicating larger possibility for future expansion.

Electrical resistivity tomography (ERT) measurements during water flow in a date palm stem segment

Commercial cultivation of date palms has high economic significance, particularly in arid and hyper-arid regions. Achieving commercially viable yield of dates amid water scarcity and enforced restrictions on water use requires optimising the amount and timing of irrigation. To that end, better understanding of the temporal dynamics of the water use of date palm is of great importance. Traditionally, this can be achieved through sap flow estimates obtained using heat dissipation probes. However, such measurements lack the ability to provide information on the spatial distribution of sap flow, which is important considering that date palms transport water in the entire stem cross-section. The aim of this study is to evaluate whether electrical resistivity tomography measurements have the potential to provide information on the spatial variability of flow in date palm stems. For this, flow was induced through a stem segment that was obtained from a felled date palm tree. ERT measurements were continuously obtained throughout a cycle of flow and no-flow periods. The results showed that the mean bulk electrical conductivity varied strongly due to changes in the flow conditions. In addition, it was found that the electrical conductivity of the outflow was much higher than that of the inflow, which indicates the release of stored salt from the stem segment. Analysis of the spatial distribution of the electrical conductivity suggested that flow mainly occurred in a limited part of the cross-sectional area of the stem. Overall, it was concluded that the ERT is a promising tool to investigate the spatial variability of water flow in date palm stems.

An easy, convenient statistical method to analyze bark beetle populations

A non-invasive method to estimate the number of Trypodendron lineatum holes on dead standing pines (Pinus sylvestris L.) was developed using linear and nonlinear estimations. A classical linear regression model was first used to analyze the relationship between the number of holes caused by T. lineatum on selected stem units and the total number of holes on an entire dead stem of P. sylvestris. Then, to obtain a better fit of the regression function to the data for the stem unit selected in the first step, piecewise linear regression (PLR) was used. Last, in an area used to evaluate wood decomposition (method validation), the total and mean numbers of T. lineatum holes were estimated for single dead trees and for a sample (n = 8 dead trees). Data were collected in 2009 (data set D1), in 2010–2014 (data set D2) and in 2020 (data set D3) in forests containing P. sylvestris located within Suchedniów–Oblęgorek Landscape Park, Poland. A model was constructed with three linear equations. An evaluation of model accuracy showed that it was highly effective regardless of the density of T. lineatum holes and sample size. The method enables the evaluation of the biological role of this species in the decomposition of dead standing wood of P. sylvestris in strictly protected areas.

Evaluation of the Occurrence of Hollows in Trees in Managed Forest in the Eastern Brazilian Amazon

Abstract This study proposed to generate information related to the abundance and the structural characteristics of hollows at the tree and species levels in an area of managed forest in the Amazon. A database was used that was composed of 29,899 trees from thirty-eight species that were inventoried, harvested, and measured in ten annual production units that were managed between 2008 and 2017 in the Tapajós National Forest, state of Pará, Brazil. The data was tabulated and reported in absolute and percentage values. Contingency tables were created to identify patterns of occurrence of hollows in commercial stems. A total of 24% of the harvested trees had hollows in at least one section of the commercial stem, and species had different propensities for hollow occurrence. It was found that the larger the tree diameter the greater the possibility for occurrence of hollows, and these hollows were proportionally larger. Most of the hollows in harvested trees were small. Patterns of occurrence in commercial stem hollows were observed, and these were dependent on tree species and size. Most trees had hollows distributed along the entire stem or only at the base of the stem. Study Implications: The presence of hollows in managed native forest trees in the Amazon depends on the species, and trees with larger diameters have a greater probability of having hollows. Furthermore, trees with larger diameters have hollows that have larger diameters, lengths, and volumes. Commercial trees have different patterns of hollows along the stem, and these patterns are dependent on tree species and size. The results of this study will contribute to management of trees with hollows in the Amazon Forest as well as to serve as a base for future studies related to this theme.

Design and Experimental Study of a Bionic Blade for Harvesting the Wild Chrysanthemum Stem

Wild chrysanthemum has a high medicinal value. Its mechanized harvest can improve harvesting efficiency, reduce labor costs and improve planting benefits, which is an important way to promote artificial planting. However, one of the difficulties in mechanized harvesting is the large diameter and hardness of the stem, leading to high cutting resistance and power consumption. In order to reduce cutting resistance and power consumption, a bionic cutting blade is designed in this paper by employing the bionics principle and the contour of the cricket’s upper jaw incisor lobe instead of the sharp triangular teeth of the standard harvester blade. Using the finite element method, the cutting-edge angle, cutting angle, and reciprocating speed were taken as test factors. The maximum shear force and power consumption were taken as evaluation indexes. At the same time, the center combination simulation test was carried out to optimize the cutting body and to determine the optimal cutting speed. When the cutting-edge angle was 21°, the cutting angle was 66°, the reciprocating speed was 1.29 m/s, and the maximum shear force and power consumption were minimal. The results showed that the maximum shear force of the bionic cutter was reduced by 18% and the power consumption by 15.8%. The bench test showed that the maximum shear force and power consumption of the bionic cutter were reduced by 10.5% and 10.8%, respectively, when the entire wild chrysanthemum stem was cut. The results can provide a reference for the mechanical harvesting of wild chrysanthemum stems.

Aseptic loosening following Custom Megaprosthesis Reconstruction presenting as a Pseudoarthrosis - A case report

IntroductionCustom megaprosthesis reconstruction is a common treatment modality used for the management of large bone defects. Aseptic loosening was found to be the third most common cause of failure of megaprosthesis. Case reportA 40 year old gentleman had recurrent left proximal tibia giant cell tumor. He underwent a resection of the tumor and reconstruction with cemented custom megaprosthesis of the knee. Two years following the surgery, abnormal movement was noted in middle 1/3rd of the leg. Radiographs revealed radiolucency between the tibial component and bone. He was managed conservatively, and the patient continued to mobilise with walker support. ConclusionAseptic loosening can occur isolated in the middle portion of the megaprosthesis tibial component, with an intact tibial stem-bone interface, resulting in a presentation mimicking pseudoarthrosis. The pseudoarthrosis can be managed conservatively unless there is loosening of the entire tibial component and stem.

Seasonally driven internal P and N nutrient (re)cycling strategies of beech saplings are element specific

Excessive N deposition leads to the conversion of previously N limited to N saturated forest ecosystems. The input of N can result in severe N/P imbalance and N-induced P deficiency. The present study investigates whether N addition induces P deficiency in beech saplings or if this can be counteracted by enhanced internal P (re)cycling. Furthermore, it was tested whether addition of P can mitigate N induced P deficiency. In addition, higher need of P due to enhanced growth may be realized either by enhanced P uptake or by improved internal P (re)cycling. This assumption was tested with beech saplings growing at higher light intensity. Therefore, a mesocosm approach with beech saplings and soil (O and A horizon) originating from a P-poor forest was conducted. Mesocosms were cultivated for two growing seasons in a garden. Addition of N, P, or combined addition of N and P took place during the first year and another group of saplings was exposed to higher light intensity to enhance CO 2 assimilation and growth. Soil horizons and beech saplings were harvested during the second year of growth in spring, summer, autumn, and winter. The results show that internal (re)cycling of N and P is different and mostly determined by the season. The seasonal (re)cycling of P was driven by the metabolic P demand of tissues/organs characterized by shifting P between the perennial tissues bark and wood of branches and coarse roots and deciduous leaves, fine roots and long-distance transport paths without using major storage resources. In contrast, seasonal (re)cycling of N is characterized by N storage in perennial tissues during dormancy and by N mobilization from the entire trunk, i.e. branch, stem and coarse roots, in spring. Furthermore, these seasonal dynamics were found to be independent of the treatment. • P (re)cycling comprises the shift of P to the places of demand without P storage. • N storage and re-mobilization characterizes saplings seasonal (re)cycling of N. • High light induces N deficiency but sufficient P supply sustained by P (re)cycling. • N/P ratios used as indicator of nutrient imbalance show large seasonality. • Missing root establishment in the Of+Oh prevents P improvement of saplings.

Tone and the prosodic stem in Malawian CiTonga

AbstractIn CiTonga, a Bantu language spoken in northern Malawi, a number of different morphemes within the verbal complex can sponsor a High tone. While the High tone of a morpheme which precedes the stem is shown to be underlyingly pre-linked, those found after the beginning of the stem are argued to be underlyingly floating. This latter group of High tone autosegments can be shown to exclusively dock onto the first and last tone bearing units (TBUs) of the prosodic stem. This domain is not isomorphic with the morphological stem in that it must include the entire morphological stem as well as any of 3 different categories of enclitics which follow. The docking of the underlyingly floating Hs is shown to follow an edge-in process whereby a single H docks onto the initial TBU of the prosodic stem, a second H docks onto the final TBU of the prosodic stem, and any additional High tones remain floating, being phonologically inert. The paper provides an extensive range of newly presented data on this understudied Bantu language and constitutes a rare case of the prosodic stem being motivated by tonological factors.

Quantifying Dam‐Induced Fluctuations in Streamflow Frequencies Across the Colorado River Basin

AbstractPeriodic fluctuations in natural streamflow are a major driver of river ecosystem dynamics and water resource management. However, most U.S. rivers are impacted both by long‐term hydroclimatic trends and dams that alter flow variability. Despite these impacts, it remains largely unexplored how dams affect the dominant frequencies of natural streamflow over a highly regulated river network. We investigated the entire Colorado River Basin (CRB) to understand how the annual (10–14 months) and multi‐annual (24–60 months) frequencies in natural flow regimes have been progressively altered by dams. Given the significant alteration over the CRB, we captured changes in streamflow frequencies between naturalized and observed monthly flows via wavelet analysis. Based on the similarity of changes in streamflow frequencies (annual and multi‐annual) over the last 30 years, sections of the riverine network were classified into four groups. The annual frequency was relatively well preserved downstream of Hoover Dam, while showing a systematic trend of alteration downstream of Glen Canyon Dam until Hoover Dam. Meanwhile, the multi‐annual frequency component was highly altered for the entire Lower Colorado main stem (i.e., downstream of Glen Canyon). We also identified dams with significant impacts on streamflow frequency by comparing wavelet coherence estimates. This study advances the notion that dams fundamentally alter river flow regimes across multiple frequencies and with varying amplitudes over time and space, with alteration propagating – or being dampened – by both hydroclimatic fluctuations and water resource management.