Influence of regeneration process parameters on geometry and defects of clearance surface of planer knives used in wood planing process

A properly implemented strategy regarding the planer knife regeneration process, may not only restore the original cutting ability of the tool, but even increase its operational quality, including its durability for industrial woodworking processes. This article presents experimental results and discussion in respect of sharpening planer knives with cubic boron nitride grinding wheels. Both the grinding conditions and machining surface quality were analyzed. Application of improper size or loads of abrasive grains may lead to the appearance of grinding burns on a machined surface, or result in a surface with cracks and grooves. The results of the measurements carried out indicate that surfaces with reduced values of roughness and waviness parameters can be obtained, even up to 22% (as in the case of the reduced peak height parameter, Spk) in relation to new knives, prepared at a factory. The value of St and Sds parameters are almost the same as reference knife (deviation up to 3%). Due to machining marks, the total waviness exceeds 33%. Our research also shows that due to the technological quality of the knife surfaces, it is beneficial to use CBN grains with a low depth of cut (ae no more than 0.02 mm), but a moderate or high feed rate (the best choice is about 470 mm/min for vft). Presented results constitute an important know-how for the grinding process with the use of grinders used by operators (like WEINIG Rondamat 980) during the sharpening of planer cutter heads in the wood industry.

Spontaneous Regeneration of Plantlets Derived from Hairy Root Cultures of Lopezia racemosa and the Cytotoxic Activity of Their Organic Extracts

A histological analysis was performed with the aim of elucidating the spontaneous regeneration process of the hairy root lines LRT 2.3 and LRT 6.4, derived from Lopezia racemosa leaf explants and genetically transformed with the Agrobacterium rhizogenes strain ATCC15834/pTDT. The analysis showed both lines regenerate via indirect somatic embryogenesis; LRT 6.4 also regenerated by direct organogenesis. The morphogenic characteristics of the regenerated plantlets from both lines showed the typical characteristics, described previously, including a higher number of axillary shoot formation, short internodes, and plagiotropic roots compared with wild-type seedlings. The regeneration process occurred without the addition of plant growth regulators and was linked to the sucrose concentration in the culture medium. Reducing the sucrose concentration from 3% to 2%, 1%, and 0.5% increased the regeneration rate in LRT 6.4; the effect was less pronounced in LRT 2.3. The cytotoxic activity of different organic extracts obtained from roots and shoots were evaluated in the cancer cell lines HeLa (cervical carcinoma), HCT-15 (colon adenocarcinoma), and OVCAR (ovary carcinoma). The hexane and dichloromethane extracts from roots of both lines showed cytotoxic activity against the HeLa cell line. Only the dichloromethane extract from the roots of PLRT 2.3 showed cytotoxic activity against the OVCAR cell line. None of the methanol extracts showed cytotoxic activity, nor the shoot extracts from any solvent.

Timescapes beyond the Metropolises

The past decades have witnessed a rise of culture-led urban regeneration. The successful cultural models have travelled throughout the world, and applied to cities and urban areas regardless of their size and location. Culture, ranging between high culture and contemporary creative economies, acquires potential to contribute to physical, social and economic aspects of urban regeneration. Successful examples of culture-led urban regeneration have tempted small cities to invest in traveling global cultural policies. Academic community has criticized these travelling policies for over-simplifying the abstract notion of culture, overrating the benefits of culture-led urban regeneration and ignoring local temporal specifics. This paper argues that a temporal analysis framework would enable a holistic approach to culture-led urban regeneration, and embrace the temporal uniqueness of urban contexts. This article discusses the temporal characteristics of culture-led regeneration in a provincial city context within an empirical case study analysis of Myllytulli in Oulu, Northern Finland. Myllytulli represents a district of regional cultural relevance where cultural amenities range from museums and educational facilities to creative bottom-up initiatives. This study reframes Myllytulli’s urban regeneration process using temporal conceptions of recent interdisciplinary academic discourse. The empirical data set consists of expert interviews, observation material and municipal planning documents. The results analyse the urban regeneration process within the linear temporal ideals of rational-comprehensive planning, reactive experiential urbanism and relational dimensions of time. The paper suggests time-sensitive approaches for future research and practice of urban regeneration.

Assessing woody vegetation recovery in the Rayas River following the eruption of the Chaitén Volcano in 2008

We studied the recovery of the woody vegetation in a segment of the Rayas River, that drains the Chaitén Volcano, in southern Chile. Data collection in the river corridor was performed to assess the regeneration rates of the colonizing vegetation within the river corridor, to investigate the site-specific regeneration modes (i.e., with respect to the different morphological units), to determine the species composition and to observe potential similarities with the regeneration process on hillslopes (i.e., outside the river corridor). We first performed a sampling of the shrub and tree vegetation regenerating in the Forest adjacent to the study segment. Further samplings were executed on Islands, High bars, the Floodplain, and in association to Wood jams. Results show that nine years after the volcano's last eruption, pre-eruption remnant Islands and the Floodplain exhibited an abundant regeneration, with the highest density of recruits and species richness. In addition, a clear difference was observed between the river corridor and the Forest, both in the characteristics of the plants that were regenerating as well as in the species composition. Finally, the vegetation that has re-established after the eruption have not yet acquired the capacity to play a stabilizing role in the fluvial corridor. New insights are provided on reforestation patterns at sites impacted by Large Infrequent Disturbances.

Mechanism and Conformation Changes for the Whole Regeneration Process of Cellulose in Pyridinium-Based Ionic Liquids

In this work, mechanism and conformation changes of cellulose regenerated from ionic liquid by anti-solvents (water, ethanol and acetone) were investigated by molecular simulations. Cellulose model consists of seven glucose single chains were constructed. In order to depict the regeneration mechanism, both the dissolution and regeneration processes of cellulose in [Bpy][OAc] IL were simulated. The methyl hydroxyl group of cellulose will change its conformation during dissolution and regeneration. The conformation of initial cellulose crystal is mainly the tg conformation. After dissolved in ILs, the cellulose conformation changes into the gt conformation and the gg conformation. After regenerated by anti-solvent, the proportion of the gg and gt conformation changes, and the gg conformation increased and the gt conformation decreased. Based on energy analysis, it is concluded that the energy for tg is the lowest, and the tg widely exists in cellulose I. After cellulose is dissolved in ILs, the conformation changes into two higher energy conformations, the gt and gg. In the subsequent regeneration process, with the completion of regeneration, the gg conformation increases and the gt conformation decreases.

Il progetto urbanistico per Canosa di Puglia: tra valorizzazione e rigenerazione La rigenerazione della città di Canosa di Puglia

This paper describes the strategy for the enhancement of the archaeological and landscape heritage of Canosa di Puglia. The strategy consists in a cluster of projects and actions, which embrace three main work plans. The first one concerns the geographical area extending from the low valley of the Ofanto river to the slopes of the Murgia plateau. The second one lies on existing practices of common heritage care which many associations and groups of citizens already perform, in order to collect an important piece of the already existing cultural and ecological regeneration process. The third one includes the plan for the enhancement of the important historical-archaeological heritage spread in the inhabited city and its territory – in some cases in a state of decay and abandonment – and the process of the social re-appropriation promoted by three funded urban projects, which aim at organizing a new collective system of green spaces entrusted to sustainable usability.

Cellulose Acetate Nanofibers: Incorporating Hydroxyapatite (HA), HA/Berberine or HA/Moghat Composites, as Scaffolds to Enhance In Vitro Osteoporotic Bone Regeneration

The specific objective of this study was to stabilize a simple valid method to prepare pure nanorod hydroxyapatite (HA) mixed with berberine chloride (BER) and Moghat water extract (ME) as composites for incorporation into cellulose acetate (CA) nanofibers to be used as novel bone scaffolds and to determine their efficacy in bone regeneration process In Vitro. Preparation of HA/BER and HA/ME composites were performed by mixing powders using the ball-milling machine. The HA, HA/BER, and HA/ME composites at a concentration of 6.25, 12.5, 25, 50, 100, and 200 mg were mixed with CA solution (13%), then the fiber was formed using electrospinning technique. The properties of the obtained CA fibers were investigated (SEM, TEM, EDX, FTIR, TGA, water uptake, porosity, and mechanical tests). The efficacy of HA and HA composites loaded into CA nanofiber on osteoblast and osteoclast differentiation were measured by tacking ALP, osteocalcin, TRAcP, calcium, and total protein concentration. Moreover, their effects on cell differentiation (CD90 and PARP- ɣ) and death markers (GSK3b, MAPK, Wnt-5 and β-catenin) were evaluated by using ELISA and qPCR. The obtained TEM results indicated that the continuous CA and CA/HA composites electrospun fibers have ultrafine fiber diameters of about 200 nm and uniform distribution of discrete n-HA clusters throughout. In addition, hydrocortisone (HCT) was found to increase the formation of adipocytes and osteoclastic markers CD90 and p38-MAPK which indicated the bone lose process take placed. Treatment with CA loaded with HA, HA/BER or HA/ME decreased CD90, Wnt-5, PARP- ɣ, GSK3b and p38-MAPK associated elevation of osteogenic markers: ALP and osteocalcin. Moreover, HCT overexpressed RANKL and down expressed Osterix gene. Treatment with CA/HA/BER or CA/HA/ME downregulated RANKL and upregulated Osterix associated with a reduction in RANKL/OPG ratio, at p < 0.05. In conclusion, novel CA composite nanofibers (CA/HA/BER and CA/HA/ME) reversed the HCT adverse effect on osteoblast cell death through canonical and non-canonical pathways regulated by Wnt/β-catenin and Wnt/Ca(2+) pathways. Furthermore, our data confirmed that the novel scaffolds create a crosstalk between RUNX-2, RANKL, p38-MAPK, and Wnt signals which positively impact bone regeneration process. Treatment with CA/HA/BER is better compared to the treatment with CA/HA/ME. Nevertheless, both are considered as alternative biomaterial scaffolds with a potential for biomedical applications in the field of bone tissue engineering.

Telomerase and Alternative Lengthening of Telomeres coexist in the regenerating zebrafish caudal fins

Telomeres are essential for chromosome protection and genomic stability, and telomerase function is critical to organ homeostasis. Zebrafish has become a useful vertebrate model for understanding the cellular and molecular mechanisms of regeneration. The regeneration capacity of the caudal fin of wild-type zebrafish is not affected by repetitive amputation, but the behavior of telomeres during this process has not yet been studied. In this study, the regeneration process was characterized in a telomerase deficient zebrafish model. Moreover, the regenerative capacity after repetitive amputations and at different ages was studied. Regenerative efficiency decreases with aging in all genotypes and surprisingly, telomere length is maintained even in telomerase deficient genotypes. Our results suggest that telomere length can be maintained by the regenerating cells through the recombination-mediated Alternative Lengthening of Telomeres (ALT) pathway, which is likely to support high rates of cell proliferation during the tailfin regeneration process. As far as we know, this is the first animal model to study ALT mechanism in regeneration, which opens a wealth of possibilities to study new treatments of ALT dependent processes.