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2021 ◽  
Vol 78 (6) ◽  
pp. 426-433
Author(s):  
G.V. Shevchenko ◽  

In order to identify the mechanism of functioning of the tubulin cytoskeleton, we have investigated the impact of clinorotation on cortical microtubules organization in the process of cell differentiation in growth zones of plant roots of Zea mays and Beta vulgaris. The similar organization of cortical and endoplasmic microtubules’ network in both species is noted. Clinorotation did not significantly change the organization of microtubules in meristem cells and the central elongation root zone. However, in the distal elongation zone of roots, both Z. mays and B. vulgaris expressed deviations of individual microtubules from the ordered transverse organization (at an angle greater than 45º). This deviation of the microtubules is likely caused by clinorotation and results in discoordination of root growth under these conditions. In addition, it has been found that the scope of destruction of the MT network by taxol in the root cells of both species is not dependent on clinorotation.


Development ◽  
2021 ◽  
Author(s):  
Diego J. Hoyle ◽  
Daniel B. Dranow ◽  
Thomas F. Schilling

Secreted signals in patterning systems often induce repressive signals that shape their distributions in space and time. In developing growth plates (GPs) of endochondral long bones, Parathyroid hormone-like hormone (Pthlh) inhibits Indian hedgehog (Ihh) to form a negative feedback loop that controls GP progression and bone size. Whether similar systems operate in other bones and how they arise during embryogenesis remain unclear. We show that Pthlha expression in the zebrafish craniofacial skeleton precedes chondrocyte differentiation and restricts where cells undergo hypertrophy, thereby initiating a future GP. Loss of Pthlha leads to an expansion of cells expressing a novel early marker of the hypertrophic zone (HZ), entpd5a, and later HZ markers such as ihha, while local Pthlha misexpression induces ectopic entpd5a expression. Formation of this early pre-HZ correlates with onset of muscle contraction and requires mechanical force; paralysis leads to loss of entpd5a and ihha expression in the pre-HZ, mislocalized pthlha expression, and no subsequent ossification. These results suggest that local Pthlh sources combined with force determine HZ locations, establishing the negative feedback loop that later maintains GPs.


2021 ◽  
Vol 116 (8) ◽  
pp. 1917-1948
Author(s):  
Wei Hong ◽  
David R. Cooke ◽  
Lejun Zhang ◽  
Nathan Fox ◽  
Jay Thompson

Abstract Tasmania is the most important tin province in Australia, having been endowed with >0.65 Mt Sn. Some granitic intrusions in western Tasmania have distinctive tourmaline- and quartz-rich magmatic-hydrothermal features, whether they are mineralized (e.g., Heemskirk Granite) or barren (Pieman Heads Granite). The Devonian Heemskirk and Pieman Heads plutons crop out on the western coast of Tasmania and are characterized by similar mineralogical and geochemical compositions and ages. The magmatic-hydrothermal textural features include tourmaline patches, tourmaline orbicules, and tourmaline-muscovite veins, as well as miarolitic cavities and quartz-fluorite-sulfide veins in the Heemskirk Granite. Cathodoluminescence (CL) imaging, laser ablation-inductively coupled plasma-mass spectrometry, and microthermometric analyses of quartz have revealed the physicochemical evolution of the magmatic-hydrothermal fluids from which these tourmaline- and quartz-bearing assemblages precipitated. High Ti quartz (20–28 ppm) in tourmaline patches, orbicules, and cavities typically have homogeneous CL-bright intensity, whereas CL-dark fractures have cut and/or offset the CL-bright and -gray domains that characterize low Ti quartz (3.4–8.5 ppm) from the tourmaline veins. The earliest fluid inclusion assemblages in the quartz-tourmaline orbicules and cavities have a salinity range from 3 to 14 wt % NaCl equiv with intermediate density and were probably trapped at lithostatic pressures of 1.57 ± 0.2 kbar and temperatures of 550° to 570°C, suggesting a depth of 5.9 ± 0.8 km. Prolonged depressurization and cooling may have led to the evolution of a brine (~39 wt % NaCl equiv salinity) from the primary magmatic liquid, which formed halite-bearing hypersaline inclusions in the tourmaline orbicules. Continuous pressure decrease explains the intense brittle failure and fluid migration outward from the apical portions of the pluton, where magmatic fluids partially mixed with and were cooled by external meteoric water. These mechanisms triggered the formation of tourmaline-muscovite-quartz veins and local cassiterite-bearing greisens from a moderate-salinity fluid (~12 wt % NaCl equiv) at temperatures of ~300°C and hydrostatic pressures of 120 bars. Retrograde dissolution textures evident from CL-bright quartz cores surrounded by oscillatory growth zones with gray CL response characterize the low Ti (<1 ppm) and high Al (500–1,000 ppm) quartz from the fluorite-sulfide veins that precipitated from a low-salinity (5.7 wt % NaCl equiv) acidic fluid at temperatures of 200° ± 25°C and hydrostatic pressures of <50 bars. High Sb concentrations (up to 80 ppm) in quartz may be an indicator of low-temperature base metal mineralization related to granitic intrusions. Abundant fluid percolation, protracted fractional crystallization, and high tin concentrations in exsolved hydrothermal fluids may explain why the Heemskirk Granite is well endowed in Sn and base metal deposits, whereas the Pieman Heads Granite is barren.


2021 ◽  
Vol 24 (3-4) ◽  
pp. 125-136
Author(s):  
Jean-Marc BAELE ◽  
Hassan BOUZAHZAH ◽  
Séverine PAPIER ◽  
Sophie DECRÉE ◽  
Sophie VERHEYDEN ◽  
...  

Laser-Induced Breakdown Spectroscopy (LIBS) is a fast in-situ analytical technique based on spectroscopic analysis of atomic emission in laser-induced plasmas. Geochemical mapping at macroscopic scale using LIBS was applied to a decimetric Zn-Pb ore sample from east Belgium, which consists of alternating sphalerite and galena bands. A range of elements was detected with no or minimal spectral correction, including elements of interest for beneficiation such as Ge, Ag and Ga (although the detection of gallium could not be confirmed), and remediation, especially As and Tl. The comparison between LIBS and Energy Dispersive Spectroscopy (EDS) analyses showed that LIBS intensities reliably relate to elemental concentration although differences in spot size and detection limits exist between both techniques. The elemental images of minor and trace elements (Fe, Cu, Ag, Cd, Sb, As, Tl, Ge, Ni and Ba) obtained with LIBS revealed with great detail the compositional heterogeneity of the ore, including growth zones that were not visible on the specimen. In addition, each mineral generation has a distinct trace-element composition, reflecting a geochemical sequence whose potential metallogenic significance at the district scale should be addressed in further work. Although qualitative and preliminary, the obtained LIBS dataset already produced a wealth of information that allowed to initiate discussion on some genetical and crystallochemical aspects. Above all, LIBS appears as a powerful tool for screening geochemically large samples for the selection of zones of particular interest for further analysis.


2021 ◽  
Author(s):  
◽  
Peter Robin Todd

<p>Macroscopic and histological observations of the gonads from 1,739 non-migrant freshwater eels, the shortfin Anguilla australis schmidtii Phillipps and the longfin A. dieffenbachii Gray, showed that they pass through seven stages of development. Shortfins become sexually differentiated at body lengths of 35.0cm to 56.9cm and longfins at lengths of 50.0cm to 67.0cm. No intersexual stage was present, as in A. anguilla L., and although 1% of 350 migrating longfin males examined contained ribbon-like testes, the typical lobed organ of Syrski (testis) can be used as diagnostic of maleness. Histologically, the maximum stage of development attained in the non-migrant, immature stage, was spermatogonia in the males and vacuolated oocytes in females. At the time of seaward migration, based on gonad histology, gonadosomatic indices and ova diameters, migrating longfins were more sexually developed than shortfins. These differences may relate to the location of different oceanic spawning areas: that for the longfin possibly being closer to New Zealand. The autumnal migratory runs, from March to May, of the sexually maturing adults in the Makara stream showed no particular species or sex sequence. The movement of eels was coincident with a rise in stream level and the second half of the lunar cycle. Other relevant environmental factors are discussed. In Lake 0noke peak catches of seaward migrating shortfins were made before the longfins and movements of eels occurred throughout the lunar cycle. Once at sea, the eels apparently disappear. A published note is included on the first eel of the New Zealand species, a longfin female, to be caught at sea. Age determinations from 995 eels were made by otoliths, which were burnt lightly to intensify the growth zones for reading purposes. Shortfin males are younger than females at migration. Longfins are older than shortfins at migration but the males are younger than the females. In the non-migrant stage, sexually undifferentiated shortfins grow more slowly relative to the males, and males relatively more slowly than the females. Similar but less significant differences in growth occur in longfins. Migrant males held in seawater were induced to mature and spawn with injections of mammalian hormones or carp pituitaries, over temperatures of 11.8 degrees C to 28 degrees C. The maturation period was dependent on temperature. Testes of experimental eels that survived maturation regressed to the pre-migrant or migrant stage. Two eels that had regressed were induced to mature a second time. Females held at 20 degrees C and injected with mammalian hormones showed significant increases in sexual development but died before maturity. Females injected with carp pituitaries matured and spawned. Mature longfin eggs, 0.9mm to 1.2mm in diametar, and mature shortfin eggs, 0.9mm to 1.2mm in diameter, are translucent and contain one to many oil globules. A blastodisc formed in water hardened eggs but attempts at fertilization were unsuccessful. Gametogenesis, observed from non-migrant, migrant and hormone injected eels is similar to that described for other teleosts. Electron microscope observations showed parallel features of spermiogenesis in both species. Mature spermatozoa have crescent shaped heads with an anteriorly placed mitochondrion. A flagellum of the unusual 9 + 0 pattern arises from the posterior region of the head, and a short, striated rod-like structure is positioned adjacent to the main flagellum. A complex of subfibrils which extend along either side of the head to the mitochondrion arise from the proximal centriole.</p>


2021 ◽  
Author(s):  
◽  
Peter Robin Todd

<p>Macroscopic and histological observations of the gonads from 1,739 non-migrant freshwater eels, the shortfin Anguilla australis schmidtii Phillipps and the longfin A. dieffenbachii Gray, showed that they pass through seven stages of development. Shortfins become sexually differentiated at body lengths of 35.0cm to 56.9cm and longfins at lengths of 50.0cm to 67.0cm. No intersexual stage was present, as in A. anguilla L., and although 1% of 350 migrating longfin males examined contained ribbon-like testes, the typical lobed organ of Syrski (testis) can be used as diagnostic of maleness. Histologically, the maximum stage of development attained in the non-migrant, immature stage, was spermatogonia in the males and vacuolated oocytes in females. At the time of seaward migration, based on gonad histology, gonadosomatic indices and ova diameters, migrating longfins were more sexually developed than shortfins. These differences may relate to the location of different oceanic spawning areas: that for the longfin possibly being closer to New Zealand. The autumnal migratory runs, from March to May, of the sexually maturing adults in the Makara stream showed no particular species or sex sequence. The movement of eels was coincident with a rise in stream level and the second half of the lunar cycle. Other relevant environmental factors are discussed. In Lake 0noke peak catches of seaward migrating shortfins were made before the longfins and movements of eels occurred throughout the lunar cycle. Once at sea, the eels apparently disappear. A published note is included on the first eel of the New Zealand species, a longfin female, to be caught at sea. Age determinations from 995 eels were made by otoliths, which were burnt lightly to intensify the growth zones for reading purposes. Shortfin males are younger than females at migration. Longfins are older than shortfins at migration but the males are younger than the females. In the non-migrant stage, sexually undifferentiated shortfins grow more slowly relative to the males, and males relatively more slowly than the females. Similar but less significant differences in growth occur in longfins. Migrant males held in seawater were induced to mature and spawn with injections of mammalian hormones or carp pituitaries, over temperatures of 11.8 degrees C to 28 degrees C. The maturation period was dependent on temperature. Testes of experimental eels that survived maturation regressed to the pre-migrant or migrant stage. Two eels that had regressed were induced to mature a second time. Females held at 20 degrees C and injected with mammalian hormones showed significant increases in sexual development but died before maturity. Females injected with carp pituitaries matured and spawned. Mature longfin eggs, 0.9mm to 1.2mm in diametar, and mature shortfin eggs, 0.9mm to 1.2mm in diameter, are translucent and contain one to many oil globules. A blastodisc formed in water hardened eggs but attempts at fertilization were unsuccessful. Gametogenesis, observed from non-migrant, migrant and hormone injected eels is similar to that described for other teleosts. Electron microscope observations showed parallel features of spermiogenesis in both species. Mature spermatozoa have crescent shaped heads with an anteriorly placed mitochondrion. A flagellum of the unusual 9 + 0 pattern arises from the posterior region of the head, and a short, striated rod-like structure is positioned adjacent to the main flagellum. A complex of subfibrils which extend along either side of the head to the mitochondrion arise from the proximal centriole.</p>


2021 ◽  
pp. 000313482110505
Author(s):  
Jason Michael Clark ◽  
Huazhi Liu ◽  
Susan Collins ◽  
Carrie Watson ◽  
Laurence Ferber ◽  
...  

Objectives Mucormycosis is a rare angioinvasive infection caused by filamentous fungi with a high lethality among the immunocompromised. In healthy people, the innate immune system is sufficient to prevent infection. The exception to this is deep tissue exposure seen during trauma. The purpose of this study is to evaluate the epidemiology of mucormycosis using a statewide population-based data set. Methods This is a retrospective cohort study of all hospital admissions for mucormycosis within the state of Florida from 1997 through the beginning of 2020. A distribution map was created to evaluate for geographic variation. Botanical growth zones, based on plant hardiness, used by state environmental agencies and landscapers were also used to detect possible patterns based on climate conditions throughout Florida. A multivariable regression analysis was performed to account for confounders and limit bias. Results A total of 1190 patients were identified for mucormycosis infection. Only 86 of these patients were admitted for trauma. Cutaneous infections were more prevalent among trauma patients while non-trauma patients had more pulmonary infections ( P = .04). Trauma patients with infection tended to be younger and less likely to suffer from comorbidities such as immunosuppression (36% vs 46%, P = .07) and diabetes (22.1% vs 47.1%, P ≤ .0001) as compared to their non-trauma counterparts. Mortality was similar with 17.8% for non-trauma patients and 15.1% for traumatized patients (AOR .80 [.42, 1.52]). Length of stay was longer for trauma patients (37.3 vs 23.0, P < .0001). Infections were less prominent in plant hardiness Zone 9 and Zone 10 as compared to Zone 8 (AOR .71 [.61, .82]; AOR .54 [.46, .64], respectively). Conclusion Trauma patients who develop infection from mucormycosis are at high risk of death despite being a younger and healthier population. Mucormycosis infections were primarily soft tissue based among trauma patients. These infections are more prevalent in colder regions within Florida.


Author(s):  
Cheng Hong Charity Low ◽  
Tze Jui Goh ◽  
Yiong Huak Chan ◽  
Daniel Shuen Sheng Fung ◽  
Pak Yean Cheong

Front-line doctors are at high risk of exposure to COVID-19. The mental resilience of general practitioners and their areas of concerns and support required are important during this COVID-19 period. A total of 403 general practitioners attending a webinar on resiliency, hosted by the College of Family Physicians, Singapore, participated in the survey anonymously. Participants provided responses to questions relating to COVID-19 in the domains of Family and friends, Myself, Practice, and Community. Responses are categorized into LEARNING, FEAR, and GROWTH zones. The majority of the doctors reported to be in the GROWTH zone in relation to Family and friends (39%) and Myself (38%) as compared to Practice and Community, aOR = 4.5 (95% CI 3.4 to 5.9), p < 0.001. 34% of the participants reported being in the FEAR zone in relation to Family and friends, aOR = 8.0 (95% CI = 5.6 to 11.2), p < 0.001; at least 81% reported being in the LEARNING zone in relation to Practice and Community, aOR = 7.5 (95% CI = 5.8 to 9.6), p < 0.001, compared to other domains. Supporting and protecting the doctors is important in strategic planning and management of the current pandemic and building preparedness and an effective response towards future crises.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0254760
Author(s):  
David J. Nash ◽  
T. Jake R. Ciborowski ◽  
Timothy Darvill ◽  
Mike Parker Pearson ◽  
J. Stewart Ullyott ◽  
...  

Little is known of the properties of the sarsen stones (or silcretes) that comprise the main architecture of Stonehenge. The only studies of rock struck from the monument date from the 19th century, while 20th century investigations have focussed on excavated debris without demonstrating a link to specific megaliths. Here, we present the first comprehensive analysis of sarsen samples taken directly from a Stonehenge megalith (Stone 58, in the centrally placed trilithon horseshoe). We apply state-of-the-art petrographic, mineralogical and geochemical techniques to two cores drilled from the stone during conservation work in 1958. Petrographic analyses demonstrate that Stone 58 is a highly indurated, grain-supported, structureless and texturally mature groundwater silcrete, comprising fine-to-medium grained quartz sand cemented by optically-continuous syntaxial quartz overgrowths. In addition to detrital quartz, trace quantities of silica-rich rock fragments, Fe-oxides/hydroxides and other minerals are present. Cathodoluminescence analyses show that the quartz cement developed as an initial <10 μm thick zone of non-luminescing quartz followed by ~16 separate quartz cement growth zones. Late-stage Fe-oxides/hydroxides and Ti-oxides line and/or infill some pores. Automated mineralogical analyses indicate that the sarsen preserves 7.2 to 9.2 area % porosity as a moderately-connected intergranular network. Geochemical data show that the sarsen is chemically pure, comprising 99.7 wt. % SiO2. The major and trace element chemistry is highly consistent within the stone, with the only magnitude variations being observed in Fe content. Non-quartz accessory minerals within the silcrete host sediments impart a trace element signature distinct from standard sedimentary and other crustal materials. 143Nd/144Nd isotope analyses suggest that these host sediments were likely derived from eroded Mesozoic rocks, and that these Mesozoic rocks incorporated much older Mesoproterozoic material. The chemistry of Stone 58 has been identified recently as representative of 50 of the 52 remaining sarsens at Stonehenge. These results are therefore representative of the main stone type used to build what is arguably the most important Late Neolithic monument in Europe.


2021 ◽  
Vol 27 (4) ◽  
pp. 487-492
Author(s):  
D.A. Popkov ◽  
◽  
Ju.V. Nesterova ◽  
A.M. Aranovich ◽  
◽  
...  

Introduction Achondroplasia (ACP) is a common skeletal dysplasia. Vozoritide is the first drug that has an effect on the pathogenesis of impaired enchondral growth in achondroplasia. Clinical trials of the second and third phases have shown its effectiveness according to the latest literature data presented. After providing scientifically grounded information, a questionnaire was completed by parents of children with ACP to have their opinion before the introduction of the drug into medical practice. Materials and methods The survey was conducted on June 21-24, 2021 at the Ilizarov Center supported by the patient’s organization Small People Support Center for Patients with Achondroplasia and Other Bone Dysplasias and Their Families. The questionnaire included 5 questions, compiled by the first author of this study. 65 completed questionnaires were received for the analysis. Results and discussion The overwhelming majority of parents have confidence in the use of vozoritide as a means of achieving targeted growth which may allow to avoid surgical treatment. However, the parallel use of this drug and surgical treatment for incomplete growth of a child is not excluded if the growth graphs show that the required parameters have not been achieved by the time the growth zones are closed. Despite the fact that at present only the influence of vozoritide on the growth of a child with ACP has been reliably proven, parents feel confident with the information about the possible effect of the drug on other problems associated with impaired enchondral growth, and are ready to start therapy at an earlier age and for a longer period. Parents do not oppose the pharmacological treatment to surgical treatment. Vozoritide is seen as the main component of treatment, and surgery as a complementary one that follows (if necessary). This reasonable combination increases the parents' confidence in the predicted favorable treatment outcome.


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