Histological effects of vitamin A on the tail amputated tadpoles of Bufo melanostictus

Vitamin A has manifold effects on the development, growth and pattern formation of several amphibians. At the same time it causes severe embryonic malformations. The histological changes brought about by vitamin A in the tail tissues of anurans are quite amazing. A common morphological change brought about by vitamin A in tail-amputated tadpoles of Bufo melanostictus include the formation of a large bulbular mass at the distal end of the tail following tail regeneration. Histology revealed that the bulbular mass consisted of notochordal cells only. Other histological changes are: a thickening of the epidermis and the basement membrane, enlargement of the notochord and the nerve cord, thickening of the sheath covering the notochord and the myelin sheath covering the nerve cord and the disorganization of muscle bundles. The significance of such changes is discussed

Vitamin A-mediated homeotic transformation of tail to limbs, limb suppression and abnormal tail regeneration in the Indian jumping frog polypedates maculatus

In this study the effects of vitamin A on tadpoles of Polypedates maculatus with an amputated tail were investigated. After amputation of half the tail at the hindlimb-bud stage, tadpoles were exposed to vitamin A (palmitate) 10 IU/ml solution for 24 hr (Group I), 48 hr (II), 72 hr (Ill), 96 hr (IV), 120 hr (V) or 144 hr (VI). Vitamin A was deleterious to survival of the tadpoles since 10, 30 and 30% tadpoles died from Group IV, V and VI, respectively before the emergence of forelimbs. Regeneration of the tail was abnormal in 91.7% of the tadpoles. Vitamin A induced homeotic transformation of the amputated tail to hindlimbs in 11.6% of the animals. Normal limb development was suppressed partially or completely in 48.3% tadpoles. These results indicate that in addition to traumatic effects, vitamin A can lead to homeotic transformation of the tail into hindlimbs and can also interfere with normal development of limbs

How do learning technologies impact on undergraduates’ emotional and cognitive engagement with their learning?

A common theme in the literature on learning technologies is the way in which they can facilitate engagement both within and outside of the classroom. However, a lack of a scholarly consensus on what constitutes engagement renders problematic the issue of how one makes meaningful sense of the data presented in studies. This paper presents an integrative review that explores student engagement with learning technologies and identifies major themes and trends within the field. When viewed against the evidence-based claims of individual studies, common ubiquitous narratives concerning learning technologies are problematised. The paper concludes with suggestions for future research in this area in the light of its findings

Deformasi Bentuk Hanoman dalam Karya Keramik

Berawal dari pengalaman pada masa kecil yang sering mendengarkan cerita pewayangan Jawa terutama pewayangan Ramayana dan Mahabarata, penulis tertarik untuk menjadikan tokoh Hanoman sebagai sumber ide dalam penciptaan karya keramik. Hal tersebut dikarenakan Hanoman memiliki bentuk yang cukup unik. Selain itu, penulis ingin mengingatkan kembali kepada masyarakat terutama kalangan muda untuk terus melestarikan kebudayaan Jawa seperti halnya seni pewayangan. Selain beberapa alasan di atas penulis juga mempunyai keinginan untuk menciptakan kembali tokoh Hanoman ke dalam media keramik sesuai dengan versi penulis. Proses penciptaan karya-karya ini dilakukan dengan hati-hati dan berurutan. Dari pencarian sumber ide, sketsa, pemilihan bahan, sampai pada tahap pengerjaan karya mentah yang menggunakan beberapa macam teknik yaitu: teknik pijit, teknik pilin, teknik gores, dan teknik slab, pengeringan, pembakaran, pengglasiran, hingga yang terakhir pemajangan karya. Pemilihan materi yang dijadikan sumber ide pada penciptaan karya ini menggunakan beberapa teori pendukung, seperti: teori estetika, semiotika, teori “metode penciptaan 3 Tahap 6 langkah”, teori keramik, dan teori deformasi. Setelah melalui proses penciptaan yang panjang, terlahirlah sembilan karya seni dengan tema Hanoman. Secara keseluruhan terlihat bahwa pada karya-karya ini terdapat perubahan bentuk(deformasi) pada bentuk tubuh Hanoman yang menjadikannya terlihat imut dan lucu, berbeda dari Hanoman pada umumnya. Selain itu terdapat juga menambahkan sayap pada bagian punggungnya. Sayap ini diberikan sebagai simbol kebebasan yang dimiliki sang Hanoman. Terciptanya karya-karya ini diharapkan dapat melestarikan budaya Jawa sekaligus juga diharapkan dapat dijadikan referensi dalam dunia keramik, khususnya kepada seniman keramik. Kata Kunci: Deformasi, Hanoman, Kerami

Hypoxia signalling and regulation in chemosensory behaviour of<i> Caenorhabditis elegans</i>

Adaptation to hypoxia is essential to survival in most organisms; disruption of oxygen homeostasis is linked to the pathology of multiple diseases including neurodegeneration, ischaemic stroke and cancer. Hypoxia-inducible factor 1 (HIF-1) is a key transcription factor in the detection of oxygen depletion and in mediating the response to hypoxia to maintain cellular oxygen homeostasis. This study investigated hypoxia signalling in vivo using a Caenorhabditis elegans HIF-1 mutant model. The chemosensory behaviour of C. elegans was analysed through the use of chemosensory assays with a chemoattractant and a chemorepellent; the response was quantified by calculating the chemotaxis index of species. Chemosensory assays were used to analyse behavioural changes of C. elegans under oxic and hypoxic conditions and to analyse the effects of mood stabilizing drugs lithium chloride (LiCl) and valproic acid (VA). HIF-1 mutant C. elegans showed an impaired chemosensory response to a 48 h hypoxia exposure. Treatment with LiCl significantly rescued the chemosensory response of HIF-1 mutants under hypoxia, suggesting a protective effect. Treatment with VA decreased the chemosensory response of HIF-1 mutants with hypoxia exposure. Interestingly, VA also decreased the chemosensory response of wild-type species under oxic conditions, suggesting a mechanism of action independent of hypoxia.</p

Environmental education in the classroom:pilot study in Cabo Verde suggests differing impacts on local knowledge and environmental attitudes.

To execute environmental education effectively, the success and impacts of educational activities must be assessed. In areas of high biodiversity there is generally a lack of evaluation of the impact of environmental education. In this study we investigate the effect of a one-time classroom activity on student knowledge of local environmental issues, environmental attitudes and aspirations. The project was conducted on the island of Maio, Cabo Verde, a small, highly biodiverse island, as part of a classroom visit programme with the local environmental organization, Maio Biodiversity Foundation. We visited every fourth-grade class (i.e. students with an age range of 9-10 years) on the island (a total of 142 students) and delivered a half-day classroom activity. The results show that this activity did not influence environmental attitudes; however, it did significantly improve student knowledge and awareness of local environmental issues. This study shows that environmental education should not be assumed to improve attitudes and knowledge but requires individual evaluation for each type of activity. For environmental education to reach its full potential, activities should be planned in response to evaluation results.</p

Calciphylaxis following kidney transplantation: a case report

Introduction: Calciphylaxis occurring after kidney transplantation is rare and rarely reported. It results in chronic non-healing wounds and is associated with a poor prognosis and is often fatal. We present a case of proximal lower limb calciphylaxis that occurred early after kidney transplantation. The patient had no classic associated risk factors. He had previously had a total parathyroidectomy but had normal serum calcium-phosphate product and parathyroid hormone levels. The clinical outcome of this case was favorable and highlights some fundamental issues relating to management. Case prsentation: A 70-year-old British Caucasian man with end-stage renal failure secondary to IgA nephropathy presented six months post kidney transplantation with cutaneous calciphylaxis lesions involving the medial aspect of the thigh bilaterally. Conclusion: To the best of our knowledge, this is the first reported case of rapid onset cutaneous calciphylaxis occurring soon after kidney transplantation that was associated with a favorable outcome. Cutaneous calciphylaxis lesions should be promptly managed with meticulous wound care, antimicrobial therapy and the correction of calcium-phosphate product where indicated

Scientific aptitude better explains poor responses to teaching of evolution than psychological conflicts

It is considered a myth that non-acceptance of scientific consensus on emotive topics is owing to difficulties processing scientific information and is, instead, owing to belief-associated psychological conflicts, the strongest non-acceptors being highly educated. It has been unclear whether these results from adults explain variation in response to school-level teaching. We studied a cohort of UK secondary school students (aged 14-16) and assessed their acceptance and understanding of evolution. In addition, to address their aptitude for science we assessed their understanding of genetics and their teacher-derived assessment of science aptitude. As both models predict, students with low initial evolution acceptance scores showed lower increases in the understanding of evolution. Contrary to conventional wisdom, this effect is better explained by lack of aptitude: Before teaching, students with low acceptance had lower understanding of both evolution and of genetics; the low-acceptance students sat disproportionately in the foundation (rather than higher) science classes; low-acceptance students showed lower increments in the understanding of genetics; and student gain in the understanding of evolution correlated positively with gain in the understanding of genetics. We find no evidence either for a role for psychological conflict in determining response to teaching or that strong rejectors are more commonly of a higher ability. From qualitative data we hypothesize that religious students can avoid psychological conflict by adopting a compatibilist attitude. We conclude that there are students recalcitrant to the teaching of science (as currently taught) and that these students are more likely to not accept the scientific consensus. Optimizing methods to teach recalcitrant students is an important avenue for research.</p

A new high-pressure recycle-flow calorimeter and results of determinations with ethane

A new recycle-flow calorimeter is described with which the thermodynamic properties of fluids can be determined between pressures of 2 to 20 MPa and temperatures of 90 to 400 K. Precise control of both flowrate and pressure is provided by dual precision metering pumps. Details are presented on a new calorimeter which incorporates several innovations. Heat losses from this calorimeter are reduced by a novel shielding arrangement and were shown to be less than the experimental precision of +/- 0.1 per cent. The calorimeter can be operated in either the isobaric or the throttling mode. The results of experimental determinations around the critical point of ethane are described. Enthalpies of vaporization and heat capacities were obtained by operating in the isobaric mode. Determinations in the throttling mode yielded isothermal throttling coefficients and Joule-Thomson coefficients. Analysis of these results showed that the thermodynamic consistency of the enthalpies in the isobaric and isothermal mode is better than 0.1 per cent, and that of the derived values of properties is 0.4 per cent or better.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/23368/1/0000312.pd