Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 107
Filtrar
Más filtros

Bases de datos
Tipo del documento
Intervalo de año de publicación
1.
Nat Mater ; 22(9): 1065-1070, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37081172

RESUMEN

Circularly polarized light sources with free-space directional emission play a key role in chiroptics1, spintronics2, valleytronics3 and asymmetric photocatalysis4. However, conventional approaches fail to simultaneously realize pure circular polarization, high directionality and large emission angles in a compact emitter. Metal-halide perovskite semiconductors are promising light emitters5-8, but the absence of an intrinsic spin-locking mechanism results in poor emission chirality. Further, device integration has undermined the efficiency and directionality of perovskite chiral emitters. Here we realize compact spin-valley-locked perovskite emitting metasurfaces where spin-dependent geometric phases are imparted into bound states in the continuum via Brillouin zone folding, and thus, photons with different spins are selectively addressed to opposite valleys. Employing this approach, chiral purity of 0.91 and emission angle of 41.0° are simultaneously achieved, with a beam divergence angle of 1.6°. With this approach, we envisage the realization of chiral light-emitting diodes, as well as the on-chip generation of entangled photon pairs.

2.
Nano Lett ; 23(18): 8704-8711, 2023 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-37681647

RESUMEN

Exciton polaritons are widely considered as promising platforms for developing room-temperature polaritonic devices, owing to the high-speed propagation and nonlinear interactions. However, it remains challenging to explore the dynamics of exciton polaritons specifically at room temperature, where the lifetime could be as small as a few picoseconds and the prevailing time-averaged measurement cannot give access to the true nature of it. Herein, by using the time-resolved photoluminescence, we have successfully traced the ultrafast coherent dynamics of a moving exciton polariton condensate in a one-dimensional perovskite microcavity. The propagation speed is directly measured to be ∼12.2 ± 0.8 µm/ps. Moreover, we have developed a time-resolved Michelson interferometry to quantify the time-dependent phase coherence, which reveals that the actual coherence time of exciton polaritons could be much longer (nearly 100%) than what was believed before. Our work sheds new light on the ultrafast coherent propagation of exciton polaritons at room temperature.

3.
HPB (Oxford) ; 26(4): 486-502, 2024 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-38310080

RESUMEN

BACKGROUND: The annular pancreas (AP) is a rare gastrointestinal congenital malformation, in which malrotation of the pancreatic ventral bud in the seventh week of embryonic development manifests in a partial or complete ring of tissue around the second part of the duodenum. METHODS: The main online medical databases such as PubMed, ScienceDirect, Wiley online library, Web of Science, and EBSCO discovery service were used to gather all relevant studies on the AP. RESULTS: A total of 12,729,118 patients were analyzed in relation to the prevalence of AP. The pooled prevalence of AP was 0.0045% (95% CI: 0.0021%-0.0077%). The most frequent comorbidity in adults and children was duodenal obstruction, with a pooled prevalence of 24.04% and 52.58%, respectively (95% CI: 6.86%-46.48% and 35.56%-69.31%, respectively). The most frequent operation in adult patients with AP was duodenojejunostomy, with pooled prevalence established at 3.62% (95% CI: 0.00%-10.74%). CONCLUSION: The diagnostic complexity of AP is accentuated by its nonspecific clinical symptoms, making accurate identification reliant on imaging studies. Therefore, having a thorough knowledge of the clinical characteristics of the AP and its associated anomalies becomes paramount when faced with this rare congenital condition.


Asunto(s)
Anomalías del Sistema Digestivo , Obstrucción Duodenal , Páncreas/anomalías , Enfermedades Pancreáticas , Adulto , Niño , Humanos , Prevalencia , Páncreas/cirugía , Enfermedades Pancreáticas/epidemiología , Enfermedades Pancreáticas/cirugía , Enfermedades Pancreáticas/complicaciones , Obstrucción Duodenal/complicaciones , Obstrucción Duodenal/diagnóstico , Obstrucción Duodenal/cirugía , Anomalías del Sistema Digestivo/epidemiología , Anomalías del Sistema Digestivo/cirugía
4.
J Anat ; 243(6): 1031-1051, 2023 12.
Artículo en Inglés | MEDLINE | ID: mdl-37525506

RESUMEN

Anatomy has always been at the intersection of the socio-cultural and political landscape, where new ideas constantly replace older wisdom. From ancient Egyptians through the Greeks, and then the Romans, finally culminating into the European Renaissance-all the significant eras of human civilisation have left their insignia and distinct marks on the evolution of anatomical practices. Despite its utility as a tool for anatomy pedagogy and research that has proven its worth over millennia, cadaveric dissection has particularly been subject to political and social vicissitudes. A major debate about anatomical dissection lay with the ethical considerations, or its lack thereof, while acquiring corpses for demonstration in the dissection halls. From antiquity, anatomical dissection-often synonymous with medical studies-had typically been carried out on the dead bodies of executed criminals with certain laws, such as the Murder Act of 1752, facilitating such uses. Gradually, the uses of unclaimed bodies, resourced primarily from the impoverished sections of society, were also introduced. However, these body acquisition protocols often missed the crucial element of humanism and ethical considerations, while knowledge augmentation was taken as sufficient reasoning. Unfortunately, a gross disregard towards humanistic values promulgated heinous and illegal practices in acquiring corpses, including grave robbery and even murders like in the case of Burke and Hare murders of 1828. Follow-up legislation, such as the Anatomy Act of 1832, and comparable laws in other European nations were passed to curb the vile. What distils from such a historical discourse on humane values in anatomy dissection, or medical science in general, is that the growth and integration of humanism in anatomy have never been linear, but there were intermittent and, yet, significant disruptions in its timeline. For example, there were serious human rights violations in anatomical practices during the Third Reich in Germany that perpetrated the holocaust. The medical community has kept evolving and introducing new moral values and principles while using such egregious events as lessons, ultimately resulting in the Declaration of Helsinki in 1964. This article revisits the heterogeneous journey of integrating humanistic values in anatomy practice. Such humanistic traits that, like medical science, have also developed over centuries through the inputs of physicians, researchers, and philosophers-from Greece to modernity with an important stopgap at the Renaissance-are a fascinating lore that deserves to be re-envisioned through the lens of contemporary values and ethos. In parallel to human medicine, humanistic values continue to influence veterinary medicine, a welcome development, as our society condemns animal cruelty in any form. There are lessons to be learned from this historical journey of how humanism shaped many of the concepts that anatomists use now. Finally, and most importantly, it might prevent the medical community from repeating the same mistakes by cautioning against the traps that are there, and in a convoluted world where morality as such is eroding from our social fabric, will always be there. Such historical account acts as a righteous, ethical, and contextual compass to guide the existing and upcoming anatomists in discerning between light and dark, right and wrong, and roads-to be or not to be-taken.


Asunto(s)
Anatomía , Holocausto , Animales , Humanos , Humanismo , Disección/historia , Cadáver , Alemania , Anatomía/historia
5.
Clin Anat ; 36(7): 1040-1045, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37526461

RESUMEN

The concept of evidence-based anatomy (EBA) emerged in 2014 and has become a significant element in contemporary anatomy education. The evolving fabric of the medical education curriculum has necessitated critical changes in practice. EBA enables these changes to be incorporated seamlessly and implemented congruently into anatomy education programs. However, in parallel, non-evidence-based (classical) knowledge that has been built up through centuries of anatomical practice continues to be the core element of anatomy education in some countries/regions. Its inherent limitations hinder integration with clinical practice, leading to a rise in misadventures in the clinical setting. This viewpoint commentary highlights the strengths of EBA vis-à-vis the related attributes of classical anatomy. Appropriate arguments show that EBA helps to reduce cognitive load and enables knowledge to be delivered through innovative education tools. EBA also helps to create an inclusive learning environment in a technology-driven era. Moreover, empowered by robust resources, it is driving the pertinent amalgamation of anatomy knowledge with clinical practice. This viewpoint article endorses the adoption of EBA in contemporary anatomy education on the basis of its potential for shaping future anatomical practice.


Asunto(s)
Anatomía , Educación de Pregrado en Medicina , Educación Médica , Humanos , Curriculum , Aprendizaje , Evaluación Educacional , Anatomía/educación
6.
Clin Anat ; 36(3): 527-541, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36597929

RESUMEN

BACKGROUND: The subscapularis (SSC) is the largest rotator cuff muscle and is involved in the medial rotation, abduction, adduction, and anterior stabilization of the shoulder. It is anatomically variable, as is the morphology and prevalence of the accessory SSC (aSSC), a rare muscle slip attached to the SSC. There is no current review investigating the prevalence and morphometrics of the SSC and aSSC. PURPOSE: To investigate the prevalence of the morphological variants of the SSC and aSSC via meta-analysis and review the relevant literature involving cadaveric, magnetic resonance imaging, and ultrasonographic studies. STUDY DESIGN: Meta-analysis. MATERIALS AND METHODS: Literature data reporting the prevalence rates and morphometrics of the SSC and aSSC and their variants were pooled. Literature searches and data analyses were performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Anatomical Quality Assurance guidelines. RESULTS: Forty-six studies, totaling 2166 shoulders, were assessed. The SSC showed an overall length, thickness, cross-sectional area, and volume of 152.2 mm (95% confidence interval, CI, 103.8-200.5 mm), 5.6 mm (95% CI, 4.6-6.6 mm), 18.1 cm2 (95% CI, 14.2-22.0 cm2 ), and 126.9 cm3 (95% CI, 87.2-166.5 cm3 ), respectively. The SSC displayed substantial variations in its origin and insertion points and in the composition of its tendon. The aSSC had an overall pooled prevalence of 24.6% (95% CI, 0.0%-76.9%). CONCLUSIONS: The SSC and aSSC have been implicated in multiple shoulder pathologies, including muscle and tendon ruptures and neurovascular compromise. A better understanding of SSC and aSSC variants when diagnosing and treating their related pathologies will reduce patient morbidity and improve treatment regimens.


Asunto(s)
Lesiones del Manguito de los Rotadores , Articulación del Hombro , Humanos , Manguito de los Rotadores/diagnóstico por imagen , Prevalencia , Hombro , Artroscopía/métodos
7.
Nano Lett ; 21(7): 3120-3126, 2021 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-33788571

RESUMEN

Comparing with pure photons, higher nonlinearity in polariton systems has been exploited in various proof-of-principle demonstrations of efficient optical devices based on the parametric scattering effect. However, most of them demand cryogenic temperatures limited by the small exciton binding energy of traditional semiconductors or exhibit weak nonlinearity resulting from Frenkel excitons. Lead halide perovskites, possessing both a large binding energy and a strong polariton interaction, emerge as ideal platforms to explore nonlinear polariton physics toward room temperature operation. Here, we report the first observation of nonlinear parametric scattering in a lead halide perovskite microcavity with multiple polariton branches at room temperature. Driven by the scattering source from condensation in one polariton branch, correlated polariton pairs are obtained at high k states in an adjacent branch. Our results strongly advocate the ability to reach the nonlinear regime essential for perovskite polaritonics working at room temperature.

8.
Surg Radiol Anat ; 44(1): 75-79, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34415384

RESUMEN

INTRODUCTION: In view of the ongoing COVID-19 pandemic, anatomy education programs were amended so as to shift to primarily online mode from physical classes. In the whole process, main concern area that has emerged is regarding dearth of physical human dissection sessions. There is enough evidence available in literature to suggest that dissection room is an ideal place to cultivate and inculcate discipline independent skills or humanistic skills among the students. These include attributes in relation to ethical practice, professionalism, communication skills, empathy and compassion. Imbibing these skills are an essential element of medical education curriculum as it is desirable that students exhibit these traits when they begin medical practice. Hence deficiency in terms of exposure to physical dissection sessions can adversely affect training of medical students on a long term. METHODS: A literature search of relevant, peer-reviewed, published articles was undertaken from indexed databases (Medline and PubMed, Scopus, Embase, CINAHL Plus, Web of Science and Google Scholar) for this study. RESULTS: To counter the pertinent issue in online anatomy teaching program, a few measures have been suggested in this paper based on identification of actual deficit areas in terms of learning and analysis thereof. Live streaming of real time dissection, awareness sessions on human dissection, online interactive learning sessions and reflective thoughts-based exercise can contribute to building discipline independent skills in present scenario. CONCLUSION: Incorporation and implementation of these interventions within the realm of online anatomy education programs during COVID-19 pandemic can possibly contribute towards desirable learning outcomes.


Asunto(s)
Anatomía , COVID-19 , Educación de Pregrado en Medicina , Estudiantes de Medicina , Anatomía/educación , Curriculum , Disección , Humanos , Pandemias , SARS-CoV-2 , Enseñanza
9.
Surg Radiol Anat ; 44(8): 1185-1192, 2022 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-35895100

RESUMEN

INTRODUCTION: Anatomical sciences involve handling of human tissues and, therefore, application of principles of bioethics is central to anatomical practice. For a considerable period of time, anatomy was practiced without ethical norms as concept of ethics developed during second half of twentieth century. Hence, possible glimpse into contrast in ethical standards between anatomy in the past and present was deemed as an intriguing research theme. METHODS: A literature search was undertaken from indexed databases (Medline and Pubmed, Scopus, Embase, CINAHL Plus, Web of Science and Google Scholar). Relevant data were extracted from 37 articles that were selected from an initial pool of 752 articles based on search criteria set for the study. RESULTS: Prevalent anatomical practices in the past such as dissection of executed criminals, acts of vivisection, illegal procurement of human remains, use of human tissues obtained as part of war crimes and dissection of human fetuses as well as their archival were analyzed through prism of established ethical norms in present day. The observations from past were presented vis-à-vis ethical practices undertaken in present times such as use of donated bodies and/or body parts procured through legal means for dissection, adherence to ethical norms during dissection, archival of human tissues mandating stringent regulation and dignified disposal of human remains. Existing loop holes were identified and future prospects regarding ethical standards in anatomy were highlighted based on rational judgment of existing trends. CONCLUSION: The article concludes with defense on future prospects of ethics in anatomy based on documented arguments.


Asunto(s)
Anatomía , Restos Mortales , Anatomía/historia , Cadáver , Disección/historia , Cuerpo Humano , Humanos
10.
Nano Lett ; 20(5): 3506-3512, 2020 05 13.
Artículo en Inglés | MEDLINE | ID: mdl-32251601

RESUMEN

Machine learning software applications are ubiquitous in many fields of science and society for their outstanding capability to solve computationally vast problems like the recognition of patterns and regularities in big data sets. In spite of these impressive achievements, such processors are still based on the so-called von Neumann architecture, which is a bottleneck for faster and power-efficient neuromorphic computation. Therefore, one of the main goals of research is to conceive physical realizations of artificial neural networks capable of performing fully parallel and ultrafast operations. Here we show that lattices of exciton-polariton condensates accomplish neuromorphic computing with outstanding accuracy thanks to their high optical nonlinearity. We demonstrate that our neural network significantly increases the recognition efficiency compared with the linear classification algorithms on one of the most widely used benchmarks, the MNIST problem, showing a concrete advantage from the integration of optical systems in neural network architectures.

11.
Phys Rev Lett ; 123(1): 013602, 2019 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-31386407

RESUMEN

We introduce a dynamical blockade phenomenon occurring in a nonlinear bosonic mode induced by a combination of continuous and pulsed excitations. We find that the underlying mechanism for the blockade is general, enhancing antibunching in the strongly nonlinear regime and inducing it in the weakly nonlinear regime, without fine-tuning the system parameters. Moreover, this mechanism shows advantages over existing blockade mechanisms and is suitable for implementation in a wide variety of systems due to its simplicity and universality.

12.
Phys Rev Lett ; 123(26): 260404, 2019 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-31951463

RESUMEN

We develop a scheme of quantum reservoir state preparation, based on a quantum neural network framework, which takes classical optical excitation as input and provides desired quantum states as output. We theoretically demonstrate the broad potential of our scheme by explicitly preparing a range of intriguing quantum states, including single-photon states, Schrödinger's cat states, and two-mode entangled states. This scheme can be used as a compact quantum state preparation device for emerging quantum technologies.

13.
J Org Chem ; 84(18): 12031-12039, 2019 09 20.
Artículo en Inglés | MEDLINE | ID: mdl-31461274

RESUMEN

A set of three highly selective probes for sulfide detection has been developed. Two novel mechanistic strategies for the detection, including (a) transformation of a pro-fluorophore into an active fluorophore and (b) destruction of a fused ring to activate a fluorophore, have been explored. The structural features of the probes including azido groups ("active" and "latent") and leaving groups (with or without being attached to the fluorophore) have been investigated. During the course of the mechanistic studies, the single-crystal structures of all the probes and the products were obtained. One of the probes proved to be superior in terms of its ability to detect sulfide in pure water via an in situ formation of a fluorophore from a nonfluorescent precursor. These cheap and easy-to-prepare probes offer practical applications of sulfide recognition in environmental water samples and in the ovaries of fruit flies. A detection and quantification method using one of these probes and analysis with a smartphone enabled nonspecialists to detect sulfide reliably.

14.
BMC Public Health ; 19(1): 962, 2019 Jul 18.
Artículo en Inglés | MEDLINE | ID: mdl-31319828

RESUMEN

BACKGROUND: India faces a high burden of child undernutrition. We evaluated the effects of two community strategies to reduce undernutrition among children under 3 years in rural Jharkhand and Odisha, eastern India: (1) monthly Participatory Learning and Action (PLA) meetings with women's groups followed by home visits; (2) crèches for children aged 6 months to 3 years combined with monthly PLA meetings and home visits. METHODS: We tested these strategies in a non-randomised, controlled study with baseline and endline cross-sectional surveys. We purposively selected five blocks of Jharkhand and Odisha, and divided each block into three areas. Area 1 served as control. In Area 2, trained local female workers facilitated PLA meetings and offered counselling to mothers of children under three at home. In Area 3, workers facilitated PLA meetings, did home visits, and crèches with food and growth monitoring were opened for children aged 6 months to 3 years. We did a census across all study areas and randomly sampled 4668 children under three and their mothers for interview and anthropometry at baseline and endline. The evaluation's primary outcome was wasting among children under three in areas 2 and 3 compared with area 1, adjusted for baseline differences between areas. Other outcomes included underweight, stunting, preventive and care-seeking practices for children. RESULTS: We interviewed 83% (3868/4668) of mothers of children under three sampled at baseline, and 76% (3563/4668) at endline. In area 2 (PLA and home visits), wasting among children under three was reduced by 34% (adjusted Odds Ratio [aOR]: 0.66, 95%: 0.51-0.88) and underweight by 25% (aOR: 0.75, 95% CI: 0.59-0.95), with no change in stunting (aOR: 1.23, 95% CI: 0.96-1.57). In area 3, (PLA, home visits, crèches), wasting was reduced by 27% (aOR: 0.73, 95% CI: 0.55-0.97), underweight by 40% (aOR: 0.60, 95% CI: 0.47-0.75), and stunting by 27% (aOR: 0.73, 95% CI: 0.57-0.93). CONCLUSIONS: Crèches, PLA meetings and home visits reduced undernutrition among children under three in rural eastern India. These interventions could be scaled up through government plans to strengthen home visits and community mobilisation with Accredited Social Health Activists, and through efforts to promote crèches. TRIAL REGISTRATION: The evaluation was registered retrospectively with Current Controlled Trials as ISCRTN89911047 on 30/01/2019.


Asunto(s)
Trastornos de la Nutrición del Niño/terapia , Consejo/métodos , Desnutrición/terapia , Educación del Paciente como Asunto/métodos , Mujeres/psicología , Adulto , Trastornos de la Nutrición del Niño/epidemiología , Trastornos de la Nutrición del Niño/psicología , Preescolar , Estudios Transversales , Femenino , Visita Domiciliaria , Humanos , India/epidemiología , Lactante , Masculino , Desnutrición/epidemiología , Desnutrición/psicología , Madres/psicología , Ensayos Clínicos Controlados no Aleatorios como Asunto , Aceptación de la Atención de Salud , Población Rural
15.
J Biol Inorg Chem ; 23(6): 917-927, 2018 08.
Artículo en Inglés | MEDLINE | ID: mdl-30006868

RESUMEN

A ternary system comprising of a Eu(III) complex of the drug Tetracycline hydrochloride (Eu3TC) bound to bovine ß-lactoglobulin variant A (BLGA) in aqueous buffer at physiological pH (pH = 7.4) has been investigated to exploit the enhanced "antenna effect" to locate the bound drug and find the microenvironment of the binding site. Steady-state and time-resolved emission studies at room temperature as well as at 77 K have been carried out to evaluate the binding parameters in the binary system consisting of BLGA and tetracycline hydrochloride (TC). Low-temperature phosphorescence studies at 77 K of pure BLGA confirm Trp 19 to be the emitting residue, while Trp 61 is silent. Enhancement of BLGA phosphorescence emission in the ternary system at 77 K indicates that Trp 19 is very close to Eu(III) in the Eu3TC complex. The molecular docking results further confirm that TC binds close to Trp 19 in a hydrophobic domain. The results thus obtained can provide guidelines to design and synthesize target-oriented drugs as well as suitable bio-probes.


Asunto(s)
Lactoglobulinas/metabolismo , Mediciones Luminiscentes , Tetraciclina/metabolismo , Animales , Sitios de Unión , Bovinos , Frío , Simulación del Acoplamiento Molecular , Espectrofotometría Ultravioleta
16.
Inorg Chem ; 54(20): 9715-26, 2015 Oct 19.
Artículo en Inglés | MEDLINE | ID: mdl-26407121

RESUMEN

A new family of pentanuclear 3d-4f heterometal complexes of general composition [Ln(III)2(M(II)L)3(µ3-O)3H](ClO4)·xH2O (1-5) [Ln = Nd, M = Zn, 1; Nd, Ni, 2; Nd, Cu, 3; Gd, Cu, 4; Tb, Cu, 5] have been synthesized in moderate yields (50-60%) following a self-assembly reaction involving the hexadentate phenol-based ligand, viz., N,N-bis(2-hydroxy-3-methoxy-5-methylbenzyl)-N('),N(')-diethylethylenediamine (H2L). Single-crystal X-ray diffraction analyses have been used to characterize these complexes. The compounds are all isostructural, having a 3-fold axis of symmetry that passes through the 4f metal centers. The [M(II)L] units in these complexes are acting as bis-bidentate metalloligands and, together with µ3-oxido bridging ligands, complete the slightly distorted monocapped square antiprismatic nine-coordination environment around the 4f metal centers. The cationic complexes also contain a H(+) ion that occupies the central position at the 3-fold axis. Magnetic properties of the copper(II) complexes (3-5) show a changeover from antiferromagnetic in 3 to ferromagnetic 3d-4f interactions in 4 and 5. For the isotropic Cu(II)-Gd(III) compound 4, the simulation of magnetic data provides very weak Cu-Gd (J1 = 0.57 cm(-1)) and Gd-Gd exchange constants (J2 = 0.14 cm(-1)). Compound 4 is the only member of this triad, showing a tail of an out-of-phase signal in the ac susceptibility measurement. A large-spin ground state (S = 17/2) and a negative value of D (-0.12 cm(-1)) result in a very small barrier (8 cm(-1)) for this compound. Among the three Nd(III)2M(II)3 (M = Zn(II), Ni(II), and Cu(II)) complexes, only the Zn(II) analogue (1) displays an NIR luminescence due to the (4)F(3/2) → (4)I(11/2) transition in Nd(III) when excited at 290 nm. The rest of the compounds do not show such Nd(III)/Tb(III)-based emission. The paramagnetic Cu(II) and Ni(II) ions quench the fluorescence in 2-5 and thereby lower the population of the triplet state.

18.
J Bioenerg Biomembr ; 46(1): 71-82, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24214386

RESUMEN

Energy distribution between photosystems (PSI & PSII) under prolonged and continuous white light irradiance was assessed by monitoring the progress of their fluorescence emission (FPSI/FPSII) at 77 K. Our observations indicate FPSI/FPSII to oscillate with the progress of irradiance treatments at all intensities tested (100, 200, 500, and 800 µE m(-2) S(-1)). The amplitude of the oscillation increased with the progress, whereas the periodicity of the oscillation increased with the intensity of the incident irradiance. Spectral analysis indicated fluctuation of FPSI to be the major determinant of the observed oscillation. The first rise and fall of FPSI/FPSII overlapped with phosphorylation and dephosphorylation of LHCII, but oscillation of FPSI/FPSII continued for several cycles without any further phosphorylation of LHCII. Moreover, in presence of DCMU where linear electron flow (LEF) is suppressed and LHCII phosphorylation is completely abolished, the oscillation of FPSI/FPSII was not abolished. These data indicated that LHCII phosphorylation was not essential for the observed oscillation of energy distribution between the photosystems. In contrast, in the presence of inhibitors of cyclic electron flow (CEF) like Antimycin A (AA) and rotenone, the oscillation of FPSI/FPSII was either abolished or severely dampened. Additionally, the oscillation was also abolished in presence of uncouplers like NH4Cl and nigericin that cancels the trans-thylakoid ∆pH. Thus, trans-thylakoid ∆pH, generated through CEF, appear to be an important determinant of oscillation of FPSI/FPSII in isolated thylakoids. The phenomenon of oscillation could be associated with a CEF mediated chromatic adaptation of PSI in presence of excess irradiance.


Asunto(s)
Arachis/metabolismo , Arachis/efectos de la radiación , Complejo de Proteína del Fotosistema I/metabolismo , Complejo de Proteína del Fotosistema II/metabolismo , Tilacoides/metabolismo , Electrones , Concentración de Iones de Hidrógeno , Luz , Fosforilación , Hojas de la Planta/metabolismo , Hojas de la Planta/efectos de la radiación
19.
Clin Anat ; 27(8): 1122-7, 2014 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25125074

RESUMEN

Johann Vesling (1598-1649) was a German anatomist and surgeon who belonged to the golden period of the illustrious University of Padua. He made significant contributions to the advancement of anatomical knowledge during the 17th century and is remembered most for his remarkable anatomical work, the Syntagma Anatomicum, which was published in 1641. He was the first to describe the soleus muscle and to emphasize its resemblance to the sole fish. He produced the earliest illustrations of the human lymphatic system and was one of the first to document observations about the thoracic duct. He was also the first to report the bifurcation of the human hepatic portal vein on entering the fissure of the liver. His observations from embryological experiments were critical for understanding the development of the four-chambered heart. He was one of the first authors to state that four pulmonary veins empty into the left atrium of the heart. Syntagma Anatomicum (1641) was the most widely used anatomical text in Europe for almost a century and was republished a number of times with editions in Latin, German, Dutch, and English. Syntagma was the first illustrated western anatomical text to reach Japan and laid the foundation for the development of European medicine there. The illustrations used in it deviated from the artistic convention that had characterized anatomical figures from the time of Vesalius, and focused instead on representing anatomical details to make them helpful for medicine and surgery. Clin. Anat. 27:1122-1127, 2014. © 2014 Wiley Periodicals, Inc.


Asunto(s)
Anatomía/historia , Cirugía General/historia , Ilustración Médica/historia , Historia del Siglo XVI , Historia del Siglo XVII
20.
Clin Anat ; 27(7): 952-7, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-24811238

RESUMEN

Adriaan van den Spiegel (1578-1625) was a Flemish anatomist and physician. He was one of the most prominent anatomists at the University of Padua during the 17th century and became professor of anatomy and surgery there in 1619. He was privileged to have two of the most accomplished anatomists of that period, Fabricius ab Aquapendente and Iulius Casserius, as his teachers. His anatomical works were published after his death by his pupil Bucretius and his son-in-law Liberalis Crema, with illustrations procured from Casserius's unpublished anatomical atlas. He contributed significantly to establishing basic morphological facts about the developing embryo in his text De formato foetu liber singularis. In his book De humani corporis fabrica libri decem, Spiegel's lobe (caudate lobe) of the liver and the linea semilunaris (Spiegel's line) on the lateral side of the rectus abdominis muscle were described for the first time. Subsequently, Spigelian aponeurosis (between the lateral margin of the rectus abdominis and the linea semilunaris) and Spigelian hernia (lateral ventral hernia) were named after him. He was a renowned physician in his time and was the first to give a detailed description of malaria. He made significant contributions as a botanist: the genus Spigelia, which has six species, is named after him.


Asunto(s)
Anatomía/historia , Botánica/historia , Embriología/historia , Cirugía General/historia , Historia del Siglo XVI , Historia del Siglo XVII
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA