8 research outputs found
Advancing the manufacture of complex geometry GFRC for today's building envelopes
Get PDFThin-walled glass fibre reinforced concrete (GFRC) panels are being used as the primary cladding material on many landmark buildings especially in the last decade. GFRC is an ideal material for building envelopes because it is durable, it can resist fire and the environmental impact is low compared to other materials, because the base materials used in the production of GFRC are widely available throughout the world. Thin-walled GFRC was initially developed as a cladding material in the 1970s and 1980s where the majority of the available research lies.
The introduction of 3D CAD software has enabled the design of buildings with complex shapes that, in the past, would have been rationalised to meet budget and time constraints. However, when GFRC has been proposed for buildings with a complex free-form geometry it has been replaced with alternative materials such as glass reinforced plastic (GFRP) due to the high cost and time required to fabricate suitable GFRC panels using conventional manufacturing methods. The literature showed that empirical performance characterization of GFRC had not been researched in detail regarding the limits of functionality or any systematic approach to understanding their use in complex geometry building envelopes.
As a first step the key architectural demands, the main barriers and limitations in the manufacture of complex geometry thin-walled GFRC were identified by interviewing and visiting manufacturers, designers and key buildings. This identified the key barrier to be the process of producing the mould for casting the complex geometry GFRC panels. Solutions to resolve them were tested over several stages for each of the main production methods most suited for the manufacture of thin-walled GFRC, namely; the automated premixed method, the premixed method and the sprayed method. The results from the laboratory testing over all the stages, and the prototype structure manufactured with the identified solution from the testing, answered the main research question:
How can the manufacture of complex geometry thin-walled GFRC be advanced to meet today’s architectural demands?
So, the architectural demands for thin-walled GFRC cladding were identified, together with a clearly defined range of complexity of thin-walled GFRC panels. The key demands were; a smooth surface texture, no visual fibres in the surface, minimal air-bubbles or voids, consistent colour across all thin-walled GRFC elements, no visible cracks, and the need for edge-returns and panel offsets. The suitability of selected production methods were evaluated against these demands. Firstly the automated premixed method was tested on a flexible table, (single reconfigurable mould surface, with computer controlled actuators capable of forming free-formed geometries). This showed that the flexible table alone would not meet the requirements for an edge-return, with the manufacturing speed required, to produce many unique shaped panels within normal building project time-schedules. Following this test a solution was proposed that used the flexible table to produce free-formed shaped moulds using fast curing foam, enabling moulds to be produced within hours allowing more rapid utilization of the flexible table.
This solution was first tested for the premixed method by casting positive and negative mould parts enabling an edge-return to be cast because flexible tables are only able to produce moulds with a continuous surface. The new mould solution for complex geometry shapes also demonstrated that it was difficult to avoid air-bubbles and voids when casting the GFRC panels using the premixed method. So a second mould solution was developed for the sprayed method. This resolved the challenges of forming an edge-barrier on the mould, while allowing an edge-return to be successfully cast on a double curved panel that met the key architectural demands.
From the research and the tests it was possible to devise a fully automated process for the manufacture of complex geometry thin-walled GFRC, comprised of:
— Stage 1: Initial architectural geometric concept. — Stage 2: Panelization and geometric offsetting. — Stage 3: Identifying the right production method. — Stage 4: Casting process. — Stage 5: Transportation and Installation.
Solutions for each of these stages all contributed to advances that will enable current and future free-form thin-walled GFRC architectural designs to be realised.
The contribution to knowledge from the tests and the resulting automated process was used to produce the moulds for 9 unique double curved elements to form each row of a 10m tall self-supporting thin-walled shell. This show-cased how the identified solution enabled a faster and more cost effective method to produce free-form thin-walled GFRC panels. One of the main conclusions of the research showed that the sprayed method currently provides most flexibility in the manufacture of complex geometry thin-walled GFRC panels when the identified architectural demands must be met.
To advance the manufacture of complex geometry thin-walled panels further a fully automated and digital manufacturing process must be developed. As identified in the research this can be done by upgrading current automated premixed production lines by integrating the new solution for complex geometry shaped moulds into the production line and automatically spaying the GFRC onto the mould.
When fully developed this fully automated method would enable free-form shell elements to be produced, that may also incorporate insulation, allowing segments for a self-supporting free-form shell to be constructed.
With this research the current architectural knowledge base has been advanced in terms of complex geometry thin-walled GFRC for building envelopes. The identified solutions should allow building with complex geometries to be realised using thin-walled GFRC as the envelope cladding
The dynamics of single spike-evoked adenosine release in the cerebellum
Get PDFThe purine adenosine is a potent neuromodulator in the brain, with roles in a number
of diverse physiological and pathological processes. Modulators such as adenosine are difficult
to study as once released they have a diffuse action (which can affect many neurones) and,
unlike classical neurotransmitters, have no inotropic receptors. Thus rapid postsynaptic currents
(PSCs) mediated by adenosine (equivalent to mPSCs) are not available for study. As a result
the mechanisms and properties of adenosine release still remain relatively unclear. We have
studied adenosine release evoked by stimulating the parallel fibres in the cerebellum. Using
adenosine biosensors combined with deconvolution analysis and mathematical modelling, we
have characterised the release dynamics and diffusion of adenosine in unprecedented detail.
By partially blocking K+ channels, we were able to release adenosine in response to a single
stimulus rather than a train of stimuli. This allowed reliable sub-second release of reproducible
quantities of adenosine with stereotypic concentration waveforms that agreed well with predictions
of a mathematical model of purine diffusion. We found no evidence for ATP release
and thus suggest that adenosine is directly released in response to parallel fibre firing and does
not arise from extracellular ATP metabolism. Adenosine release events showed novel short-term
dynamics, including facilitated release with paired stimuli at millisecond stimulation intervals
but depletion-recovery dynamics with paired stimuli delivered over minute time scales. These
results demonstrate rich dynamics for adenosine release that are placed, for the first time, on a
quantitative footing and show strong similarity with vesicular exocytosis
Life in the Cold
Get PDFPreface; First and Corresponding Author Contact Information; An Evolutionary Framework for Studies of Hibernation and Short-term Torpor -- Gordon C. Grigg; Was Adaptive Hypothermia a Prerequisite for the
Colonization of Madagascar By Mammals? -- Barry G. Lovegrove; No Evidence for Torpor in a Small African Mainland Primate: The Lesser Bushbaby, Galago moholi -- Nomakwezi Mzilikazi, Barry G. Lovegrove, and Judith C. Masters; The Origin of Mammalian Heterothermy: A Case for Perpetual Youth? -- Michael B. Harris, Link E. Olson, and William K. Milsom; Passive Rewarming from Torpor in Mammals and Birds:
Energetic, Ecological and Evolutionary Implications -- Fritz Geiser, Rebecca L. Drury, Gerhard Kortner, Christopher Turbill, Chris R. Pavey, and R. Mark Brigham; Solar Radiation and the Energetic Cost of Rewarming from Torpor -- Andrew M. McKechnie and Blair O. Wolf; The Role of α-Linolenic Acid (18:3) in Mammalian Torpor -- Craig L. Frank, Wendy R. Hood, and Mary C. Donnelly; Heat Transfer in Humans: Lessons from Large Hibernators -- Dennis Grahn and H. Craig Heller; Factors Influencing the Timing of Dormancy in the Pocket Mouse,Perognathus longimembris -- Alan R. French; The Energetic State-dependency of Autumn
Immergence in Eastern Chipmunks -- Murray M. Humphries and Brandon Rodgers; Seasonal Timing of Reproduction and Hibernation
in the Edible Dormouse (Glis glis) -- Claudia Bieber and Thomas Ruf; Reproduction and Hibernation in Females: A Comparison of Two Sympatric Ground-Dwelling Rodents -- Eva Millesi, Ilse E. Hoffmann, Anna Aschauer, and Claudia Franceschini; How the Photoperiod Times the Annual
Reproductive and Hibernation Cycles -- P. Pevet, M. Saboureau, and P. Klosen; Behaviour, Body Temperature, and Hibernation in Tasmanian Echidnas (Tachyglossus aculeatus) -- Stewart Nicol, Christina Vedel-Smith, and Niels A. Andersen; Metabolic Diversity in Yellow-Bellied Marmots -- Kenneth B. Armitage; Metabolic Rate Reduction During Hibernation and Daily Torpor -- Fritz Geiser; How to Enter Torpor: Thermodynamic and Physiological Mechanisms of Metabolic Depression -- Gerhard Heldmaier and Ralf Elvert; Slow Loss of Protein Integrity During Torpor: A Cause for Arousal? -- Sandra L. Martin, Timothy Dahl, and L. Elaine Epperson; A Technique for Modelling Thermoregulatory Energy Expenditure in Free-ranging Endotherms -- Craig K. R. Willis, Jeffery E. Lane, Eric T. Liknes, David L. Swanson, and R. Mark Brigham; Sex Differences in the Response of Torpor to Exogenous Corticosterone
During the Onset of the Migratory Season in Rufous Hummingbirds -- Sara M. Hiebert, John C. Wingfield, Marilyn Ramenofsky, Leah Deni, and Antoinette Grafin zu Elz; The Avian Enigma: “Hibernation” by Common Poorwills
(Phalaenoptilus nuttalli) -- Christopher P. Woods and R. Mark Brigham; Shivering Thermogenesis in Birds and Mammals -- Esa Hohtola; The Impact of Social Interactions on Torpor Use in Hummingbirds -- Donald Powers; The Energetics of the Rewarming Phase of Avian Torpor -- Andrew E. McKechnie and Blair O. Wolf; Insect Cold-Hardiness: New Advances Using Gene Screening Technology -- Kenneth B. Storey and David C. McMullen; Advantages and Disadvantages of Freeze-Tolerance and Freeze-Avoidance Overwintering Strategies -- Karl Erick Zachariassen, Sindre Andre Pedersen, and Erlend Kristiansen; Live and Let Diapause: Cell Cycle Regulation During Insect Overwintering -- Savvas c. Pavlides, Kenneth A. Weir, and Steven P. Tammariello; Vertebrate Freeze Tolerance: Role of Freeze-Responsive Gene Expression -- Kenneth B. Storey; Ice, Antifreeze Proteins, and Antifreeze Genes in Polar Fishes -- Arthur L. DeVries; Overwintering in Submerged Turtles -- Donald C. Jackson; Environmental Physiology of Terrestrial Hibernation in Hatchling Turtles -- Patrick J. Baker, Jon P. Costanzo, and Richard E. Lee, Jr.; Overwintering in Tegu Lizards -- Denis V. Andrade, Colin Sanders, William K. Milsom, and Augusto S. Abe; Overwintering in Cold-Submerged Frogs -- Glenn J. Tattersall; Effect of Temperature on Regular and Modified Circannual Rhythms
in the European Ground Squirrel Under Free-Running Conditions -- Radoslav K. Andjus, Marina Marjanovic, and Dragoslava Zivadinovic; The Role of the Suprachiasmatic Pacemaker (SCN) in Energy Expenditure
During Hibernation of Golden-mantled Ground Squirrels -- Patricia J. DeCoursey; Does Hibernation Violate Biological Laws? -- Andre Malan; The Suprachiasmatic Nucleus Influences Energy Balance of Golden-mantled Ground Squirrels During Hibernation -- Norman E. Ruby; Pesticide Effects on Body Temperature of Torpid/Hibernating Rodents
(Peromyscus leucopus and Spermophilus tridecemlineatus) -- Thomas E. Tomasi, Peta Elsken-Lacy, Jean A. Perry, and Kerry Withers; Steroidogenesis and the HPA Axis During Hibernation: Differential Expression of the StAR Protein -- Matthew T. Andrews, Meaghan M. Tredrea, and Aubie K. Shaw; A Quest for the Origin of Mammalian Uncoupling Proteins -- Marton Jastroch, Sigrid Stohr, Kerry Withers, and Martine Klingenspor; Brown-Fat-Derived and Thyroid-Hormone Thermogenesis: Mechanisms and Interactions -- Jan Nedergaard, Valeria Golozoubova, and Barbara Cannon; Alterations in Localization of Hippocampal Protein Kinase Cγ
(PKCγ), but Not PKCα, -β1, or –β2, in European Ground Squirrels During Hibernation -- Eddy A. Van der Zee, Jens Stieler, Roelof A. Hut, Martin de Wilde, and Arjen M. Strijkstra; The Role of the Medial Septum in the Control of Hibernation -- Irina Yu. Popova and Yurii M. Kokoz; Proteolysis in Hibernators -- Frank can Breukelen; Post-genomic Approaches to the Mechanisms of Cold Response in Fish and Hibernating Small Mammals -- Daryl Williams, L. Elaine Epperson, Andrew R. Cossins, Jane Fraser, Weizhong Li, Sandra Martin, and Andrew Y. Gracey; Use of Suppression Subtractive Hybridization to Elucidate Novel Gene
Products Related to Physiological Events in a Hibernator -- Gregory L. Florant, Chris Pittman, and Scott A. Summers; Clinical Applications and Limitations of Hypothermia -- Philip E. bickler; Hibernation in Mammals: A Model for Alzheimer-type
Phosphorylation of the Microtubule-associated Protein Tau -- Thomas Arendt, Jens Stieler, Arjen M. Strijkstriam Roelof A. Hut, Eddy A. Van der Zee, max Holzer, and Woldfgang Hartig; Resistance of Livers to Cold Ischemia/Reperfusion Injury During
Hibernation: Involvement of Matrix Metalloproteinase and Nitric Oxide Synthase -- Hannah V. Carey, Timothy M. Piazza, Sarah E. Davis, Susanne L. Lindell, Anna Durranis, Kieran Clarke, and James H. Southard; Anti-Proliferative Effects of Plasma from Hibernating Rodents -- Donna G. Sieckmann, Decheng Cai, Howard Jaffe, John Hallenbeck, and Richard M. McCarron; Antifreeze Proteins in Terrestrial Arthropods -- John G. Duman, Valerie A. Bennett, N. Li, L. Wang, L. Huang, T. Sformo, and B.M. Barnes; Cardiac Conduction and Resistance to Ventricular Fibrillation in Siberian Hibernator Ground Squirrel Citellus undulatus -- Vadim V. Fedorov, Rubin R. Aliev, Alexey V. Glukhov, Andrey V. Resnik, Andrey Anufriev, Irina A. Ivanova, Olga V. Nakipova, Stella G. Kolaeva, Leonid V. Rosenshtraukh, and Igor R. Efimov; The Correlation Between Akt Activity and Hibernation -- Decheng Cai, Richard M. McCarron, Donna Sieckmann, and John M. Hallenbeck; Protection from Traumatic Brain Injury During Hibernation -- Kelly L. Drew, Fang Zhou, Xiongwei Zhu, Rudy J. Castellani, and Mark A. Smith; δ-Opioid Agonists Protect the Rat Liver From Cold Storage and Ischemia/Reperfusion Injury -- Thomas L. Husted, Wen-Jian Chang, Alex B. Lentsch, Steven M. Rudich;Animal Adaptability to Oxidative Stress:
Gastropod Estivation and Mammalian Hibernation -- Marcelo Hermes-Lima, Gabriella R. Ramos-Vasconcelos, Luciano A. Cardoso, Adrienne l. Orr, Patricia M. Rivera, and Kelly L. Drew
Mechanisms by which interleukin-4 suppresses inflammatory cytokine production by activated human monocytes
Get PDFImproving understanding of how inflammatory responses by monocytes and macrophages are regulated may aid in the development of more targeted therapies for chronic inflammatory disease. In this thesis the mechanisms by which the cytokine, IL-4, can suppress inflammatory cytokine production by LPS-stimulated human monocytes have been examined.
IL-4 suppressed LPS-induced TNFα transcription, without inhibiting LPS signalling through IκB, the mitogen-activated protein kinase (MAPK) pathways, or LPS-mediated activation of the transcription factor NF-κB. Histone acetylation regulated LPS-induced cytokine production but not the suppression of these cytokines by IL-4. IL-4 induced three molecules with potential anti-inflammatory properties, suppressor of cytokine signalling-1 (SOCS1), peroxisome proliferator-activated receptor gamma (PPARγ) and triggering receptors expressed on myeloid cells-2 (TREM-2), but suppressed LPS-induced TNFα production independently of these molecules.
Targeted gene arrays for Toll-like receptor (TLR) signalling pathways revealed that IL-4 down-regulated mRNA levels of LPS-induced inflammatory cytokines and chemokines, without altering other NF-κB-dependent genes or mRNA levels of TLR-related signalling molecules. Instead, the anti-inflammatory actions of IL-4 may be mediated by up-regulation of an unknown signalling molecule or transcriptional regulator. In LPS-treated monocytes, IL-4 up-regulated mRNA levels for IL-10, receptor-interacting serine-threonine kinase 2 (RIPK2), RP105 and c-Maf. However, the anti-inflammatory actions of IL-4 did not require IL-10 or the kinase activity of RIPK2. While the TLR-homolog, RP105, is likely to negatively regulate LPS responses by monocytes, IL-4 had no effect on cell surface expression of RP105. Additional studies may determine whether c-Maf, a transcription factor which induces IL-10, also regulates the suppression inflammatory cytokine production by IL-4.
This study identified novel candidates induced by IL-4 in LPS-stimulated human monocytes. However, the molecules involved in the regulation by IL-4 of LPS-induced TNFα production were not definitively identified. Further studies may identify the mechanisms by which IL-4 is anti-inflammatory. Ultimately, this research will contribute towards the development of novel therapies for inflammatory disease
Metabolic consequences of neuronal mitochondrial fission ablation
Get PDFDynamin-related protein 1 (Drp1), the main mammalian mediator of mitochondrial fission, has an especially important role in neuronal development, such that its deletion gives rise to pre- or perinatal lethality. However, less is known about the need for Drp1 in adult neurons; this is relevant because inhibition of Drp1 could prevent pre-apoptotic mitochondrial fragmentation, and therefore be neuroprotective.
In our mouse model, inducible Drp1 ablation in the forebrain of adult mice leads to swollen, perinuclearly aggregated mitochondria and to impaired synaptic transmission. Of note, ablated mice also develop a complex and ultimately lethal catabolic phenotype, marked by weight loss, increased lipolysis and elevated corticosterone. We traced this back to the activation of the integrated stress response in Drp1-ablated brain regions, culminating in the ectopic induction of metabolic cytokine Fgf21. Fgf21 is normally produced in liver, fat and muscle tissue in response to fasting or exercise, and no reports exist of it being produced in the brain. This “mitokine” increases insulin sensitivity and stimulates corticosterone production via receptors in the hypothalamus, thus explaining essential aspects of the catabolic phenotype.
This work has implications not only for mitochondrial biology but also for the understanding of the central regulation of systemic metabolism
Purinergic receptor expression in neuronal, bladder smooth muscle and urothelial cells: characterization and inhibition by low molecular weight antagonists
No full textP2 purinoceptors comprise ionotropic (P2X) and metabotropic (P2Y) receptor families, responsive to nucleotide ligands and diversely distributed on virtually every mammalian cell. Most cells and tissues co-express multiple subtypes of purinoceptor; thus, unraveling the functional role – and pharmacological potential – of any subtype is a complex task. Additionally limiting is the paucity of potent, selective antagonists, particularly those with suitable physicochemical and pharmacokinetic properties for animals models and clinical development.
These studies address questions initially debated >10 years ago, following the successful cloning of purinoceptor families. First, given the large, polyanionic or nucleotide chemical probes available for pharmacology, are these receptors medicinally tractable? Secondly, given the admixture of purinoceptor expression in mammalian cells, would selective interference impact pathophysiology and disease burden; or would redundancy dominate?
Through the current investigations some answers can be offered. First, a resounding “yes”, second, a more equivocal “possibly”. Importantly, in addressing these queries, our investigations – and others - have furnished both important data on biological relevance of P2 subtype expression and function, as well as excellent chemical and biological tools for future investigators, so that more answers can be found.
Meanwhile, the pharmacological characteristics of two novel prototype antagonists have been detailed: for P2X1 (RO-1) and P2X3-containing receptors (RO-4). Additionally, the potential value of these compounds for the study of P2X signaling in vitro and in vivo, as well as templates for candidate medicines with a wide variety of potential therapeutic uses are demonstrated. It has also been possible to elucidate the potential of selective interference in certain target tissues – urological and sensory – and increasing the apparent therapeutic potential.
We can indeed conclude that P2X channels of focus in this work, P2X1, P2X3 and P2X2/3, are druggable; the true therapeutic value of antagonists of these channels is awaited
Evaluación ultrasonográfica de la masa muscular del cuádriceps femoral en personas mayores de 60 o más años ingresados en la unidad de cuidados intensivos de una institución de salud de la ciudad de Manizales, Colombia
No full textTablasIntroducción
A medida que las personas envejecen, aumenta la probabilidad de requerir hospitalización en la Unidad de Cuidados Intensivos (UCI), lo que eleva el riesgo de desarrollar síndromes geriátricos como la pérdida de masa muscular (sarcopenia). En la población mayor que permanece en UCI se observa una alta prevalencia de baja masa muscular esquelética, que puede alcanzar hasta el 51%.
Objetivo
Evaluar la variación de la masa muscular del cuádriceps femoral en personas de 60 años o más ingresadas en la Unidad de Cuidados Intensivos de una institución de salud.
Metodología
Se realizó un estudio observacional analítico con diseño antes-después. Se efectuó valoración ultrasonográfica de la masa muscular del cuádriceps femoral al ingreso y al séptimo día de estancia hospitalaria en pacientes de 60 años o más, con patologías médicas o quirúrgicas, admitidos y atendidos en la UCI del Hospital Departamental Santa Sofia de la ciudad de Manizales durante el periodo 2024–2025.
Resultados
Se evaluaron prospectivamente 50 pacientes en UCI entre 2024 y 2025, con predominio masculino (60%) y una mediana de edad de 72,5 años. Tras siete días de hospitalización, la masa muscular del cuádriceps femoral mostró reducciones significativas en todos los parámetros evaluados: 16,2% en el área de sección transversal del recto femoral, 14,6% en el grosor del cuádriceps femoral derecho, 20,2% en el izquierdo y 18,2% en el ángulo de penación.
Los modelos multivariados identificaron factores asociados con mayor pérdida muscular: edad avanzada, sexo femenino, uso de hipoglucemiantes, mayor puntuación SOFA y menor índice de Barthel premórbido. De manera destacada, el análisis de correlación mostró que la gravedad de la disfunción orgánica (SOFA) se asoció de forma negativa e independiente con los parámetros musculares, particularmente con la arquitectura muscular al ingreso, mientras que la mortalidad en UCI (30%) se relacionó significativamente con un menor ángulo de penación.Introduction
As people age, the likelihood of requiring hospitalization in the Intensive Care Unit (ICU) increases, which elevates the risk of developing geriatric syndromes such as loss of muscle mass (sarcopenia). Among older adults who remain in the ICU, a high prevalence of low skeletal muscle mass is observed, reaching up to 51%.
Objective
To evaluate the variation in quadriceps femoris muscle mass in individuals aged 60 years or older admitted to the Intensive Care Unit of a healthcare institution.
Methodology
An analytical observational study with a before-and-after design was conducted. Ultrasonographic assessment of quadriceps femoris muscle mass was performed at admission and on the seventh day of hospitalization in patients aged 60 years or older with medical or surgical conditions, admitted and cared for in the ICU of the Hospital Departamental Santa Sofia in the city of Manizales during the 2024–2025 period.
Results
A total of 50 ICU patients were prospectively evaluated between 2024 and 2025, with a male predominance (60%) and a median age of 72.5 years. After seven days of hospitalization, the quadriceps femoris muscle showed significant reductions across all evaluated parameters: 16.2% in rectus femoris cross-sectional area, 14.6% in right quadriceps femoris thickness, 20.2% in left quadriceps femoris thickness, and 18.2% in pennation angle.
Multivariable models identified factors associated with greater muscle loss: advanced age, female sex, use of hypoglycemic agents, higher SOFA score, and lower premorbid Barthel Index. Notably, correlation analysis revealed that the severity of organ dysfunction (SOFA) was independently and negatively associated with muscle parameters, particularly with muscle architecture at admission, while ICU mortality (30%) was significantly associated with a lower pennation angle.Información general del proyecto -- Resumen -- Planteamiento del problema -- Justificación -- Marco conceptual -- Marco teórico -- Antecedentes históricos -- Antecedentes clínicos -- Pérdida de masa muscular -- Ecografía muscular -- Objetivos -- Objetivo general -- Objetivos específicos -- Planteamiento de hipótesis -- Metodología -- Enfoque investigativo -- Diseño y tipo de estudio -- Población de estudio -- Diseño muestral -- Criterios de selección -- Criterios de inclusión -- Criterios de exclusión -- Variables del estudio -- Recolección de información -- Proceso de recolección de la información -- Control de errores y sesgos -- Procedimientos -- Protocolo del ultrasonido institucional -- Toma de medidas -- Técnicas de procesamiento -- Plan de análisis estadístico -- Aspectos éticos -- Resultados -- Características demográficas y clínicas -- Mediciones de masa muscular del cuádriceps femoral al ingreso y a los 7 días de estancia UCI -- Distribución de las mediciones musculares -- Variación en las mediciones de la masa muscular del cuádriceps femoral -- Distribución absoluta y porcentual de los cambios de la masa muscular del cuádriceps femoral a los 7 días de estancia UCI -- Correlación entre el cambio en la masa muscular del cuádriceps femoral y los aspectos clínicos del paciente -- Análisis multivariado de la regresión cuantílica -- Discusión -- Fortalezas y limitaciones metodológicas -- Conclusiones -- Anexos -- BibliografíaEspecializaciónSe desarrolló un estudio enmarcado en el paradigma empírico-analítico, en el cual se emplearon herramientas matemáticas, especialmente de tipo estadístico, aplicadas a la epidemiología clínica. El enfoque utilizado fue predominantemente cuantitativo.
Diseño y tipo de estudio
Se utilizó un diseño epidemiológico observacional de intención analítica, tipo antes y después, con el objetivo de evaluar la variación en la masa muscular del cuádriceps femoral al ingreso hospitalario y tras 7 días de estancia. No se realizó ningún tipo de intervención ni modificación en la atención habitual del paciente; únicamente se efectuaron dos mediciones transversales de las variables de estudio.
Población de estudio
Pacientes de 60 años o más, con patologías médicas o quirúrgicas, admitidos en la Unidad de Cuidados Intensivos (UCI) del Hospital Departamental Santa Sofía de Manizales durante el periodo 2024-2025.
Diseño Muestral
Se realizó una búsqueda en los registros de historias clínicas de personas mayores de 60 o más años, admitidos y atendidos por patologías médicas o quirúrgicas en la Unidad de Cuidados Intensivos del Hospital Departamental Santa Sofía, en la ciudad de Manizales, durante el período comprendido entre el 6 de diciembre de 2024 y el 30 de mayo de 2025.
Para la selección de las unidades de análisis se utilizó una muestra censal, aplicando posteriormente un muestreo por cuotas (69), conforme a los criterios de inclusión establecidos por el estudio, relacionados principalmente con la edad y las condiciones médicas específicas del paciente hospitalizado en la UCI.Especialista Medicina Interna - Geriatrí
