Spectral statistics of the quenched normal modes of a network-forming molecular liquid

We evaluate the density of states of the quenched normal modes of ST2 water, and their statistical fluctuations, for a range of densities spanning three regimes of behavior of a hydrogen bonded liquid: a lower-density regime of random tetrahedral network formation; in the vicinity of a liquid-liquid critical point; and in a higher-density regime of fragile glass-forming behavior. For all cases we find that the fluctuations around the mean spectral densities obey the predictions of the Gaussian orthogonal ensemble of random matrix theory. We also measure the participation ratio of the normal modes across the entire frequency range, and find behavior consistent with the majority of modes being of an extended nature, rather than localized.Comment: Accepted for publication in The Journal of Chemical Physic

Impact of maximum borehole depths on inverted temperature histories in borehole paleoclimatology

A quantitative assessment is presented for the impact of the maximum depth of a temperature-depth profile on the estimate of the climatic transient and the resultant ground surface temperature (GST) reconstruction used in borehole paleoclimatology. The depth of the profile is important because the downwelling climatic signal must be separated from the quasi-steady state thermal regime established by the energy in the Earth's interior. This component of the signal is estimated as a linear increase in temperature with depth from the lower section of a borehole temperature profile, which is assumed to be unperturbed by recent changes in climate at the surface. The validity of this assumption is dependent on both the subsurface thermophysical properties and the character of the downwelling climatic signal. Such uncertainties can significantly impact the determination of the quasi-steady state thermal regime, and consequently the magnitude of the temperature anomaly interpreted as a climatic signal. The quantitative effects and uncertainties that arise from the analysis of temperature-depth profiles of different depths are presented. Results demonstrate that widely different GST histories can be derived from a single temperature profile truncated at different depths. Borehole temperature measurements approaching 500-600 m depths are shown to provide the most robust GST reconstructions spanning 500 to 1000 yr BP. It is further shown that the bias introduced by a temperature profile of depths shallower than 500-600 m remains even if the time span of the reconstruction target is shortened

On the static length of relaxation and the origin of dynamic heterogeneity in fragile glass-forming liquids

The most puzzling aspect of the glass transition observed in laboratory is an apparent decoupling of dynamics from structure. In this paper we recount the implication of various theories of glass transition for the static correlation length in an attempt to reconcile the dynamic and static lengths associate with the glass problem. We argue that a more recent characterization of the static relaxation length based on the bond ordering scenario, as the typical length over which the energy fluctuations are correlated, is more consistent with, and indeed in perfect agreement with the typical linear size of the dynamically heterogeneous domains observed in deeply supercooled liquids. The correlated relaxation of bonds in terms of energy is therefore identified as the physical origin of the observed dynamic heterogeneity.Comment: 6 pages, 1 figur

Biobanking from the patient perspective

Biobanks and biobanking research plays an increasingly important role in healthcare research and delivery as health systems become more patient-centred and medicine becomes more personalised. There is also growing acceptance and appreciation of the value that patients, patient advocacy organisations and the public can bring as stakeholders in biobanking and more generally in research. Therefore, the importance of active, early and sustained engagement and involvement of patient and public representatives in biobanks will become increasingly relevant. Organising and facilitating patient and public involvement in biobanking takes considerable time and effort for all stakeholders involved. Therefore, for any biobank operator considering involving patients and the public in their biobanking activities, consideration of best practices, current guidance, ethical issues and evaluation of involvement will be important. In this article, we demonstrate that patients are much more than donors to biobanks—they are collaborators at the heart of biobanking with an important voice to identify perspective, which can be an extremely valuable resource for all biobanks to utilise. The case studies herein provide examples of good practice of patient involvement in biobanking as well as outcomes from these practices, and lessons learned. Our aim is to provide useful insights from these efforts and potential future strategies for the multiple stakeholders that work with patients and the public involved in biobank-based research

Harnessing Generative AI for Optimizing Power Generation Innovations and Applications in Energy Efficiency

This article explores modern approaches to the integration of advanced technologies such as generative artificial intelligence (AI), the Internet of Things (IoT), and 5G, aimed at developing digital infrastructure and strategic partnerships with technology companies in the energy sector. The focus is on methods such as the use of generative AI models for big data analysis, failure prediction, and the optimization of energy grid operational processes. Special attention is given to the integration of IoT and 5G to create a flexible and resilient infrastructure capable of adapting to real-time changes. The key conclusions from this work show that these technologies not only reduce operational costs but also significantly enhance environmental sustainability through the integration of renewable energy sources. Furthermore, the analysis indicates that the implementation of Vehicle-to-Grid systems contributes to more efficient energy management, and when combined with IoT and Phasor Measurement Units (PMUs), improves the monitoring and control of electrical networks. The article emphasizes that despite the need for adaptation of existing infrastructure and significant computational resources, the potential of these technologies will continue to grow, offering innovative solutions for reducing energy consumption and enhancing productivity in the long term

Spontaneous back-pain alters randomness in functional connections in large scale brain networks: A random matrix perspective

We use randomness as a measure to assess the impact of evoked pain on brain networks. Randomness is defined here as the intrinsic correlations that exist between different brain regions when the brain is in a task-free state. We use fMRI data of three brain states in a set of back pain patients monitored over a period of 6 months. We find that randomness in the task-free state closely follows the predictions of Gaussian orthogonal ensemble of random matrices. However, the randomness decreases when the brain is engaged in attending to painful inputs in patients suffering with early stages of back pain. A persistence of this pattern is observed in the patients that develop chronic back pain, while the patients who recover from pain after six months, the randomness no longer varies with the pain task. The study demonstrates the effectiveness of random matrix theory in differentiating between resting state and two distinct task states within the same patient. Further, it demonstrates that random matrix theory is effective in measuring systematic changes occurring in functional connectivity and offers new insights on how acute and chronic pain are processed in the brain at a network level.Comment: 18 Pages, 5 Figure

Avaliação da Combinação de Microagulhamento com Tacrolimus no Tratamento de Vitiligo Estável

Introduction: Vitiligo is an amelanotic disorder that can manifest as localized patches to near total body depigmentation. It is considered a cosmetic disease but it is accompanied by extensive psychological effects. Multiple treatments have been tried until now but no single method has achieved the desired response. Tacrolimus is frequently used for vitiligo treatment with few adverse effects. Microneedling is a newer modality of therapeutic wounding that augments drug absorption. Combination of microneedling and tacrolimus have been tried to improve the repigmentation response in vitiligo. Our objective was to assess the safety and efficacy of this combined modality. Methods: Forty patients were subjected to combination of tacrolimus 0.1% ointment and microneedling at 2 week intervals for maximum 10 sessions with a follow-up period of 6 months. Assessment was based on grading of repigmentation and clinical improvement according to vitiligo noticeability scale. Results: Excellent repigmentation was observed in 30% cases. Improvement was significantly higher in lesions present on the head and neck. Mucosal vitiligo also showed good to excellent response. No severe side effects were reported. No complications or recurrences were observed during the follow-up period. Conclusion: Combination of microneedling and tacrolimus was found to be safe and efficacious in the treatment of stable vitiligo.Introdução: O vitiligo é uma doença amelanótica que pode se manifestar como manchas localizadas até quase à despigmentação total. É considerada uma doença cosmética, mas é acompanhada por extensos efeitos psicológicos. Vários tratamentos foram tentados até agora, mas nenhum método atingiu a resposta desejada. O tacrolimus é um agente frequentemente usado para o tratamento do vitiligo com um perfil mínimo de efeitos colaterais. O microagulhamento é uma modalidade mais recente de ferimento terapêutico que aumenta a absorção de fàrmacos. A combinação de microagulhamento e tacrolimus tem sido tentada para melhorar a resposta de repigmentação no vitiligo. Nosso objetivo foi avaliar a segurança e eficácia desta modalidade combinada. Métodos: Quarenta pacientes foram submetidos à combinação de tacrolimus 0,1% pomada e microagulhamento em intervalos de 2 semanas por um máximo de 10 sessões com um período de acompanhamento de 6 meses. A avaliação foi baseada na graduação de repigmentação e melhora clínica de acordo com a escala de perceptibilidade do vitiligo. Resultados: Excelente repigmentação foi observada em 30% dos casos. A melhora foi significativamente maior nas lesões presentes na cabeça e pescoço. O vitiligo mucoso também mostrou boa a excelente resposta. Não foram relatados efeitos colaterais graves. Nenhuma complicação ou recorrência foi observada durante o período de acompanhamento. Conclusão: A combinação de microagulhamento e tacrolimus é considerada segura e eficaz no tratamento do vitiligo estável. Compreender e estudar o risco de infeção na utilização de terapêutica imunossupressora permite a sua aplicação de forma mais informada e segura

DEVELOPMENT OF A MICROFLUIDIC OXYGENATOR AS AN OXYGENATING UNIT OF A LUNG ASSIST DEVICE FOR TERM AND PRE-TERM NEONATES WITH RESPIRATORY DISTRESS SYNDROME

Respiratory distress syndrome is a major cause of mortality among infants. Current therapies are limited in terms of invasiveness, cost, infrastructure, and leads to long term morbidities such as bronchopulmonary dysplasia. As a result a form of respiratory support termed as “artificial placenta” has been developed that allows natural development of lungs and avoids long term morbidities. The artificial placenta is connected via the umbilical vessels and provide pumpless respiratory support and is characterized by non-invasiveness, low cost and low infrastructure. Our group previously reported on a development of porous PDMS membrane artificial placenta. To build upon its development, one of the objectives of this thesis was to reduce the variation in the oxygen saturation of the input blood for testing the oxygenator. Another objective was to setup a mathematical model to predict the oxygen uptake in an oxygenating unit and use the model to optimize the geometric parameters of a design. The final objective was to improve the oxygen uptake of the oxygenating unit of the artificial placenta by redesigning the blood flow path and the membrane material. The experimental setup was improved to employ an active controller that actively maintained the oxygen saturation of the input blood for testing the oxygenator within a variation of ±3% of the set point for at least an hour. As compared to previous experimental setup the blood deviated from the set point by 9%. Later, the blood flow path in the oxygenator was redesigned from a flat height profile to a sloping height profile; and the PDMS membrane was reinforced with a thin steel mesh. Such changes improved the oxygen uptake at the operating pressure of 30 mmHg from 16 µL/min in case of an oxygenator with flat height profile and PDMS membrane to 26 µL/min in case of an oxygenator with flat profile and composite membrane. Finally, a mathematical model was developed that coupled oxygen uptake, pressure drop and membrane expansion. The model was validated against experimental results and was later used to optimize the configuration of the oxygenator with sloping profile and composite membrane. The predicted oxygen uptake of the optimized configuration at the operating pressure of 30 mmHg was 78.8 µL/min.ThesisMaster of Applied Science (MASc

Sparse random matrices and vibrational spectra of amorphous solids

A random matrix approach is used to analyze the vibrational properties of amorphous solids. We investigated a dynamical matrix M=AA^T with non-negative eigenvalues. The matrix A is an arbitrary real NxN sparse random matrix with n independent non-zero elements in each row. The average values =0 and dispersion =V^2 for all non-zero elements. The density of vibrational states g(w) of the matrix M for N,n >> 1 is given by the Wigner quarter circle law with radius independent of N. We argue that for n^2 << N this model can be used to describe the interaction of atoms in amorphous solids. The level statistics of matrix M is well described by the Wigner surmise and corresponds to repulsion of eigenfrequencies. The participation ratio for the major part of vibrational modes in three dimensional system is about 0.2 - 0.3 and independent of N. Together with term repulsion it indicates clearly to the delocalization of vibrational excitations. We show that these vibrations spread in space by means of diffusion. In this respect they are similar to diffusons introduced by Allen, Feldman, et al., Phil. Mag. B 79, 1715 (1999) in amorphous silicon. Our results are in a qualitative and sometimes in a quantitative agreement with molecular dynamic simulations of real and model glasses.Comment: 24 pages, 7 figure