189 research outputs found
Quantifying radar-rainfall uncertainties in urban drainage flow modelling
AbstractThis work presents the results of the implementation of a probabilistic system to model the uncertainty associated to radar rainfall (RR) estimates and the way this uncertainty propagates through the sewer system of an urban area located in the North of England. The spatial and temporal correlations of the RR errors as well as the error covariance matrix were computed to build a RR error model able to generate RR ensembles that reproduce the uncertainty associated with the measured rainfall. The results showed that the RR ensembles provide important information about the uncertainty in the rainfall measurement that can be propagated in the urban sewer system. The results showed that the measured flow peaks and flow volumes are often bounded within the uncertainty area produced by the RR ensembles. In 55% of the simulated events, the uncertainties in RR measurements can explain the uncertainties observed in the simulated flow volumes. However, there are also some events where the RR uncertainty cannot explain the whole uncertainty observed in the simulated flow volumes indicating that there are additional sources of uncertainty that must be considered such as the uncertainty in the urban drainage model structure, the uncertainty in the urban drainage model calibrated parameters, and the uncertainty in the measured sewer flows
Effect of the pore fluid salinities on the behaviour of an electrokinetic treated soft clayey soil
Dredging activities of harbours and rivers are becoming very important in many countries all over the world and, as a consequence, the disposal of dredged sediments is a critical concern from an environmental point of view. In order to facilitate the disposal or the reuse of large volume of dredged soils, usually under-consolidated and with a high water content, an electrokinetic treatment can be adopted with the goal to dewater and strengthen the sediments. This paper presents the results of some electrokinetic tests performed on reconstituted clayey specimens at different pore fluid salinities (0.2 < sc < 30 g/l) treated with electrokinetic (EK) technique. The results indicate that the presence of small quantities of salts in the pore fluid enhances the electro-osmotic consolidation. On the contrary, for high salt concentrations of the pore fluid the electro-osmotic dewatering is significantly reduced. The mechanical behaviour of treated specimens has been investigated at the micro (SEM) and macro scale (triaxial and oedometer tests). The experimental results highlighted the relevant and expected contribution of the pore fluid characteristic on the effectiveness of the treatment as ground improvement technique
The Sensitivity of PsbS to the Environment, Residue by Residue
Under strong sunlight, plants avoid photooxidation by quenching the excess absorbed energy. Quenching is triggered by PsbS, a membrane protein that is activated and deactivated by the light-dependent pH changes in the thylakoid lumen. The mechanism of action of this protein is unknown, but it was suggested that several glutamates act as pH sensors. However, the pK a of glutamate is several pH units below the physiological values in the lumen. Thus, how can PsbS sense the pH of the lumen, and how does it respond to it? By applying a nonstandard molecular dynamics method that treats pH explicitly, we show that the lumen-exposed glutamates of PsbS have strongly shifted pK a values and that such shifts are crucial for the pH sensitivity in physiological conditions. We also demonstrate that protonation drives a systematic unfolding of a region key for protein-protein interactions, indicating that PsbS response to pH is a functional conformational switch.publishersversionpublishe
Bone fragility: conceptual framework, therapeutic implications, and COVID-19-related issues
Bone fragility is the susceptibility to fracture even for common loads because
of structural, architectural, or material alterations of bone tissue that result in poor bone
strength. In osteoporosis, quantitative and qualitative changes in density, geometry, and
micro-architecture modify the internal stress state predisposing to fragility fractures. Bone
fragility substantially depends on the structural behavior related to the size and shape of the
bone characterized by different responses in the load–deformation curve and on the material
behavior that reflects the intrinsic material properties of the bone itself, such as yield and
fatigue. From a clinical perspective, the measurement of bone density by DXA remains the
gold standard for defining the risk of fragility fracture in all population groups. However,
non-quantitative parameters, such as macro-architecture, geometry, tissue material
properties, and microcracks accumulation can modify the bone’s mechanical strength. This
review provides an overview of the role of different contributors to bone fragility and how
these factors might be influenced by the use of anti-osteoporotic drugs and by the COVID-19
pandemi
Rehabilitation of Neuromuscular Diseases During COVID-19: Pitfalls and Opportunities
The outbreak of COVID-19 caused by SARS-CoV-2 has spread worldwide with a huge impact on the healthcare system. Compared to the previous coronaviruses-related pandemics, COVID-19 is more transmissible with potential systemic involvement and peculiar neurological manifestations, such as Guillan-Barrè syndrome up to critical illness myopathy, occurring in the intensive care setting. In this clinical scenario, people living with a neuromuscular disease (NMD) represent a vulnerable category with a high risk of a severe course of COVID-19. Moreover, in the NMD population, the management of respiratory and muscular impairments after SARS-CoV-2 infection might be troubling in terms of both pharmacological and rehabilitative approaches. To date, rehabilitation is still an unmet need in this population with several implications on NMD progression with and without SARS-CoV-2 infection. In particular, rehabilitation intervention for patients with NMD after COVID-19 are lacking. Therefore, in the current paper, we analyze the critical issues of COVID-19 on NMDs patients and propose a home-based rehabilitation program targeted for this population after mild to moderate SARS-CoV-2 infection
Muscle Regeneration and Function in Sports: A Focus on Vitamin D
Muscle is one of the main targets for the biological effects of vitamin D. This hormone
modulates several functions of skeletal muscles, from development to tissue repair after injury,
through genomic and non-genomic mechanisms. Vitamin D deficiency and supplementation seem to
significantly affect muscle strength in different populations, including athletes, although optimal
serum 25(OH)D3 level for sport performance has not been defined so far. Additionally, vitamin D de-
ficiency results in myopathy characterized by fast-twitch fiber atrophy, fatty infiltration, and fibrosis.
However, less is known about regenerative effects of vitamin D supplementation after sport-related
muscle injuries. Vitamin D receptor (VDR) is particularly expressed in the embryonic mesoderm
during intrauterine life and in satellite cells at all stages of life for recovery of the skeletal muscle after
injury. Vitamin D supplementation enhances muscle differentiation, growth, and regeneration by
increasing the expression of myogenic factors in satellite cells. The objective of this narrative review
is to describe the role of vitamin D in sport-related muscle injury and tissue regeneration
Transient osteoporosis of the hip and subclinical hypothyroidism: an unusual dangerous duet? Case report and pathogenetic hypothesis
Background: Transient osteoporosis of the hip (TOH) is a rare and temporary clinical condition characterised by
bone marrow edema (BME), severe pain, and functional limitation. It commonly occurs in middle-aged men or in
women in the last trimester of pregnancy. TOH usually resolves with conservative therapy but may predispose to
hip fracture or progression to avascular necrosis (AVN). Etiology is still unclear, although several pathophysiological
mechanisms underpinning this condition has been proposed. We describe the management of an unusual case of
TOH occurred in a patient with subclinical hypothyroidism.
Case presentation: A clinical case of a 46-year-old man with severe pain in the left anterior thigh is presented.
After a comprehensive clinical and radiological approach, a TOH was diagnosed. Moreover, biochemical assessment
suggested the presence of subclinical hypothyroidism. After 3 months of treatment with clodronate, physical
therapy and hormone replacement therapy (HRT) a significant improvement of clinical and radiological outcomes
was observed.
Conclusion: Several pathological conditions have been related to development of TOH. In our case, we suggested
for the first time a role of subclinical hypothyroidism as novel contributory factor for the onset of this condition,
providing pathophysiological mechanisms and a scientific rationale for pharmacological treatment
Complex Regional Pain Syndrome Type I Following Non-Orthopedic Surgery: Case Report and Narrative Review
Complex regional pain syndrome type I (CRPS I)—or algodystrophy—is a rare disease
that usually occurs after a traumatic event. It is characterized by typical clinical findings such as
severe and disabling pain disproportionate to the injury, functional limitations, as well as sensory
and vasomotor alterations. However, some people do not report any injury associated with
algodystrophy onset in personal history. We describe the management of an unusual case of CRPS
I which occurred during the long-term follow-up of percutaneous transluminal coronary
angioplasty (PTCA) and performed a narrative review of algodystrophy in non-orthopedic surgery.
A clinical case of a 44-year-old man with a spontaneous onset of CRPS I of the right ankle is
presented. He did not refer to history of any memorable significant trigger event. Approximately 5
months before the onset of clinical manifestations, he received a PTCA via the right femoral
approach. We suppose an association between CRPS and this procedure and propose a possible
pathophysiologic mechanism. The patient was treated with intramuscular neridronate, which
resulted in significant pain relief and improved his quality of life. A comprehensive clinical and
instrumental evaluation in patients with CRPS is challenging but mandatory for a correct diagnosis.
An extensive analysis of patient history is important for identifying any potential trigger event,
including non-orthopedic procedures. Bone scan could have a pivotal role for improving diagnostic
sensitivity and specificity in CRPS I. Neridronate was a safe and effective therapeutic approach for
this patient, confirming the results of the high-quality evidence availabl
Characterization of neuropathic component of back pain in patients with osteoporotic vertebral fractures
BACKGROUND: Osteoporotic vertebral fractures (OVFs) are often followed by chronic back pain which may have a nociceptive, neuropathic, or mixed component. However, literature on this topic is lacking.
OBJECTIVE: The objective of this cross-sectional study is to characterize the neuropathic component of chronic back pain in patients with OVFs.
METHODS: Spine fractures were detected by morphometric examination. Pain severity and its impact on daily living activities (ADL) were evaluated through the Brief Pain Inventory (BPI). Neuropathic pain was investigated through the Italian Versions of the Leeds Assessment of Neuropathic Symptoms and Signs pain scale (LANSS) and the painDETECT questionnaire (PD-Q).
RESULTS: We included 72 patients, mainly women (88.8%), with mean age of 69.2 years. The 70.8% of patients had multiple OVFs, of which 47% located at the thoracic spine, 43.1% at the thoracic and at lumbar spine, and 9.8% at the lumbar spine. The BPI showed moderate back pain in 23.6% of cases and severe in 8.3% of cases, with high interference with ADL in 38.9% of patients. The PD-Q revealed the presence of neuropathic pain in 5.5% of cases, while the S-LANSS in 23.6% of cases.
CONCLUSIONS: In our study, the prevalence of neuropathic component of chronic back pain ranged from 5.5% to 23.6%, according to PD-Q and LANSS respectively, in patients with OVFs. Further studies should investigate if the characterization of chronic back pain might contribute to appropriateness of interventions for this population
The Role of Hyaluronic Acid in Sport-Related Tendinopathies: A Narrative Review
Tendinopathy is a complex clinical condition with a rising incidence and prevalence, particularly during sports practice. For the return to play in affected patients, adequate functional and structural recovery of the tendon is the ultimate goal, avoiding the high risk of recurrence. In this perspective, local therapies alongside exercise are showing promising results. Despite evidence suggesting hyaluronic acid (HA) injections as effective in the treatment of tendinopathy, current recommendations about the management of this condition do not include this intervention. HA seems to be an effective therapeutic option for the management of sport-related tendinopathies, but further studies with a larger sample size are needed to confirm available findings. In this narrative review, we analyzed available literature about the rationale of the use of HA in the management of tendon injury and, particularly, in sport-related tendinopathies
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