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Background: Spinal cord compression is a formidable complication of advanced cancer, and clinicians of copious specialities often have to encounter significant complex challenges in terms of diagnosis, management, and prognosis. Metastatic lesions from cancer are a common cause of spinal cord compression, affecting a substantial portion of oncology patients, and only in the US has the percentage risen to 10%. Acute metastasis-correlated spinal cord compression poses a considerable clinical challenge, necessitating timely diagnosis and intervention to prevent neurological deficits. Clinical presentation is often non-specific, emphasizing the importance of thorough evaluation and appropriate differential diagnosis. Diagnostic workup involves various imaging modalities and laboratory studies to confirm the diagnosis and assess the extent of compression. Treatment strategies focus on pain management and preserving spinal cord function without significantly increasing patient life expectancy, while multidisciplinary approaches are often required for optimal outcomes. Prognosis depends on several factors, highlighting the importance of early intervention. We provide an up-to-date overview of acute spinal cord compression in metastases, accentuating the importance of comprehensive management strategies. Objectives: This paper extensively explores the pathophysiology, clinical presentation, diagnostic strategies, treatment modalities, and prognosis associated with spinal cord metastases. Materials and Methods: A systematic literature review was conducted in accordance with the PRISMA guidelines. Conclusions: We aim to help healthcare professionals make informed clinical decisions when treating patients with spinal cord metastases by synthesizing current evidence and clinical insights. [ABSTRACT FROM AUTHOR]

Background: The COVID-19 pandemic has presented numerous challenges to the global healthcare system and emerging evidence suggests a potential link between COVID-19 treatment, specifically steroid therapy, and the development of avascular necrosis (AVN) of the hip. This review aims to provide a comprehensive overview of recent studies and case reports investigating the relationship between COVID-19, corticosteroid therapy, and the development of AVN. Understanding the nuances of AVN in the context of COVID-19 is crucial for healthcare professionals to navigate treatment decisions and mitigate potential complications. Materials and Methods: The Preferred Reporting Items for Systematic Reviews and a Meta-Analysis (PRISMA) were used in the systematic review until 1 September 2023. The full texts of the remaining twenty-three (n = 23) articles were independently reviewed by the authors of this review. Conclusions: The association between steroid therapy for COVID-19 and the development of hip AVN is a noteworthy concern even though no relationship is evident between the duration of treatment, cumulative dosage of medication, maximum daily dosage received, and presence of AVN. Further research with larger cohorts and long-term follow up is needed to better understand the causative relationship and optimal management strategies for hip AVN in the context of COVID-19 and steroid therapy. [ABSTRACT FROM AUTHOR]

Key Clinical Message: The treatment of long bone fractures in post‐polio survivors is indubitably an exacting task. Out of this complicated case presented in this paper, it can be deduced that it is attainable to repair a peri‐implant subtrochanteric refracture or a complex non‐union of the proximal femur with plate and screws with grafting. Post‐polio survivors are prone to low‐energy bone fractures. The management of such cases is exigent, as no literature data indicate the best surgical approach. This paper presents an intricate peri‐implant proximal femoral fracture in a polio survivor treated in our institution and accentuates the various challenges we encountered. [ABSTRACT FROM AUTHOR]

The main categories of solar water heating systems (SWHSs) are the thermosyphon and the forced circulation (FC). This paper presents an experiment carried out with the aim to compare the energy performance of the FC with a thermosyphon SHWS. Identical SWHSs were installed side by side at the University of West Attica in Athens, Greece. Domestic hot water load was applied to both systems via a microcontroller-based dispensing unit which mimics the demand profile. The trial period comprised the last two months of spring (April and May). For the first law assessment, two energy indicators were utilized: the solar fraction (SF) and the thermal efficiency of the system (ηth). On days with distinctive weather conditions, both systems obtained approximately equal SF and ηth values, without a specific preference between the ambient conditions and the type of SWHS. Regarding a four-day nonstop operation, the FC overperformed the thermosyphon system at both energy indicators. Namely, for the FC and the thermosyphon SWHS, the SF was calculated to be 0.62 and 0.48, and the ηth was 68.2% and 53.3%, respectively. [ABSTRACT FROM AUTHOR]

In this study, a PVT-based solar-assisted ground source heat pump (SAGSHP) system with a small size borefield as the long-term heat storage component was energetically evaluated. The mathematical model of the system was formulated in TRNSYS and three cities with distinctive climates were chosen: Athens (Greece); Melbourne (Australia); and Ottawa (Canada). The parametric analyses were carried out for 10 years by varying the number of the PVT collectors and the size of the earth energy bank (EEB). The evaluation of the systems was made via two energy indicators, and the heat flow across the EEB was analyzed. The under-consideration system was found capable of establishing self-sufficiency as regards the energy consumption (renewable power fraction RPF > 1) for all locations. Namely, for Athens, any system with more than four PVT collectors, and for Melbourne, any system with more than eight PVTs was found with an RPF higher than 1, regardless of the EEB size. For Ottawa, self-sufficiency can be achieved with PVT arrays larger than 12 collectors for small EEBs, and with eight collectors for larger EEBs. The storage capacity was found to be an important parameter for the energy performance of the system. In particular, it was determined that, as the storage capacity enlarges the RPF and the seasonal performance factor (SPF) of the system improves, mainly due to the reduction of the electricity consumed by the heat pump and the auxiliary heating. Moreover, a larger storage capacity facilitates solar heat production by enlarging the available heat storage volume and by maintaining the EEB at relatively low temperatures. [ABSTRACT FROM AUTHOR]

• Large EEB and the PHE's effectiveness benefit the system's energy efficiency. • PVTs' power generation is influenced slightly from parameters variation. • The SP found an adequate tool for SAGSHP system's energy evaluation. A solar assisted ground source heat pump (SAGSHP) system is a promising technology which pairs two widely abundant renewable energy sources, solar and shallow geothermal. In space heating dominated regions, the addition of solar collectors to conventional ground source systems improves their feasibility. There are many aspects which influence the system's efficiency; but experimentation to optimize these would requires high capital investment and take a very long time. Therefore, mathematical modeling and computer-based simulations are preferable methods to conduct sensitivity and feasibility analyses. In this work, a PVT based solar assisted ground source heat pump system was modeled using TRNSYS program, and sensitivity analyses were conducted. For the PVT collectors, an experimentally verified transient model was utilized, while experimental data were used to validate a novel very shallow borefield. For the heat pump model, manufacturer's performance data along with a new novel method were combined, and a new component was created in the simulation platform. A single family dwelling with domestic hot water demand was assumed for the heating load, and weather data from Birmingham, West Midlands, UK was used. The simulation results were evaluated by utilizing the annual specific productivity metric rather than the systems seasonal performance factor, which is the current choice for SAGSHP systems. The proposed evaluation approach was found be capable of clarifying, in detail, the effect of the parametric variation on the system's energy performance. The sensitivity analyses are focused on six parameters on the energy conversion side, with the heat pump's evaporator as the physical boundary. It was found that the storage capacity and the plate heat exchanger's effectiveness, contribute the most to the system's and PVTs' heat productivity. Whilst heat productivity depended more on the parameters' variation, the power generation was influenced mainly by the collectors' tilt. The results of this study are significant for design and operation of these systems. [ABSTRACT FROM AUTHOR]

Highlights • By considering the PVT's absorber heat-inertia on energy balance equation the model accuracy is improved. • A PVT one-dimension transient model which can be easily adapted for systems' feasibility studies. • The model proved capable of estimating the PVT collector efficiency for transient operation conditions. • The proposed dynamic model estimates the PVT operation with better accuracy than the steady state. Abstract A first order dynamic model was developed and validated via experimental data for a PVT retrofitted collector. The model utilizes the analytic solution of collector's energy balance equation, with the purpose to estimate the absorber mean temperature via an iterative process. All collector's crucial parameters like the overall heat loss coefficient and collector efficiency factor are estimated for every simulation time-step, while PVT's optical efficiency is calculated analytically via the principal laws of optics. The simulation results fount to be in good agreement with experimental data. In more details, the RMS deviation for collector's outlet temperature was estimated to 0.66% for stable weather conditions and to 4.22% for extremely transient conditions with sporadic showers. Also, the discrepancy for power generation fount to be 5.05% and 14.91% for stable and transient weather conditions respectively. Moreover, for unstable weather without rain but with abrupt changes on flow-rate, the model found at sufficient accuracy with RMS deviation of 2.06% for water outlet temperature and 4.15% for power generation. Finally, by considering the absorber's heat inertia on the collector energy balance equation, a positive contribution on model's accuracy can be obtained, contrary to the steady-state version. [ABSTRACT FROM AUTHOR]

A retrofitted PVT collector assembled and installed together with a conventional PV panel, on northern hemisphere, facing south-west and tilted to 40°. In order to evaluate the system’s performance during the autumn to winter period, outdoor experiments were conducted and a PC-based automatic data acquisition unit has been used. The results show that the PVT collector managed to slightly increase its average electrical energy yield by 0.32% during the experimentation period and obtained additional thermal energy with daily average efficiency of 20.33%. Moreover, PVT’s moderate thermal insulation revealed a detrimental factor regarding its thermal energy generation. Furthermore, a steady state model was created based on Hotel-Wilier equation modified for PVT collectors by Florschuetz. Two typical days were chosen and simulated for the model’s evaluation. The simulation outcomes revealed good agreement between the model and the measurements, with average figures of 3.12% for useful heat and for electricity between −4.46% and 10.72%. Finally, the PVT’s model, managed to predict the system’s operation on an average day’s values with −8.25% and 7.49% for useful thermal energy and electrical energy respectively, while the corresponding monthly figures of standard deviation were 2.23% for useful heat energy and 5.71% for electricity. [ABSTRACT FROM AUTHOR]

This paper presents a theoretical evaluation of the prices of mixed briquettes produced from coconut shells (CCS), banana peels (BNP), rattan waste (RWT), and sugarcane bagasse (SGC) and, on the other hand, an analysis of the economic viability of their use as a replacement for conventional household fuels (liquefied petroleum gas, fuelwood, and wood charcoal) in households in Cameroon. The investigation was carried out using the life cycle cost method on a typical household over a ten-year period with annual cooking energy requirements of 950 kWhth. The SGC–CCS and SGC–RWT mixed briquettes with ratios higher than 7.75% and 11.1%, respectively, have prices lower than EUR 0.063/kWhth. The Present Value of the Net Benefit is positive for the use of SGC–CCS and SGC–RWT mixed briquettes. The results show that by making the right mixes of residues, it is possible to obtain biomass briquettes that are less expensive than conventional fuels. [ABSTRACT FROM AUTHOR]

Silicon based photovoltaic modules (PV) are a wide spread technology and are used for small and large PV power stations. At the moment, the most efficient method which can be used to improve the annual electrical energy production of PVs is solar tracking systems. However, solar tracking systems increase substantially the initial cost of the investment and insert maintenance costs. During the last few decades, alternative improving methods have been investigated. These methods are based on the reduction of the PV cell temperature, which adversely affects the power production. In the present study, a system with water based photovoltaic-thermal (PVT) collector paired with geothermal heat exchanger (GHE) is compared on the electrical energy basis with a conventional PV system. As the first approach on the topic, the aim is to find out in which extent the PVT-GHE system improves the electrical energy generation by cooling down the PV cells and which parameters influence the most its energy performance. With this aim in mind, the model of the system with the PV, PVT, and GHE was formulated in TRNSYS and validated via experimental data. Meteorological data for Athens (Greece) were used and parametric analyses were conducted. The results showed that the PVT based system can increase the generated electricity from 0.61 to 5.5%. The flowrate, the size of the GHE and the number in-series connected PVTs are the parameters which influence the most the energy performance of the system. [ABSTRACT FROM AUTHOR]

• The energy performance of the system is not directly influenced by the storage soil volume. • The system's performance was found to improve by enlarging the boreholes' spacing. • The economy of the investigated system found to be lower than this of the gas boiler. • The proposed system can decarbonize in total the annual space heating load. The performance of a solar assisted ground source heat pump (SAGSHP) system was evaluated and compared with a conventional gas boiler system using simulation, for a central England location. The earth energy bank was the long-term heat store element of the system and consisted of a very shallow field (1.5 m deep) of borehole heat exchangers (BHE). The mathematical model of the system was formulated, and parametric analyses were carried out by varying the number of BHEs and their spacing. The energy performance was expressed using four energy metrics, while its economy and CO 2 e emissions were compared with a natural gas boiler (NGB) system via the life cycle cost method and the fractional CO 2 e savings, respectively. The system can be energy self-sufficient by installing 40 BHEs at 1.25 m spacing or with 32 BHEs at 1.5 m spacing. The NGB system appears more economic than the SAGSHP system, due to low natural gas prices, the high price of the imported electricity, the low price of the exported electricity and the higher capital cost of the SAGSHP system. However, the SAGSHP system was found to have net negative carbon emissions, in contrast to the high positive emissions of the NGB system. [ABSTRACT FROM AUTHOR]

• Proposed system with more than 14 collectors can be energetically self-sufficient. • With 13 PVTs, the solar system is more economic than the natural gas boiler system. • The capital cost of the solar assisted system significantly affects its economy. In this study, a PVT based solar assisted ground source heat pump (SAGSHP) system was investigated regarding its energy performance and cost-effectiveness for the city of Thessaloniki (Greece). The SAGSHP system was set to cover the space heating and domestic hot water needs for a low-rise dwelling. A mathematic model formulated in TRNSYS was used with the aim to carry out parametric analysis by varying the number of the PVTs. It is worth noting that, two of the most important components of the employed model, the PVT collector and the geothermal heat exchanger, have already been validated via experimental data. Simulations were conducted and through the results seven energy metrics were estimated, with the objective to examine the system's energy performance from various perspectives. The SAGSHP system with 16 PVTs was found capable to covering 73% of the heating load and to generate 1.22 times more electricity than that consumed by the system. The electricity yield of PVTs was not affected throughout the parametric analysis, and the maximum specific productivity was estimated at 301.5 kWh e PVT−1 per year. The results suggest that a SAGSHP system equipped with about 14 PVTs can reach energy self-sufficiency. As regards the economics of the SAGSHP system, this was compared with a natural gas boiler system via two methods, the life cycle cost (LCC) and the life cycle savings (LCS). A sensitivity analysis with major economic parameters of the systems was carried out. It was found that the cost-effectiveness of the SAGSHP system is influenced mainly by its capital cost and by the price of the natural gas. Systems equipped with less than 12 PVTs can be cost-competitive by subsiding from 8% up to 42% of their capital cost. Also, system with more than 12 collectors were found of more benefit than the smaller ones, in the case where feed-in-tariff schemes are applied, or the bank loan's interest rate is low. It can be concluded that, the proposed system can be an attractive monetary solution for covering the heating load in comparable dwellings with a similar climate to Thessaloniki. [ABSTRACT FROM AUTHOR]

• Seasonal performance factor is inadequate to assess the energy performance of PVTs. • The proposed index can provide the overall PVT system's performance, heat and power. • The proposed index can be used for the energy optimization of PVT systems. Applications with photovoltaic thermal collectors (PVTs) are becoming popular due to their capability of cogenerating heat and power from the same surface. Solar assisted ground source heat pump (SAGSHP) systems are considered a potential solution for utilization of PVTs. Up to now, the seasonal performance factor (SPF) has been used by most of the existing literature to evaluate the energy performance of the PVT based SAGSHP systems. However, the PVTs coproduce heat and power, and the SPF omits the generated electricity and overlooks the influence of the system on the collectors' electrical efficiency. Driven by the limitation of the SPF to illustrate the overall system's energy performance, this study introduces a new improved energy performance metric. The study was carried out by varying the size of the PVT array and via the results six energy indexes were evaluated. The parametric analysis was conducted by a validated model formulated in TRNSYS. Based on the results, the renewable power fraction (RPF) was found as the most suitable index to assess the performance of PVT-SAGSHP system. A 7% reduction was estimated in the PVTs' electricity generation, by choosing the higher SPF instead the higher RPF. The proposed RPF index overcomes restrictions of doing calculations with both electricity and heat at the same equation. Thus, the RPF is considered capable of indicating the overall energy performance of the systems, without limitations. Finally, the proposed metric (RPF) can be used to study the energy performance of any solar system equipped with PVTs. [ABSTRACT FROM AUTHOR]

Hip pain is indubitably a frequent clinical problem deriving from copious etiologies. Hip impingement syndromes are one of the most prevalent causes of persistent groin pain, especially in young and active patients. Diligent imaging of the hip region is indispensable to discern femoroacetabular impingement, as the differential diagnosis of hip pain can be exceedingly arduous. Despite hip radiography being plain and broadly attainable, it offers narrow information concerning soft tissue pathologies around the hip joint (extra-articular hip impingement syndromes). Magnetic resonance imaging and arthrography remain the gold standard examination for detecting intra-articular pathologies; however, they are widely considered expensive, time-consuming and characterized by confined. Consequently, ultrasonography has emerged as an alternative valuable diagnostic tool for distinguishing the underlying abnormalities that trigger femoroacetabular impingement. Proper hip ultrasound examination provides dynamic assessment, while also beneficial for guided intervention around the hip joint. Ultrasound hip examination is exacting due to its complex regional anatomy and deep location. It is capable of providing detailed information about various hip quadrants. An adept operator can identify both intra-articular and extra-articular pathologies. In addition, with ultrasonography, hip injections have been rendered relatively undemanding, aiding in therapeutic and diagnostic purposes. This paper aims to provide a succinct and compendious review of the existing literature, accentuating the crucial role of ultrasonography in diagnosing hip impingement syndromes and determining whether an additional examination is required regarding distinguishing between intra-articular and extra-articular syndromes. [ABSTRACT FROM AUTHOR]

• Energy analysis and Economic viability of briquetting conversion of crop residues are investigated. • Coconut shells, rattan waste, banana peels and sugarcane bagasse are residues selected. • Energy balance, Life Cycle Analysis method and sensitivity analysis are applied. • Biomass briquettes production could offer benefit for plant industry. This paper aims to analyse the energy consumption and economic viability of biomass briquettes production from agricultural residues. The work focus on briquetting conversion of coconut shells, rattan waste, sugarcane bagasse and banana peels based on a small-scale production plant located in Cameroon. Balance energy shows that the useful energy, mainly consumed during the briquetting process, is mechanical and thermal energy. Rattan waste, coconut shells, sugarcane bagasse, and banana peels briquettes need 0.78 kWh/kg, 0.75 kWh/kg, 1.46 kWh/kg, and 2.60 kWh/kg of primary energy, respectively. Economic analysis was carried out of 20 years' span. The manufacturing cost is comprised mainly by the labour cost of the employees, which stands for about the 30% of total expenses, following the expenses for the gasoil (10–16% of total expenses). Net Present Values for rattan waste, coconut shells, sugarcane bagasse, and banana peel briquetting systems were discovered to be 66,526€; 67,189€; −34,317€; and −44,932€, respectively. The economic viability of the briquette production is sensitive to briquette market price, discount rate and capital cost. In conclusion, briquettes production from crop residues could be economically benefited by adopting suitable strategies in Cameroon and in any developing country. [ABSTRACT FROM AUTHOR]