Bile duct injury (BDI) is perhaps the most feared complication of laparoscopic cholecystectomy (LC). Proper management of iatrogenic BDI is mandatory to avoid immediate or later life-threatening ...sequelae. The results of surgery depend mainly on the type of injury, prompt detection of the injury, and timing of the surgery.
Twelve patients with BDI after LC were treated. Eight of them were referred to our institution for further treatment. The follow-up evaluation was focused on clinical outcome and biochemical analysis.
Five of the patients had minor BDI with leakage. In all of them, the BDI was recognized postoperatively. Two of these patients were managed by endoscopic retrograde cholongio pancreatographic sphincterotomy and stent placement. The other three patients underwent open laparotomy and bile duct ligation. Seven of the patients had major BDI. In two patients, biliary injuries were identified at the time of LC, and the procedure was converted to laparotomy. At the time of conversion, primary suture repair with T-tube drainage of the injured bile duct was performed. Strictures developed in these patients after 2 and 6 months, respectively, and they were treated with a Roux-en-Y hepaticojejunostomy. In five additional patients, BDI was recognized postoperatively. One of these patients died because of delayed detection of biliary peritonitis. At this writing, during a median follow-up period of 52 months, neither clinical nor biochemical evidence of biliary disease has been found in the remaining patients.
Laparoscopic BDI has a high morbidity and mortality rate. Late recognition of the BDI remains a problem.
Two different nanoclay minerals were combined with nanophase anatase TiO2 for the synthesis of clay-based nanocomposites for improved photocatalytic properties. A new Halloysite (Hal) + Sepiolite (S) ...- TiO2 ternary nanocomposite was prepared using halloysite from Utah, USA and a recently discovered sepiolite from Greece. Three nanocomposites were synthesized with Hal-TiO2, S-TiO2 and Hal+S to TiO2. As a result, TiO2 particles (anatase) were homogeneously deposited and dispersed on the clay surfaces. Phase composition, particle morphology and physical properties of these nanocomposites were characterized by XRD, ATR-FTIR, FE-SEM, DRS-UV–Vis and N2-sorption/desorption isotherms at 77 K. The photocatalytic activity of the clay mineral-TiO2 nanocomposites was examined in the decomposition of paracetamol and tetracycline antibiotics as well as dye Rhodamine-B. The nanocomposites exhibited higher photocatalytic activity under UV irradiation for the decomposition of the targeted pollutants than the benchmark in the field, i.e. TiO2- P25 photocatalyst.
Several parts of the Mediterranean basin are experiencing grid parity nowadays, which is a sign that Photovoltaic (PV) technology has become competitive to conventional energy sources and may ...continue to develop without support. The net-metering policy takes advantage of the grid parity situation and is considered a step away from fading Feed-in Tariff schemes. Nevertheless, several policy variations make the decision about a specific net-metering scheme a complicated task. Therefore, the aim of this paper that deals with residential PV systems is two-fold. The first aim is to present a methodology that identifies the appropriate general net-metering scheme given the particularities and local conditions. The second goal is to examine the parity situation and compose net-metering policy recommendations in 6 Mediterranean countries. The current net-metering policy in Cyprus, which sets a grid charge on PV prosumers, is used as a case study under 3 scenarios. The first simulates the current policy in Cyprus, the second simulates self-consumption and different partial-netting schemes, and the third a partial-netting scheme with variable netted network charges. The results reveal that partial-netting policies with shorter timeframes of rolling credits and higher grid charges offer advantages that can be utilized for effective net-metering policies.
•A methodology to configure net-metering policies involving 3 parity assessments.•LCOE calculated for MED region with varying discount rate and initial investment.•Modified LCOE including the grid charge is evaluated.•MED countries exhibit considerably different parity results.•Grid charge and shorter rolling credits timeframes reduce cross-subsidization without compromising prosumer’s profits.
This work presents a unique single center experience with intra-arterial delivery of tissue plasminogen activator (t-PA) doses as high as 100mg for thrombolysis. Hemorrhage volumes, hemorrhage rates, ...clinical outcomes and radiographic outcomes were assessed.
Prospectively collected angiographic, clinical and laboratory information on 67 consecutive patients with acute ischemic stroke involving either the m1 segment of the middle cerebral artery, the intracranial internal carotid artery or the basilar artery were retrospectively analyzed. Patients who received more than 50 mg t-PA were compared with those patients receiving 50 mg or less. Outcome measures included: symptomatic hemorrhage, significant hemorrhage volume (greater than 25 ml), hemorrhage rate, change in National Institutes of Health stroke scale score at 24 hours and at hospital discharge, modified Rankin score at 90 days, in-hospital deaths, death within 90 days, reperfusion rate, and infarct volume.
Multivariate logistic regression analysis demonstrated that t-PA dose over 50 mg was associated with higher rates of hemorrhage and larger hemorrhages. Poor pial collateral formation, poor reperfusion (less than 50% of the territory involved), and platelet count below 200 K/μL influenced hemorrhage. Limiting t-PA dose to 100mg rather than 50mg improved documented reperfusion rates from 37% to 61%.
Restricting intra-arterial t-PA administration to 100mg rather than 50mg, is associated with higher overall reperfusion rates and improves overall outcomes, however, the hemorrhage rate is also elevated. Poor pial collateral formation and platelet count less than 200 K/μL may be reasons to curtail the use of higher t-PA dose to reduce hemorrhage rate.
Three load matching indicators (self-consumption rate, self-sufficiency rate, loss of load probability) and the CO2 emissions were evaluated for 55 Cypriot households with 3 kWp rooftop photovoltaic ...(PV) generators. The calculations were performed using 30-minute generation and consumption data from a large scale smart meter project in Cyprus. To investigate the effects of recent advances in local legislation, an analysis for higher PV capacities (5 kWp and 10 kWp) was also performed. The PV generation profiles for 5 kWp and 10 kWp PVs were obtained by scaling the 3 kWp PV generation profiles. The results showed that the self-consumption of the analyzed households varied seasonally, as it was related to their heating and cooling demand. More interestingly, the ratio between the households’ annual electricity generation and demand, formally defined here as generation-to-demand ratio (GTDR), was found to be related to the value ranges of the studied load matching indicators. Hence, on average, households with 3 kWp PV generators annually self-consumed 48.17% and exported 2,415.10 kWh of their PV generation. On the other hand, households with larger PV generators were characterized by a higher GTDR, but lower load matching capabilities. For the cases of 5 kWp and 10 kWp PV generators, the average self-consumption fell to 34.05% and 19.31%, while the exported PV generation was equal to 5,122.47 kWh, and 12,534.90 kWh, respectively. Along with lower load matching capabilities, households that generated more than they consumed were also found to have a lower potential for CO2 emissions reduction per installed kWp within the boundaries of the building. In this context, the GTDR could be used by stakeholders to characterize buildings, infer possible value ranges of more complex indicators and make evidence based decisions on policy and legislation.
The photovoltaic market has recently experienced an enormous expansion, mainly due to the generous Feed-in-Tariffs (FiTs) adopted by many countries. However, in the recent years FiTs have been ...considerably reduced or even disappeared as their role in the PV deployment has ended. One of the alternatives is the Net-Metering (NEM) policy, which has attracted the interest of stakeholders as it provides a basis for the efficient collaboration between generation and the consumption profiles of the consumer. Currently, there is a lack of a universal policy harmonizing the respective legislations of the E.U. member countries. This paper proposes a novel generalized methodology for the techno-economic assessment of different NEM policies in terms of profitability for the prosumer. The methodology is tested in a formulated case study based on the current NEM policy in Greece. The method proposed uses as inputs the averaged load profiles constructed from real measurements collected from 31 consumers in the Thessaloniki area and evaluated PV production. The current NEM policy and four alternatives are examined, using as additional input the average system marginal prices of the year 2013. The results show that the proposed methodology is capable of evaluating a wide variety of NEM policies and can lead to suggestions for policy adaptation in order to establish a win-win contract between all interested stakeholders.
Novel heteroarchitectures made of graphitic carbon nitride (g-C3N4) and halloysite nanotubes (HNTs) were prepared by a facile and soft self-assembly strategy. The morphological, structural and ...electronic properties of the HNTs/g-C3N4 nanocomposites were determined by means of a plethora of techniques including N2 physisorption, XRD, FT-IR, TEM, UV-Vis absorption, XPS, zeta potential and photoluminescence (PL). Their photocatalytic activity was evaluated under both simulated solar light and pure visible light irradiation against the photodegradation of neutral, positively and negatively charged pollutants, namely phenol, methylene blue (MB) and methyl orange (MO), respectively. The prepared HNTs/g-C3N4 nanocomposites were proven to be durable and significantly more efficient than the pure g-C3N4 reference for the degradation of positively charged and neutral organics. The nanocomposites presented increased charge carrier formation and reduced recombination rates due to the tight contact between the two components. The enhanced photoactivity was attributed to the dual function of HNTs enhancing (a) the abundance and stability of the photogenerated e- and h+ pairs and (b) the adsorption of positively charged organics on the nanocomposite. Both functions originate from the charged surface of HNTs.
Summary
This work presents a generic optimization framework based on linear Mixed Integer Programming to assess energy storage options' influence on the operational scheduling and the economic ...performance of a given power system with high penetration of intermittent renewable energy sources. In particular, three power markets‐clearing algorithms with different order types and modeling of technical characteristics have been developed, including energy storage devices and cross‐border trading capabilities as additional flexibility sources. A representative case study of the future Greek power system in 2030 with an hourly time span has been utilized to assess the developed framework's applicability. Several case studies have been studied to quantify the impacts of the market‐clearing procedure and the electricity storage capacity. The results highlight the improvements in the power system due to the utilization of energy storage in terms of the system's operational cost, operational scheduling through the provision of ramping capabilities, environmental impact, and increased renewables' utilization. Energy storage has to be considered in an integrated way along with other flexibility providers (electric vehicles, interconnections, demand response, and flexible generation) to achieve synergies and fully exploit its contributions.
This work presents a MILP model to address the problem of the optimal yearly energy mix of a power system, incorporating energy storage options. The approach models a whole year with an hourly time step and determines the optimal energy scheduling and economic performance of a power system by capturing the value added by the flexibility provision from energy storage.
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