22,651 research outputs found
A blockchain-based authentication protocol for cooperative vehicular ad hoc network
The efficiency of cooperative communication protocols to increase the reliability and range of transmission for Vehicular Ad hoc Network (VANET) is proven, but identity verification and communication security are required to be ensured. Though it is difficult to maintain strong network connections between vehicles because of there high mobility, with the help of cooperative communication, it is possible to increase the communication efficiency, minimise delay, packet loss, and Packet Dropping Rate (PDR). However, cooperating with unknown or unauthorized vehicles could result in information theft, privacy leakage, vulnerable to different security attacks, etc. In this paper, a blockchain based secure and privacy preserving authentication protocol is proposed for the Internet of Vehicles (IoV). Blockchain is utilized to store and manage the authentication information in a distributed and decentralized environment and developed on the Ethereum platform that uses a digital signature algorithm to ensure confidentiality, non-repudiation, integrity, and preserving the privacy of the IoVs. For optimized communication, transmitted services are categorized into emergency and optional services. Similarly, to optimize the performance of the authentication process, IoVs are categorized as emergency and general IoVs. The proposed cooperative protocol is validated by numerical analyses which show that the protocol successfully increases the system throughput and decreases PDR and delay. On the other hand, the authentication protocol requires minimum storage as well as generates low computational overhead that is suitable for the IoVs with limited computer resources
Family reported outcomes, an unmet need in the management of a patient's disease: appraisal of the literature
Abstract: Background: A person’s chronic health condition or disability can have a huge impact on the quality of life (QoL) of the whole family, but this important impact is often ignored. This literature review aims to understand the impact of patients' disease on family members across all medical specialities, and appraise existing generic and disease-specific family quality of life (QoL) measures. Methods: The databases Medline, EMBASE, CINHAL, ASSIA, PsycINFO and Scopus were searched for original articles in English measuring the impact of health conditions on patients' family members/partner using a valid instrument. Results: Of 114 articles screened, 86 met the inclusion criteria. They explored the impact of a relative's disease on 14,661 family members, mostly 'parents' or 'mothers', using 50 different instruments across 18 specialities including neurology, oncology and dermatology, in 33 countries including the USA, China and Australia. These studies revealed a huge impact of patients' illness on family members. An appraisal of family QoL instruments identified 48 instruments, 42 disease/speciality specific and six generic measures. Five of the six generics are aimed at carers of children, people with disability or restricted to chronic disease. The only generic instrument that measures the impact of any condition on family members across all specialities is the Family Reported Outcome Measure (FROM-16). Although most instruments demonstrated good reliability and validity, only 11 reported responsiveness and only one reported the minimal clinically important difference. Conclusions: Family members' QoL is greatly impacted by a relative's condition. To support family members, there is a need for a generic tool that offers flexibility and brevity for use in clinical settings across all areas of medicine. FROM-16 could be the tool of choice, provided its robustness is demonstrated with further validation of its psychometric properties.Peer reviewe
Lingulodinium machaerophorum expansion over the last centuries in the Caspian Sea reflects global warming
This article is made available through the Brunel Open Access Publishing Fund. Copyright @ Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.We analysed dinoflagellate cyst assemblages in four short sediment cores, two of them dated by radionuclides, taken in the south basin of the Caspian Sea. The interpretation of the four sequences is supported by a collection of 27 lagoonal or marine surface sediment samples. A sharp increase in the biomass of the dinocyst occurs after 1967, especially owing to Lingulodinium machaerophorum. Considering nine other cores covering parts or the whole of Holocene, this species started to develop in the Caspian Sea only during the last three millennia. By analysing instrumental data and collating existing reconstructions of sea level changes over the last few millennia, we show that the main forcing of the increase of L. machaerophorum percentages and of the recent dinocyst abundance is global climate change, especially sea surface temperature increase. Sea level fluctuations likely have a minor impact. We argue that the Caspian Sea has entered the Anthropocene
Frequency reconfiguration mechanism of a PIN diode on a reconfigurable antenna for LTE and WLAN Applications
Microstrip patch antennas are increasingly gaining popularity for usage in portable wireless system applications due to their light weight, low profile structure, low cost of production and robust nature. The patch is generally made of a conducting material such as copper or gold and can take any possible shapes, but rectangular shapes are generally used to simplify analysis and performance prediction. Microstrip patch antenna radiates due to the fringing fields between the patch edge and ground plane. In this work, a frequency reconfigurable antenna with a BAR63-02V Positive-Intrinsic-Negative (PIN) diode is designed, simulated and fabricated. The antenna operates at 2.686GHz for Long-Term Evolution (LTE2500) and 5.164GHz for Wireless Local Area Network (WLAN) applications. In the OFF state, the antenna operates at 5.302GHz, which is also suitable for WLAN application. The proposed antenna is fabricated on a FR-4 substrate with a relative dielectric constant, εr of 4.5, thickness, h of 1.6mm and loss tangent, tan δ of 0.019. The fabrication process is carried out at the Advanced Printed Circuit Board (PCB) Design Laboratory in UTHM
An improved search ability of particle swarm optimization algorithm for tracking maximum power point under shading conditions
Introduction. Extracting maximum possible power from solar energy is a hot topic of the day as other sources have become costly and lead to pollution. Problem. Dependency on sunlight for power generation makes it unfeasible to extract maximum power. Environmental conditions like shading, partial shading and weak shading are the major aspect due to which the output of photovoltaic systems is greatly affected. Partial shading is the most known issue. Goal. There have been many proposed techniques and algorithms to extract maximum output from solar resources by use of photovoltaic arrays but every technique has had some shortcomings that couldn’t serve the complete purpose. Methodology. Nature inspired algorithms have proven to be good to search global maximum in a partially shaded multipeak curve which includes particle swarm optimization, artificial bee colony algorithm, and flower pollination algorithm. Methods. Particle swarm optimization algorithm is best among these in finding global peaks with less oscillation around maximum power point, less complexity, and easy to implement nature. Particle swarm optimization algorithm has the disadvantage of having a long computational time and converging speed, particularly under strong shading conditions. Originality. In this paper, an improved opposition based particle swarm optimization algorithm is proposed to track the global maximum power point of a solar photovoltaic module. Simulation studies have been carried out in MATLAB/Simulink R2018a. Practical value. Simulation studies have proved that opposition based particle swarm optimization algorithm is more efficient, less complex, more robust, and more flexible and has better convergence speed than particle swarm optimization algorithm, perturb and observe algorithm, hill climbing algorithm, and incremental conductance algorithm.Вступ. Отримання максимально можливої потужності із сонячної енергії є надзвичайно актуальним наразі, оскільки інші джерела енергії стали коштовними та призводять до забруднення. Проблема. Залежність від сонячного світла для вироблення електроенергії унеможливлює отримання максимальної потужності. Умови навколишнього середовища, такі як затінення, часткове затінення і слабке затінення, є основним аспектом, від якого сильно залежить потужність фотоелектричних систем. Часткове затінення – найвідоміша проблема. Мета. Було запропоновано багато методів та алгоритмів для отримання максимальної віддачі від сонячних ресурсів за допомогою фотоелектричних батарей, але кожен метод мав деякі недоліки, які не могли служити досягненню повної мети. Методологія. Алгоритми, натхненні природою, виявилися хорошими для пошуку глобального максимуму на частково затіненій кривій з багатьма піками, включаючи оптимізацію рою частинок, алгоритм штучної бджолиної колонії та алгоритм запилення квітів. Методи. Алгоритм оптимізації рою частинок найкраще підходить для пошуку глобальних піків з меншими коливаннями навколо точки максимальної потужності, меншою складністю та простотою реалізації. Алгоритм оптимізації рою частинок має недолік, що полягає у тривалому часі обчислень та швидкості збіжності, особливо в умовах сильного затінення. Оригінальність. У цій статті пропонується покращений алгоритм оптимізації рою частинок на основі протилежності для відстеження глобальної точки максимальної потужності сонячного фотоелектричного модуля. Розрахункові моделювання проводились у MATLAB/Simulink R2018a. Практична цінність. Дослідження за допомогою моделювання довели, що алгоритм оптимізації рою частинок на основі протилежності є більш ефективним, менш складним, надійнішим і гнучкішим і має кращу швидкість збіжності, ніж алгоритм оптимізації рою частинок, алгоритм збурення та спостереження, алгоритм сходження на пагорб та алгоритм інкрементальної провідності
Multifunctional Silver-based Nanomaterials for Non-conventional Oral Cancer Therapy through Simultaneous LOX and Selective COX-2 inhibition
Neoplastic cells have co-opted inflammatory receptors and signaling molecules that potentiate inflammation. Activated inflammatory pathways lead to neo-angiogenesis, lymph-angiogenesis, immunosuppression, tumor growth, proliferation and metastasis. This cancer-sustaining inflammation is a critical target to arrest cancer growth. Multiple drug resistance, high cost, low oral bioavailability and serious side effects have rendered conventional cytotoxic chemotherapeutics less impressive. The aim of this research was to achieve cancer debulking and proliferation prevention by limiting ‘cancer-sustaining’ tumor niche inflammation through non-conventional oral approach employing anti-inflammatory agents and avoiding conventional cytotoxic agents. Synergistic anti-inflammatory agents, i.e. celecoxib as selective COX-2 inhibitor and montelukast as cysteinyl leukotriene receptor antagonist, were selected. Silver nanoparticles (AgNPs) were used as nanocarriers because of their efficient synergistic anti-neoplastic effects and excellent oral drug delivery potential. Specifically, selected drugs were co-conjugated onto AgNPs. Synthesized nanoparticles were then surface-modified with poly (vinyl alcohol) to control particle size, avoid opsonization/preferred cellular uptake and improve dispersion. Surface plasmon resonance analysis, particle size analysis, DSC, TGA, XRD, FTIR and LIBS analysis confirmed the successful conjugation of drugs and efficient polymer coating with high loading efficiency. In-vitro, the nanoparticles manifested best and sustained release in moderately acidic (pH 4.5) milieu enabling passive tumor targeting potential. In-vivo, synthesized nanoparticles exhibited efficient dose-dependent anti-inflammatory activity reducing the dose up to 25-fold. The formulation also manifested hemo-compatibility, potent anti-denaturation activity and dose-dependent in-vitro and in-vivo anti-cancer potential against MCF-7 breast cancer and Hep-G2 liver cancer cell lines in both orthotopic and subcutaneous xenograft cancer models. The anti-inflammatory nanoparticles manifested tumor specific release potential exhibiting selective cytotoxicity at cancerous milieu with slightly acidic environment and activated inflammatory pathways. The formulation displayed impressive oral bioavailability, sustained release, negligible cytotoxicity against THLE-2 normal human hepatocytes, low toxicity (high LD50) and wide therapeutic window. Results suggest promise of developed nanomaterials as hemo-compatible, potent, cheaper, less-toxic oral anti-inflammatory and non-conventional anti-cancer agents
Detection of extended-spectrum β-lactamase and carbapenemase activity in Gram-negative bacilli using liquid chromatography - tandem mass spectrometry
PURPOSE: Several mass spectrometry-based methods for antimicrobial sensitivity testing have been described in recent years. They offer an alternative to commercially available testing systems which were considered to have disadvantages in terms of cost- and time-efficiency. The aim of this study was to develop a LC-MS/MS-based antibiotic hydrolysis assay for evaluating antimicrobial resistance of Gram-negative bacteria.
METHODS: Four species of Gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Providencia stuartii and Acinetobacter baumannii) were tested against six antibiotics from three different classes: ampicillin, meropenem, imipenem, ceftazidime, ceftriaxone and cefepime. Bacterial suspensions from each species were incubated with a mixture of the six antibiotics. Any remaining antibiotic following incubation were measured using LC-MS/MS. The results were interpreted using measurements obtained for an E. coli strain sensitive to all antibiotics and expressed as percentage of hydrolyzed antibiotic. These were subsequently compared to commercially-available system for the bacteria identification and susceptibility testing.
RESULTS: Overall, LC-MS/MS assay and commercial antimicrobial susceptibility platform results showed good agreement in terms of an organism being resistant/sensitive to an antibiotic. The time required to complete the LC-MS/MS-based hydrolysis test was under 5 h, significantly shorter that commercially available susceptibility testing platforms.
CONCLUSION: By using a sensitive strain for results interpretation and simultaneous use of multiple antibiotics, the proposed protocol offers improved robustness and multiplexing over previously described methods for antibiotic sensitivity testing. Nevertheless, further research is needed before routine assimilation of the method, especially for strains with intermediate resistance
Mathematical Model for Impact of Media on Cleanliness Drive in India
A mathematical model on cleanliness drive in India is analysed for active cleaners and passive cleaners. Cleanliness and endemic equilibrium points are found. Local and global stability of these equilibrium points are discussed using Routh-Hurwitz criteria and Lyapunov function respectively. Impact of media (as a control) is studied on passive cleaners to become active. Numerical simulation of the model is carried out which indicates that with the help of media transfer rate to active cleaners from passive cleaners is higher
Validation of Multicultural Counselling Competencies Scale among Malaysian Counsellor Trainees: A Confirmatory Factor Analysis
The competency of multicultural counselling is an aspect which needs to be mastered by a counsellor in order to provide good counselling services to clients especially when dealing with clients of different culture. The purpose of this research is to examine the validity and reliability of the Multicultural Counselling Competencies Scale which was developed based on the local culture by using confirmatory factor analysis (CFA). A total of 290 final year students participating in the first-degree counselling program from six public universities were selected randomly. The results of the analysis showed that the fit value for the comparative fit index (CFI), Tucker Lewis index (TLI), and normed fit index (NFI) respectively had fulfilled the fit value of 0.90 and above as suggested by the literature. The analysis also showed the average variance extracted (AVE) values for all three constructs were 0.669 (awareness), 0.764 (skills) and 0.642 (knowledge) respectively, indicating the validity convergent and discriminant reliability were achieved. CFA analysis has removed 7 out of 26 original items due to low loading factor. Overall, CFA analysis has successfully proven that competencies of multicultural counselling questionnaire as a multidimensional construct as it has been theorized and is appropriate for measuring the competencies of multicultural counselling in Malaysia
Comparative evaluation of the sealing ability of a bioceramic sealer (iRoot SP) with AH plus sealer with root canal dentin using three different techniques of sealer application: a combined dye extraction and scanning electron microscope study
The adaptation of a sealer along with the periphery of the dentinal tubules of the root canal is studied. Various techniques have been used for the application of these sealers onto the canal wall for better adaptation but have not been compared to date. The purpose of the study was to comparatively evaluate the sealing ability of a bioceramic sealer with AH plus sealer with root canal dentin using three different techniques for the application of sealer. One hundred twenty extracted maxillary and mandibular anterior teeth were collected, disinfected, and decoronated at the cemento-enamel junction to maintain a standard working length for all samples. The establishment of the working length (40.10) and instrumentation was performed using a rotary instrument, along with a standard irrigation regimen. The teeth were then divided into two main groups according to the sealer used, i.e., Group A (AH Plus) and Group B (iRoot SP). These two main groups were categorized into three sub-groups depending on the technique of sealer placement, i.e., Subgroup 1 (master cone gutta-percha), Subgroup 2 (bidirectional spiral), and Subgroup 3 (passive ultrasonic activation). Out of the 20 samples, 15 samples were randomly allocated for the assessment of sealing ability using the routine dye extraction method, and to verify the results of the dye extraction method, a more advanced evaluation method, i.e., SEM evaluation, was utilized further. To this end, five random samples from each subgroup were allocated for SEM analysis. The obtained scores were then statistically analyzed using an ANOVA test and Post Hoc Tukey’s test. In the current study, statistical significance was seen among the three main groups and six subgroups with p-values < 0.005. Subgroup B3 performed significantly better than the other subgroups in both the dye extraction method as well as in SEM analysis. The highest microleakage was shown by subgroup A1; it also exhibited poor penetration of sealer in SEM evaluation. The bioceramic sealer (iRoot SP), when applied using passive ultrasonic activation, showed the best results in both the dye extraction method and the SEM evaluation
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