Effects of non-stationary forced oscillation on electromechanical modes

The forced oscillation (FO) containing variable frequencies, known as non-stationary FO, has yet been well understood in power system engineers. This paper analyzes the effects of the non-stationary FO on electromechanical modes (EMs) in the range of 0.2 to 2.0 Hz. The non-stationary forced disturbance (FD) with such variable frequency bands is mathematically modeled. The injection of the non-stationary FD results in the non-stationary FO. A modified subspace-based state-space identification (so-called 4SID) method is applied to estimate the non-stationary frequencies and damping ratios of the EMs along with a moving window. Effects of the non-stationary FO on the EMs are compared to those of the conventional FO. Simulation results are verified in the future 14-machine Southeast Australian power system with converter controlled-based generations under various FO conditions

Techno-economic Assessment of a Hydrogen-based Islanded Microgrid in North-east

Currently, renewable energy-based generators are considered worldwide to achieve net zero targets. However, the stochastic nature of renewable energy systems leads to regulation and control challenges for power system operators, especially in remote and regional grids with smaller footprints. A hybrid system (i.e., solar, wind, biomass, energy storage) could minimise this issue. Nevertheless, the hybrid system is not possible to develop in many islands due to the limited land area, geographical conditions, and others. Hydrogen as a carrier of clean energy can be used in locations where the installation of extensive or medium-scale renewable energy facilities is not permissible due to population density, geographical constraints, government policies, and regulatory issues. This paper presents a techno-economic assessment of designing a green hydrogen-based microgrid for a remote island in North-east Australia. This research work determines the optimal sizing of microgrid components using green hydrogen technology. Due to the abovementioned constraints, the green hydrogen production system and the microgrid proposed in this paper are located on two separate islands. The paper demonstrates three cost-effective scenarios for green hydrogen production, transportation, and electricity generation. This work has been done using Hybrid Optimisation Model for Multiple Energy Resources or HOMER Pro simulation platform. Simulation results show that the Levelized Cost of Energy using hydrogen technology can vary from AU$0.37/kWh to AU$1.08/kWh depending on the scenarios and the variation of key parameters. This offers the potential to provide lower-cost electricity to the remote community. Furthermore, the CO2 emission could be reduced by 17,607,77 kg/year if the renewable energy system meets 100% of the electricity demand. Additionally, the sensitivity analysis in this paper shows that the size of solar PV and wind used for green hydrogen production can further be reduced by 50%. The sensitivity analysis shows that the system could experience AU$0.03/kWh lower levelized cost if the undersea cable is used to transfer the generated electricity between islands instead of hydrogen transportation. However, it would require environmental approval and policy changes as the islands are located in the Great Barrier Reef

Patients' Perceptions of Dehumanization of Patients in Dental School Settings: Implications for Clinic Management and Curriculum Planning.

Although the importance of empathy, rapport, and anxiety/pain awareness in dentist-patient relations has been well documented, these factors continue to be an issue with patients in many dental school clinics. The aim of this study was to develop an in-depth understanding of how patients at an urban, university-affiliated medical center and its dental school's clinic experienced oral health care and to generate ideas for improving the dental school's clinical curriculum and management of the clinic. Although patient satisfaction surveys are common, in-depth patient narratives are an underutilized resource for improving dental education. In-depth qualitative interviews were conducted with 20 uninsured or underinsured dental patients at these sites, and the results were analyzed using content analysis. Major phenomena that participants discussed were the importance of empathy and good rapport with their oral health providers and provider awareness of dental pain and anxiety. Many patients also discussed feeling dehumanized during dental visits. Based on their positive and negative experiences, the participants made suggestions for how oral health professionals can successfully engage patients in treatment

NICE 2022 guidelines on the management of melanoma: Update and implications

Aims: In July 2022, NICE updated the guidelines on the management of melanoma by lowering the number of follow-up appointments and sentinel lymph node biopsy (SLNB) but increasing the number of scans. This study aims to evaluate the implications of executing the new guidelines in terms of cost-effectiveness and personnel. Methods: All patients newly diagnosed with melanoma in 2019 at a regional skin cancer specialist center were reviewed. Data were analyzed for their journey on an idealized pathway modeled over a 5-year follow-up period when adhering to both the previous and new guidelines. Differences in the management of melanoma were elucidated by comparing these changes. The cost was quantified on a perpatient basis and the financial implication on each department was considered. Results: One hundred and ten patients were diagnosed with melanoma in 2019, stages I-III. The changes ease the burden on plastic surgery and dermatology; however, increased pressure is faced by radiologists and histopathologists. An overall cost benefit of £141.85 perpatient was calculated, resulting in a decrease of 1.22 hospital visits on average and an increase in the time spent there (19.55 min). The additional expenses of implementing the new guidelines due to the added BRAF tests, CT, and ultrasound scans are outweighed by savings from the reduction in follow-up appointments and SLNB. Conclusion: The focus has shifted to less invasive procedures for lower melanoma stages and fewer follow-up appointments, at the expense of more genetic testing and imaging. This paper serves as a useful baseline for other centers to plan their service provision and resource allocation to adhere to the updated guidelines

Open pulled straw vitrification of in vitro matured sheep oocytes using different cryoprotectants

The aim of this study was to compare the survival and in vitro development of sheep oocytes after open pulled straw vitrification and different final concentrations of permeable cryoprotectants.In 5 identical replicates of two experiments, in vitro matured (IVM) oocytes were vitrified by the Open Pulled Straw (OPS) method, then warmed, and the surviving ones were subjected to parthenogenetic activation. In Experiment 1, survival rate of oocytes aftervitrification in 33% ethylene glycol was higher than in 33% DMSO or a mixture of 17.5% ethylene glycol and 17.5% DMSO (87.64 vs. 77.43 vs. 69.39%, respectively). The cleavage and blastocyst rates were higher after vitrification in mixture group than in ethylene glycol and DMSO (46.81 and 15.5 vs. 37.55 and 9.12 vs. 29.51 and 6.40%, for cleavage and blastocyst rates in different groups, respectively). In Experiment 2, elevated concentrations of vitrification solutions were used. The survival rate was higher after vitrification in 40% ethylene glycol and in the mixture of 20% ethylene glycol and 20% DMSO than in 40% DMSO(90.22 vs. 87.56 vs. 75.34%, respectively). Cleavage and blastocyst rates were also higher in the ethylene glycol and ethylene glycol – DMSO mixture group than in DMSO alone group (50.67 and17.60 vs. 49.13 and 14.45 vs. 33.86 and 9.81% for cleavage and blastocyst ratesin different groups, respectively). The survival rates between the two experimental groups was higher in 40% ethylene glycol group, 40% mixture group and 33% ethylene glycol group than in 40% DMSO group, 33% mixture group and 33% DMSO group. Cleavage and blastocystrates were higher in 40% ethylene glycol group, 40% mixture group and 33% mixture group than in 40% DMSO group, 33% ethylene glycol group and 33% DMSO group. All cleavage and blastocyst rates in both the experiments were lower than those of the non-vitrified controlgroup (87.00 and 45.00, respectively). In conclusion, although ethylene glycol group and ethylene glycol – DMSO mixture group gave better survival and cleavage – blastocyst rates than DMSO group, the survival rates were lower than the control group and hence the technique could be further improved to get better results after OPS vitrification of IVMsheep oocytes

Open pulled straw vitrification and slow freezing of sheep IVF embryos using different cryoprotectants

The aim of the present study was to evaluate the post-thaw survival and hatching rates of sheep blastocysts using different cryoprotectants. In Experiment 1, Day 6 sheep embryos were cryopreserved by a slow freezing protocol using 10% ethylene glycol (EG), 10% dimethyl sulfoxide (DMSO) or a mixture of 5% EG and 5% DMSO. Hatching rates were higher in the 10% EG group than in the 10% DMSO or EG + DMSO groups (30% vs 18% and 20%, respectively). In Experiment 2, embryos were cryopreserved by open pulled straw (OPS) vitrification using either 33% EG, 33% DMSO or a mixture of 16.5% EG + 16.5% DMSO. Re-expansion and hatching rates in the EG + DMSO group (79.16% and 52.74%, respectively) were higher than those in the EG group (64.28% and 30.02%, respectively), whereas the outcomes for the DMSO group were the lowest (45.18% and 8.6%, respectively). In Experiment 3, embryos were cryopreserved by OPS vitrification using either 40% EG, 40% DMSO or a mixture of 20% EG + 20% DMSO. Re-expansion and hatching rates were highest in the EG group than in the EG + DMSO and DMSO groups (92.16% vs 76.30% and 55.84% re-expansion, respectively; and 65.78% vs 45.55% and 14.46% hatching, respectively). In conclusion, OPS vitrification was found to be more efficient for cryopreservation of in vitro-developed sheep embryos than traditional freezing

Evaluating the Effects of SARS-CoV-2 Spike Mutation D614G on Transmissibility and Pathogenicity

Analysis of the spread and frequency of SARS-CoV-2 D614G in the United Kingdom suggests a selective advantage for this strain that is associated with higher viral loads in younger patients but not higher COVID-19 clinical severity or mortality

Tracking early lung cancer metastatic dissemination in TRACERx using ctDNA

Circulating tumour DNA (ctDNA) can be used to detect and profile residual tumour cells persisting after curative intent therapy1. The study of large patient cohorts incorporating longitudinal plasma sampling and extended follow-up is required to determine the role of ctDNA as a phylogenetic biomarker of relapse in early-stage non-small-cell lung cancer (NSCLC). Here we developed ctDNA methods tracking a median of 200 mutations identified in resected NSCLC tissue across 1,069 plasma samples collected from 197 patients enrolled in the TRACERx study2. A lack of preoperative ctDNA detection distinguished biologically indolent lung adenocarcinoma with good clinical outcome. Postoperative plasma analyses were interpreted within the context of standard-of-care radiological surveillance and administration of cytotoxic adjuvant therapy. Landmark analyses of plasma samples collected within 120 days after surgery revealed ctDNA detection in 25% of patients, including 49% of all patients who experienced clinical relapse; 3 to 6 monthly ctDNA surveillance identified impending disease relapse in an additional 20% of landmark-negative patients. We developed a bioinformatic tool (ECLIPSE) for non-invasive tracking of subclonal architecture at low ctDNA levels. ECLIPSE identified patients with polyclonal metastatic dissemination, which was associated with a poor clinical outcome. By measuring subclone cancer cell fractions in preoperative plasma, we found that subclones seeding future metastases were significantly more expanded compared with non-metastatic subclones. Our findings will support (neo)adjuvant trial advances and provide insights into the process of metastatic dissemination using low-ctDNA-level liquid biopsy.</p