Route to synchronization in coupled phase oscillators with frequency-dependent coupling: Explosive or continuous?

Interconnected dynamical systems often transition between states of incoherence and synchronization due to changes in system parameters. These transitions could be continuous (gradual) or explosive (sudden) and may result in failures, which makes determining their nature important. In this study, we abstract dynamical networks as an ensemble of globally coupled Kuramoto-like phase oscillators with frequency-dependent coupling and investigate the mechanisms for transition between incoherent and synchronized dynamics. The characteristics that dictate a continuous or explosive route to synchronization are the distribution of the natural frequencies of the oscillators, quantified by a probability density function g(ω), and the relation between the coupling strength and natural frequency of an oscillator, defined by a frequency-coupling strength correlation function f(ω). Our main results are conditions on f(ω) and g(ω) that result in continuous or explosive routes to synchronization and explain the underlying physics. The analytical developments are validated through numerical examples.

Knowledge and Awareness about Systemic Effects of Periodontal Disease among Medical, Dental and Alternate Medical Practitioners and Their Referral Practice to Periodontists

In the past few decades, many medical professionals and dentists have paid close notice to their own fields, specializing in medicine pertaining to body and oral cavity respectively. Currently, this void is rapidly closing between all medical specialties, in presence of significant findings that supports association between periodontal disease and systemic conditions. Till now, some practitioners are not aware about the specialties of dentistry that results in improper referral practices. There are few studies on referral practice pertaining to periodontist, not with standing the fact that clear and effective communication between all health practitioners is essential for good practice. A cross-sectional study was carried out to assess the knowledge and awareness about systemic effects of periodontal disease among medical, dental and alternate medical practitioners and their referral practice to periodontist in Kanpur city. This cross-sectional study was carried out using self-reported questionnaire, distributed to 560 practitioners of various medical fields from January 2020 to August 2021. A total of 206(36.8%) Medical, 194(34.6%) Dentists and 160(28.6%) alternative practitioners participated in study. More than half participants agreed about relationship between periodontal diseases and Diabetes Mellitus, Cardio-VascularDisease and Adverse Pregnancy Outcomes. Among all 31.3% showed good knowledge level while 2.7% showed perfect level of practitioner's referral practice to periodontist. Dentists had statistically higher level of awareness compared to physicians. Referral practice to periodontist was deficit by medical and alternate medical practitioners despite of fact; they have good knowledge of relationship between periodontal disease and systemic health. Hence, interdisciplinary dental and medical training of practitioners is recommended.

P11.38.A Case reports on aggressive Pilocytic astrocytoma in TYA and adults: patient tailored approach or standard of care?

Background

Pilocytic astrocytoma (piloA) is a low grade brain tumour and most of the literature is based on paediatric patients with limited data on adults. Surgical resection followed by adjuvant treatment for recurrent lesions is standard of care. While previous literature was mainly based on historical classification, molecular analysis of tumour is adding to the subgroup classification.

Material and Methods

We are reporting 3 cases of adult piloA treated at our institute.

Results: Case1

31y female with headaches and visual problems was diagnosed with optic nerve glioma, biopsy confirmed piloA, and was treated with conventional radiotherapy 50Gy/30fr. A month later developed CSF dissemination requiring 10xTemozolamide. Two years later, developed L5 and S2 deposits which were resected and confirmed piloA. 5 years later there was progression of primary disease treated with 12xTemozolamide and a year later developed further progression and hydrocephalus. She received 1xPCV and succumbed to disease at the age of 42. Case 2: 29y female with severe dizziness on moving head, worsening headaches, word finding difficulty, and positive family history of anaplastic astrocytoma, was diagnosed with Tectal plate lesion. Surgical debulking was performed and pathology showed piloA with Methylated MGMT promoter, IDH wild-type, H3K27M negative, and no BRAF fusion. 3 years later developed recurrence which was treated with chemotherapy (5xPCV: 6th omitted due to recurrent infections) as patient was reluctant for radiotherapy. Follow up scans 6 months post chemotherapy remain stable. Case 3: 24y female with background of 2 haemorrhagic strokes, left spastic hemi-paralysis and left hemianopia, and negative family history, had a biopsy performed for Right Mesotemopral Cavenous Angioma. Pathology showed low grade neoplasm favouring Ganglioglioma with CD34 and IDH1 negative, ATRX retained, KI-67 focal index 5%, and no BRAF fusion or mutation. Surveillance imaging showed progressively increasing suprasellar mass and right temporal region enhancement which was surgically debulked at the age of 27. Repeat pathology examination favoured piloA considering the radiological progression. Methylation array failed but immunohistochemistry showed tumour cells positive with synaptophysin, ATRX and trimethylated H3K27 retained, H3K27M, NeuN, H3G34R and CD34 negative, p53 negative, and Ki-67 3-4%. Repeat imaging 10 months later showed further progressive suprasellar tumour and enhancing lesion in the right temporal area accompanied by rapid loss of right side vision. We have planned for radical radiotherapy 54Gy/30fr with IMRT.

Conclusion

There is a gap in management of piloA in adults with treatment extrapolated from paediatrics and does require further research. We want to approach other centres to establish consensus on treating such cases.

Mirroring of synchronization in a bi-layer master-slave configuration of Kuramoto oscillators

The phenomenon of mirroring of synchronization is investigated in dynamically dissimilar, unidirectionally coupled, bi-layer master-slave configuration of globally coupled Kuramoto oscillators. The dynamics of the master layer depends solely on the distribution of the natural frequencies of its oscillators. On the other hand, the slave layer dynamics depends not only on the distribution of the natural frequencies of its oscillators but also on the unidirectional coupling with the master layer. The standard Kuramoto order parameter is used to study synchronization in the individual layers and of the bi-layer network. A transition to a completely mirroring state is observed in the dynamics of the slave layer, as the mirroring coefficient in the unidirectional coupling is increased. We derive analytically and verify numerically the conditions for the slave layer to fully mimic the synchronization properties of the master layer. It is further shown that while the master and slave layers are individually synchronized, the bi-layer network exhibits a state of frustrated synchronization.

An automated liquid jet for fluorescence dosimetry and microsecond radiolytic labeling of proteins

X-ray radiolytic labeling uses broadband X-rays for in situ hydroxyl radical labeling to map protein interactions and conformation. High flux density beams are essential to overcome radical scavengers. However, conventional sample delivery environments, such as capillary flow, limit the use of a fully unattenuated focused broadband beam. An alternative is to use a liquid jet, and we have previously demonstrated that use of this form of sample delivery can increase labeling by tenfold at an unfocused X-ray source. Here we report the first use of a liquid jet for automated inline quantitative fluorescence dosage characterization and sample exposure at a high flux density microfocused synchrotron beamline. Our approach enables exposure times in single-digit microseconds while retaining a high level of side-chain labeling. This development significantly boosts the method’s overall effectiveness and efficiency, generates high-quality data, and opens up the arena for high throughput and ultrafast time-resolved in situ hydroxyl radical labeling.

A high-speed liquid jet delivery system improves the X-ray footprinting and mass spectrometry method to label proteins for structural studies.

Aqueously altered igneous rocks sampled on the floor of Jezero crater, Mars

The Perseverance rover landed in Jezero crater, Mars, to investigate ancient lake and river deposits. We report observations of the crater floor, below the crater's sedimentary delta, finding the floor consists of igneous rocks altered by water. The lowest exposed unit, informally named Séítah, is a coarsely crystalline olivine-rich rock, which accumulated at the base of a magma body. Fe-Mg carbonates along grain boundaries indicate reactions with CO₂-rich water, under water-poor conditions. Overlying Séítah is a unit informally named Máaz, which we interpret as lava flows or the chemical complement to Séítah in a layered igneous body. Voids in these rocks contain sulfates and perchlorates, likely introduced by later near-surface brine evaporation. Core samples of these rocks were stored aboard Perseverance for potential return to Earth.

An olivine cumulate outcrop on the floor of Jezero crater, Mars

The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigate the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the Perseverance rover, we performed a petrographic analysis of the Bastide and Brac outcrops within this unit. We find that these outcrops are composed of igneous rock, moderately altered by aqueous fluid. The igneous rocks are mainly made of coarse-grained olivine, similar to some Martian meteorites. We interpret them as an olivine cumulate, formed by settling and enrichment of olivine through multi-stage cooling of a thick magma body.

Maintenance therapy with a poly(ADP-ribose) polymerase inhibitor in patients with newly diagnosed advanced epithelial ovarian cancer: individual patient data and trial-level meta-analysis

Background

We synthesize the efficacy and toxicity of poly(ADP-ribose) polymerase inhibitors (PARPis) in patients with newly diagnosed advanced ovarian cancer.

Patients and methods

We manually extracted individual patient data (IPD) for progression-free survival (PFS) from published survival curves of randomized controlled trials (RCTs) that compared PARPi versus placebo as maintenance therapy in first-line treatment, for whole study populations and subgroups, based on BRCA1/BRCA2 mutation (germline and/or somatic) and homologous recombination deficiency (HRD) status, using WebPlotDigitizer software. The respective PFS curves for each study and combined population were reconstructed from extracted IPD. The primary outcome was PFS in combined whole population and subgroups.

Results

In IPD analysis of combined population from three RCTs, with 2296 patients and 1287 events, PFS was significantly longer in PARPi versus placebo [median 20.4 (95% confidence interval (CI) 18.6-21.9) versus 14.9 (95% CI 13.9-16.5) months, respectively; hazard ratio (HR) 0.67, 95% CI 0.60-0.75; P < 0.001]. In IPD subgroup analyses from four eligible RCTs (2687 patients and 1485 events), median PFS was significantly longer in PARPi versus placebo arm, in the BRCA-mutated (45.7 versus 17.7 months, respectively; HR 0.38, 95% CI 0.32-0.46; P < 0.001), HRD-positive including BRCA-mutated (34.7 versus 17.9 months, respectively; HR 0.45, 95% CI 0.38-0.54; P < 0.001), and HRD positive excluding BRCA-mutated (22.3 versus 13.1 months, respectively; HR 0.47, 95% CI 0.34-0.65; P < 0.001) subgroups, but not in the HRD-negative (15.0 versus 11.3 months, respectively; HR 0.90, 95% CI 0.76-1.05; P = 0.75) subgroup. Results of trial-level meta-analysis were concordant with IPD analysis in whole population and subgroups.

Conclusions

Among newly diagnosed ovarian cancer patients, PARPi maintenance therapy significantly improves PFS in those with germline and/or somatic BRCA mutation and/or HRD-positive tumor but not in those with HRD-negative tumor.

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Maintenance PARPi resulted in significant PFS improvement in total population, but benefit varied in subgroups.

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PARPi showed PFS gain in BRCA-mutated (45.7 versus 17.7 m) and HRD-positive subgroups.

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No significant PFS benefit was seen in the HRD-negative subgroup (15.0 versus 11.3 months; P = 0.75).

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PARPi should be a standard treatment in newly diagnosed ovarian cancer patients except those with HRD-negative tumors.

742 Quality of Operative Notes for Renal Transplant Surgery - Is Our Documentation Satisfactory?

Introduction

Operation notes are essential in providing details of the procedure undertaken. The Royal College of Surgeons (RCS) Good Surgical Practice (GSP) guidelines recommend a checklist of 18 documentation items. Although these guidelines are useful, their broad and non-specific nature provides limitations to fields like transplantation, where additional information is needed. Ghoneima et al recommended transplant specific GSP checklist of 32 criteria for operation notes in transplantation. Our aim is to evaluate renal transplantation operation notes against these criteria.

Method

A retrospective audit of renal transplant operation notes was undertaken within Cardiff Transplant Unit between October 2020–2021. Notes were reviewed against new transplant specific GSP checklist.

Results

A total of 85 renal transplants were performed by 8 Consultant Surgeons. Sixty-two (73%) operation notes were hand-written and 23 (27%) electronically typed. Eleven standards had documentation compliance of &gt;95% (e.g., date, surgeons’ names, recipient blood vessels, incision, allograft vascular anatomy, perfusion timings, closure, signature, etc).

Some important transplant-specific information (e.g., primary renal disease, details of current renal replacement therapy, reperfusion characteristics, donor details (e.g., age, comorbidities), HLA mismatch, prosthesis (ureteric stent) details) were poorly documented (0–27% documentation compliance). Antibiotic and DVT prophylaxis documentation was also very poor (1–30%). Post-operative instructions did not record target blood pressure (0%) and postoperative potassium and ultrasound scan instructions were recorded in 65% of notes.

Discussion

Clear documentation is important for good surgical practice. This study highlights the need for a transplant-specific operation notes template, to not only improve the documentation but to standardize the key information recorded for every transplant performed.