Multi-Link Operation with Enhanced Synchronous Channel Access in IEEE 802.11be Wireless LANs: Coexistence Issue and Solutions

Multi-link operation is a new feature of IEEE 802.11be Extremely High Throughput (EHT) that enables the utilization of multiple links using individual frequency channels to transmit and receive between EHT devices. This paper aims to illustrate enhanced multi-link channel access schemes, identify the associated coexistence challenge, and propose solutions. First, we describe the multi-link operation of IEEE 802.11be and how the asynchronous and synchronous channel access schemes facilitate multi-link utilization. Next, we describe the design variants of the synchronous channel access scheme and demonstrate the associated coexistence challenge. Subsequently, we propose four features to address this challenge by assigning penalties to multi-link devices (repicking a backoff count, doubling the contention window size, switching to another contention window set, and compensating the backoff count) as well as five coexistence solutions derived from combinations of these features. Comparative simulation results are provided and analyzed for dense single-spot and indoor random deployment scenarios, demonstrating that the throughput and latency gains of multi-link operation differ between schemes. At the same time, we investigate the coexistence performance of multi-link operation with and without the capability of simultaneous transmission and reception and demonstrate that the proposed solutions mitigate the coexistence problem. In particular, compensating the backoff count achieves the highest coexistence performance among the proposed solutions, with a marginal throughput decrease of multi-link devices. A metric for evaluating both the throughput and latency gains and the coexistence performance of a multi-link channel access scheme using a single value is also proposed.

Comparison of a self-automated blood pressure measurement according to the American Heart Association recommendation versus a routine practice, a randomized-controlled trial

Background Home blood pressure monitoring is currently a gold standard for guiding an adjustment of antihypertensive medications. According to the American Heart Association (AHA), the self-automated blood pressure (BP) measurement may represent accurate home BP. However, there is a limited data in real-world practice Objective To explore the accuracy of a self-automated BP measurement in representing the actual home BP monitoring, in comparison with a single spot-arm automated BP measurement, which is routinely used in the clinical setting. Methods We conducted a single center, randomized cross-over trial. At the Cardiology clinic, hypertensive patients aged between 18 and 80 years, who were able to perform self-automated BP measurement, were included in the study. The patients were categorized into two groups using different BP measurement methods: a self-automated BP measurement according to the AHA Recommendation 2017 and a single spot-arm automated BP measurement, and then crossed over to alternative methods. All participants were instructed to rest at least 5 minutes prior to undergo BP measurement in both methods. The data of BP measurements were subsequently compared with the standard home BP monitoring. Results Overall, 190 patients underwent randomization. Mean differences of systolic blood pressure (SBP) in the self-automated AHA measurement and the single spot-arm measurement, compared with the standard home BP monitoring, were 3.57 mmHg (95% confidence interval (CI); 1.39 to 5.74 mmHg) and 9.44 mmHg (95% CI; 7.03 to11.86 mmHg), respectively (P<0.001) (table1). Mean differences of diastolic blood pressure (DBP) in the self-automated AHA and the single spot-arm measurements, compared with the standard home BP were −1.51 mmHg (95% CI; −2.76 to −0.25) and 2.69 mmHg (95% CI; 1.07–4.31), respectively (P<0.001) (table 1). White coat hypertension was detected in 7 (3.72%) of patients by AHA measurement and 17 (9.04%) by the single-spot arm measurement (P=0.008). Conclusion The self-automated BP measurement according to the AHA Recommendation 2017 was more accurate than the single spot-arm automated BP measurement in representing the actual home BP monitoring and reduced the possibility of the white coat effect. FUNDunding Acknowledgement Type of funding sources: None. Table 1

Dataset for predicting single-spot proton ranges in proton therapy of prostate cancer

The number of radiotherapy patients treated with protons has increased from less than 60,000 in 2007 to more than 220,000 in 2019. However, the considerable uncertainty in the positioning of the Bragg peak deeper in the patient raised new challenges in the proton therapy of prostate cancer (PCPT). Here, we describe and share a dataset where 43 single-spot anterior beams with defined proton energies were delivered to a prostate phantom with an inserted endorectal balloon (ERB) filled either with water only or with a silicon-water mixture. The nuclear reactions between the protons and the silicon yield a distinct prompt gamma energy line of 1.78 MeV. Such energy peak could be identified by means of prompt gamma spectroscopy (PGS) for the protons hitting the ERB with a three-sigma threshold. The application of a background-suppression technique showed an increased rejection capability for protons hitting the prostate and the ERB with water only. We describe each dataset, document the full processing chain, and provide the scripts for the statistical analysis.

Strengths and limitations of in situ U-Pb titanite petrochronology in polymetamorphic rocks: An example from western Maine, USA.

Titanite is a potentially powerful U-Pb petrochronometer that may record metamorphism, metasomatism, and deformation. Titanite may also incorporate significant inherited Pb, the correction for which may introduce inaccuracies and result in geologically ambiguous U-Pb dates. Here we present laser ablation inductively coupled mass spectrometry (LA-ICP-MS)-derived titanite U-Pb dates and trace element concentrations for two banded calc-silicate gneisses from south-central Maine, USA (SSP18-1A & -1B). Single spot common Pb-corrected dates range from 400 to 280 Ma with 12–20 Ma propagated 2SE. Titanite in sample SSP18-1B exhibit regular core-to-rim variations in texture, composition, and date. We identify four titanite populations: 1) 399 ± 5 Ma (95 % CL) low Y + HREE cores and mottled grains, 2) 372 ± 7 Ma high Y + REE mantles and cores, 3) 342 ± 6 Ma cores with high Y + REE and no Eu anomaly, and 4) 295 ± 6 Ma LREE-depleted rims. We interpret the increase in titanite Y + HREE between ca. 400 and ca. 372 Ma to constrain the timing of diopside fracturing and recrystallization and amphibole breakdown. Apparent Zr-in-titanite temperatures (803 ± 36 °C at 0.5 ± 0.2 GPa) and increased XDi suggest a thermal maximum at ca. 372 Ma. Population 3 domains dated to ca. 342 Ma exhibit no Eu anomaly and are observed only in compositional bands dominated by diopside (> 80 vol %), suggesting limited equilibrium between titanite and plagioclase. Finally, low LREE and high U/Th in Population 4 titanite date the formation of hydrous phases, such as allanite, during high XH2O fluid infiltration at ca. 295 Ma. In contrast to the well-defined date-composition-texture relationships observed for titanite from SSP18-1B, titanite grains from sample SSP18-1A exhibit complex zoning patterns and little correlation between texture, composition, and date. We hypothesize that the incorporation of variable amounts of radiogenic Pb from dissolved titanite into recrystallized domains resulted in mixed ages spanning 380–330 Ma. Although titanite may reliably record multiple phases of metamorphism, these data highlight the importance of considering U-Pb data along with chemical and textural data to screen for inherited radiogenic Pb.

Isolation and NMR Characterization of Ursane-Type Triterpenoid from the Leaves of Peperomia pellucida

Peperomia pellucida is a member of the Piperaceae family. Extraction of plant material was carried out by Soxhlet extraction method using hexane and ethylacetate as solvents respectively. The extract was concentrated using a rotary evaporator, followed by isolation and purification using column and thin layer chromatographic techniques. Fraction C20 showed a clearly defined single spot with Rf value of 0.51. Using 1HNMR, 13C-DEPT, COSY, HSQC and HMBC and by comparison with literature values, the structure of the compound was established as an Ursane-type triterpenoid. The use of P. pellucida in ethnomedicine for the treatment of various ailments could be attributed to the Ursane-type triterpenoid and other bioactive chemical compounds present in the plant. Keywords: Peperomia pellucida, extraction, isolation, chromatographic techniques, ursane-type triterpenoid