End-to-End Latency Prediction for General-Topology Cut-Through Switching Networks

Low latency networking is gaining attention to support futuristic network applications like the Tactile Internet with stringent end-to-end latency requirements. In realizing the vision, cut-through (CT) switching is believed to be a promising solution to significantly reduce the latency of today's store-and-forward switching, by splitting a packet into smaller chunks called flits and forwarding them concurrently through input and output ports of a switch. Nevertheless, the end-to-end latency performance of CT switching has not been well studied in heterogeneous networks, which hinders its adoption to general-topology networks with heterogeneous links. To fill the gap, this paper proposes an end-to-end latency prediction model in a heterogeneous CT switching network, where the major challenge comes from the fact that a packet's end-to-end latency relies on how and when its flits are forwarded at each switch while each flit is forwarded individually. As a result, traditional packet-based queueing models are not instantly applicable, and thus we construct a method to estimate per-hop queueing delay via M/G/c queueing approximation, based on which we predict end-to-end latency of a packet. Our extensive simulation results show that the proposed model achieves 3.98-6.05% 90th-percentile error in end-to-end latency prediction

Flit Scheduling for Cut-through Switching: Towards Near-Zero End-to-end Latency

Achieving low end-to-end latency with high reliability is one of the key objectives for future mission-critical applications, like the Tactile Internet and real-time interactive Virtual/Augmented Reality (VR/AR). To serve the purpose, cut-through (CT) switching is a promising approach to significantly reduce the transmission delay of store-and-forward switching, via flit-ization of a packet and concurrent forwarding of the flits belonging to the same packet. CT switching, however, has been applied only to well-controlled scenarios like network-on-chip and data center networks, and hence flit scheduling in heterogeneous environments (e.g., the Internet and wide area network) has been given little attention. This paper tries to fill the gap to facilitate the adoption of CT switching in the general-purpose data networks. In particular, we first introduce a packet discarding technique that sheds the packet expected to violate its delay requirement and then propose two flit scheduling algorithms, fEDF (flit-based Earliest Deadline First) and fSPF (flit-based Shortest Processing-time First), aiming at enhancing both reliability and end-to-end latency. Considering packet delivery ratio (PDR) as a reliability metric, we performed extensive simulations to show that the proposed scheduling algorithms can enhance PDR by up to 30.11% (when the delay requirement is 7 ms) and the average end-to-end latency by up to 13.86% (when the delay requirement is 10 ms), against first-in first-out (FIFO) scheduling

Prognostic Value of p53 and bcl-2 Expression in Patients Treated with Breast Conservative Therapy

Prognostic value of p53 and bcl-2 expression on treatment outcome in breast cancer patients has been extensively evaluated, but the results were inconclusive. We evaluated the prognostic significance of these molecular markers in patients treated with breast conserving surgery and radiotherapy. One hundred patients whose immunostaining of p53 and bcl-2 expression was available among 125 patients who underwent radiotherapy after breast conserving surgery and axillary lymph node dissection were enrolled into this study. Eighty-seven patients also received adjuvant chemotherapy and/or hormonal therapy. Conventional clinicopathologic variables and treatment-related factors were also considered. The 5-yr loco-regional relapse-free and distant metastasis-free survival rates were 91.7% and 90.9%, respectively. On univariate analysis, age, T stage and the absence of bcl-2 & estrogen receptor (ER) expression were associated with loco-regional relapse-free survival. When incorporating these variables into Cox proportional hazard model, only bcl-2(-)/ER(-) phenotype was an adverse prognostic factor (P=0.018). As for the distant metastasis-free survival, age, T stage, and p53 expression were significant on univariate analysis. However, p53 expression was the only prognosticator on multivariate analysis (P=0.009). A bcl-2(-)/ER(-) phenotype and p53 expression are useful molecular markers predicting loco-regional relapse-free and distant metastasis-free survival, respectively, in patients treated with breast conserving surgery and radiotherapy

Frontal Sinus Lymphoma Presenting As Progressive Multiple Cranial Nerve Palsy

Primary frontal sinus lymphoma is a very uncommon disease. In all the previously reported cases, the presenting symptoms have been due to the tumor mass effect. We present an unusual case report of an immunocompetent patient who presented with facial palsy, and then progressively developed other cranial nerve palsies over several months. He was later diagnosed with diffuse large B cell lymphoma originating from the frontal sinus. The patient underwent chemotherapy, but eventually had to receive autologous peripheral blood stem cell transplantation. He is currently disease-free. The clinical course, diagnostic workup, and therapeutic outcome are described

Breast cancer radiation therapy: A bibliometric analysis of the scientific literature

Background and purpose: Breast cancer is the most common malignancy in women and radiation therapy (RT) is crucial in its multimodality management. Since bibliometrics is a powerful tool to reveal the scientific literature, we decided to perform a bibliometric analysis of the literature on breast cancer radiotherapy. We explored emerging trends and common patterns in research, tracking collaboration and networks, and foreseeing future directions in this clinical setting. Material and methods: The electronic Scopus database was searched using the keywords "breast cancer" and "radiotherapy" to include manuscripts published in English, between 2000 and 2021. Data analysis was performed using R-Studio 0.98.1091 software with a machine-learning bibliometric method, based on the bibliometrix R package. The most relevant authors were quantified per number and fractionalized number of authored documents. Author productivity was analysed through Lotka's law. Bradford's law was applied to identify the nucleus of journals focused on the addressed topic. Mainstream themes area included isolated topics (niche themes), new topics (emerging themes), hot topics (motor themes) and essential topics (basic themes). Results: A total of 27 184 documents was found, mainly original articles (76 %). The annual growth rate was 6.98 %, with an increase in scientific production from 485 to 2000 documents between 2000 and 2021. Overall, 2 544 journals published ≥ 1 documents. The most relevant authors were affiliated in the United States. Surgical procedures, cancer type and treatment strategies represented basic themes, while primary systemic therapy and sentinel lymph node biopsy were emerging themes. Health-related quality of life was a niche theme, while RT techniques had high centrality. Conclusion: The primary interests of breast cancer radiation oncologists have evolved over time, adding safety, health related quality of life, sustainability of treatments and combination to systemic therapies to radiotherapy efficacy and effectiveness and treatment outcomes

Munc18b is an essential gene in mice whose expression is limiting for secretion by airway epithelial and mast cells

Airway mucin secretion and MC (mast cell) degranulation must be tightly controlled for homoeostasis of the lungs and immune system respectively. We found the exocytic protein Munc18b to be highly expressed in mouse airway epithelial cells and MCs, and localized to the apical pole of airway secretory cells. To address its functions, we created a mouse with a severely hypomorphic Munc18b allele such that protein expression in heterozygotes was reduced by∼50%. Homozygous mutant mice were not viable, but heterozygotes showed a ∼50% reduction in stimulated release of mucin from epithelial cells and granule contents from MCs. The defect in MCs affected only regulated secretion and not constitutive or transporter-mediated secretion. The severity of passive cutaneous anaphylaxiswas also reduced by ∼50%, showing that reduction of Munc18b expression results in an attenuation of physiological responses dependent on MC degranulation. The Munc18b promoter is controlled by INR (initiator), Sp1 (specificity protein 1), Ets, CRE (cAMP-response element), GRE (glucocorticoid-response element), GATA and E-box elements in airway epithelial cells; however, protein levels did not change during mucous metaplasia induced by allergic inflammation. Taken together, the results of the present study identifyMunc18b as an essential gene that is a limiting component of the exocytic machinery of epithelial cells and MCs

The influence of the treatment response on the impact of resection margin status after preoperative chemoradiotherapy in locally advanced rectal cancer

This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Circumferential resection margin (CRM) and distal resection margin (DRM) have different impact on clinical outcomes after preoperative chemoradiotherapy (CRT) followed by surgery. Effect and adequate length of resection margin as well as impact of treatment response after preoperative CRT was evaluated. Methods: Total of 403 patients with rectal cancer underwent preoperative CRT followed by total mesorectal excision between January 2004 and December 2010. After applying the criterion of margin less than 0.5 cm for CRM or less than 1 cm for DRM, 151 cases with locally advanced rectal cancer were included as a study cohort. All patients underwent conventionally fractionated radiation with radiation dose over 50 Gy and concurrent chemotherapy with 5-fluorouracil or capecitabine. Postoperative chemotherapy was administered to 142 patients (94.0%). Median follow-up duration was 43.1 months. Results: The 5-year overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS) rates, and locoregional control rates (LRC) were 84.5%, 72.8%, 74.2%, and 86.3%, respectively. CRM of 1.5 mm and DRM of 7 mm were cutting points showing maximal difference in a maximally selected rank method. In univariate analysis, CRM of 1.5 mm was significantly related with worse clinical outcomes, whereas DRM of 7 mm was not. In multivariate analysis, CRM of 1.5 mm, and ypN were prognosticators for all studied endpoints. However, CRM was not a significant prognostic factor for good responders, defined as patients with near total regression or T down-staging, which was found in 16.5% and 40.5% among studied patients, respectively. In contrast, poor responders demonstrated a significant difference according to the CRM status for all studied end-points. Conclusions: Close CRM, defined as 1.5 mm, was a significant prognosticator, but the impact was only prominent for poor responders in subgroup analysis. Postoperative treatment strategy may be individualized based on this finding. However, findings from this study need to be validated with larger cohort

The influence of the treatment response on the impact of resection margin status after preoperative chemoradiotherapy in locally advanced rectal cancer

Background : Circumferential resection margin (CRM) and distal resection margin (DRM) have different impact on clinical outcomes after preoperative chemoradiotherapy (CRT) followed by surgery. Effect and adequate length of resection margin as well as impact of treatment response after preoperative CRT was evaluated. Methods : Total of 403 patients with rectal cancer underwent preoperative CRT followed by total mesorectal excision between January 2004 and December 2010. After applying the criterion of margin less than 0.5 cm for CRM or less than 1 cm for DRM, 151 cases with locally advanced rectal cancer were included as a study cohort. All patients underwent conventionally fractionated radiation with radiation dose over 50 Gy and concurrent chemotherapy with 5-fluorouracil or capecitabine. Postoperative chemotherapy was administered to 142 patients (94.0%). Median follow-up duration was 43.1 months. Results : The 5-year overall survival (OS), disease-free survival (DFS), distant metastasis-free survival (DMFS) rates, and locoregional control rates (LRC) were 84.5%, 72.8%, 74.2%, and 86.3%, respectively. CRM of 1.5 mm and DRM of 7 mm were cutting points showing maximal difference in a maximally selected rank method. In univariate analysis, CRM of 1.5 mm was significantly related with worse clinical outcomes, whereas DRM of 7 mm was not. In multivariate analysis, CRM of 1.5 mm, and ypN were prognosticators for all studied endpoints. However, CRM was not a significant prognostic factor for good responders, defined as patients with near total regression or T down-staging, which was found in 16.5% and 40.5% among studied patients, respectively. In contrast, poor responders demonstrated a significant difference according to the CRM status for all studied end-points. Conclusions : Close CRM, defined as 1.5 mm, was a significant prognosticator, but the impact was only prominent for poor responders in subgroup analysis. Postoperative treatment strategy may be individualized based on this finding. However, findings from this study need to be validated with larger cohort.Peer Reviewe

MU-MIMO User Grouping for WLANs supporting Indoor VR Applications

Virtual Reality (VR) applications require low latency transmission of high-definition video frames to support immersive user experience without incurring side-effects like motion sickness. In this paper, we claim that state-of-the-art MU-MIMO user selection schemes fail to achieve the aforementioned goal due to their focus on building the best MU-MIMO group with maximal throughput. To fill the gap, we propose two new scheduling schemes to effectively reduce the user-experienced latency in WLAN-based VR systems. Via extensive simulations, we compare the performance of our proposed schedulers with that of Guidepost, a well-known MU-MIMO scheduler, to show the need of considering inter-group dependency in user scheduling to best support VR service provisioning. The latency enhancement by the proposed algorithms is revealed as up to 23.2% in the average sum airtime and up to 36.9% in the maximum sum airtime