Interval job scheduling with machine launch cost

We study an interval job scheduling problem in distributed systems. We are given a set of interval jobs, with each job specified by a size, an arrival time and a processing length. Once a job arrives, it must be placed on a machine immediately and run for a period of its processing length without interruption. The homogeneous machines to run jobs have the same capacity limits such that at any time, the total size of the jobs running on any machine cannot exceed its capacity. Launching each machine incurs a fixed cost. After launch, a machine is charged a constant cost per time unit until it is terminated. The problem targets to minimize the total cost incurred by the machines for processing the given set of interval jobs. We focus on the algorithmic aspects of the problem in this article. For the special case where all the jobs have a unit size equal to the machine capacity, we propose an optimal offline algorithm and an optimal 2-competitive online algorithm. For the general case where jobs can have arbitrary sizes, we establish a non-trivial lower bound on the optimal solution. Based on this lower bound, we propose a 5-approximation algorithm in the offline setting. In the non-clairvoyant online setting, we design a O(μ)-competitive Modified First-Fit algorithm which is near optimal (μ is the max/min job processing length ratio). In the clairvoyant online setting, we propose an asymptotically optimal O(logμ)-competitive algorithm based on our Modified First-Fit strategy.Ministry of Education (MOE)This work was supported by the Singapore Ministry of Education Academic Research Fund Tier 1 under Grant 2019-T1002-042, by the NationalNatural Science Foundation of China under Grant 61902063, and by the Provincial Natural Science Foundation of Jiangsu, China under Grant BK20190342

Evaluation of the Laboratory Degradation Performance of a Straw Drainage Board

Plastic drainage boards are installed into the foundation as vertical drainage channels in vacuum preloading projects. After construction, numerous plastic drainage boards are left in the foundation, causing not only white pollution but also potential groundwater contamination. Straw was utilized to produce degradable drainage boards in this study, and the feasibility of straw drainage boards was confirmed by laboratory degradation tests. The results revealed that Zhuhai’s soft marine soil is rich in degrading bacteria such as Bacteroidota and Firmicutes, which have adverse effects on the performance of the straw drainage board. The straw drainage board was deteriorated by bacteria in the foundation, and the discharge capacity and tensile strength dropped with time, with the discharge capacity degradation relationship as qw(t) = qw0(1 − 3.83 × 10−6t2). The discharge capacity and tensile strength of straw drainage boards are lower than those of plastic drainage boards, but they all meet the engineering requirements. Straw drainage boards can replace plastic drainage boards in vacuum preloading reinforcement projects, which not only solves the problem of environmental pollution but also expands the comprehensive utilization of straw resources in a new way

The In-Situ Mechanical Properties of Carbon Fiber/Epoxy Composite under the Electric-Current Loading

The Joule heating behavior of the carbon fiber/epoxy composite (CF/EP) was studied in this work, as well as their influence on the in-situ mechanical properties of the composites and their de-icing performance. The equilibrium temperature of the CF/EP composite could be conveniently adjusted by tuning the current according to the Joule’s law. Dynamic mechanical analysis (DMA) tests indicated that the rigidity and stiffness of the fiber-reinforced composite decreased with increasing temperature, and the glass transition temperature (Tg) of the composites was around 104 °C. It was found that the flexural properties of the composites in situ, measured under the electric-current loading, depended on the current value in the range of room temperature to Tg. With increasing the loading current, either the flexural modulus or strength of CF/EP decreased gradually. Such results could be explained that the higher current loading, the larger Joule heat, led to the higher operating temperature of the composite samples and the evolution of their mechanical properties accordingly. Vickers hardness tests indicated that the micro-hardness of the composite decreased with the increase of the operating temperature, which coincided with the evolution of its flexural properties with the electric-current loading. The dependence of the failure behaviors of the CF/EP on the loading current was revealed by the analysis of their fractured surface, where micro-buckling, kinking, fiber pull-out and breakage were involved. A preliminary study indicated that less energy was consumed for the deicing of the same amount of the ice with the CF/EP composite in the case of less electric-current loading. The research on the Joule heating effect of CF/EP and their corresponding mechanical properties benefits the design and direct application of the composites under the electric-current loading

The Electric–Thermal Effect of a Carbon-Fibre-Reinforced Epoxy Composite and Its Corresponding Mechanical Properties

In this work, the electric–thermal effect of a carbon-fibre-reinforced epoxy composite (CFRE) panel was studied, as well as the influence of the electric heating treatment on the mechanical properties of the composite. It was observed that the temperature of the composite increased rapidly once the current was loaded, and the equilibrium surface temperature was reached within 2 min. The electric–thermal effect and mechanical properties depended on both the current loading time and the current intensity. At 5A, the flexural modulus and strength of the CFRE increased before decreasing with the current loading time. Under the same treatment time, the flexural strength of the samples treated with 5A was evidently larger than that under the small current, and all the treated samples displayed enhanced flexural strength compared to that of untreated samples. The results depicted that the low-current treatment and short time could improve the interfacial properties between CF/epoxy, along with enhancing the flexural properties of the samples. However, a large amount of the joule heating from the larger current and a more extensive time frame is predicted to cause irreversible defects to the composite, which consequently leads to the reduction in flexural strength of the composite. TGA results indicated decreased thermal stability of the CFRE composite panels after the electric heating treatment was applied

Inhibition of MYC suppresses programmed cell death ligand-1 expression and enhances immunotherapy in triple-negative breast cancer

Abstract. Background:. Cancer immunotherapy has emerged as a promising strategy against triple-negative breast cancer (TNBC). One of the immunosuppressive pathways involves programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1), but many patients derived little benefit from PD-1/PD-L1 checkpoint blockades treatment. Prior research has shown that MYC, a master transcription amplifier highly expressed in TNBC cells, can regulate the tumor immune microenvironment and constrain the efficacy of immunotherapy. This study aims to investigate the regulatory relationship between MYC and PD-L1, and whether a cyclin-dependent kinase (CDK) inhibitor that inhibits MYC expression in combination with anti-PD-L1 antibodies can enhance the response to immunotherapy. Methods:. Public databases and TNBC tissue microarrays were used to study the correlation between MYC and PD-L1. The expression of MYC and PD-L1 in TNBCs was examined by quantitative real-time polymerase chain reaction and Western blotting. A patient-derived tumor xenograft (PDTX) model was used to evaluate the influence of a CDK7 inhibitor THZ1 on PD-L1 expression. Cell proliferation and migration were detected by 5-ethynyl-2′-deoxyuridine (EdU) cell proliferation and cell migration assays. Tumor xenograft models were established for in vivo verification. Results:. A high MYC expression level was associated with a poor prognosis and could alter the proportion of tumor-infiltrating immune cells (TIICs). The positive correlation between MYC and PD-L1 was confirmed by immunostaining samples from 165 TNBC patients. Suppression of MYC in TNBC caused a reduction in the levels of both PD-L1 messenger RNA and protein. In addition, antitumor immune response was enhanced in the TNBC cancer xenograft mouse model with suppression of MYC by CDK7 inhibitor THZ1. Conclusions:. The combined therapy of CDK7 inhibitor THZ1 and anti-PD-L1 antibody appeared to have a synergistic effect, which might offer new insight for enhancing immunotherapy in TNBC

c‑Myc-Targeting PROTAC Based on a TNA-DNA Bivalent Binder for Combination Therapy of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is highly aggressive with a poor clinical prognosis and no targeted therapy. The c-Myc protein is a master transcription factor and a potential therapeutic target for TNBC. In this study, we develop a PROTAC (PROteolysis TArgeting Chimera) based on TNA (threose nucleic acid) and DNA that effectively targets and degrades c-Myc. The TNA aptamer is selected in vitro to bind the c-Myc/Max heterodimer and appended to the E-box DNA sequence to create a high-affinity, biologically stable bivalent binder. The TNA-E box-pomalidomide (TEP) conjugate specifically degrades endogenous c-Myc/Max, inhibits TNBC cell proliferation, and sensitizes TNBC cells to the cyclin-dependent kinase inhibitor palbociclib in vitro. In a mouse TNBC model, combination therapy with TEP and palbociclib potently suppresses tumor growth. This study offers a promising nucleic acid-based PROTAC modality for both chemical biology studies and therapeutic interventions of TNBC