Laboratory-Scale Evaluation of Single Analyte Bacterial Monitoring Strategies in Water Injection Systems

Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires the development of online and automated technologies for monitoring microbial activities in the system. A previous system review and technology screening has identified five single-analyte strategies [1], which were evaluated in this study with a laboratory-scale setup to determine their applicability for automated determination of microbial activity in the injection water system. Four of the five single-analyte measuring principles tested in the laboratory setup were deemed less suitable for automation and/or reliable for use in the detection of microbial activity in the company injection water system. These four principles were: luminescence assay for adenosine-5’-triphosphate (ATP), detection and electrochemical measurements of H2S, determination of pH by electrochemical sensor, and measurement of oxidation-reduction potential (ORP). The strategy of staining cells with fluorescent DNA dyes, followed by quantification of fluorescence signals, was identified to hold, with proper optimization of DNA staining and fluorescence detection, a very promising potential for integration in automated, online sensors for microbial activity in the injection water system.

Optimization of DNA Staining Technology for Development of Autonomous Microbe Sensor for Injection Seawater Systems

Microbial activity in the water injection system in oil and gas industry leads to an array of challenges, including biofouling, injectivity loss, reservoir plugging, and microbiologically influenced corrosion (MIC). An effective mitigation strategy requires online and real-time monitoring of microbial activity and growth in the system so that the operators can apply and adjust counter-measures quickly and properly. The previous study [1] identified DNA staining technology-with PicoGreen and SYBR Green dyes—as a very promising method for automated, online determination of microbial cell abundance in the vast Saudi Aramco injection seawater systems. This study evaluated DNA staining technology on detection limit, automation potential, and temperature stability for the construction of automated sensor prototype. DNA staining with SYBR Green dye was determined to be better suited for online and real-time monitoring of microbial activity in the Saudi Aramco seawater systems. SYBR Green staining does not require sample pre-treatment, and the fluorescence signal intensity is more stable at elevated temperatures up to 30℃. The lower detection limit of 2 × 103/ml was achieved under the optimized conditions, which is sufficient to detect microbial numbers in Saudi Aramco injection seawater. Finally, the requirements for design and construction of SYBR-based automated sensor prototype were determined.

Validation of Autonomous Microbe Sensor Prototype for Monitoring of Microorganisms in Injection Seawater Systems

Microbial growth in the water injection system is a well-known problem with severe operational and financial consequences for the petroleum industry, including microbiologically influenced corrosion (MIC), reduced injectivity, reservoir plugging, production downtime, and extensive repair costs. Monitoring of system microbiology is required in any mitigation strategy, enabling operators to apply and adjust countermeasures properly and in due time. In previous studies [1] [2], DNA staining technology with SYBR Green dye was evaluated to have a sufficient detection limit and automation potential for real-time detection of microbial activity in the Saudi Aramco injection seawater. In this study, technical requirements and design solutions were defined, and an autonomous microbe sensor (AMS) prototype was constructed, tested and optimized in the laboratory, and validated in the field for automated detection of microorganisms in the harsh Saudi Arabia desert environment and injection seawater. The AMS prototype was able to monitor and follow the general microbial status in the system, including detection of periods with increased microbial growth or decreased microbial numbers following biocide injection. The infield AMS detection limit was 105 cells/mL. The long-term field testing also identified the areas for technical improvement and optimization for further development of a more robust and better performing commercial microbial sensing device.

Applicability of Dimedone Assays for the Development of Online Aldehyde Sensor in Seawater Flooding Systems

Biocides are oilfield chemicals that are widely used to control bacterial activity throughout the oil industry. A feasibility study has been explored to develop detection techniques for biocide batch treatments, preferably on-line and in real-time, for their potential use in seawater flooding system. Several methods to measure key components of the biocide formulation were investigated and reported in previous study [1]. The enzymatic activity of an immobilized acetylcholine esterase (AChE) on the column material was successfully inhibited by some model compounds, but not by the actual biocides commonly used in Saudi Aramco seawater flooding system. In this paper, an alternative assay for biocide detection in the Saudi Aramco seawater flooding system was investigated for its applicability for the development of on-line biocide sensor. The assay was based on the detection of aldehyde functionality in the biocide mixture through measurement of a fluorescent derivative formed in the reaction of aldehyde groups and dimedone in the presence of ammonium acetate. The reaction of aldehyde groups with dimedone was demonstrated in seawater matrix, and the formed fluorescent product was successfully measured. The results showed that the dimedone-based assay was very sensitive, and relatively straightforward to perform. The ruggedness test also indicated that the assay is sensitive to minor changes of various specific conditions of the method. It is concluded that the dimedone assay is suitable for further development of a real-time biocide monitoring system to detect the presence of biocide slugs in seawater flooding system. The development of an automated on-line biocide sensor based on dimedone assay is underway.

Interfacial engineering of transition-metal sulfides heterostructures with built-in electric-field effects for enhanced oxygen evolution reaction

Developing highly efficient,durable,and non-noble electrocatalysts for the sluggish anodic oxygen evolution reaction(OER)is the pivotal for meeting the practical demand in water splitting.However,the current transition-metal electrocatalysts still suffer from low activity and durability on account of poor interfacial reaction kinetics.In this work,a facile solid-state synthesis strategy is developed to construct transition-metal sulfides heterostructures(denoted as MS_(2)/NiS_(2),M=Mo or W)for boosting OER electrocatalysis.As a result,MoS2/NiS2 and WS2/NiS2 show lower overpotentials of 300 mV and 320 mV to achieve the current density of 10 mA·cm^(-2),and smaller Tafel slopes of 60 mV.dec^(-1) and 83 mV.dec^(-1)in 1 mol·L^(-1) KOH,respectively,in comparison with the single MoS2,WS2,NiS2,as well as even the benchmark RuO2.The experiments reveal that the designed heterostructures have strong electronic interactions and spontaneously develop a built-in electric field at the heterointerface with uneven charge distribution based on the difference of band structures,which promote interfacial charge transfer,improve absorptivity of OH-,and modulate the energy level more comparable to the OER.Thus,the designed transition-metal sulfides heterostructures exhibit a remarkably high electrocatalytic activity for OER.This study provides a simple strategy to manipulate the heterostructure interface via an energy level engineering method for OER and can be extended to fabricate other heterostructures for various energy-related applications.

Novel magnetic carbon supported molybdenum disulfide catalyst and its application in residue upgrading

A novel hybrid material consisted of carbon covered Fe_(3)O_(4)nanoparticles and MoS_(2)nanoflower(FCM)was designed and prepared by micelle-assisted hydrothermal methods.Multiple techniques,including X-Ray diffraction(XRD),high-resolution transmission electron microscopy(HRTEM)and X-ray photoelectron spectroscopy(XPS)were employed to characterize it.The results show that FCM has a flower-like morphology with a 330 nm Fe_(3)O_(4)core as well as 70 nm highly crystalline MoS_(2)shell.FCM is superparamagnetic with a saturation magnetization of 35 emu g-1.Then hydrocracking of Canadian bitumen residue(CBR)was applied to estimate its catalytic activity.The results show that FCM exhibits superior catalytic hydrocracking activity compared to bulk MoS_(2)and commercial oil-dispersed Mo(CO)6 by the same Mo loading.Further measurement by elemental analysis,XPS and XRD reveals that the MoS_(2)nanoflower with abundant catalytic active sites and covered carbon layer with anti-coke ability donate to the superior upgrading performance.Besides,the catalysts can be easily recovered by the external magnetic field.This work provides a novel kind magnetic nanocatalyst which is potential for slurry-phase hydrocracking applications.■2020,Institute of Process Engineering,Chinese Academy of Sciences.Publishing services by Elsevier B.V.on behalf of KeAi Communications Co.,Ltd.This is an open access article under the CC BY-NC-ND license(http://creativecommons.org/licenses/by-nc-nd/4.0/).

To Explore the Correlation between Tumor and Immune Markers and HPV Expression and Prognosis in Patients with Cervical Cancer

The aim of this study was to investigate the correlation between immune cells and tumor markers and HPV levels in patients with cervical cancer with high-risk human papilloma virus(HPV)rate and their prognosis.Firstly,83 cases of cervical intraepithelial neoplasia were selected as CINI group,72 cases of cervical carcinoma as cervical cancer group and 50 cases of chronic cervicitis as chronic cervicitis group.The different expression levels of immune cells(CD4+,CD8+,Treg,CD4+/CD8+,CD56+,)and the positive expression of tumor markers(K-ras,Ki-67)inpatients with HPV were studied to explore the correlation between HPV levels and immune cells and tumor markers in cervical cancer patients with high-risk HPV infection,and that between positive expression of immune cells and tumor markers in patients with lymph node metastasis of cervical cancer with high-risk HPV infection,as well as that between the survival rate of patients and the immune cell levels and positive expression of tumor markers in patients who die of cervical cancer.The results showed that the levels of CD8+and Treg in cervical cancer patients were higher than those in CIN group and chronic cervicitis group(P<0.05).The levels of tumor markers were lower in those in CIN group and chronic cervicitis group(P<0.05).The positive expression rates of K-ras and KI-67 in the three groups were significantly different(P<0.05).In cervical cancer group,CD4+and CD56+were negatively correlated with HPV-DNA levels,and CD8+and Treg levels as well as k-RAS and KI-67 positive expression were positively correlated with HPV-DNA levels.The levels of immune markers in cervical cancer group were significantly lower than those in surviving patients(P<0.01),while the levels of CD8+and Treg,the proportion of K-RA and KI-67 were significantly higher than those in surviving patients(P<0.01).Therefore,for patients with CIN,chronic cervicitis patients with high-risk HPV infection,and cervical cancer patients with reduced immune function and high-risk HPV infection,the expression of tumor markers K-ras and Ki-67 was increased.The detection of immune cells and tumor markers is helpful for the early prevention,diagnosis and prognosis evaluation of high-risk HPV infection in patients with cervical cancer.

Microbial Monitoring and Mitigaiton in Cementing Operations

Microbial contamination and bacteria growth in the cementing makup water impact cementing operation and integrity.To avoid the premature cement setting caused by microbial growth,the water is usually treated with biocides for microbial control before mixing.This treatment will also prevent biodegradation of the added polymers and stabilize the slurry rheological properties.Make-up water and cementing mix samples were collected from active drilling rigs in the field.In 12 hours biocide addition program,the tested biocide at 50,100,250,and 500 ppm for cementing operations revealed acceptable control of both GAB and SRB numbers in one Field,but not in another Field.In 24 hours biocide addition program,revealed varying levels for control microbial contamination in cementing operations,with higher efficiency with Field B samples opposed to field A,and with better control at higher concentrations of tested biocide at 250,and 500 ppm.As a recommendation therefore,usage of another biocide with a different chemistry at Field A is encouraged once a new biocide is selected.

Deployment of Pre-Industrial Autonomous Microbe Sensor in Saudi Arabia’s Injection Seawater System

Microbial growth in water injection systems can lead to many problems, including biofouling, water quality deterioration, injectivity loss, microbial corrosion, and reservoir formation damage. Monitoring of microbial activities is required in any mitigation strategy, enabling operators to apply and adjust countermeasures properly and in due time. In this study, the pre-industrial autonomous microbe sensor (AMS) was constructed with technical improvements from the prototype for increased sensitivity, durability, robustness, and maintainability. The pre-industrial AMS was lab validated, field proven, and deployed at critical locations of seawater injection network for automated detection of microorganisms under the Saudi Arabia’s harsh environment. An excellent correlation between AMS measurement data (fluorescence count) and actual count of microbial cell number under microscope was established (coefficient of determination, R2 > 0.99) for converting AMS fluorescence count to cell numbers (cell mL-1) in the injection seawater. The pre-industrial AMS only required monthly maintenance with solutions refill, and was able to cope with hot summer months even without protection in an air-conditioned shelter. The study team recommended wider deployment of the online AMS for real-time monitoring of bacteria numbers in the various strategic locations in Saudi Aramco’s complex seawater injection network, as an integral component of pipeline corrosion and leak mitigation program.

铁氧体磁性纳米催化剂的制备及其在资源能源领域的应用

随着石油开采技术的不断提高,石油资源的开发和利用规模逐渐增大,然而现存的石油资源组成复杂、黏度高,使用常规的催化剂进行改质存在利用率低、回收困难等问题。生物质能已成为化石燃料的潜在替代品,生物质的催化转化是制备各种商品化学品或液体燃料的主要途径之一。然而生物质催化转化中常用的均相催化剂及非均相催化剂同样具有难回收再利用以及分离损失大等问题,限制了其应用。磁性纳米催化剂不仅具有高催化活性,在外加磁场作用下还能实现催化剂的回收与重复利用,在工业生产得以连续化的同时,也降低了生产成本,提高了生产效率。本综述介绍了铁氧体磁性纳米催化剂的制备方法,阐述了近年来铁氧体磁性纳米催化剂在催化脱硫、生物质催化转化为化学品、生物柴油的制备、煤液化领域的研究进展,指出了铁氧体磁性纳米催化剂在资源能源领域应用存在的问题,并对铁氧体磁性纳米颗粒的应用前景进行了展望。

Noncoaxial RDE of circular asymmetry optical vortex for rotating axis detection

We reveal the mechanism of the noncoaxial rotational Doppler effect(RDE) of an optical vortex and report its application in discriminating the orientation of the rotating axis of the rotating body. In most cases of the RDEbased measurement, the beam axis must be aligned with the rotating axis of the rotational body to observe a good signal. Once the beam axis is not coaxial with the rotating axis, the RDE frequency shift would change related to the misalignment distance, which can be called the noncoaxial RDE. Here, we take the advantage of the misaligned RDE augment with precise light-field modulation and successfully realize the discrimination of the orientation of the rotating axis relative to the illuminating beam. We clarify the principle of noncoaxial RDE and explain why the incomplete optical vortex(OV) is sensitive to the position of the rotating axis. We switch the OV field into four quadrants synchronized with sampling by the data acquisition system, and conduct Fourier transformation of the signals. Combined with the fitting algorithm, the orientation of the rotating axis can be recognized directly. This method may find applications for the noncontact detection of rotating bodies in both industrial and astronomical scenarios.

Selegiline improves excessive daytime sleepiness in Parkinson’s disease:an open-label observational study

To the Editor:Parkinson’s disease(PD)is the second most common neurodegenerative disorder,and sleep disturbance is a major disabling non-motor symptom.[1]Excessive daytime sleepiness(EDS)is defined as inappropriate and undesirable sleepiness during waking hours,which may occur during activities such as talking or driving.In PD patients,EDS increased the risk of accidents and resulted in a poor quality of life.[2]

Augmented efficacy of exogenous extracellular vesicles targeted to injured kidneys

Dear Editor,Extracellular vesicles(EVs)derived from mesenchymal stem/stromal cells(MSCs)contain genetic and protein material that stimulate tissue repair and ameliorate injury in recipient cells.Advantages of particulate MSC-EVs over MSCs in treating kidney disease include better penetration of injured glomerular filtration barrier to access podocytes or tubular cells.However,systemic EV delivery yields low kidney retention efficiency,limiting their regenerative benefits.1 Previously,we coated adipose tissue-derived(AD)-MSC with antibodies against kidney injury molecule(KIM)‐1(ab-KIM1),a protein upregulated in damaged kidneys.2 Conjugating ab-KIM1 did not impair MSC function but increased their retention and reparative potency in murine renal artery stenosis(RAS).2 We hypothesized that ab-KIM1 conjugation would similarly enhance retention of exogenously delivered EVs in ischemic kidneys and confer superior therapeutic benefits.