Microscopic Monitoring Research Articles

Microscopic Investigation of Rate Dependence on Three‐Point Notched‐Tip Bending Sandstone

The cracking process in rock or concrete is usually characterized by the formation of microcracks that eventually form a propagating macrocrack. A series of three‐point bending experiments were performed on sandstone containing Mode I crack under different loading rates. The microscopic monitoring system was established to capture the cracking process at notch tip. The loading rate dependence of microcracking behaviour was analysed based on load‐time curves, acoustic emission (AE), microscopic images, and micrograph‐based digital image correlation (DIC) technology. Results showed that the specimens underwent a short period of compression and elastic deformation stage under high loading rate, and the peak loads increased with the increase in loading rate. The AE results revealed that the fracturing process can be divided into elastic stage, damage stage, and postpeak stage, and more extensive damage occurred before the peak under low loading rate. It can be observed from microscopic images that the crack was initiated during the elastic stage, which was earlier than that determined from the AE monitoring. In addition, the microcracks were initiated at multiple locations and were mainly located at the interfaces between dense grains under low loading rate, while microcracks were observed inside the grains under high loading rate. Furthermore, the DIC results showed that the crack opening displacement (COD) of 0.6 mm/min at the peak was almost twice than that of 3.0 mm/min. The COD under the same loading rate at the peak can be considered as the material property of sandstone.

Microscopic Monitoring of Erythrocytes Deformation under Different Shear Stresses Using Computerized Cone and Plate Flow Chamber: Analytical Study of Normal Erythrocytes and Iron Deficiency Anemia.

Erythrocytes deformation is one of the exciting properties of erythrocytes. It is still under investigation by many of the researchers in different disciplines. The clinicians and researchers are still looking for a simple and efficient method to monitor and tracking the erythrocytes deformation. This research article represented a microscopic technique that could be a helpful tool in evaluation and studying of erythrocytes deformation under different shear stresses. This technique was used to compare the deformation of normal erythrocytes and iron deficiency anemia. Elongation index was calculated and used in the quantitative analysis of erythrocytes deformation. It was found that the deformability of normal erythrocytes was higher than that of iron deficiency anemia. Normal erythrocytes and iron deficiency anemia showed strong negative correlations with the mean cell volume and the mean cell hemoglobin concentration under different shear stresses. This study introduces more understanding of the erythrocytes deformation by using a simple microscopic technique. The elongation index could be used as a measurable parameter to evaluate the deformability of the erythrocyte in normal and abnormal cases.

A microfluidic device for isolating intact chromosomes from single mammalian cells and probing their folding stability by controlling solution conditions

Chromatin folding shows spatio-temporal fluctuations in living undifferentiated cells, but fixed spatial heterogeneity in differentiated cells. However, little is known about variation in folding stability along the chromatin fibres during differentiation. In addition, effective methods to investigate folding stability at the single cell level are lacking. In the present study, we developed a microfluidic device that enables non-destructive isolation of chromosomes from single mammalian cells as well as real-time microscopic monitoring of the partial unfolding and stretching of individual chromosomes with increasing salt concentrations under a gentle flow. Using this device, we compared the folding stability of chromosomes between non-differentiated and differentiated cells and found that the salt concentration which induces the chromosome unfolding was lower (≤500 mM NaCl) for chromosomes derived from undifferentiated cells, suggesting that the chromatin folding stability of these cells is lower than that of differentiated cells. In addition, individual unfolded chromosomes, i.e., chromatin fibres, were stretched to 150–800 µm non-destructively under 750 mM NaCl and showed distributions of highly/less folded regions along the fibres. Thus, our technique can provide insights into the aspects of chromatin folding that influence the epigenetic control of cell differentiation.

Fundamental Characteristics of Single-Cell Aging in Diploid Yeast

SummarySingle-cell-level experimentation can elucidate key biological insights about cellular aging that are masked in population-level studies. However, the extensive time requirement of tracking single cells has historically prevented their long-term longitudinal observation. Using a microfluidic device that automates microscopic monitoring of diploid Saccharomyces cerevisiae cells throughout their replicative lifespan, here we report the fundamental characteristics of single-cell aging for diploid yeast. We find that proteins with short versus long half-lives exhibit distinct dynamics as cells age and that the intercellular gene expression noise increases during aging, whereas the intracellular noise stays unchanged. A stochastic model provides quantitative mechanistic insights into the observed noise dynamics and sheds light on the age-dependent intracellular noise differences between diploid and haploid yeast. Our work elucidates how a set of canonical phenotypes dynamically change while the host cells are aging in real time, providing essential insights for a comprehensive understanding on and control of lifespan at the single-cell level.

PO-304 Three-dimensional co-culture of colorectal cancer spheroid with cancer-associated fibroblast as a model to study immune cell modulation

IntroductionColorectal cancer (CRC) is a complex disease in which inflammation is often a prominent feature. Hence, it serves as an appropriate paradigm to unveil the clinical importance of tumour microenvironment especially the infiltrating immune and inflammatory cells in the pathology of the disease. A 3-dimensional (3D) in vitro spheroid co-culture model that allows the interaction with stromal components is considered an essential element in developing a more clinically relevant tumour model. Hence, in this project, we aim to establish a model consisting of different subtypes of CRC and cancer-associated fibroblast (CAF), a major component of the tumour microenvironment, to study the role of immune cells, for example, macrophages, in CRC biology.Material and methodsCRC cell lines, HCT116 and DLD-1, and cancer-associated fibroblast (CAF) isolated from CRC patient tumour tissue were seeded together at the total number 2000 cells/well on 96-well round bottom ultra-low cluster/attachment plates at different ratios (1:1 and 1:2) to form tumour spheroids. Then, different numbers of monocytes isolated from a healthy human volunteer were added (100, 250 and 500 cells) into the CRC-CAF co-culture system. The CRC cells and CAF were stably transduced with TdTomato and GFP fluorescent proteins respectively for microscopic visualisation and monitoring of growth. Spheroid growth was also monitored by volumetric measurement using image analysis software (Fiji).Results and discussionsCo-culture of HCT116 showed that the presence of CAF increased CRC spheroid growth compared to monoculture of the cancer cells. Meanwhile, no growth stimulation of CAF-enriched culture of DLD-1 cells was observed despite the smaller size of the spheroids. Similarly, no enhancement of HCT116 growth was observed when monocytes were added to the co-cultures yet this resulted in the more disrupted morphology of spheroids.ConclusionThis preliminary study highlights the differential enhancement of tumour growth by CAF stimuli on different types of CRC. Further studies on characterisation of the spheroids containing monocytes and the monocyte differentiation are required to investigate their effect on tumour biology. The findings will be correlated to the observation found in our cohort of patient tissues.

Real-Time Microscopic Monitoring of Flow, Voltage and Current in the Proton Exchange Membrane Water Electrolyzer

Looking for alternative energy sources has been an inevitable trend since the oil crisis, and close attentioned has been paid to hydrogen energy. The proton exchange membrane (PEM) water electrolyzer is characterized by high energy efficiency, high yield, simple system and low operating temperature. The electrolyzer generates hydrogen from water free of any carbon sources (provided the electrons come from renewable sources such as solar and wind), so it is very clean and completely satisfies the environmental requirement. However, in long-term operation of the PEM water electrolyzer, the membrane material durability, catalyst corrosion and nonuniformity of local flow, voltage and current in the electrolyzer can influence the overall performance. It is difficult to measure the internal physical parameters of the PEM water electrolyzer, and the physical parameters are interrelated. Therefore, this study uses micro-electro-mechanical systems (MEMS) technology to develop a flexible integrated microsensor; internal multiple physical information is extracted to determine the optimal working parameters for the PEM water electrolyzer. The real operational data of local flow, voltage and current in the PEM water electrolyzer are measured simultaneously by the flexible integrated microsensor, so as to enhance the performance of the PEM water electrolyzer and to prolong the service life.

Modeling the Effect of Modified Atmospheres on Conidial Germination of Fungi from Dairy Foods.

Modified atmosphere packaging (MAP) is commonly applied to extend food shelf-life. Despite growth of a wide variety of fungal contaminants has been previously studied in relation to modified-atmospheres, few studies aimed at quantifying the effects of dioxygen (O2) and carbon dioxide (CO2) partial pressures on conidial germination in solid agar medium. In the present study, an original culture method was developed, allowing microscopic monitoring of conidial germination under modified-atmospheres in static conditions. An asymmetric model was utilized to describe germination kinetics of Paecilomyces niveus, Mucor lanceolatus, Penicillium brevicompactum, Penicillium expansum, and Penicillium roquefoti, using two main parameters, i.e., median germination time (τ) and maximum germination percentage (Pmax). These two parameters were subsequently modeled as a function of O2 partial pressure ranging from 0 to 21% and CO2 partial pressure ranging from 0.03 to 70% (8 tested levels for both O2 and CO2). Modified atmospheres with residual O2 or CO2 partial pressures below 1% and up to 70%, respectively, were not sufficient to totally inhibit conidial germination,. However, O2 levels < 1% or CO2 levels > 20% significantly increased τ and/or reduced Pmax, depending on the fungal species. Overall, the present method and results are of interest for predictive mycology applied to fungal spoilage of MAP food products.

Parotid tumours: clinical and oncologic outcomes after microscope-assisted parotidectomy with intraoperative nerve monitoring.

SUMMARYTemporary and permanent facial nerve dysfunctions can be observed after parotidectomy for benign and malignant lesions. Intraoperative nerve monitoring is a recognised tool for the preservation of the nerve, while the efficacy of the operative microscope has been rarely stated. The authors report their experience on 198 consecutive parotidectomies performed on 196 patients with the aid of the operative microscope and intraoperative nerve monitoring. 145 parotidectomies were performed for benign lesions and 53 for malignancies. Thirteen patients treated for benign tumours experienced temporary (11 cases) or permanent facial palsy (2 cases, both of House-Brackmann grade II). Ten patients with malignant tumour presented with preoperative facial nerve weakness that did not improve after treatment. Five and 6 patients with malignant lesion without preoperative facial nerve deficit experienced postoperative temporary and permanent weakness respectively (the sacrifice of a branch of the nerve was decided intraoperatively in 2 cases). Long-term facial nerve weakness after parotidectomy for lesions not directly involving or originating from the facial nerve (n = 185) was 2.7%. Patients treated for benign tumours of the extra facial portion of the gland without inflammatory behaviour (n = 91) had 4.4% facial nerve temporary weakness rate and no permanent palsy. The combined use of the operative microscope and intraoperative nerve monitoring seems to guarantee facial nerve preservation during parotidectomy.

Laboratory Rearing System for Ischnura senegalensis (Insecta: Odonata) Enables Detailed Description of Larval Development and Morphogenesis in Dragonfly.

In an attempt to establish an experimental dragonfly model, we developed a laboratory rearing system for the blue-tailed damselfly, Ischnura senegalensis. Adoption of multi-well plastic plates as rearing containers enabled mass-rearing of isolated larvae without cannibalism and convenient microscopic monitoring of individual larvae. Feeding Artemia brine shrimps to younger larvae and Tubifex worms for older larvae resulted in low mortality, synchronized ecdysis, and normal development of the larvae. We continuously monitored the development of 118 larvae every day, of which 49 individuals (41.5%) reached adulthood. The adult insects were fed with Drosophila flies in wet plastic cages, attained reproductive maturity in a week, copulated, laid fertilized eggs, and produced progeny. The final larval instar varied from 9th to 12th, with the 11th instar (56.5%) and the 12th instar (24.2%) constituting the majority. From the 1st instar to the penultimate instar, the duration of each instar was relatively short, mainly ranging from three to 11 days. Afterwards, the duration of each instar was prolonged, reaching 7-25 days for the penultimate instar and 14-28 days for the final instar. Some larvae of final, penultimate and younger instars were subjected to continuous and close morphological examinations, which enabled developmental staging of larvae based on size, shape, and angle of compound eyes and other morphological traits. This laboratory rearing system may facilitate the understanding of physiological, biochemical, and molecular mechanisms underlying metamorphosis, hormonal control, morphogenesis, body color polymorphism, and other biological features of dragonflies.

In Vivo-Like Culture Conditions in a Bioreactor Facilitate Improved Tissue Quality in Corneal Storage.

The cornea is the most-transplanted tissue worldwide. However, the availability and quality of grafts are limited due to the current methods of corneal storage. In this study, a dynamic bioreactor system is employed to enable the control of intraocular pressure and the culture at the air-liquid interface. Thereby, in vivo-like storage conditions are achieved. Different media combinations for endothelium and epithelium are tested in standard and dynamic conditions to enhance the viability of the tissue. In contrast to culture conditions used in eye banks, the combination of the bioreactor and biochrom medium 1 allows to preserve the corneal endothelium and the epithelium. Assessment of transparency, swelling, and the trans-epithelial-electrical-resistance (TEER) strengthens the impact of the in vivo-like tissue culture. For example, compared to corneas stored under static conditions, significantly lower optical densities and significantly higher TEER values were measured (p-value <0.05). Furthermore, healing of epithelial defects is enabled in the bioreactor, characterized by re-epithelialization and initiated stromal regeneration. Based on the obtained results, an easy-to-use 3D-printed bioreactor composed of only two parts was derived to translate the technology from the laboratory to the eye banks. This optimized bioreactor facilitates noninvasive microscopic monitoring. The improved storage conditions ameliorate the quality of corneal grafts and the storage time in the eye banks to increase availability and reduce re-grafting.

Micro-scale processes occurring in ionic liquid–water phases during extraction

• The process of extraction in ionic liquids was visualized by electron microscopy. • Intrinsic micro-heterogeneous nature of ionic-liquid-based systems was revealed. • The factors controlling retention ability and extraction efficiency in ionic liquid–water systems have been investigated. For the first time, extraction process in ionic liquids was visualized by direct electron microscopy observation. Microscopy images revealed the micro-heterogeneous nature of the studied extraction systems. Depending on the nature of ionic liquids and studied compounds, four main systems were observed at micro-scale level: (a) uniform homogeneous phase; (b) microcompartments in the liquid phase; (c) solid microinclusions on the phase boundary; and (d) solid microinclusions inside the separated microphases. The microscopic monitoring showed the stepwise sequence of the extraction process, and the retention ability of the ionic liquid–water system decreased in the following order: homogeneous phase > microcompartments > solid microinclusions.

The treatment for the first branchial cleft anomalies in children.

The objective of this study is to make a clinical analysis for first branchial cleft anomalies (FBCAs), especially introduce the relationship between the Type I/II FBCA with the facial nerve and to demonstrate the importance of using intraoperative microscope and facial nerve monitoring. This is a retrospective review of patients with FBCAs treated in Beijing Children's Hospital, from Jan 2013 to Dec 2015. Clinical data of patients, including sex, age, chief complains, history of surgery, incision and drainage, the relationship with the facial nerve, pre and post-operative facial paralysis, recurrent rate and complications were recorded. FBCAs were divided into two subtypes according to Work's Classification. All patients had an MRI examination for diagnosis and to locate the lesions before surgery. Both microscope and facial nerve monitors were routinely used for detecting and protecting the facial nerve. The study cohort included 42 patients with ages ranging from 10months to 14years. The chief complaint was recurrent swelling or abscess near the ear or angle of mandibular. 76.2% of them (32/42) had incision and drainage histories. Two of them had suffered from facial palsy during the infectious period. Seven patients had undergone surgeries once or twice in other hospitals. Four patients with Type II FBCAs developed temporary facial palsy. We had follow-ups for each patient from 3months to 3years. 4 (9.5%) patients with Type I FBCA had got postoperative external auditory canal (EAC) stenosis. There were no cases of recurrence. Type II FBCAs has closer relationship with facial nerve than Type I FBCAs. The facial nerve of Type II FBCAs may lie more superficially and ascending to the fistula. Intraoperative microscope and facial nerve monitoring were necessary for protecting the facial nerve and decreasing the recurrent rate.

Mechanical properties of macrosynthetic fibre-reinforced concrete exposed to sulfate attack

The performance and durability of concrete is always affected by atmospheric conditions, chemical ions and mechanical loads, which reduce its bearing capacity, leading to the occurrence of accidents. Macrosynthetic fibre-reinforced concrete, as an alternative material, is used to improve the corrosion resistance of underground structures. In this study, accelerated corrosion tests were designed to investigate the change in compressive strength, elastic modulus and fracture toughness of concrete soaked in sulfate environment. Microscopic monitoring techniques, including scanning electron microscopy and energy-dispersive X-ray spectroscopy, were adopted to find changes in the structure. Compared to macrosynthetic fibre-reinforced concrete and ordinary concrete soaked in sulfate corrosion environment, the results indicated that macrosynthetic fibre improved the structure compactness of concrete; the losses of elastic moduli and compressive strength of the specimens soaked in sulfate were reduced. The maximum crack initiation load of macrosynthetic fibre-reinforced concrete was enhanced. Through microstructure monitoring, it is found that macrosynthetic steel fibre contributes to a remarkable improvement in the fracture resistance of concrete.

A data-aware confidential tunnel for wireless sensor media networks

A Wireless Sensor Media Network (WSMN) provides an economical and feasible solution to microscopic visual monitoring in real time. Compared to macrographic monitoring (e.g. aerial photography), it can also provide a flexible solution by means of the facility of setup and integration of microscopic data. Security is one of the significant issues for the applications of monitoring due to the visuality of the content in a WSMN. Besides the visual data, the confidentiality of the communication is also important since a WSMN serves as both a media network and a sensor network. Impersonation and key recovery attack are two particular harmful threats to the sensor networks. A spying agent masquerades as a normal node in the network, overhearing the data and signaling. In this paper, we present a data-aware scheme for a wireless sensor media network (WSMN) to guarantee the security of information system against both the impersonation and key recovery attacks during communication. With the consideration of the characteristics of visual data regarding both volatility and correlation, a chaos-driven strategy is used to design the protocol for tunnel establishment. The data-aware scheme is proposed to enhance the security for confidential communication by public key cryptography based attack detection. A simulation and related analysis are presented in this paper. The robustness against anti-attack is also discussed. The results show that the scheme is able to protect the system against both the impersonal intrusion and key recovery attack simultaneously based on data-aware attack-detection.

Energy-Harvesting Nanosensor Networks: Efficient event detection

Advances in nanotechnology are paving the way for a new generation of sensor networks at the nanoscale, promising radically new applications in medical, biological, and chemical fields. At the nanoscale, it is difficult to use large batteries for prolonged operations, necessitating energy harvesting as the most viable solution for these nanosensor networks. Unfortunately, the rate at which energy can be harvested at the nanoscale may not be sufficient to simultaneously power all of the conventional device components, including the microprocessor, memory, sensor, and the communication radio. We propose a simplified architecture for energy-harvesting nanosensor networks that uses the energy signatures of monitored events for efficient event recognition at the sink. Using the instantaneous harvested energy to transmit a short pulse of proportional amplitude, the proposed architecture obviates the need for several conventional sensor node elements, including the microprocessor, memory, and sensor. In this article, we validate the feasibility of the architecture using a novel application of nanosensor networks for microscopic monitoring of chemical reactors, and we demonstrate that different types of reactions can be detected accurately at a remote sink.

Integrated microsensor for real-time microscopic monitoring of local temperature, voltage and current inside lithium ion battery

The lithium ion battery overcharge may cause thermal runaway, even hazardous conditions like explosion, resulting in safety problem. High charge/discharge rate is required for 3C products like smart phone and tablet PC and electric vehicles, but it will cause steep rise of internal temperature of lithium ion battery, unstable voltage and current and safety problem.This study used micro-electro-mechanical systems (MEMS) to develop an integrated microsensor of temperature, voltage and current microsensors, embedded in the lithium ion battery for real-time microscopic monitoring of internal temperature, voltage and current. This integrated microsensor is characterized by quick response, real-time measurement and batch manufacturing.

Durability of glass fiber-reinforced polymer bridge panel based on differential thermal analysis, dynamic mechanical analysis, and differential scanning calorimetry analysis

Modern bridge structures need light decks with long durability and promising technical parameters. Glass fiber-reinforced polymer orthotropic bridge deck creates unconventional possibilities in bridge designing. Parallel identification of glass fiber-reinforced polymer deck panel by differential thermal analysis, spectroscopy analysis, scanning and optical microscope monitoring, dynamic mechanical analysis and differential scanning calorimetry analysis, tensile and flexural tests will be presented in the paper. Differential thermal analysis was carried out for estimation of the physical and chemical transformation of glass fiber. The differential scanning calorimetry experiments were performed in the glass fiber-reinforced polymer–bridge deck material for determining the mass variation and the energy changes suffered by the materials, as a function of temperature and time. Dynamic mechanical analysis was allowed to detect thermal effects based on the changes in the modulus or damping behavior. Tensile and flexural tests allowed the observation of the decomposition process and information about the basic stress parameters of glass fiber-reinforced polymer material used in bridge applications was taken. Aforementioned analyses are necessary to examine the durability description of the composite element.

Hybrid Electrocatalytic Nanomaterials for Isopropanol Oxidation

Recently, there has been growing interest in development of electrochemical energy conversion systems utilizing small organic molecules as alternative technologies to hydrogen based fuel cells. Such organic molecules as methanol, ethanol or isopropanol can be ideally oxidized to carbon dioxide. But realistically the reactions are rather slow at ambient conditions. Obviously, there is a need to develop novel electrocatalytic materials. Platinum has been recognized as the most active catalytic metal towards oxidation of alcohols at low and moderate temperatures. But Pt anodes are readily poisoned by the strongly adsorbed intermediates, namely by CO-type species, requiring fairly high overpotentials for their removal. Up to now lot of materials have been tested as electrocatalysts for small organic molecules in acidic media, such as Pt, its alloys Pt–M (M= Ru, Sn, Rh, Pb, Ir, W or Mo) in binary or ternary form and even different methods to prepare Pt thin film electrodes. Complete oxidation of alcohols into CO2 via C–C bond cleavage is mechanistically difficult at ambient (low) temperature, and the surface of catalytic platinum readily undergoes poisoning with intermediates of the alcohols oxidation. This problem may be partially solved by applying bifunctional electrocatalysts. In general, metals, like ruthenium, tin or rod are oxophilic, which provide oxygen at low potentials and mitigates the poisoning effect by oxidizing the metastable intermediates with adsorbed water fragments. In order to increase the overall kinetic of electrooxidation of isopropanol, we have utilized as carriers (matrices) carbon nanotubes (CNTs) modified with the cesium salt of Keggin-type heteropolyacids of molybdenum and tungsten (Cs2.5H0.5PMo12O40, Cs2.5H0.5PW12O40) or metal oxide (MoO3, ZrO2, CeO2, IrO2). The presence of metals oxide and cesium salt are capable of generating of interfacial reactive hydroxy groups on the surfaces and also increase the catalytic surface. Remarkable increases of electrocatalytic currents measured under voltammetric and chronoamperometric conditions have been observed. Electrochemical diagnostic experiments have been supported with microscopic monitoring of morphology using transmission electron microscopy (TEM) and ATR-FTIR measurements.

Mechanistic aspects of hydrazine-induced Pt colloid instability and monitoring aggregation kinetics with nanoparticle impact electroanalysis

Here we investigate the mechanistic aspects of Pt nanoparticle (NP) aggregation in solutions typically used for detecting NP/electrode impacts by electrocatalytic amplification (ECA). We previously proposed a general mechanism for Pt colloid destabilization that involved the participation of both the hydrazine redox probe and the pH buffer species as coagulants. Herein the Pt NP coagulation and aggregation mechanisms were further investigated with microscopic kinetic NP concentration monitoring and zeta potential measurements using nanoparticle tracking analysis (NTA), as well as open circuit potential experiments with a citrate-treated polycrystalline Pt surface to assess electrical double layer potential. After considering the combined results of these experiments we propose that the colloidal stability of citrate-capped platinum nanoparticles involves much more than the typical physicochemical interactions predicted by DLVO theory. A structure based on intermolecular H-bonding in the citrate capping layer is the most plausible explanation for the exceptional stability of large Pt NPs in high ionic strength buffers. Thus, the mechanism of Pt NP aggregation includes specific reactive contributions from hydrazine. The catalytic decomposition of hydrazine, in particular, is thought to occur to some extent at the citrate-coated Pt surface while the citrate remains adsorbed. Evolved gases such as ammonia and possible surface bound intermediates from Pt-catalyzed decomposition of hydrazine may disrupt the stability of the citrate layer, causing colloidal instability and thus promoting Pt NP coagulation. In the closing section, we demonstrate nanoparticle impact electroanalysis by ECA detection as a method to quantify Pt NP concentration with adequate time resolution for monitoring the kinetics of Pt NP coagulation.

Monitoring situation of eliminating malaria in Shaoguan City from 2001 to 2014

To analyze the malaria monitoring situation in Shaoguan City from 2001 to 2014, and evaluate the efficacy of the malaria control and prevention work, so as to provide the evidence for formulating the effective eliminating malaria measures. The microscopic examination monitoring points of "four-fever" patients were established in medical institutions at all levels in Shaoguan City from 2001 to 2014, and the fever patients were examined by microscopy and the active case monitoring was performed. By using the epidemiology method, the malaria incidence and classification of cases were described and analyzed statistically. From 2001 to 2014, 91 381 "four-fever" patients were monitored and 22 malaria patients were found with the average positive rate of 0.02%. Among the 22 malaria patients, 20 were imported (90.91%) and 2 were local cases (9.09%). The local patients were infected with Plasmodium vivax, and among the imported patients, 16 patients were infected with P. vivax, 2 infected with P. falciparum and 2 infected with P. ovale. No local infection cases were found since 2006. All the patients were timely treated and no second generation cases were found. From 2011 to 2014, 2 611 person-times were actively investigated in 7 counties (city) and no malaria patients were found. In Shaoguan City, there are remarkable achievements in the malaria prevention and control work. However, there are still imported cases in recent years, and therefore, the monitoring system should be perfected and the effective monitoring should be strengthened.