Sterile Zone Research Articles

Влияние состава и свойств поверхности образцов из титановых сплавов медицинского назначения на способность поддерживать адгезию Escherichia coli и формирование биопленки

The effect of 6 types of jet treatment and electrolytic plasma polishing on the roughness and wettability of the surface and interaction with the bacterium Escherichia coli of two commercial titanium-based alloys used in medicine, VT1-0 (pure titanium) and VT6 (titanium alloy with aluminum and vanadium) and Ti alloy developed at IMET RAS was studied-Nb-Zr. It is noted that all created surfaces are wettable, the wetting angle is naturally higher the lower the surface roughness, however, in the case of all materials after sandblasting with mixtures with a wide range of particles in size, an increase in the wetting angle is noted. All metal samples do not have antibacterial activity and do not contribute to the formation of a sterile zone. However, when studying the ability to form biofilms from the bacterium Escherichia coli on the surface of metals. It was found out that their number is significantly lower compared to the control, which was cultivated under ideal conditions for the growth of this bacterium. The alloy under development, which potentially has better biomechanical compatibility than the commercial ones used, did not show a deterioration in surface characteristics and an effect on the growth of bacteria.

Simple or simplistic? Sensitivity of an operating room CFD model to refinement and detailing

Indoor air quality is critical in healthcare facilities since it directly relates to infection risk, mainly in operating rooms (OR). Nowadays, air movement in such environments is often evaluated with computational fluid dynamics (CFD) simulations. However, many users typically oversimplify their OR models by including only major equipment (such as operating tables and surgical lights) that do not require refined computational meshes. This work analyzes the sensitivity of CFD simulations to mesh refinement, air circulation layout, geometry detailing, placement of furniture and equipment, as well as the presence of the surgical staff in the OR. An OR of a Brazilian university hospital was modeled and validated with environmental parameters assessed in-loco. Results showed relative differences up to 375% in air velocity depending on mesh resolution. Including small furniture and changing the OR layout resulted in nine-fold differences in air velocity. Finally, modeling the surgical staff in the OR significantly interfered with air circulation patterns, preventing inflow from the polluted towards the clean and sterile zone. The present work demonstrates the alarming fact that even a validated, sound, but overly simple CFD model may be phenomenologically insufficient to assess real contamination risks in an OR — and, by extension, in other healthcare facilities. Therefore, detailed CFD models regarding the number of elements in the simulation mesh, the positioning and the operating condition of the ventilation system, the inclusion and detailing of furniture, and the presence of the surgical staff in the OR should be employed since early design stages.

Laser Bioprinting with Cell Spheroids: Accurate and Gentle.

Laser printing with cell spheroids can become a promising approach in tissue engineering and regenerative medicine. However, the use of standard laser bioprinters for this purpose is not optimal as they are optimized for transferring smaller objects, such as cells and microorganisms. The use of standard laser systems and protocols for the transfer of cell spheroids leads either to their destruction or to a significant deterioration in the quality of bioprinting. The possibilities of cell spheroids printing by laser-induced forward transfer in a gentle mode, which ensures good cell survival ~80% without damage and burns, were demonstrated. The proposed method showed a high spatial resolution of laser printing of cell spheroid geometric structures at the level of 62 ± 33 µm, which is significantly less than the size of the cell spheroid itself. The experiments were performed on a laboratory laser bioprinter with a sterile zone, which was supplemented with a new optical part based on the Pi-Shaper element, which allows for forming laser spots with different non-Gaussian intensity distributions. It is shown that laser spots with an intensity distribution profile of the "Two rings" type (close to Π-shaped) and a size comparable to a spheroid are optimal. To select the operating parameters of laser exposure, spheroid phantoms made of a photocurable resin and spheroids made from human umbilical cord mesenchymal stromal cells were used.

Antibacterial Electrospun Polycaprolactone Nanofibers Reinforced by Halloysite Nanotubes for Tissue Engineering.

Due to its slow degradation rate, polycaprolactone (PCL) is frequently used in biomedical applications. This study deals with the development of antibacterial nanofibers based on PCL and halloysite nanotubes (HNTs). Thanks to a combination with HNTs, the prepared nanofibers can be used as low-cost nanocontainers for the encapsulation of a wide variety of substances, including drugs, enzymes, and DNA. In our work, HNTs were used as a nanocarrier for erythromycin (ERY) as a model antibacterial active compound with a wide range of antibacterial activity. Nanofibers based on PCL and HNT/ERY were prepared by electrospinning. The antibacterial activity was evaluated as a sterile zone of inhibition around the PCL nanofibers containing 7.0 wt.% HNT/ERY. The morphology was observed with SEM and TEM. The efficiency of HNT/ERY loading was evaluated with thermogravimetric analysis. It was found that the nanofibers exhibited outstanding antibacterial properties and inhibited both Gram- (Escherichia coli) and Gram+ (Staphylococcus aureus) bacteria. Moreover, a significant enhancement of mechanical properties was achieved. The potential uses of antibacterial, environmentally friendly, nontoxic, biodegradable PCL/HNT/ERY nanofiber materials are mainly in tissue engineering, wound healing, the prevention of bacterial infections, and other biomedical applications.

Subject Review: Image Processing Techniques for Object Tracking in Video Surveillance

The article is devoted to real-time algorithms for detecting events described by four scenarios: movement in a forbidden direction, being in a sterile zone, leaving (stealing) an object, throwing an object. The main idea of the algorithms is the analysis of the trajectories of moving objects, for which two different approaches are proposed in the article.

Antimycotic activity of bacterial strains against the pathogen of grape necrotic leaf spotting Alternaria sp.

Species of the genera Bacillus Cohn and Pseudomonas Migula are successfully used as biocontrol agents for many mycopathogens, including Alternaria sp. To assess the bacteria antagonistic potential against Alternaria sp, we used the method of counter cultures on various nutrient media – universal and specialized. Of the 24 bacterial strains of the genus Bacillus, 18 strains were developed antagonistic activity to Alternaria sp. after 10 days of co-cultivation on the Tylona-3 medium. The maximum sterile zone (8.0 mm) was formed by bacterial strains (R-9, 5B-1, 01 cor f Bacillus sp.). 3 strains of 9 bacteria of the genus Pseudomonas, developed antagonistic activity to Alternaria sp. on Kinga B medium - 14-3 Pseudomonas sp., Oif 2-1 Pseudomonas sp., 14-4 Pseudomonas sp. The maximum antibiotic activity on potato-sucrose agar was established in strains 3-3 Bacillus sp., and K 1-1 Bacillus sp. (sterile zone 7.5 mm). All the tested bacteria most often caused one sign of antagonism – antibiosis.

Deep, hot, and more alive than we thought

Deep Biosphere Marine sediments represent a massive microbial ecosystem, but we still do not fully understand what factors shape and limit life underneath the seafloor. Analyzing samples from a subduction zone off the coast of Japan, Heuer et al. found that microbial life, in particular bacterial vegetative cells, decreases as depth and temperature increases down to ∼600 meters below the seafloor, corresponding to temperatures of ∼70°C. Below this limit, endospores are common—a remnant, and a potential reservoir, of bacterial life. Deeper still is a sterile zone, and below 1000 meters is a scalding realm populated by vegetative cells. At such great depths, high concentrations of acetate and sulfate coexist, and there are also signs of hyperthermophilic methanogenesis. These data provide a fascinating window into an extreme and inhospitable environment that nonetheless supports microbial life. Science , this issue p. [1230][1] [1]: /lookup/doi/10.1126/science.abd7934

Temperature limits to deep subseafloor life in the Nankai Trough subduction zone.

Microorganisms in marine subsurface sediments substantially contribute to global biomass. Sediments warmer than 40°C account for roughly half the marine sediment volume, but the processes mediated by microbial populations in these hard-to-access environments are poorly understood. We investigated microbial life in up to 1.2-kilometer-deep and up to 120°C hot sediments in the Nankai Trough subduction zone. Above 45°C, concentrations of vegetative cells drop two orders of magnitude and endospores become more than 6000 times more abundant than vegetative cells. Methane is biologically produced and oxidized until sediments reach 80° to 85°C. In 100° to 120°C sediments, isotopic evidence and increased cell concentrations demonstrate the activity of acetate-degrading hyperthermophiles. Above 45°C, populated zones alternate with zones up to 192 meters thick where microbes were undetectable.

Первичный скрининг бактериальных штаммов антагонистов из коллекции лаборатории биометода ВНИИМК к возбудителю фомоза подсолнечника (часть 2)

There are presented data of the primary screening of bacterial strains antagonists from a collection of the biological methods lab of the V.S. Pustovoit All-Russian Research Institute of Oil Crops (VNIIMK) to an aggressive isolate of the Phoma rot pathogen (Phoma macdonaldii Boerema) affecting sunflower by a method of double or crops. We estimated 27 bacterial strains of Bacillus genus on the three nutrient mediums (potato-sucrose agar (PSA), Taylon-3 and oat agar (OA). We stated 21 of them possessing antagonistic activity with a type of action mode against Phoma pathogen on sunflower named antibiosis. We determined for three strains presence of a competition for nutrient area without formation of a sterile zone with pathogen. Maximal sterile zone to Phoma rot pathogen was formed by strains: 11-3 Bacillus sp. (21.0 mm) on PSA; B-4 B. circulans (19.0 mm) on a Taylon-3 medium and D 1-1 Bacillus sp. (17.0 mm) on OA. Eight from the nine collection bacterial strains of Pseudomonas genus demonstrated antagonistic activity to Phoma rot on PSA and King’s B, and seven strains – on OA with one type of action mode – antibiosis. Maximal sterile zone to Phoma rot pathogen was formed by strains: Oif 2-1 Pseudomonas sp., 16-2 Pseudomonas sp. and 12-2 Pseudomonas sp. (12.5– 12.0 mm) – on PSA; 16-2 Pseudomonas sp. (16.5 mm) – on King’s B; Oif 2-1 Pseudomonas sp. (18.0 mm) – on ОА.

Thermogenesis in four species of Schismatoglottis Calyptrata Clade (Schismatoglottideae: Araceae)

Spadix temperature was measured in Schismatoglottis ahmadii, S. lowiae, S. sp. nov., and S. wallichii. The anthesis of S. lowiae, S. sp. nov., and S. wallichii started just after dawn but in S. ahmadii, it began two hours later. Spadix temperatures of the four species increased at the beginning of each of the two successive flowering mornings, corresponding respectively to the pistillate and staminate phases of anthesis. The appendices of S. ahmadii, S. lowiae, and S. sp. nov. underwent the highest temperature increases (average 9.5°C above ambient air) compared to the staminate zone (6.5°C above ambient air); almost no thermogenic activity was recorded in the pistillate zone (0.4°C above ambient air). In inflorescences of S. wallichii, in which the spadix lacks an appendix, the pistillate zone also heated up (2.3°C above ambient air), together with the sterile (2.6°C above ambient air) and the staminate zones (5.2°C above ambient air). Thermogenic patterns varied across species owing to differences in timing of anthesis or spadix structures. The absence of an appendix (sterile floral tissue) in S. wallichii, is not only partially compensated by heat production from the (intermediate) sterile zone but also heat production from the pistillate zone, recorded here for the first time in Tribe Schismatoglottideae.

Inserting central lines via the peripheral circulation in neonates

Peripherally inserted central catheters (PICCs) are extensively used in neonatal intensive and high-dependency care settings. These intravenous catheters provide medium to longer-term access to the circulatory system for the delivery of medications, parenteral nutrition and the like. Catheters are available in a variety of bespoke designs and materials, each with their unique characteristics, benefits and limitations. PICCs are frequently inserted in a sterile zone cot-side procedure, one that requires an advanced knowledge base, technical skill and training. This article relates some important practical advice around managing minor complications that can be encountered while using the modified Seldinger technique (MST) to insert neonatal PICCs, which can make this procedure a less stressful experience for both infants and health professionals.

Enhanced Unsupervised Change Detector for Industrial Surveillance Systems

Detecting an intruder that is trespassing a prohibited area is a critical task of intelligent surveillance systems. This task requires a change detector to segment an intruder (foreground object) from the background. The task suffers the inherent drawbacks of change detectors due to the dual-camera sensor (color/IR), illumination changes, night time, static, and camouflaged foreground objects. This article proposes an enhanced unsupervised change detector to compensate for the aforementioned challenges for industrial sterile zone monitoring. The camera switch detection based on skewness patterns detects a switch between the dual-camera sensors (color/IR). The optimal color space selection based on the mean squared error will select tolerant color space (RGB/YCbCr) to illumination changes for modeling the background. In addition, the IR camera frames are contrast-enhanced to tackle the camouflaged intruders during the night. The incoming frames are split into respective channels before modeling the background. The background is modeled by Gaussian mixture models. The adaptive background model update scheme is proposed to tackle the various challenges posed by environment and object such as a static foreground object. The comparison is performed on three databases with top-ranked unsupervised change detection algorithms.

Improved Change Detector Using Dual-Camera Sensors for Intelligent Surveillance Systems

Unauthorized entrance in a prohibited area might create a security risk. An intelligent surveillance system should be able to mitigate such a problem by incorporating a sterile zone monitoring algorithm. The algorithm is challenged by a dual-camera sensors (color/IR), dynamic backgrounds, illumination changes, camouflaged, and static foreground objects, etc. This paper proposes an improved change detector (ICD) to mitigate the above-mentioned challenges. It employs a novel statistical decision criterion (SDC) based on skewness patterns. The SDC helps to differentiate time of day using the camera sensors (color/IR). The input frames are processed according to the time of day. For instance, IR input is image-enhanced to differentiate between camouflaged intruders from the background. Then input goes through Gaussian Mixture Models (GMM) based change detector to segment foreground (intruder). The foreground object is further cleansed using morphological operations for possible isolated noise and holes. The ICD was tested on three datasets and outperformed top-ranked change detection algorithms.

Ultrafine particle transport inside an operating room equipped with turbulent diffusers

ABSTRACT The present study numerically and experimentally investigates, for the first time in the literature, the thermo-fluid dynamics and ultrafine particle (UFP) concentration in surgical smoke, with diameters smaller than 100 nm, inside an actual operating room (OR) equipped with a turbulent circular diffuser system. The velocity values and temperature fields measured during the experimental analysis at different points in the OR are in reasonable agreement with the numerical results. For UFP diameters smaller than 70 nm, the particle concentration obtained from the numerical analysis agrees with the experimental data. The numerical results have demonstrated that at the sterile zone, UFP concentration caused by candles smoke is around particles/cm3, which are exposed by the occupants in OR. UFP decay time of 25 and 20 minutes are obtained in current analysis, respectively, in order to evaluate the time needed by the ventilation system to evacuate the particles from the OR.

Evaluation of the Efficacy of Erbium, Chromium-doped Yttrium, Scandium, Gallium, and Garnet Laser in Partial Pulpotomy in Permanent Immature Molars: A Randomized Controlled Trial

IntroductionThe use of the erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser in vital pulp therapy contributes to the formation of dentin bridges and a sterile zone as well as the maintenance of the vitality of the pulp. However, no prior studies have used the Er,Cr:YSGG laser in partial pulpotomy of immature permanent teeth. The aim of this study was to compare the efficacy of partial pulpotomy treatment using mineral trioxide aggregate (MTA) alone and MTA with the Er,Cr:YSGG laser in permanent immature molars. MethodsA total of 90 caries-exposed permanent immature molar teeth were included and randomly divided into 2 groups: the MTA group (n = 45) and the laser + MTA group (n = 45). In the MTA group, MTA was applied to the exposed area on the pulp after bleeding control. In the same session, the tooth was restored with a composite resin. In the laser + MTA group, before MTA condensation, the Er,Cr:YSGG laser was applied to the exposure area. Patients were recalled at 1, 3, 6, and 12 months after treatment. The Mann-Whitney U and chi-Square tests were used for statistical analysis. ResultsThe success rate (95.5%) of the laser + MTA group was similar to that of the MTA group (88.8%). There was no significant difference between groups in terms of the frequency of at least 1 pathologic clinical or radiographic failure at 12 months (P > .05). ConclusionsPartial pulpotomy treatment showed a high success rate in immature permanent molars; however, the use of the laser did not contribute to the success rate compared with MTA alone.

An experimental study of the flow characteristics and velocity fields in an operating room with laminar airflow ventilation

A critical aspect of the role of ventilation in hospital operating rooms (ORs) is the prevention of surgical site infection (SSI) which is largely attributable to airborne infection. Ventilation using clean filtered air is the primary means of airborne infection control. Many modern OR ventilation systems use laminar airflow (LAF) for air distribution. Conventional LAF ventilation supplies air directly over the surgical area which creates a sterile zone and uses wall-mounted air returns located at low level. A problem avoided with this design is the formation of recirculation in the non-sterile zone which arises due to disruption of LAF. This recirculation can lead to entrainment of the contaminated room air to the supply airflow which can increase the risk of SSI. In order to prevent this entrainment, airflow in the non-sterile zone has to be significantly altered. In this study, the application of ceiling returns and skirts in order to prevent the recirculation is experimentally investigated. Airflow patterns were analyzed using smoke flow visualization and particle image velocimetry (PIV). A novel laser sheet generator was used for illumination of the smoke particles. The effects of the supply flow rate, skirt length, and percentage of ceiling-return flow rate on the recirculation were assessed using Taguchi method. The results show that the application of ceiling return can eliminate the recirculation. Ceiling-return flow rate has the greatest influence, followed by the supply flow rate and the skirt. The findings of this study could contribute to the improvement of the conventional LAF ventilation design.

<i>Colocasia hassanii</i> (Araceae), A new species of aroid from Bangladesh

Colocasia hassanii, a new species of Araceae from Bangladesh, is described and illustrated. C. hassanii is closely related to C. esculenta (L.) Schott but differs from the later by the number of constriction (two) in spathe,presence of a sterile male zone in spadix, and bitter in taste. A morphologicalcomparison between C. hassanii and C. esculenta is provided.Bangladesh J. Plant Taxon. 25(1): 101-106, 2018 (June)

Preparation and Biological Activity of New Collagen Composites Part II: Collagen/Reduced Graphene Oxide Composites

: With the idea of exploring the biological activity of some newly synthetized chemical compounds and their combinations for development of novel antimicrobial collagen biomaterials, a serial investigation was initiated, starting with the preparation and biological activity study of Collagen/ZnTiO3 nano-composites. This serial investigation continued with the preparation and biological activity study of new collagen-based composites in which self-prepared reduced graphene oxide (RGO) sheets were included as an antimicrobial agent. The new porous collagen/RGO composites demonstrated specific antimicrobial activity to different types microbial species; well pronounced activity against Gram-positive microorganisms (Listeria innocua and Bacillus cereus, both bacteria with typical chains forming, large size cells, and Candida lusitaniae, fungus with specific micelle organization) and lack of activity against Gram-negative bacteria (Pseudomonas putida, Salmonella enterica, Pseudomonas aeruginosa, and Escherichia coli; all bacteria with small size cells) combined with lack of cytotoxicity to eukaryotic cells. For the first time, well-pronounced antifungal activity of collagen/RGO composites, depending on the RGO concentration was observed. Sterile zone of 17 mm was measured for C. lusitaniae on collagen/RGO composite, 2:1 wt/wt. The possible mechanism of the biological activity of the new collagen/RGO composites was correlated with their characteristics and the specific cell morphology and size of the test microorganisms. The results of this investigation demonstrated that with their specific and adjustable bioactivity, the new collagen/RGO composites are promising antimicrobial biomaterial for variety of biomedical applications, including tissue engineering.

The selective florivory of Erioscelis emarginata matches its role as a pollinator of Philodendron

AbstractFlowers commonly face the dilemma of needing to be attractive to pollinators but unattractive to nectar robbers or florivores. When the pollinator has chewing mouthparts, there is also a considerable risk of the pollinator consuming the flowers. Scant field records indicate that the florivorous beetle Erioscelis emarginata (Mannerheim) (Coleoptera: Scarabaeidae: Cyclocephalini), which pollinates Philodendron spp., feeds selectively on the sterile staminate flowers. Here, the hypothesis was tested that E. emarginata prefers sterile staminate flowers of Philodendron bipinnatifidum Schott and Philodendron melinonii Brongn. ex Regel (Araceae) over fertile flowers. This study also examined whether such a preference exists regardless of the proportion of fertile vs. sterile flowers in each Philodendron species. Analysis of nutritional and defensive compounds plus scanning electron microscopy on each flower type were performed. The feeding preference of florivores for either P. bipinnatifidum or P. melinonii was also examined. In both species, sterile flowers were significantly more consumed than fertile ones. The sterile zone of P. bipinnatifidum was significantly larger than that of P. melinonii, and sterile staminate flowers of both plants were consumed at similar rates. Calcium oxalate was markedly low in sterile flowers, which also presented smaller papillae than the other flowers. This study presents evidence that the balance between pollination and florivory has most likely evolved through a strong feeding preference for less‐defended sterile flowers regardless of the size of the sterile zone.

Local feature saliency classifier for real-time intrusion monitoring

We propose a texture saliency classifier to detect people in a video frame by identifying salient texture regions. The image is classified into foreground and background in real time. No temporal image information is used during the classification. The system is used for the task of detecting people entering a sterile zone, which is a common scenario for visual surveillance. Testing is performed on the Imagery Library for Intelligent Detection Systems sterile zone benchmark dataset of the United Kingdom’s Home Office. The basic classifier is extended by fusing its output with simple motion information, which significantly outperforms standard motion tracking. A lower detection time can be achieved by combining texture classification with Kalman filtering. The fusion approach running at 10 fps gives the highest result of F 1=0.92 for the 24-h test dataset. The paper concludes with a detailed analysis of the computation time required for the different parts of the algorithm.