Factors affecting the bacterial colonization of various surfaces in a river

1984 ◽  
Vol 30 (4) ◽  
pp. 511-515 ◽  
Author(s):  
J. H. Baker
Keyword(s):  
Surface Charge ◽  
Current Velocity ◽  
Bacterial Population ◽  
Bacterial Colonization ◽  
High Surface ◽  
Factors Affecting ◽  
Naturally Occurring ◽  
Different Types ◽  
Temperate River ◽  
Colonization Rates

The colonization rates of substrates, differing in their surface charge and asperity, have been determined in a temperate river. Glass, which has a high surface charge, was colonized by the natural bacterial population just as fast as polystyrene with a low surface charge. However, roughening the surface of either substrate greatly increased the rate of bacterial colonization. On the roughened surfaces bacteria did not selectively colonize cavities or grooves and current velocity was not an important factor. It is suggested that different sections of the naturally occurring bacterial population are the initial colonizers of different types of surface.

NMR Assisted Antimicrobial Peptide Designing: Structure Based Modifications and Functional Correlation of a Designed Peptide VG16KRKP

2020 ◽  
Vol 27 (9) ◽  
pp. 1387-1404 ◽  
Author(s):  
Karishma Biswas ◽  
Humaira Ilyas ◽  
Aritreyee Datta ◽  
Anirban Bhunia
Keyword(s):  
Antimicrobial Agents ◽  
Biological Properties ◽  
Structure Characterization ◽  
Drug Resistant ◽  
Functional Correlation ◽  
Naturally Occurring ◽  
High Resolution Nmr ◽  
Different Types ◽  
Reduced Activity ◽  
Poor Stability

Antimicrobial Peptides (AMPs), within their realm incorporate a diverse group of structurally and functionally varied peptides, playing crucial roles in innate immunity. Over the last few decades, the field of AMP has seen a huge upsurge, mainly owing to the generation of the so-called drug resistant ‘superbugs’ as well as limitations associated with the existing antimicrobial agents. Due to their resilient biological properties, AMPs can very well form the sustainable alternative for nextgeneration therapeutic agents. Certain drawbacks associated with existing AMPs are, however, issues of major concern, circumventing which are imperative. These limitations mainly include proteolytic cleavage and hence poor stability inside the biological systems, reduced activity due to inadequate interaction with the microbial membrane, and ineffectiveness because of inappropriate delivery among others. In this context, the application of naturally occurring AMPs as an efficient prototype for generating various synthetic and designed counterparts has evolved as a new avenue in peptide-based therapy. Such designing approaches help to overcome the drawbacks of the parent AMPs while retaining the inherent activity. In this review, we summarize some of the basic NMR structure based approaches and techniques which aid in improving the activity of AMPs, using the example of a 16-residue dengue virus fusion protein derived peptide, VG16KRKP. Using first principle based designing technique and high resolution NMR-based structure characterization we validate different types of modifications of VG16KRKP, highlighting key motifs, which optimize its activity. The approaches and designing techniques presented can support our peers in their drug development work.

scholarly journals Electrospun Nanofibers for Sensing and Biosensing Applications—A Review

2021 ◽  
Vol 22 (12) ◽  
pp. 6357
Author(s):  
Kinga Halicka ◽  
Joanna Cabaj
Keyword(s):  
High Surface ◽  
High Surface Area ◽  
Toxic Metal ◽  
Volume Ratio ◽  
Electrospun Nanofibers ◽  
Clinical Diagnostics ◽  
Loading Capacity ◽  
Electrospun Nanofiber ◽  
Sensing Platforms ◽  
Different Types

Sensors and biosensors have found applications in many areas, e.g., in medicine and clinical diagnostics, or in environmental monitoring. To expand this field, nanotechnology has been employed in the construction of sensing platforms. Because of their properties, such as high surface area to volume ratio, nanofibers (NFs) have been studied and used to develop sensors with higher loading capacity, better sensitivity, and faster response time. They also allow to miniaturize designed platforms. One of the most commonly used techniques of the fabrication of NFs is electrospinning. Electrospun NFs can be used in different types of sensors and biosensors. This review presents recent studies concerning electrospun nanofiber-based electrochemical and optical sensing platforms for the detection of various medically and environmentally relevant compounds, including glucose, drugs, microorganisms, and toxic metal ions.

A multi-dielectric-layered triboelectric nanogenerator as energized by corona discharge

Nanoscale ◽  
2017 ◽  
Vol 9 (27) ◽  
pp. 9668-9675 ◽  
Author(s):  
Jia Jia Shao ◽  
Wei Tang ◽  
Tao Jiang ◽  
Xiang Yu Chen ◽  
Liang Xu ◽  
...  
Keyword(s):  
Charge Density ◽  
Surface Charge ◽  
Corona Discharge ◽  
Surface Charge Density ◽  
High Surface ◽  
Cycling Stability ◽  
Triboelectric Nanogenerator ◽  
Excellent Cycling Stability ◽  
Vertical Contact ◽  
High Surface Charge Density

A multi-dielectric-layered vertical contact-separation mode TENG through a corona discharge approach results in outstanding output performances, i.e., a high surface charge density of 283 μC m−2 and excellent cycling stability (92.6% retention after 200 000 cycles).

scholarly journals Diurnal variations in the UV albedo of arctic snow

2008 ◽  
Vol 8 (21) ◽  
pp. 6551-6563 ◽  
Author(s):  
O. Meinander ◽  
A. Kontu ◽  
K. Lakkala ◽  
A. Heikkilä ◽  
L. Ylianttila ◽  
...  
Keyword(s):  
High Surface ◽  
Measured Temperature ◽  
Snow Melt ◽  
Clear Sky ◽  
Different Types ◽  
Essential Parameter ◽  
Surface Reflectivity ◽  
Climate Studies ◽  
Radiative Transfer Modeling ◽  
Surface Layer Thickness

Abstract. The relevance of snow for climate studies is based on its physical properties, such as high surface reflectivity. Surface ultraviolet (UV) albedo is an essential parameter for various applications based on radiative transfer modeling. Here, new continuous measurements of the local UV albedo of natural Arctic snow were made at Sodankylä (67°22'N, 26°39'E, 179 m a.s.l.) during the spring of 2007. The data were logged at 1-min intervals. The accumulation of snow was up to 68 cm. The surface layer thickness varied from 0.5 to 35 cm with the snow grain size between 0.2 and 2.5 mm. The midday erythemally weighted UV albedo ranged from 0.6 to 0.8 in the accumulation period, and from 0.5 to 0.7 during melting. During the snow melt period, under cases of an almost clear sky and variable cloudiness, an unexpected diurnal decrease of 0.05 in albedo soon after midday, and recovery thereafter, was detected. This diurnal decrease in albedo was found to be asymmetric with respect to solar midday, thus indicating a change in the properties of the snow. Independent UV albedo results with two different types of instruments confirm these findings. The measured temperature of the snow surface was below 0°C on the following mornings. Hence, the reversible diurnal change, evident for ~1–2 h, could be explained by the daily metamorphosis of the surface of the snowpack, in which the temperature of the surface increases, melting some of the snow to liquid water, after which the surface freezes again.

Deceleration of sliding motorcycles (mainly scooters) in accident reconstructions

2017 ◽  
Vol 232 (7) ◽  
pp. 866-876 ◽  
Author(s):  
Carlo Cialdai ◽  
Dario Vangi ◽  
Antonio Virga
Keyword(s):  
Urban Areas ◽  
Test Session ◽  
Road Accidents ◽  
Factors Affecting ◽  
Different Types ◽  
Energy Dissipated ◽  
Comparison Of The Results ◽  
Two Wheeler ◽  
The Impact ◽  
Good Agreement

This paper presents an analysis of the situation in which a two-wheeler (i.e. a motorcycle, where the term motorcycles includes scooters) falls over to the side and then successively slides; this typically occurs in road accidents involving this type of vehicle. Knowing the deceleration rate of the sliding phase allows the kinetic energy dissipated and the speed of the motorcycle just before the fall to the ground to be calculated. These parameters are very important in the analysis and reconstruction of accidents. The work presented in this paper was developed in two experimental test sessions on fully faired motorcycles which are mainly of the scooter type and widely used in urban areas. In the first session, sliding tests were carried out, with the speed in the range 10–50 km/h, on three different types of road surface. Analysis of the evidence allowed the dissipative main phases of motion of the motorcycle (the impact with the ground, the rebounds and the stabilized swiping) to be identified and some factors affecting the phenomenon to be studied. The coefficient of average deceleration was calculated using two typical equations. The second test session consisted of drag tests. In these tests, the motorcycle, which had previously laid on its side, was dragged for a few metres at a constant speed of about 20 km/h, while the drag force was measured. A comparison of the results obtained in these tests with those obtained in the sliding tests yielded very good agreement in the coefficients of deceleration.

Treating Afro hair loss: signs, symptoms and specialist interest

2021 ◽  
Vol 10 (5) ◽  
pp. 190-197
Author(s):  
Ingrid Wilson
Keyword(s):  
Black Women ◽  
Hair Loss ◽  
Factors Affecting ◽  
Different Types ◽  
Recent Developments ◽  
Hair Care ◽  
Care Practices ◽  
The Aesthetic ◽  
The Impact ◽  
Symptoms And Signs

This article explores the different types of hair loss that black women may experience more than other groups of patients. Properties of African hair and the impact of hair care practices are discussed, as well as factors affecting the presentation of other hair loss conditions. It is important for the aesthetic practitioner to be able to distinguish between the temporary forms of hair loss that they can help to treat and the permanent or scarring forms of hair loss, which need a prompt referral to a dermatologist with a specialist interest in hair. Prompt recognition and referral can help to delay the progression of hair loss. The symptoms and signs that patients and practitioners should be alerted to are explored, as well as the treatments that can help and where referrals may be necessary. Recent developments and gaps in knowledge are summarised.

Factors affecting pharyngeal Haemophilus influenzae type b colonization rates in children

1976 ◽  
Vol 4 (5) ◽  
pp. 413-417
Author(s):  
R H Michaels ◽  
C S Poziviak ◽  
F E Stonebraker ◽  
C W Norden
Keyword(s):  
Haemophilus Influenzae ◽  
Throat Swab ◽  
Economic Status ◽  
Health Department ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Older Children ◽  
Factors Affecting ◽  
Colonization Rates

Over 1,300 children were studied in an analysis of factors that might affect pharyngeal colonization with Haemophilus influenzae type b. Our semiquantitative methods for the culture of H. influenzae type b, consisting of inoculation of 0.001 ml of throat swab fluid on antiserum agar plates and division of the results into three grades of intensity, showed agreement as to intensity of colonization in over 80% of repeat throat cultures. Our data also suggest that throat swabs are more efficient than nasopharyngeal swabs for detecting colonization, particularly for older children. All 17 H. influenzae type b carriers found with either method were detected with throat swabs, but six had negative nasopharyngeal cultures; four of these six were lightly colonized older children. Furthermore, colony counts were apt to be higher on plates inoculated with throat swab fluids. The frequency of pharyngeal H. influenzae type b colonization in children visiting health department clinics and pediatricians' offices was low during the first 6 months of life (0.7%) but averaged 3 to 5% throughout the rest of childhood. Approximately two-thirds of the carriers were colonized at an intensity too low to be detected by standard laboratory techniques. No influence on colonization rates was found for sex, race, season, economic status, or common childhood infectious diseases such as coryza or otitis media.

scholarly journals Mutual fund investors perception in India-a study

2017 ◽  
Vol 7 (1.1) ◽  
pp. 60
Author(s):  
R. Udhayasankar ◽  
K. Maran
Keyword(s):  
Mutual Funds ◽  
Mutual Fund ◽  
Financial Risk ◽  
Fund Raising ◽  
Factors Affecting ◽  
Derivative Instruments ◽  
Different Types ◽  
Small Investors ◽  
Investment Option ◽  
Short Span

Mutual fund is four decades old in India.  It was started by UTI during the year 1964 with few schemes for small investors. During this short span of time it has made tremendous growth in Indian small investors. But now a day’s its volume of investors and sources of investment also growing tremendous level. Moreover mutual fund scheme have added new dimension to overcome financial risk of small investors and also in fund raising capacity of corporate sectors. Mutual fund investors can diversify even more by purchasing different kind of stocks which will helps to spreading out investors’ money across different types of derivative instruments and hence it reduces the risk tremendously up to certain extent and it is automatically diversify in a predetermined category of investments. This serves bridge work between small investors and corporate sectors likewise considering those points in this paper is an attempt to know the investors’ perceptions towards selected mutual funds. This paper makes an attempt to identify various factors affecting perception of investors regarding investment in mutual funds. The findings will helpful to identify the investors’ interest base and factors clearly and it reveals that the investors consider mutual funds as flexible investment option and it creates interest of investment among small investors.

scholarly journals Synthesis, and Characterization, and Evaluation of Cellular Effects of the FOL-PEG-g-PEI-GAL Nanoparticles as a Potential Non-Viral Vector for Gene Delivery

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
S. Ghiamkazemi ◽  
A. Amanzadeh ◽  
R. Dinarvand ◽  
M. Rafiee-Tehrani ◽  
M. Amini
Keyword(s):  
Gene Delivery ◽  
Zeta Potential ◽  
Surface Charge ◽  
Cell Line ◽  
Graft Copolymer ◽  
Viral Vector ◽  
Transfection Efficiency ◽  
High Surface ◽  
Liver Cells ◽  
Dna Complexes

In this manuscript, we synthesized the potential non viral vector for gene delivery with proper transfection efficiency and low cytotoxicity. Polyethylenimine (PEI) is a well-known cationic polymer which has high positive surface charge for condensing plasmid DNA. However; it is highly cytotoxic in many cell lines because of the high surface charge, non-biodegradability and non-biocompatibility. To enhance PEI biodegradability, the graft copolymer “PEG-g-PEI” was synthesized. To target cancer liver cells, two targeting ligands folic acid and galactose (lactobionic acid) which are over expressed on human hepatocyte carcinoma were attached to graft copolymer and “FOL-PEG-g-PEI-GAL” copolymer was synthesized. Composition of this grafted copolymer was characterized using1H-NMR and FTIR spectra. The molecular weight and zeta potential of this copolymer was compared to PEI. The particle size and zeta potential of FOL-PEG-g-PEI-GAL/DNA complexes at various N/P ratio were measured using dynamic light scattering (DLS). Cytotoxicity of the copolymer was also studied in cultured HepG2 human hepatoblastoma cell line. The FOL-PEG-g-PEI-GAL/DNA complexes at various N/P ratios exhibited no cytotoxicity in HepG2 cell line compared to PEI 25K as a control. The novel copolymer showed enhanced biodegradability in physiological conditions in compared with PEI and targeted cultured HepG2 cells. More importantly, significant transfection efficiency was exhibited in cancer liver cells. Together, our results showed that “FOL-PEG-g-PEI-GAL” nanoparticals could be considered as a useful non-viral vector for targeted gene delivery.

scholarly journals Early-Age Cracking in Concrete: Causes, Consequences, Remedial Measures, and Recommendations

2018 ◽  
Vol 8 (10) ◽  
pp. 1730 ◽  
Author(s):  
Md. Safiuddin ◽  
A. Kaish ◽  
Chin-Ong Woon ◽  
Sudharshan Raman
Keyword(s):  
Service Life ◽  
Concrete Structures ◽  
Real Life ◽  
Early Age ◽  
Structural Elements ◽  
Remedial Measures ◽  
Curing Conditions ◽  
Factors Affecting ◽  
Different Types ◽  
Service Conditions

Cracking is a common problem in concrete structures in real-life service conditions. In fact, crack-free concrete structures are very rare to find in real world. Concrete can undergo early-age cracking depending on the mix composition, exposure environment, hydration rate, and curing conditions. Understanding the causes and consequences of cracking thoroughly is essential for selecting proper measures to resolve the early-age cracking problem in concrete. This paper will help to identify the major causes and consequences of the early-age cracking in concrete. Also, this paper will be useful to adopt effective remedial measures for reducing or eliminating the early-age cracking problem in concrete. Different types of early-age crack, the factors affecting the initiation and growth of early-age cracks, the causes of early-age cracking, and the modeling of early-age cracking are discussed in this paper. A number of examples for various early-age cracking problems of concrete found in different structural elements are also shown. Above all, some recommendations are given for minimizing the early-age cracking in concrete. It is hoped that the information conveyed in this paper will be beneficial to improve the service life of concrete structures. Concrete researchers and practitioners may benefit from the contents of this paper.

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