scholarly journals Deciphering the Roles of Interspace and Controlled Disorder in the Bactericidal Properties of Nanopatterns against Staphylococcus aureus

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 347 ◽  
Author(s):  
Khashayar Modaresifar ◽  
Lorenzo B. Kunkels ◽  
Mahya Ganjian ◽  
Nazli Tümer ◽  
Cornelis W. Hagen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Mammalian Cells ◽  
Recent Progress ◽  
Design Parameters ◽  
Patterned Surfaces ◽  
Cross Sectional ◽  
Micro Fabrication ◽  
Future Studies ◽  
Bactericidal Properties ◽  
Direct Penetration

Recent progress in nano-/micro-fabrication techniques has paved the way for the emergence of synthetic bactericidal patterned surfaces that are capable of killing the bacteria via mechanical mechanisms. Different design parameters are known to affect the bactericidal activity of nanopatterns. Evaluating the effects of each parameter, isolated from the others, requires systematic studies. Here, we systematically assessed the effects of the interspacing and disordered arrangement of nanopillars on the bactericidal properties of nanopatterned surfaces. Electron beam induced deposition (EBID) was used to additively manufacture nanopatterns with precisely controlled dimensions (i.e., a height of 190 nm, a diameter of 80 nm, and interspaces of 100, 170, 300, and 500 nm) as well as disordered versions of them. The killing efficiency of the nanopatterns against Gram-positive Staphylococcus aureus bacteria increased by decreasing the interspace, achieving the highest efficiency of 62 ± 23% on the nanopatterns with 100 nm interspacing. By comparison, the disordered nanopatterns did not influence the killing efficiency significantly, as compared to their ordered correspondents. Direct penetration of nanopatterns into the bacterial cell wall was identified as the killing mechanism according to cross-sectional views, which is consistent with previous studies. The findings indicate that future studies aimed at optimizing the design of nanopatterns should focus on the interspacing as an important parameter affecting the bactericidal properties. In combination with controlled disorder, nanopatterns with contrary effects on bacterial and mammalian cells may be developed.

Relationship of Scabies With Pioderma: As a Risk Factor

2018 ◽  
Vol 1 (1) ◽  
pp. 33-42
Author(s):  
Yulia Farida Yahya ◽  
Fifa Argentina ◽  
Rusmawardiana Rusmawardiana
Keyword(s):  
Staphylococcus Aureus ◽  
Elementary School ◽  
Risk Factor ◽  
Low Income ◽  
Primary Schools ◽  
Pediatric Patients ◽  
Group A Streptococcus ◽  
Cross Sectional ◽  
The Government ◽  
Scabies Infestation

Scabies is a parasitic infestation of the skin, that is affecting on the low income and crowded community in many tropical countries, especially developing countries such as Indonesia. Scabies infestation increases the incidence of secondary pyoderma include impetigo, folliculitis, cellulitis, ecthyma, abscess. Secondary pyoderma is a skin infection disease mainly caused by     group A Streptococcus (GAS) and Staphylococcus aureus (SA). Pyoderma is a risk factor for the glomerulonephritis infection, rheumatic diseases, which significantly increases morbidity and mortality, causing the government burden. The aim of this study is  determining the etiology and correlation of pyoderma infection in scabies patient. To determine sosio-demographic included sex, age in pediatric patients in primary schools (SD) in the district of Kertapati Palembang. The study design was cross sectional, and study samples were new scabies patients in the elementary school (age 6-14-year-old) with or without pyoderma. Clinical findings included history, physical examination and diagnostic procedure, which was investigation of skin scraping specimen material (SSB = skin surface biopsy) in confirmation with dermoscopic polar examination (DS) to show Sarcoptes scabiei mites. Microbiological examination with Gram stain identified the etiology of pyoderma.  Results of this study shows that there was a significance relationship between scabies infestation and pyoderma in children in elementary school. Staphylococcus aureus dan GAS are the most common caused of pyoderma in pediatric patients with scabies. Conclusion is there is a significant correlation between scabies and pyoderma. There is  a need to provide scabies and pyoderma medication at primary care health center as well as counseling for prevention in Palembang area with crowded population periodically.  

Suppurative Infections in Hospitalized Patients – An Ongoing MRSA Threat

2020 ◽  
Author(s):  
Sadaf Razzak
Keyword(s):  
Staphylococcus Aureus ◽  
Medical Science ◽  
Great Influence ◽  
Antibiotic Sensitivity ◽  
Skin Lesions ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Inducible Clindamycin Resistance ◽  
Empiric Antibiotic ◽  
Medical Wards

Background: Penicillin resistance among Staphylococcus aureus commonly encountered in the hospital admitted patients. Detection of antibiotic sensitivity in hospital acquired methicillin resistant Staphylococcus aureus infections is important as it has great influence on empiric antibiotic prescription, successful control of infection, prevention of spread of disease and successful patient management. This study aimed to detect the frequency of HA-MRSA from pus samples in a hospital setup with assessment of their antibiotic susceptibility patterns. Method: A cross-sectional study was conducted in the Microbiology department of Basic Medical Science Institute, JPMC, Karachi from January 2015 until December 2015. Pus samples from surgical site wounds, skin lesions, abscesses from surgical and medical wards and ICUs were collected. According to the standards given by CLSI 2014, MRSA testing of the samples was done and susceptibility testing for antibiotics was performed. Inducible clindamycin resistance was detected by D-Test; E Test. determined MIC (minimum inhibitory concentration) for vancomycin. The data was analyzed by SPSS version 16. Result: Out of the 149 MRSA identified from the pus samples, 106 (71.14%) samples were HA-MRSA. The number of male patients was more than the female patients (67.66%). Out of the 106 HA-MRSA, 91(85.8%) were sensitive to TMP/SMX, 98(92.5%) to rifampicin, 12(11.6%) to gentamicin, 85(80.2%) to tetracycline, 11(10.4%) to erythromycin, 37(34.9%) to clindamycin, 20(18.9%) to ciprofloxacin, 106 (100%) to both vancomycin and linezolid. Conclusion: HA-MRSA showed sensitivity to TMP/SMX and vancomycin making them effective drugs to use in combination in superficial infections. The drug linezolid also showed 100% sensitivity.

scholarly journals Spectral and Antibiotic Susceptibility of Pathogens Isolated from Saudi Patients with Diabetic Foot Infections

2021 ◽  
Vol 12 (1) ◽  
pp. 16-20
Author(s):  
Samiah Hamad S Al-Mijalli
Keyword(s):  
Staphylococcus Aureus ◽  
Diabetic Foot ◽  
Antibiotic Susceptibility ◽  
Empirical Therapy ◽  
Multidrug Resistant ◽  
Foot Ulcers ◽  
Sensitivity Testing ◽  
Cross Sectional ◽  
Diabetic Foot Infections ◽  
Microbiological Methods

Diabetic foot infections (DFIs) are a significant health issue and a common complication among patients with diabetes. To develop antibiotic therapy for these high-risk patients, the current study evaluates the scope of DFIs and identifies the causing microbes. It also measures spectrum and antibiotic susceptibility of the pathogens isolated from adults with DFIs in Saudi Arabia. To achieve the study objectives, a cross-sectional study was implemented and the baseline characteristics for 44 patients with DFIs were defined. Optimal aerobic and anaerobic microbiological techniques were utilized to culture specimens isolated from infected foot ulcers. The standard microbiological methods were employed to identify the bacterial isolates and antibiotic susceptibility testing was conducted following the procedures of the Clinical and Laboratory Standards Institute (CLSI). Results showed that 12 microorganisms were isolated from the participants’ diabetic foot ulcers. Staphylococcus Aureus was ranked first because it appeared in 29 (65.9%) cases. Streptococcus Agalactiae was ranked second and multi-microbial infections were also found. Most of the organisms were susceptible to Vancomycin, Ciprofloxacin, and Cefalexin, but they were resistant to Methicillin, Gentamicin, and Ampicillin antibiotics. Staphylococcus Aureus was most sensitive to Ciprofloxacin, while it was resistant to Methicillin. About 10% of the isolates were multidrug-resistant. The study concludes that while Vancomycin should be used empirically for Gram-positive isolates, Ciprofloxacin can be taken into consideration for most of the Gram-negatives aerobes. Based on including various microorganisms and the advent of multidrug-resistant strains, proper culture and sensitivity testing are necessary prior to the empirical therapy.

scholarly journals What Matters for Job Security? Exploring the Relationships among Symbolic, Instrumental Images, and Attractiveness for Corporations in South Korea

2021 ◽  
Vol 13 (9) ◽  
pp. 4854
Author(s):  
Juyeon Oh ◽  
Seunghwan Myeong
Keyword(s):  
Undergraduate Students ◽  
Organizational Context ◽  
Job Security ◽  
Corporate Image ◽  
Causal Claim ◽  
Cross Sectional ◽  
Future Studies ◽  
Collectivistic Cultures ◽  
Symbolic Image ◽  
The Relationship

This study examines the extent to which the symbolic and instrumental images and attractiveness toward an organization are related. This study further focuses on global human resource management and reports findings from two studies: Study 1 uses the data from undergraduate students, and Study 2 cross-validates the findings of Study 1 by using actual data from employees. The distinction of this study from previous works is that the present work focuses on a Korean organizational context (collectivistic cultures) and the differences between the potential applicants and employees in the perception of an organization′s attractiveness. Furthermore, it investigates the relationship between the symbolic and instrumental images toward organizations, unlike existing relative research. The results show that the symbolic and instrumental images are related, and the perceptions of the corporate image differ for the potential applicants and employees in the context of collectivistic cultures. The more competent employees consider their organization to be, the more job security they perceive their organization to provide. Moreover, the symbolic image of being competent is negatively related to the instrumental image of job security. Since this study used cross-sectional data, future studies need to use longitudinal data to establish our model′s causal claim empirically and investigate the underlying reasons behind these differences.

scholarly journals Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Wan ◽  
Ximing Liu ◽  
Jichen Miao ◽  
Peng Cong ◽  
Yuai Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Helical Ct ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Safe Operation ◽  
Cross Sectional ◽  
Ct System ◽  
Near Future ◽  
Pebble Flow

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.

scholarly journals Design of an Ultra-Wideband Microstrip-to-Slotline Transition on Low-Permittivity Substrate

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1329
Author(s):  
Jung Seok Lee ◽  
Gwan Hui Lee ◽  
Wahab Mohyuddin ◽  
Hyun Chul Choi ◽  
Kang Wook Kim
Keyword(s):  
Microstrip Line ◽  
Return Loss ◽  
Analytical Formula ◽  
Parameter Tuning ◽  
Ultra Wideband ◽  
Design Parameters ◽  
Analytical Line ◽  
Cross Sectional ◽  
Analysis And Design ◽  
Low Permittivity

Analysis and design of an ultra-wideband microstrip-to-slotline transition on a low permittivity substrate is presented. Cross-sectional structures along the proposed transition are analyzed using conformal mapping assuming quasi-TEM modes, attaining one analytical line impedance formula with varying design parameters. Although the slotline is a non-TEM transmission line, the transitional structures are configured to have quasi-TEM modes before forming into the slotline. The line impedance is optimally tapered using the Klopfenstein taper, and the electric field shapes are smoothly transformed from microstrip line to slotline. The analytical formula is accurate within 5% difference, and the final transition configuration can be designed without parameter tuning. The implemented microstrip-to-slotline transition possesses insertion loss of less than 1.5 dB per transition and return loss of more than 10 dB from 4.4 to over 40 GHz.

The optimism-pessimism ratio as predictor of employee creativity: the promise of duality

2018 ◽  
Vol 21 (3) ◽  
pp. 423-442 ◽  
Author(s):  
Arménio Rego ◽  
Miguel Pina e Cunha ◽  
Dálcio Reis Júnior ◽  
Cátia Anastácio ◽  
Moriel Savagnago
Keyword(s):  
Cross Sectional ◽  
Content Type ◽  
Future Studies ◽  
Positive Effects ◽  
The Status ◽  
Single Moment ◽  
Quasi Experimental ◽  
Creativity And Innovation ◽  
The Relationship ◽  
Practical Implications

Purpose The purpose of this paper is to study if the employees’ optimism-pessimism ratio predicts their creativity. Design/methodology/approach In total, 134 employees reported their optimism and pessimism, and the respective supervisors described the employees’ creativity. Findings The relationship between the optimism-pessimism ratio and creativity is curvilinear (inverted U-shaped); beyond a certain level of the optimism-pessimism ratio, the positive relationship between the ratio and creativity weakens, suggesting that the possible positive effects of (high) optimism may be weakened by a very low level of pessimism. Research limitations/implications Being cross-sectional, the study examines neither the causal links between the optimism-pessimism ratio and creativity nor other plausible causal links. The study was carried out at a single moment and did not capture the dynamics that occur over the course of time involving changes in optimism/pessimism and creativity. Future studies may adopt longitudinal or quasi-experimental designs. Practical implications Managers and organizations must consider that, even though positivity promotes creativity, some level of negativity may help positivity to produce creativity. Originality/value This study suggests that scholars who want to study the antecedents of creativity (and innovation) must be cautious in focusing only on the positive or the negative sides of individuals’ characteristics, and rather they must explore the interplay between both poles. Individuals may experience both positive and negative states/traits (Smith et al., 2016), and this both/and approach may impel them to think divergently, to challenge the status quo and to propose “out the box” and useful ideas.

Effect of Design Parameters on Drop Test Performance of Wafer Level Chip Scale Packages (WLCSP)

2011 ◽  
Author(s):  
Pushkraj Tumne ◽  
Vikram Venkatadri ◽  
Santosh Kudtarkar ◽  
Michael Delaus ◽  
Daryl Santos ◽  
...  
Keyword(s):  
Flip Chip ◽  
Bulk Solder ◽  
Consumer Electronics ◽  
Drop Test ◽  
Design Parameters ◽  
Mechanical Shock ◽  
Wafer Level ◽  
Cross Sectional ◽  
Right Censored Data ◽  
Solder Balls

Today’s consumer market demands electronics that are smaller, faster and cheaper. To cater to these demands, novel materials, new designs, and new packaging technologies are introduced frequently. Wafer Level Chip Scale Package (WLCSP) is one of the emerging package technologies that have the key advantages of reduced cost and smaller footprint. The portable consumer electronics are frequently dropped; hence the emphasis of reliability is shifting towards study of effects of mechanical shock loading increasingly. Mechanical loading typically induces brittle fractures (also known as intermetallic failures) between the solder bumps and bond pads at the silicon die side. This type of failure mechanism is typically characterized by the board level drop test. WLCSP is a variant of the flip-chip interconnection technique. In WLCSPs, the active side of the die is inverted and connected to the PCB by solder balls. The size of these solder balls is typically large enough (300μm pre-reflow for 0.5mm pitch and 250μm pre-reflow for 0.4mm pitch) to avoid use of underfill that is required for the flip-chip interconnects. Several variations are incorporated in the package design parameters to meet the performance, reliability, and footprint requirements of the package assembly. The design parameters investigated in this effort are solder ball compositions with different Silver (Ag) content, backside lamination with different thickness, WLCSP type –Direct and Re-Distribution Layer (RDL), bond pad thickness, and sputtered versus electroplated Under Bump Metallurgy (UBM) deposition methods for 8×8, 9×9, and 10×10 array sizes. The test vehicles built using these design parameters were drop tested using JEDEC recommended test boards and conditions as per JESD22-B11. Cross sectional analysis was used to identify, confirm, and classify the intermetallic, and bulk solder failures. The objective of this research was to quantify the effects and interactions of WLCSP design parameters through drop test. The drop test data was collected and treated as a right censored data. Further, it was analyzed by fitting empirical distributions using the grouped and un-grouped data approach. Data analysis showed that design parameters had a significant effect on the drop performance and played a vital role in influencing the package reliability.

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