Biopolymer Structures and Behaviors with Comparisons to Synthetic Polymers

Conformations ◽  
2020 ◽  
pp. 179-215
Author(s):  
Alan Tonelli ◽  
Jialong Shen
Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1577
Author(s):  
Carla Villa ◽  
Eleonora Russo

Hand hygiene can be considered a strategic key useful in the containment of infections such as COVID-19 both at home and in communities because it can dramatically reduce the widespread outbreak of infections. In case of the unavailability of soap and water, “instant” hand sanitizers are recommended because their application can be considered easy, versatile, quick and often less aggressive for the skin. For these reasons, alcoholic and alcohol-free hand rub gels can be considered the best performing formulations on the market. Together with disinfectants and antiseptic agents, hydrogels play a fundamental role in obtaining stable formulations and are easy to disperse, with a pleasant skin feel and an overall good performance. Several compounds commonly used in the pharmaceutical, cosmetic and food industry are available for this purpose, in particular, cellulose derivatives and synthetic polymers derivatives. Each of them is available in several grades, presenting different thickening behavior, rheological properties and compatibility with other ingredients, alcohols in particular. For all these reasons, it is important to explore hydrogel properties and behaviors in different contexts (i.e., hydroalcoholic and aqueous media) in order to develop new and performing hand rub gels, always taking into account the different international legal frameworks regarding disinfectant and sanitizing formulations.


Author(s):  
P. Sadhukhan ◽  
J. B. Zimmerman

Rubber stocks, specially tires, are composed of natural rubber and synthetic polymers and also of several compounding ingredients, such as carbon black, silica, zinc oxide etc. These are generally mixed and vulcanized with additional curing agents, mainly organic in nature, to achieve certain “designing properties” including wear, traction, rolling resistance and handling of tires. Considerable importance is, therefore, attached both by the manufacturers and their competitors to be able to extract, identify and characterize various types of fillers and pigments. Several analytical procedures have been in use to extract, preferentially, these fillers and pigments and subsequently identify and characterize them under a transmission electron microscope.Rubber stocks and tire sections are subjected to heat under nitrogen atmosphere to 550°C for one hour and then cooled under nitrogen to remove polymers, leaving behind carbon black, silica and zinc oxide and 650°C to eliminate carbon blacks, leaving only silica and zinc oxide.


2002 ◽  
Vol 17 (S2) ◽  
pp. S48
Author(s):  
Robyn R. M. Gershon ◽  
Kristine A. Qureshi ◽  
Stephen S. Morse ◽  
Marissa A. Berrera ◽  
Catherine B. Dela Cruz

Crisis ◽  
2013 ◽  
Vol 34 (2) ◽  
pp. 82-97 ◽  
Author(s):  
Bonnie Klimes-Dougan ◽  
David A. Klingbeil ◽  
Sarah J. Meller

Background: While the ultimate goal of adolescent suicide-prevention efforts is to decrease the incidence of death by suicide, a critical intermediary goal is directing youths toward effective sources of assistance. Aim: To comprehensively review the universal prevention literature and examine the effects of universal prevention programs on student’s attitudes and behaviors related to help-seeking. Method: We systematically reviewed studies that assessed help-seeking outcomes including prevention efforts utilizing (1) psychoeducational curricula, (2) gatekeeper training, and (3) public service messaging directed at youths. Of the studies reviewed, 17 studies evaluated the help-seeking outcomes. These studies were identified through a range of sources (e.g., searching online databases, examining references of published articles on suicide prevention). Results: The results of this review suggest that suicide-prevention programming has a limited impact on help-seeking behavior. Although there was some evidence that suicide-prevention programs had a positive impact on students’ help-seeking attitudes and behaviors, there was also evidence of no effects or iatrogenic effects. Sex and risk status were moderators of program effects on students help-seeking. Conclusions: Caution is warranted when considering which suicidal prevention interventions best optimize the intended goals. The impact on adolescents’ help-seeking behavior is a key concern for educators and mental-health professionals.


Crisis ◽  
2020 ◽  
Vol 41 (4) ◽  
pp. 288-295 ◽  
Author(s):  
Nadia Bounoua ◽  
Jasmeet P. Hayes ◽  
Naomi Sadeh

Abstract. Background: Suicide among veterans has increased in recent years, making the identification of those at greatest risk for self-injurious behavior a high research priority. Aims: We investigated whether affective impulsivity and risky behaviors distinguished typologies of self-injurious thoughts and behaviors in a sample of trauma-exposed veterans. Method: A total of 95 trauma-exposed veterans (ages 21–55; 87% men) completed self-report measures of self-injurious thoughts and behaviors, impulsivity, and clinical symptoms. Results: A latent profile analysis produced three classes that differed in suicidal ideation, suicide attempts and nonsuicidal self-injury (NSSI): A low class that reported little to no self-injurious thoughts or behaviors; a self-injurious thoughts (ST) class that endorsed high levels of ideation but no self-harm behaviors; and a self-injurious thoughts and behaviors (STaB) class that reported ideation, suicide attempts and NSSI. Membership in the STaB class was associated with greater affective impulsivity, disinhibition, and distress/arousal than the other two classes. Limitations: Limitations include an overrepresentation of males in our sample, the cross-sectional nature of the data, and reliance on self-report measures. Conclusion: Findings point to affective impulsivity and risky behaviors as important characteristics of veterans who engage in self-injurious behaviors.


Crisis ◽  
2020 ◽  
Vol 41 (3) ◽  
pp. 172-178
Author(s):  
Brooke A. Ammerman ◽  
Martha K. Fahlgren ◽  
Kristen M. Sorgi ◽  
Michael S. McCloskey

Abstract. Background: Despite being a major public health concern, it is unclear how suicidal thoughts and behaviors differentially impact separate racial groups. Aims: The aim of the current study was to examine the occurrence of nonlethal suicide events, in addition to suicide attempt characteristics and factors contributing to suicide attempts. Method: A final sample of 7,094 undergraduates from a large northeastern university, identifying as members of three racial groups (White [67.30%], Black [17.30%], and Asian [15.40%]), completed online questionnaires. Results: White participants reported increased likelihood of endorsing lifetime suicidal ideation and plan, whereas Black participants reported decreased likelihood of these events; no differences were found in rates of lifetime suicide attempts. Black participants' suicidal behavior may involve greater ambivalence of intent. A higher proportion of Asian participants endorsed interpersonal factors as contributing to their suicide attempts, whereas a greater percentage of White participants reported internal contributing factors. Limitations: Findings are limited by the sample size and assessment of lifetime suicidal thoughts and behaviors. Conclusion: The findings present a more nuanced look at attitudes and actions related to suicidal thoughts and behaviors that may inform future research and risk assessment procedures.


2019 ◽  
Vol 26 (2) ◽  
pp. 56-67 ◽  
Author(s):  
Hanna Hofmann ◽  
Carl-Walter Kohlmann

Abstract. Positive affectivity (PA) and negative affectivity (NA) are basic traits that affect work-related perceptions and behaviors and should be considered in any assessment of these variables. A quite common method to assess healthy or unhealthy types of work-related perceptions and behaviors is the questionnaire on Work-Related Coping Behavior and Experience Patterns (WCEP). However, the association of PA and NA with WCEP remained unclear. In a sample of teachers, physiotherapists, and teacher students ( N = 745; Mage = 35.07, SD = 12.49; 78% females), we aimed to identify the relevance of these basic traits. After controlling for age, gender, and type of occupation, we found main effects of PA and NA, with the specific combination of PA and NA being decisive for predicting the assignment to a WCEP type. The results highlight the need to include PA and NA in future assessments with the WCEP questionnaire.


Sign in / Sign up

Export Citation Format

Share Document