scholarly journals Physicochemical considerations for bottom-up synthetic biology

2019 ◽  
Vol 3 (5) ◽  
pp. 445-458 ◽  
Author(s):  
Wojciech Mikołaj Śmigiel ◽  
Pauline Lefrançois ◽  
Bert Poolman
Keyword(s):  
Redox State ◽  
Life Sciences ◽  
Metabolic Energy ◽  
Molecular Crowding ◽  
Protein Activity ◽  
Bottom Up ◽  
Internal Ph ◽  
Synthetic Cells ◽  
Molecular Components ◽  
The Impact

The bottom-up construction of synthetic cells from molecular components is arguably one of the most challenging areas of research in the life sciences. We review the impact of confining biological systems in synthetic vesicles. Complex cell-like systems require control of the internal pH, ionic strength, (macro)molecular crowding, redox state and metabolic energy conservation. These physicochemical parameters influence protein activity and need to be maintained within limits to ensure the system remains in steady-state. We present the physicochemical considerations for building synthetic cells with dimensions ranging from the smallest prokaryotes to eukaryotic cells.

scholarly journals Imaging NAD(H) Redox Alterations in Cryopreserved Alveolar Macrophages from Ozone-Exposed Mice and the Impact of Nutrient Starvation during Long Lag Times

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 767
Author(s):  
He N. Xu ◽  
Joanna Floros ◽  
Lin Z. Li ◽  
Shaili Amatya
Keyword(s):  
Oxidative Stress ◽  
Alveolar Macrophages ◽  
Redox State ◽  
Redox Status ◽  
Nutrient Starvation ◽  
Ozone Exposure ◽  
Reduced Form ◽  
Time Period ◽  
Lag Times ◽  
The Impact

Employing the optical redox imaging technique, we previously identified a significant redox shift of nicotinamide adenine dinucleotide (NAD and the reduced form NADH) in freshly isolated alveolar macrophages (AM) from ozone-exposed mice. The goal here was twofold: (a) to determine the NAD(H) redox shift in cryopreserved AM isolated from ozone-exposed mice and (b) to investigate whether there is a difference in the redox status between cryopreserved and freshly isolated AM. We found: (i) AM from ozone-exposed mice were in a more oxidized redox state compared to that from filtered air (FA)-exposed mice, consistent with the results obtained from freshly isolated mouse AM; (ii) under FA exposure, there was no significant NAD(H) redox difference between fresh AM that had been placed on ice for 2.5 h and cryopreserved AM; however, under ozone exposure, fresh AM were more oxidized than cryopreserved AM; (iii) via the use of nutrient starvation and replenishment and H2O2-induced oxidative stress of an AM cell line, we showed that this redox difference between cryopreserved and freshly isolated AM is likely the result of the double “hit”, i.e., the ozone-induced oxidative stress plus nutrient starvation that prevented freshly isolated AM from a full recovery after being on ice for a prolonged time period. The cryopreservation technique we developed eliminates/minimizes the effects of oxidative stress and nutrient starvation on cells. This method can be adopted to preserve lung macrophages from animal models or clinical patients for further investigations.

scholarly journals Classification of standing and sitting phases based on in-socket piezoelectric sensors in a transfemoral amputee

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tawfik Yahya ◽  
Nur Azah Hamzaid ◽  
Sadeeq Ali ◽  
Farahiyah Jasni ◽  
Hanie Nadia Shasmin
Keyword(s):  
Time Domain ◽  
Classification Accuracy ◽  
Sensory System ◽  
Metabolic Energy ◽  
Support Vector ◽  
Data Set ◽  
Transfemoral Amputee ◽  
Sit To Stand ◽  
Optimal Classifier ◽  
The Impact

AbstractA transfemoral prosthesis is required to assist amputees to perform the activity of daily living (ADL). The passive prosthesis has some drawbacks such as utilization of high metabolic energy. In contrast, the active prosthesis consumes less metabolic energy and offers better performance. However, the recent active prosthesis uses surface electromyography as its sensory system which has weak signals with microvolt-level intensity and requires a lot of computation to extract features. This paper focuses on recognizing different phases of sitting and standing of a transfemoral amputee using in-socket piezoelectric-based sensors. 15 piezoelectric film sensors were embedded in the inner socket wall adjacent to the most active regions of the agonist and antagonist knee extensor and flexor muscles, i. e. region with the highest level of muscle contractions of the quadriceps and hamstring. A male transfemoral amputee wore the instrumented socket and was instructed to perform several sitting and standing phases using an armless chair. Data was collected from the 15 embedded sensors and went through signal conditioning circuits. The overlapping analysis window technique was used to segment the data using different window lengths. Fifteen time-domain and frequency-domain features were extracted and new feature sets were obtained based on the feature performance. Eight of the common pattern recognition multiclass classifiers were evaluated and compared. Regression analysis was used to investigate the impact of the number of features and the window lengths on the classifiers’ accuracies, and Analysis of Variance (ANOVA) was used to test significant differences in the classifiers’ performances. The classification accuracy was calculated using k-fold cross-validation method, and 20% of the data set was held out for testing the optimal classifier. The results showed that the feature set (FS-5) consisting of the root mean square (RMS) and the number of peaks (NP) achieved the highest classification accuracy in five classifiers. Support vector machine (SVM) with cubic kernel proved to be the optimal classifier, and it achieved a classification accuracy of 98.33 % using the test data set. Obtaining high classification accuracy using only two time-domain features would significantly reduce the processing time of controlling a prosthesis and eliminate substantial delay. The proposed in-socket sensors used to detect sit-to-stand and stand-to-sit movements could be further integrated with an active knee joint actuation system to produce powered assistance during energy-demanding activities such as sit-to-stand and stair climbing. In future, the system could also be used to accurately predict the intended movement based on their residual limb’s muscle and mechanical behaviour as detected by the in-socket sensory system.

scholarly journals A Risk-Based Strategy for Evaluating Mitigation Options for Process-Formed Compounds in Food

2016 ◽  
Vol 35 (3) ◽  
pp. 358-370 ◽  
Author(s):  
Paul Hanlon ◽  
Gregory P. Brorby ◽  
Mansi Krishan
Keyword(s):  
North America ◽  
Decision Tree ◽  
Scientific Community ◽  
Life Sciences ◽  
Technical Committee ◽  
Global Approach ◽  
Chemical Safety ◽  
The Public ◽  
The North ◽  
The Impact

Processing (eg, cooking, grinding, drying) has changed the composition of food throughout the course of human history; however, awareness of process-formed compounds, and the potential need to mitigate exposure to those compounds, is a relatively recent phenomenon. In May 2015, the North American Branch of the International Life Sciences Institute (ILSI North America) Technical Committee on Food and Chemical Safety held a workshop on the risk-based process for mitigation of process-formed compounds. This workshop aimed to gain alignment from academia, government, and industry on a risk-based process for proactively assessing the need for and benefit of mitigation of process-formed compounds, including criteria to objectively assess the impact of mitigation as well as research needed to support this process. Workshop participants provided real-time feedback on a draft framework in the form of a decision tree developed by the ILSI North America Technical Committee on Food and Chemical Safety to a panel of experts, and they discussed the importance of communicating the value of such a process to the larger scientific community and, ultimately, the public. The outcome of the workshop was a decision tree that can be used by the scientific community and could form the basis of a global approach to assessing the risks associated with mitigation of process-formed compounds.

The impact of childhood maltreatment on redox state: Relationship with oxidative damage and antioxidant defenses in adolescents with no psychiatric disorder

2016 ◽  
Vol 617 ◽  
pp. 173-177 ◽  
Author(s):  
Carine Hartmann do Prado ◽  
Rodrigo Grassi-Oliveira ◽  
Andréa Wieck ◽  
Aline Zaparte ◽  
Ledo Daruy Filho ◽  
...  
Keyword(s):  
Psychiatric Disorder ◽  
Oxidative Damage ◽  
Childhood Maltreatment ◽  
Redox State ◽  
Antioxidant Defenses ◽  
The Impact

scholarly journals Analysis of Stormwater Retention on Green Roofs / Badania Retencji Wód Opadowych Na Dachach Zielonych

2012 ◽  
Vol 38 (4) ◽  
pp. 3-13 ◽  
Author(s):  
Ewa Burszta-Adamiak
Keyword(s):  
Life Sciences ◽  
Green Roofs ◽  
Retention Capacity ◽  
Runoff Reduction ◽  
Science And Education ◽  
Peak Runoff ◽  
The Impact ◽  
Stormwater Retention ◽  
Maximum Runoff ◽  
Sewage Systems

Abstract This study presents the results of tests conducted in 2009 and 2010 on experimental sites installed on the roof of the Science and Education Building of the Wroclaw University of Environmental and Life Sciences. The aim of the analysis was to determine the retention capacity of green roofs and the runoff delays and peak runoff reduction during rainfall recorded in Wroclaw conditions. The research shows that green roofs allow to reduce the volume of runoff stormwater in comparison to conventional roofs, that they delay the runoff in time and influence the reduction of the maximum runoff intensity, and thus may limit the impact of stormwater on the stormwater drainage and combined sewage systems.

scholarly journals Actuation of synthetic cells with proton gradients generated by light-harvesting E. coli

2020 ◽  
Author(s):  
Kevin Jahnke ◽  
Noah Ritzmann ◽  
Julius Fichtler ◽  
Anna Nitschke ◽  
Yannik Dreher ◽  
...  
Keyword(s):  
Lipid Vesicles ◽  
Cellular Systems ◽  
Top Down ◽  
Ph Gradients ◽  
Proton Gradients ◽  
Bottom Up ◽  
E Coli ◽  
Genetically Engineer ◽  
Synthetic Cells ◽  
Dna Triplex

Abstract Bottom-up and top-down approaches to synthetic biology each employ distinct methodologies with the common aim to harness new types of living systems. Both approaches, however, face their own challenges towards biotechnological and biomedical applications. Here, we realize a strategic merger to convert light into proton gradients for the actuation of synthetic cellular systems. We genetically engineer E. coli to overexpress the light-driven inward-directed proton pump xenorhodopsin and encapsulate them as organelle mimics in artificial cell-sized compartments. Exposing the compartments to light-dark cycles, we can reversibly switch the pH by almost one pH unit and employ these pH gradients to trigger the attachment of DNA structures to the compartment periphery. For this purpose, a DNA triplex motif serves as a nanomechanical switch responding to the pH-trigger of the E. coli. By attaching a polymerized DNA origami plate to the DNA triplex motif, we obtain a cytoskeleton mimic that considerably deforms lipid vesicles in a pH-responsive manner. We foresee that the combination of bottom-up and top down approaches is an efficient way to engineer synthetic cells as potent microreactors.

scholarly journals Does partisan grassroots mobilization matter in the digital age?

2020 ◽  
Author(s):  
Daniel Bischof ◽  
Thomas Kurer
Keyword(s):  
Political Parties ◽  
Instrumental Variable ◽  
Digital Age ◽  
Event History ◽  
Public Event ◽  
Global Village ◽  
Bottom Up ◽  
The World ◽  
History Of ◽  
The Impact

Political parties have long thrived on systematic grassroots mobilization of support. But does traditional partisan bottom-up mobilization still matter in an interconnected digital age turning the world into a `global village'? We address this question by studying the impact of the populist Movimento Cinque Stelle (M5S) on the rejection of the 2016 constitutional referendum in Italy. The movement's unusual practice to coordinate activities on a public event platform provides a unique opportunity to collect the complete event history of a modern political party. We merge this data consisting of over 200'000 geo-coded meetings by 1'000 local chapters with referendum results and individual panel data. Relying on regression, matching, and instrumental variable models, we find a small but consistent effect of M5S activity on the referendum outcome. Our findings demonstrate the continued relevance of bottom-up mobilization and highlight direct democratic means as an influential channel for populist movements.

scholarly journals The effects of hip- and ankle-focused exercise intervention on dynamic knee valgus: a systematic review

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11731
Author(s):  
Farhah Nadhirah Aiman Sahabuddin ◽  
Nazatul Izzati Jamaludin ◽  
Nurul Hidayah Amir ◽  
Shazlin Shaharudin
Keyword(s):  
Systematic Review ◽  
Knee Joint ◽  
Intervention Program ◽  
Exercise Intervention ◽  
Free Text ◽  
Knee Valgus ◽  
Top Down ◽  
Bottom Up ◽  
Limb Injuries ◽  
The Impact

Background A range of non-contact injuries such as anterior cruciate ligament tear, and patellofemoral pain syndrome are caused by disordered knee joint loading from excessive dynamic knee valgus (DKV). Previous systematic reviews showed that DKV could be modified through the influence of hip strength and ankle range of motion. Therefore, the purpose of this systematic review was to examine the effects of exercise intervention which involved either top-down or bottom-up kinetic chains on minimizing DKV in male and female adults and adolescents, with and without existing knee pain. Methodology Electronic searches were conducted in SAGE, Science Direct, SCOPUS, and Pubmed. The search strategy consisted of medical subject headings and free-text search keywords, synonyms and variations of ‘exercise intervention,’ ‘knee alignment,’ ‘dynamic knee valgus’, ‘knee abduction’ that were merged via the Boolean operator ‘AND’ and ‘OR’. The search was conducted on full-text journals that documented the impact of the exercise intervention program involving either the bottom-up or top-down DKV mechanism on the knee kinematics. Furthermore, exercise intervention in this review should last at least one week which included two or three sessions per week. This review also considered both men and women of all ages with a healthy or symptomatic knee problem. The risk of bias of the included studies was assessed by Cochrane risk assessment tool. The protocol of this review was registered at PROSPERO (registration number: CRD42021219121). Results Ten studies with a total of 423 participants (male = 22.7%, female = 77.3%; adults = 249, adolescents = 123; pre-adolescent = 51) met the inclusion criteria of this review. Seven studies showed the significant effects of the exercise intervention program (range from two weeks to ten weeks) on reducing DKV. The exercise training in these seven studies focused on muscle groups directly attached to the knee joint such as hamstrings and gastrocnemius. The remaining three studies did not show significant improvement in DKV after the exercise intervention (range between eight weeks to twelve weeks) probably because they focused on trunk and back muscles instead of muscles crossing the knee joint. Conclusion Exercises targeting specific knee-joint muscles, either from top-down or bottom-up kinetic chain, are likely to reduce DKV formation. These results may assist athletes and coaches to develop effective exercise program that could minimize DKV and ultimately prevent lower limb injuries.

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