Mechanical fluidity of fully suspended biological cells

Mechanical characteristics of single biological cells are used to identify and possibly leverage interesting differences among cells or cell populations. Fluidity---hysteresivity normalized to the extremes of an elastic solid or a viscous liquid---can be extracted from, and compared among, multiple rheological measurements of cells: creep compliance vs. time, complex modulus vs. frequency, and phase lag vs. frequency. With multiple strategies available for acquisition of this nondimensional property, fluidity may serve as a useful and robust parameter for distinguishing cell populations, and for understanding the physical origins of deformability in soft matter. Here, for three disparate eukaryotic cell types deformed in the suspended state via optical stretching, we examine the dependence of fluidity on chemical and environmental influences around a time scale of 1 s. We find that fluidity estimates are consistent in the time and the frequency domains under a structural damping (power-law or fractional derivative)model, but not under an equivalent-complexity lumpedcomponent (spring-dashpot) model; the latter predicts spurious time constants. Although fluidity is suppressed by chemical crosslinking, we find that adenosine triphosphate (ATP) depletion in the cell does not measurably alter the parameter, and thus conclude that active ATP-driven events are not a crucial enabler of fluidity during linear viscoelastic deformation of a suspended cell. Finally, by using the capacity of optical stretching to produce near-instantaneous increases in cell temperature, we establish that fluidity increases with temperature---now measured in a fully suspended, sortable cell without the complicating factor of cell-substratum adhesion

Human urinary mutagenicity after wood smoke exposure during traditional temazcal use.

In Central America, the traditional temazcales or wood-fired steam baths, commonly used by many Native American populations, are often heated by wood fires with little ventilation, and this use results in high wood smoke exposure. Urinary mutagenicity has been previously employed as a non-invasive biomarker of human exposure to combustion emissions. This study examined the urinary mutagenicity in 19 indigenous Mayan families from the highlands of Guatemala who regularly use temazcales (N = 32), as well as control (unexposed) individuals from the same population (N = 9). Urine samples collected before and after temazcal exposure were enzymatically deconjugated and extracted using solid-phase extraction. The creatinine-adjusted mutagenic potency of urine extracts was assessed using the plate-incorporation version of the Salmonella mutagenicity assay with strain YG1041 in the presence of exogenous metabolic activation. The post-exposure mutagenic potency of urine extracts were, on average, 1.7-fold higher than pre-exposure samples (P < 0.005) and also significantly more mutagenic than the control samples (P < 0.05). Exhaled carbon monoxide (CO) was ~10 times higher following temazcal use (P < 0.0001), and both CO level and time spent in temazcal were positively associated with urinary mutagenic potency (i.e. P < 0.0001 and P = 0.01, respectively). Thus, the wood smoke exposure associated with temazcal use contributes to increased excretion of conjugated mutagenic metabolites. Moreover, urinary mutagenic potency is correlated with other metrics of exposure (i.e. exhaled CO, duration of exposure). Since urinary mutagenicity is a biomarker associated with genetic damage, temazcal use may therefore be expected to contribute to an increased risk of DNA damage and mutation, effects associated with the initiation of cancer

Reduction of speed limit from 110 km/h to 100 km/h on certain roads in South Australia: a preliminary evaluation

In July 2003, the speed limit on approximately 1,100 km of rural arterial roads in South Australia was reduced from 110 km/h to 100 km/h. The crash experience on these roads in the two years before and the two years following the change has been compared with that on other roads where the 100 km/h limit was not changed. It appears that the speed limit reduction has had the effect of reducing casualty crashes by 20 per cent. However, the number of crashes on these roads is small and the time since the change is so short that this estimate is uncertain. It is reasonable to think that in the longer term the change might be anywhere between an increase of 4 per cent and a decrease of 44 per cent. There was a decrease in crashes and casualties on the 100 km/h roads where the speed limit did not change and that has been allowed for in the calculations. At six sites, speed measurements before and after the speed limit reduction were available: an average speed reduction of 2 km/h was foundA.D. Long, C.N. Kloeden, T.P. Hutchinson and A.J. McLea

Rear end crashes

Due to the common occurrence of rear end collisions in South Australia, and the costliness of Compulsory Third Party (CTP) claims associated with them, a study was undertaken into the nature of, and possible countermeasures for, rear end collisions. This study included an analysis of five years of police-reported crash data, an analysis of a sample of rear end crashes investigated as part of the CASR metropolitan in-depth crash study, and a literature review concerned with countermeasures for rear end crashes. The most common factors contributing to these types of crashes are the lack of protection for right turning vehicles and the inadequate allocation of attention by drivers to the driving task. Countermeasures are available for both of these contributing factors. Providing greater protection for right turning vehicles requires road-based countermeasures, while the most promising countermeasure for inadequate allocation of attention is the installation in vehicles of collision avoidance systems. However, the latter countermeasure will only be available after further testing and refinement of current prototype systems.M.R.J. Baldock, A.D. Long, V.L. Lindsay and A.J. McLea

Part 1: Brackish Groundwater Desalination Technical Report

This Brackish Groundwater Desalination Technical Report examines the legal frameworks that affect desalination in Texas. The goal of this report is to provide insight into the legal and regulatory barriers, challenges, and opportunities for these technologies to go online. Each desalination implementation site has to find ways of complying with various laws and regulations. The information in this Report comes from the study of brackish groundwater desalination facilities currently operating in Texas, as well as extensive research into available literature and documents from various agencies. While there is no updated “one-stop-shop” resource that provides detailed information on all the necessary permits to build, operate, and maintain such facilities, this Technical Report aims to compile the existing, available information in an organized and accessible fashion. The Brackish Groundwater Desalination Technical Report is the first of three reports that make up the work product of a project undertaken by students at Texas A&M University School of Law in a select capstone seminar. These reports examine regulations surrounding desalination and water recycling. The companion report entitled Water Recycling Technical Report highlights building, operating, and monitoring requirements for water recycling facilities in Texas. Finally, the Case Study Report expands on regulations in San Antonio and El Paso where these water alternatives are in place

Part 3: Case Study Appendices to the Technical Reports

This Case Study Appendix to the Technical Reports expands on regulations in San Antonio and El Paso where these water alternatives are in place. The goal of this report is to provide insight into the legal and regulatory barriers, challenges, and opportunities for these technologies to go online. Each desalination and water recycling faciality implementation site must comply with various laws and regulations. The information in these Case Studies comes from the study of brackish groundwater desalination and water recycling facilities currently operating in Texas. While there is no updated “one-stop-shop” resource where a municipal leader can find a list of all the necessary permits to build, operate, and maintain such facilities, this Technical Report aims to compile the existing, available information in an organized and accessible fashion. The Desalination Technical report is the third in a series of three reports which make up the Project. These reports examine regulations surrounding desalination and water recycling. The companion reports generally highlight building, operating, and monitoring requirements for water recycling facilities in Texas

Tissue-specific in vivo genetic toxicity of nine polycyclic aromatic hydrocarbons assessed using the Muta™Mouse transgenic rodent assay

Test batteries to screen chemicals for mutagenic hazard include several endpoints regarded as effective for detecting genotoxic carcinogens. Traditional in vivo methods primarily examine clastogenic endpoints in haematopoietic tissues. Although this approach is effective for identifying systemically distributed clastogens, some mutagens may not induce clastogenic effects; moreover, genotoxic effects may be restricted to the site of contact and/or related tissues. An OECD test guideline for transgenic rodent (TGR) gene mutation assays was released in 2011, and the TGR assays permit assessment of mutagenicity in any tissue. This study assessed the responses of two genotoxicity endpoints following sub-chronic oral exposures of male Muta™Mouse to 9 carcinogenic polycyclic aromatic hydrocarbons (PAHs). Clastogenicity was assessed via induction of micronuclei in peripheral blood, and mutagenicity via induction of lacZ transgene mutations in bone marrow, glandular stomach, small intestine, liver, and lung. Additionally, the presence of bulky PAH-DNA adducts was examined. Five of the 9 PAHs elicited positive results across all endpoints in at least one tissue, and no PAHs were negative or equivocal across all endpoints. All PAHs were positive for lacZ mutations in at least one tissue (sensitivity = 100%), and for 8 PAHs, one or more initial sites of chemical contact (i.e., glandular stomach, liver, small intestine) yielded a greater response than bone marrow. Five PAHs were positive in the micronucleus assay (sensitivity = 56%). Furthermore, all PAHs produced DNA adducts in at least one tissue. The results demonstrate the utility of the TGR assay for mutagenicity assessment, especially for compounds that may not be systemically distributed.</p

Part 2: Water Recycling Technical Report for Direct Non-Potable Use

This Water Recycling Technical Report examines the legal frameworks that affect water recycling in Texas. The goal of this report is to provide insight into the legal and regulatory barriers, challenges, and opportunities for these technologies to go online. Each water recycling implementation site has to find ways of complying with various laws and regulations. The information in this Report comes from the study of water recycling facilities currently operating in Texas, as well as extensive research into available literature and documents from various agencies. While there is no updated “one-stop-shop” resource that provides detailed information on all the necessary permits to build, operate, and maintain such facilities, this Technical Report aims to compile the existing, available information in an organized and accessible fashion. The Water Recycling Technical Report is the second of three reports that make up the work product of a project undertaken by students at Texas A&M University School of Law in a select capstone seminar. These reports examine regulations surrounding desalination and water recycling. The companion report entitled Brackish Groundwater Desalination Technical Report highlights building, operating, and monitoring requirements for desalination facilities in Texas. Finally, the Case Study Report expands on regulations in San Antonio and El Paso where these water alternatives are in place

Feeding soy or fish meal to Alaskan reindeer (Rangifer tarandus tarandus) – effects on animal performance and meat quality

Fourteen reindeer (8 steers and 6 females) were used to compare the effects of two different reindeer diets (a feed mix based on barley, brome hay and soybean meal (SBM) or fishmeal (WFM) as protein source) on animal growth performance, feed conversion efficiency and ultimate meat quality. Samples from free-ranging reindeer (n=4; 2 steers and 2 females) on the Seward Peninsula were included to provide comparisons with the traditional reindeer meat produced in Alaska. No significant difference was observed in overall weight gain between the WFM and SBM animals or between females and steers; however, the feed conversion efficiency was significantly higher for the reindeer fed the WFM mix. Carcass dressing percentage from the SBM group was higher compared with the WFM animals. No differences were found in live weight, carcass characteristics, meat pH, temperature decline, shear force, meat color or cooking loss when comparing the treatment groups. The meat samples (M. longissimus) from the free-range group had the highest amount of omega-3 fatty acids and also the highest amount of polyunsaturated fatty acids (PUFA). Meat from the animals fed SBM was significantly higher in triglyceride content and lower in phospholipid content compared with the two other groups. No significant differences were found when the trained panel compared the sensory attributes of the meat. Off-flavor attributes related to &ldquo;wild&rsquo; or &ldquo;gamey&rdquo; flavor was reported by consumers for samples from the WFM and free-range reindeer (15 and 24 per cent of the consumers, respectively). No &ldquo;fish-related&rdquo; flavor was reported. In conclusion, no negative effects in either animal performance or meat quality characteristics by using fish meal as opposed to soybean meal as a protein supplement in a milled reindeer diet were found.Abstract in Swedish / Sammandrag:Utfordring av ren med soja- eller fiskmj&oslash;l &ndash; effekter p&aring; tillv&auml;xt, foderutnyttjande och k&ouml;ttkvalitet I v&aring;r unders&ouml;kning ingick 14 renar (8 kastrerade sarvar (h&auml;rkar)och 6 vajor) f&ouml;r att j&auml;mf&ouml;ra effekter av tv&aring; olika renfoder (baserade p&aring; korn, h&ouml; och soja- (SBM) eller fiskmj&ouml;l (WFM) som proteintillskott) med avseende p&aring; tillv&auml;xt, foderutnyttjande och k&ouml;ttkvalitet. K&ouml;ttprover fr&aring;n naturbetande renar (n=4; 2 h&auml;rkar och 2 vajor) fr&aring;n Seward Peninsula inkluderades i studien f&ouml;r att representera kvaliteten p&aring; traditionellt producerat renk&ouml;tt fr&aring;n Alaska. Inga signifikanta skillnader i tillv&auml;xt observerades, varken mellan SBM- och WFM-grupperna eller mellan h&auml;rkar och vajor. Foderutnyttjandet var dock signifikant b&auml;ttre hos WFM-renarna. Slaktutbytet var h&ouml;gst f&ouml;r renarna i SBM-gruppen, d&auml;remot rapporterades inga skillnader i levandevikt, slaktkroppsegenskaper, pH-v&auml;rde och temperatur i ytterfil&eacute;n, sk&auml;rmotst&aring;nd, f&auml;rg eller vattenh&aring;llande f&ouml;rm&aring;ga i k&ouml;ttet n&auml;r de tre grupperna av renar j&auml;mf&ouml;rdes (SBM, WFM och naturbetande djur). K&ouml;ttet fr&aring;n de naturbetande renarna hade det signifikant h&ouml;gsta inneh&aring;llet av b&aring;de omega-3-fettsyror och av flerom&auml;ttade fettsyror. K&ouml;tt fr&aring;n SBM-renarna hade det h&ouml;gsta inneh&aring;llet av triglycerider och det l&auml;gsta inneh&aring;llet av fosfolipider j&auml;mf&ouml;rt med de andra tv&aring; grupperna. Den tr&auml;nade smakpanelen kunde inte hitta n&aring;gra skillnader i sensoriska egenskaper hos k&ouml;ttet fr&aring;n renarna i de tre olika grupperna. I en konsumentunders&ouml;kning rapporterades kommentarer om olika &rdquo;vilt-relaterade&rdquo; bismaker i k&ouml;tt fr&aring;n naturbetande renar (24% av konsumenterna) och fr&aring;n WFM-gruppen (15% av konsumenterna), men inga &rdquo;fisk-liknande&rdquo; bismaker i k&ouml;ttet kunde p&aring;visas. Att byta ut sojamj&ouml;l mot fiskmj&ouml;l som proteintillskott i renfoder hade inga negativa effekter p&aring; renarnas tillv&auml;xt, foderutnyttjande eller p&aring; renk&ouml;ttets kvalitet