Tensile stress relaxation of wood impregnated with different ACQ formulations at various temperatures

Holzforschung ◽  
2010 ◽  
Vol 64 (1) ◽  
Author(s):  
Lili Yu ◽  
Jinzhen Cao ◽  
Guangjie Zhao
Keyword(s):  
Stress Relaxation ◽  
Tensile Stress ◽  
Phase I ◽  
Phase Ii ◽  
Initial Period ◽  
Molar Ratio ◽  
Slow Phase ◽  
Orthogonal Experimental Design ◽  
Rapid Phase ◽  
Relaxation Curves

Abstract The reactions between constituents of alkaline copper quat (ACQ) and of wood were investigated by a tensile stress relaxation approach. Small samples were stressed and impregnated with various ACQ solutions, in which the ratios of monoethanolamine (MEA), ACQ, and didecyl dimethyl ammonium chloride (DDAC) were varied. The other parameters included temperature and concentration of the treating solutions. The stress relaxation curves of wood were recorded during the impregnation period and the effects of impregnation parameters were investigated by an orthogonal experimental design (OED). The effects of water, MEA, and DDAC on stress relaxation of the samples were also observed. The bulking effect of water was tested separately in samples treated with distilled water without stretching. The results showed that the stress relaxes dramatically in the initial period and then changes slightly over a long period, which is readily visible in double logarithmic plots of f (t)/f (0) versus time (t). There are complex interactions between the components of ACQ solutions and wood matrix: (1) in rapid phase I, the splitting of the easily accessible hydrogen bonds (mainly in the amorphous hemicelluloses) are prevalent by interaction with components of ACQ solution; (2) in slow phase II, Cu penetrates deeper in less accessible regions (e.g., in paracrystalline regions of cellulose) and renders possible further relaxation. The results of range and variance analysis reveal that the molar ratio of Cu to MEA and temperature of ACQ solution have significant effects on the rate of reaction during phase I, whereas in phase II only the temperature of ACQ solution has a significant effect. The stress relaxation curves of samples impregnated in water, MEA, and DDAC all showed a quasi one phase stress relaxation rate, which suggests that phase II is mostly related to Cu in ACQ formulations. It is concluded that the formation of complexes with Cu is still the major reaction in wood although there is competition among ACQ constituents for reaction sites.

scholarly journals Analysis of the ex-vivo transformation of semen, saliva and urine as they dry out using ATR-FTIR spectroscopy and chemometric approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tanurup Das ◽  
Abhimanyu Harshey ◽  
Ankit Srivastava ◽  
Kriti Nigam ◽  
Vijay Kumar Yadav ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Ex Vivo ◽  
Body Fluids ◽  
Biochemical Changes ◽  
Partial Least Square ◽  
The Body ◽  
Slow Phase ◽  
Time Since Deposition ◽  
Dry Out

AbstractThe ex-vivo biochemical changes of different body fluids also referred as aging of fluids are potential marker for the estimation of Time since deposition. Infrared spectroscopy has great potential to reveal the biochemical changes in these fluids as previously reported by several researchers. The present study is focused to analyze the spectral changes in the ATR-FTIR spectra of three body fluids, commonly encountered in violent crimes i.e., semen, saliva, and urine as they dry out. The whole analytical timeline is divided into relatively slow phase I due to the major contribution of water and faster Phase II due to significant evaporation of water. Two spectral regions i.e., 3200–3400 cm−1 and 1600–1000 cm−1 are the major contributors to the spectra of these fluids. Several peaks in the spectral region between 1600 and 1000 cm−1 showed highly significant regression equation with a higher coefficient of determination values in Phase II in contrary to the slow passing Phase I. Principal component and Partial Least Square Regression analysis are the two chemometric tool used to estimate the time since deposition of the aforesaid fluids as they dry out. Additionally, this study potentially estimates the time since deposition of an offense from the aging of the body fluids at the early stages after its occurrence as well as works as the precursor for further studies on an extended timeframe.

Host resistance to cattle tick (Boophilus microplus) in Brahman (Bos indicus) cattle. II.* The dynamics of resistance in previously unexposed and exposed cattle

1978 ◽  
Vol 29 (2) ◽  
pp. 395 ◽  
Author(s):  
BM Wagland
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Host Resistance ◽  
Initial Period ◽  
Bos Indicus ◽  
Boophilus Microplus ◽  
Phase Iii ◽  
Cattle Tick ◽  
Development Of Resistance

The dynamics of host resistance to Boophilus microplus was investigated in previously unexposed and exposed Brahmans, and in previously unexposed Shorthorn cattle. The animals were infested each day with 1000 larvae, and the development of resistance was monitored by counting the number of female ticks which engorged. The previously unexposed cattle showed an initial period of susceptibility (phase I) which was followed by a period in which most animals developed degrees of resistance (phase II), and which stabilized in some animals (phase III). The duration of phase I was shorter in Brahmans, and they developed higher levels of resistance (phase III). In contrast, previously cxposed Brahmans manifested phase III levels of resistance immediately on infestation. The results provide further evidence that resistance to B. microplus in Brahmans, as well as in European breeds, is acquired rather than innate. __________________ *Part I, Aust. J. Agric. Res., 26: 1073 (1975).

scholarly journals Analysis of the Ex-vivo transformation of Semen, Saliva and Urine as they dry out using ATR-FTIR spectroscopy and chemometric Approach

2021 ◽  
Author(s):  
Tanurup Das ◽  
Abhimanyu Harshey ◽  
Ankit Srivast ◽  
Kriti Nigam ◽  
Vijay Yadav ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Ex Vivo ◽  
Body Fluids ◽  
Biochemical Changes ◽  
Partial Least Square ◽  
Least Square ◽  
Slow Phase ◽  
Potential Marker ◽  
Dry Out

Abstract The ex-vivo biochemical changes of different body fluids are potential marker for the estimation of TSD. Infrared spectroscopy has great potential to reveal the biochemical changes in these fluids as previously reported by several researchers. Present study is focused to analyze the spectral changes in the ATR-FTIR spectra of three body fluids, commonly encountered in violent crimes i.e., Semen, Saliva and Urine as they dry out. The whole analytical timeline is divided into relatively slow phase I due to major contribution of water and faster Phase II due significant evaporation of water. Two spectral regions i.e., 3200-3400 cm-1 and 1600-1000 cm-1 are the major contributor to the spectra of these fluids. Several peaks in the spectral region between 1600-1000 cm-1 showed highly significant regression equation with higher coefficient of determination values in the Phase II in contrary to the slow passing Phase I. Principal component and Partial Least Square Regression analysis are the two chemometric tool used to estimate the TSD of the aforesaid fluids as they dry out. This study potentially estimates the TSD of an offence at the early stages after is occurrence as well as work as the precursor for further studies on extended timeframe.

Ventilatory and gas exchange kinetics during exercise in chronic airways obstruction

1982 ◽  
Vol 53 (6) ◽  
pp. 1594-1602 ◽  
Author(s):  
L. E. Nery ◽  
K. Wasserman ◽  
J. D. Andrews ◽  
D. J. Huntsman ◽  
J. E. Hansen ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Phase I ◽  
Phase Ii ◽  
Cardiovascular Response ◽  
Phase Iii ◽  
Slow Phase ◽  
Initial Increase ◽  
O2 Pulse ◽  
Exchange Kinetics ◽  
Gas Exchange Kinetics

The influence of chronic obstructive pulmonary disease (COPD) on exercise ventilatory and gas exchange kinetics was assessed in nine patients with stable airway obstruction (forced expired volume at 1 s = 1.1 +/- 0.33 liters) and compared with that in six normal men. Minute ventilation (VE), CO2 output (VCO2), and O2 uptake (VO2) were determined breath-by-breath at rest and after the onset of constant-load subanaerobic threshold exercise. The initial increase in VE, VCO2, and VO2 from rest (phase I), the subsequent slow exponential rise (phase II), and the steady-state (phase III) responses were analyzed. The COPD group had a significantly smaller phase I increase in VE (3.4 +/- 0.89 vs. 6.8 +/- 1.05 liters/min), VCO2 (0.10 +/- 0.03 vs. 0.22 +/- 0.03 liters/min), VO2 (0.10 +/- 0.03 vs. 0.24 +/- 0.04 liters/min), heart rate (HR) (6 +/- 0.9 vs. 16 +/- 1.4 beats/min), and O2 pulse (0.93 +/- 0.21 vs. 2.2 +/- 0.45 ml/beat) than the controls. Phase I increase in VE was significantly correlated with phase I increase in VO2 (r = 0.88) and HR (r = 0.78) in the COPD group. Most patients also had markedly slower phase II kinetics, i.e., longer time constants (tau) for VE (87 +/- 7 vs. 65 +/- 2 s), VCO2 (79 +/- 6 vs. 63 +/- 3 s), and VO2 (56 +/- 5 vs. 39 +/- 2 s) and longer half times for HR (68 +/- 9 vs. 32 +/- 2 s) and O2 pulse (42 +/- 3 vs. 31 +/- 2 s) compared with controls. However, tau VO2/tau VE and tau VCO2/tau VE were similar in both groups. The significant correlations of the phase I VE increase with HR and VO2 are consistent with the concept that the immediate exercise hyperpnea has a cardiodynamic basis. The slow ventilatory kinetics during phase II in the COPD group appeared to be more closely related to a slowed cardiovascular response rather than to any index of respiratory function. O2 breathing did not affect the phase I increase in VE but did slow phase II kinetics in most subjects. This confirms that the role attributed to the carotid bodies in ventilatory control during exercise in normal subjects also operates in patients with COPD.

scholarly journals Pathways of peroxynitrite oxidation of thiol groups

1997 ◽  
Vol 322 (1) ◽  
pp. 167-173 ◽  
Author(s):  
Celia QUIJANO ◽  
Beatriz ALVAREZ ◽  
Reynaldo M. GATTI ◽  
Ohara AUGUSTO ◽  
Rafael RADI
Keyword(s):  
Oxygen Consumption ◽  
Phase I ◽  
Phase Ii ◽  
Thiol Group ◽  
Second Order ◽  
Slow Phase ◽  
Acidic Ph ◽  
Fast Phase ◽  
Rate Of Oxygen Consumption ◽  
Phase Phase

Peroxynitrite mediates the oxidation of the thiol group of both cysteine and glutathione. This process is associated with oxygen consumption. At acidic pH and a cysteine/peroxynitrite molar ratio of ≤ 1.2, there was a single fast phase of oxygen consumption, which increased with increasing concentrations of both cysteine and oxygen. At higher molar ratios the profile of oxygen consumption became biphasic, with a fast phase (phase I) that decreased with increasing cysteine concentration, followed by a slow phase (phase II) whose rate of oxygen consumption increased with increasing cysteine concentration. Oxygen consumption in phase I was inhibited by desferrioxamine and 5,5-dimethyl-1-pyrroline N-oxide, but not by mannitol; superoxide dismutase also inhibited oxygen consumption in phase I, while catalase added during phase II decreased the rate of oxygen consumption. For both cysteine and glutathione, oxygen consumption in phase I was maximal at neutral to acidic pH; in contrast, total thiol oxidation was maximal at alkaline pH. EPR spin-trapping studies using N-tert-butyl-α-phenylnitrone indicated that the yield of thiyl radical adducts had a pH profile comparable with that found for oxygen consumption. The apparent second-order rate constants for the reactions of peroxynitrite with cysteine and glutathione were 1290ŷ30 M-1ƃs-1 and 281ŷ6 M-1ƃs-1 respectively at pH 5.75 and 37 ŶC. These results are consistent with two different pathways participating in the reaction of peroxynitrite with low-molecular-mass thiols: (a) the reaction of the peroxynitrite anion with the protonated thiol group, in a second-order process likely to involve a two-electron oxidation, and (b) the reaction of peroxynitrous acid, or a secondary species derived from it, with the thiolate in a one-electron transfer process that yields thiyl radicals capable of initiating an oxygen-dependent radical chain reaction.

Phase I and Pharmacologic Study of Irinotecan Administered as a 96-Hour Infusion Weekly to Adult Cancer Patients

2000 ◽  
Vol 18 (3) ◽  
pp. 659-659 ◽  
Author(s):  
Chris H. Takimoto ◽  
Geraldine Morrison ◽  
Nancy Harold ◽  
Mary Quinn ◽  
Brian P. Monahan ◽  
...  
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Objective Response ◽  
Systemic Exposure ◽  
Maximum Tolerated Dose ◽  
Molar Ratio ◽  
Metastatic Colon Cancer ◽  
Grade 3 ◽  
Recommended Phase Ii Dose ◽  
Pharmacologic Study

PURPOSE: We conducted a phase I and pharmacologic study of a weekly 96-hour infusion of irinotecan to determine the maximum-tolerated dose, define the toxicity profile, and characterize the clinical pharmacology of irinotecan and its metabolites. PATIENTS AND METHODS: In 26 adult patients with solid tumors, the duration and dose rate of infusion were escalated in new patients until toxicity was observed. RESULTS: In 11 patients who were treated with irinotecan at 12.5 mg/m2/d for 4 days weekly for 2 of 3 weeks, dose-limiting grade 3 diarrhea occurred in three patients and grade 3 thrombocytopenia occurred in two patients. The recommended phase II dose is 10 mg/m2/d for 4 days given weekly for 2 of 3 weeks. At this dose, the steady-state plasma concentration (Css) of total SN-38 (the active metabolite of irinotecan) was 6.42 ± 1.10 nmol/L, and the Css of total irinotecan was 28.60 ± 17.78 nmol/L. No patient experienced grade 3 or 4 neutropenia during any cycle. All other toxicities were mild to moderate. The systemic exposure to SN-38 relative to irinotecan was greater than anticipated, with a molar ratio of the area under the concentration curve (AUC) of SN-38 to irinotecan of 0.24 ± 0.08. One objective response lasting 12 months in duration was observed in a patient with metastatic colon cancer. CONCLUSION: The recommended phase II dose of irinotecan of 10 mg/m2/d for 4 days weekly for 2 of 3 weeks was extremely well tolerated. Further efficacy testing of this pharmacologic strategy of administering intermittent low doses of irinotecan is warranted.

Bewegungstherapie und körperliche Aktivität bei Patienten mit Herzinsuffizienz

Praxis ◽  
2018 ◽  
Vol 107 (17-18) ◽  
pp. 951-958 ◽  
Author(s):  
Matthias Wilhelm
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Körperliche Aktivität ◽  
Phase Iii

Zusammenfassung. Herzinsuffizienz ist ein klinisches Syndrom mit unterschiedlichen Ätiologien und Phänotypen. Die überwachte Bewegungstherapie und individuelle körperliche Aktivität ist bei allen Formen eine Klasse-IA-Empfehlung in aktuellen Leitlinien. Eine Bewegungstherapie kann unmittelbar nach Stabilisierung einer akuten Herzinsuffizienz im Spital begonnen werden (Phase I). Sie kann nach Entlassung in einem stationären oder ambulanten Präventions- und Rehabilitationsprogramm fortgesetzt werden (Phase II). Typische Elemente sind Ausdauer-, Kraft- und Atemtraining. Die Kosten werden von der Krankenversicherung für drei bis sechs Monate übernommen. In erfahrenen Zentren können auch Patienten mit implantierten Defibrillatoren oder linksventrikulären Unterstützungssystemen trainieren. Wichtiges Ziel der Phase II ist neben muskulärer Rekonditionierung auch die Steigerung der Gesundheitskompetenz, um die Langzeit-Adhärenz bezüglich körperlicher Aktivität zu verbessern. In Phase III bieten Herzgruppen Unterstützung.

How to Make COVID-19 Contact Tracing Apps work: Insights from Behavioral Economics (Preprint)

2021 ◽  
Author(s):  
Ian Ayres ◽  
Alessandro Romano ◽  
Chiara Sotis
Keyword(s):  
Phase I ◽  
Phase Ii ◽  
Network Effects ◽  
Risky Behaviors ◽  
Contact Tracing ◽  
Risk Compensation ◽  
Main Function ◽  
Double Blind ◽  
Compensation Theory ◽  
Pros And Cons

BACKGROUND Due to network effects, Contact Tracing Apps (CTAs) are only effective if many people download them. However, the response to CTAs has been tepid. For example, in France less than 2 million people (roughly 3% of the population) downloaded the CTA. Consequently, CTAs need to be fundamentally rethought to increase their effectiveness. OBJECTIVE This study aimed to show that CTAs can still play a key role in containing the pandemic, provided that they take into account insights from behavioral sciences. Moreover, we study whether emphasizing the virtues of CTA to induce people to download them makes app users engage in more risky behaviors (risk compensation theory) and whether feedback on a user’s behavior affects future behaviors. METHODS We perform a double-blind online experiment (n=1500) divided in two phases. In Phase I respondents are randomly assigned to one of three different groups: Pros of the app, Pros and Cons of the app and Control I. Respondents in the Pros group were shown information on the advantages of CTAs. Participants in the Pros and Cons group were shown information on both the advantages and the problems that characterize CTAs. Last, respondents in the Control I group were not given any information on CTAs. All participants are then asked how worried they are about the pandemic, how likely they are to download the app, and on how they intend to behave (e.g. attend small and large gathering, wear a mask, etc.). A week later we carried out Phase II. Participants in Phase II were randomly assigned to different in-app notifications in which they were informed on how much risk they were taking compared to the average user. We then ask participants their intentions for future behaviors to investigate whether these notifications were effective in making respondents more prudent. RESULTS All 1500 participants completed phase I of the experiment, whereas 1303 (86.9%) completed also phase 2. The main findings are: i) informing people on the pros of the app make them less worried about the pandemic (p=.004), ii) informing people about both the pros and the cons of the app makes them more likely to download the app (p=.07); iii) carefully devised in-app notification induce people to state that they will: attend less large gatherings (p= .05) and less small gatherings (p= .001), see less people at risk (p=.004), that they stay more at home (p=.006) and wear more often the mask (p=.09). We do not find support for the risk-compensation theory. CONCLUSIONS we suggest that CTAs should be re-framed as Behavioral Feedback Apps (BFAs). The main function of BFAs would be providing users with information on how to minimize the risk of contracting COVID-19, e.g. to provide information on how crowded a store is likely to be at a given time of the day. Moreover, the BFA could have a rating system that allows users to flag stores that do not respect safety norms, such as mandating customers to wear a mask or not respecting social distancing. These functions can inform the behavior of app users, thus playing a key role in containing the spread of the virus even if a small percentage of people download the BFA. While effective contact tracing is impossible when only 3% of the population downloads the app, less risk taking by small portions of the population can produce large benefits. BFAs can be programmed so that users can also activate a tracing function akin to the one currently carried out by CTAs. Making contact tracing an ancillary, opt-in function might facilitate a wider acceptance of BFAs.

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