Rheology of Polymethylmethacrylate-Collagen Gel Filler: Physiochemical Properties and Clinical Applications

2020 ◽  
Author(s):  
Z Paul Lorenc ◽  
Brian Pilcher ◽  
Tina McArthur ◽  
Nimitt Patel
Keyword(s):  
Collagen Gel ◽  
Complex Viscosity ◽  
Clinical Applications ◽  
Published Data ◽  
Physiochemical Properties ◽  
Standard Procedures ◽  
Clinical Considerations ◽  
Selection For ◽  
The Difference ◽  
The Temple

Abstract Background Soft tissue fillers are comprised of a range of materials with differing physiochemical and rheological (ie, flow) properties. These properties can inform treatment selection for specific anatomical areas, planes of injection, and clinical applications. Objective To characterize rheological properties of polymethylmethacrylate (PMMA)-collagen gel for comparison with other available fillers. Methods Commercially available PMMA-collagen gel, hyaluronic acid (HA), and calcium hydroxylapatite (CaHA) fillers were obtained from their respective manufacturers. Measures of complex viscosity (η*) and elastic modulus (G′) for each filler were collected at 0.7 Hz in triplicate using standard procedures on a rotational rheometer fitted with a 40-mm steel plate at 25°C on a Peltier plate (500-μm gap). Results The measured η* and G′ values for HA and CaHA fillers were in agreement with previously published data. The difference in η* between CaHA (358.9 Pa-s, SD=21.56) and PMMA-collagen gel (656.41 Pa-s, SD=68.03) was statistically significant (P<0.0001), as was the difference between the G′ of CaHA (1424.8 Pa, SD=83.3) and the G′ of PMMA-collagen gel (2815.27 Pa, SD=304.07; P<0.0001). Conclusions PMMA-collagen gel exhibited the highest η* and G′ of all tested fillers. These properties likely underpin an increased capacity for lifting and support in areas where long-lasting revolumization is appropriate. In practice, PMMA-collagen gel is well suited for treatment of acne scars, as well as injection into the supraperiosteal plane in the temple, chin, mandible, and piriform using a retrograde linear threading technique. Additional clinical considerations are discussed.

Dietary Selection against Cottonseed Meal by Captive Northern Bobwhites

2018 ◽  
Vol 11 (3) ◽  
pp. 191-195 ◽  
Author(s):  
Amy L. Farthing ◽  
Thomas W. Schwertner ◽  
Heather A. Mathewson ◽  
Kimberly A. Guay
Keyword(s):  
Cottonseed Meal ◽  
Cultural Value ◽  
Feed Consumption ◽  
Published Data ◽  
Northern Bobwhites ◽  
Dietary Preference ◽  
Game Bird ◽  
Selection For ◽  
Whole Cottonseed ◽  
Preference Study

Gossypol, a secondary plant compound found in cotton (Gossypium spp.), is known to be toxic to a variety of animals, particularly monogastric mammals and birds. Because ruminants are resistant to gossypol, whole cottonseed and cottonseed meal have been used as a feed supplement for many decades. Concerns over gossypol toxicity arise because of its presence in cottonseed products, particularly livestock and wildlife feed. The concentration of cottonseed in the environment near livestock and wildlife feeding stations presents the possibility that it may be ingested in significant amounts by non-target wild animals, resulting in inadvertent gossypol dosing. A species of significant economic and cultural value is the Northern Bobwhite (Colinus virginianus). However, there are no published data regarding if Northern Bobwhites would consume cottonseed meal given the opportunity. We assessed selection for or against cottonseed meal by performing a dietary preference study. Birds (n =120) were given the choice between commercial game bird feed, scratch grains, and cottonseed meal containing 0.74% total gossypol. We measured feed consumption for five days. The birds’ diet consisted of 51.74% game bird feed, 37.72% scratch grains, and 10.54% cottonseed meal, and percentages varied significantly among all feed types (P≤0.001, n =360). We concluded that Northern Bobwhites selected against the cottonseed meal in favour of the game bird feed first and the scratch grains second. Our results suggest that given the choice, Northern Bobwhites will select against cottonseed meal if other feed choices are available.

The effect of exposure to conspecifics on restlessness in the parasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

2007 ◽  
Vol 139 (5) ◽  
pp. 678-684 ◽  
Author(s):  
B.H. King
Keyword(s):  
Habitat Quality ◽  
Parasitoid Wasp ◽  
Poor Quality ◽  
The Other ◽  
Dispersal Ability ◽  
Nasonia Vitripennis ◽  
Adult Females ◽  
Selection For ◽  
The Difference ◽  
Abundance And Distribution

AbstractWhen habitat quality is variable, there should be strong selection for the ability to detect and respond to the variation. Adult females of the parasitoid wasp Nasonia vitripennis (Walker) are known to increase their restlessness (the proportion of time in locomotion) both during and after exposure to a poor quality host. Doing so provides a mechanism for leaving a poor host and potentially finding a better host. This study examined whether restlessness also changes in response to competition as indicated by the presence of adult conspecifics. Both restlessness and the probability of dispersing across an inhospitable environment were greater when a female was with another female than when she was alone. However, restlessness did not remain elevated after the other female was removed. In contrast with females, restlessness of males did not increase either during or after exposure to other males, and the probability of dispersing across an inhospitable environment was unaffected by the presence of another male. The difference between females and males may be related to differences in dispersal ability and in the abundance and distribution of hosts versus mates.

Determination of Resistance to Abrasive Wear. VIII. Influence of Softeners in Tests with the Akron-Croydon and Du Pont Machines

1949 ◽  
Vol 22 (1) ◽  
pp. 259-262
Author(s):  
J. F. Morley
Keyword(s):  
Unit Area ◽  
Published Data ◽  
The Road ◽  
Abrasive Surface ◽  
Abrasive Power ◽  
The Difference ◽  
On The Road ◽  
The Right ◽  
Abrasion Testing

Abstract These experiments indicate that softeners can influence abrasion resistance, as measured by laboratory machines, in some manner other than by altering the stress-strain properties of the rubber. One possible explanation is that the softener acts as a lubricant to the abrasive surface. Since this surface, in laboratory abrasion-testing machines, is relatively small, and comes repeatedly into contact with the rubber under test, it seems possible that it may become coated with a thin layer of softener that reduces its abrasive power. It would be interesting in this connection to try an abrasive machine in which a long continuous strip of abrasive material was used, no part of it being used more than once, so as to eliminate or minimize this lubricating effect. The fact that the effect of the softener is more pronounced on the du Pont than on the Akron-Croydon machine lends support to the lubrication hypothesis, because on the former machine the rate of wear per unit area of abrasive is much greater. Thus in the present tests the volume of rubber abraded per hr. per sq. cm. of abrasive surface ranges from 0.03 to 0.11 cc. on the du Pont machine and from 0.0035 to 0.0045 cc. on the Akron-Croydon machine. On the other hand, if the softener acts as a lubricant, it would be expected to reduce considerably the friction between the abrasive and the rubber and hence the energy used in dragging the rubber over the abrasive surface. The energy figures given in the right-hand columns of Tables 1 and 3, however, show that there is relatively little variation between the different rubbers. As a test of the lubrication hypothesis, it would be of interest to vary the conditions of test so that approximately the same amount of rubber per unit area of abrasive is abraded in a given time on both machines; this should show whether the phenomena observed under the present test conditions are due solely to the difference in rate of wear or to an inherent difference in the type of wear on the two machines. This could most conveniently be done by considerably reducing the load on the du Pont machine. In the original work on this machine the load was standardized at 8 pounds, but no figures are quoted to show how abrasion loss varies with the load. As an addition to the present investigation, it is proposed to examine the effect of this variation with special reference to rubbers containing various amounts and types of softener. Published data on the influence of softeners on the road wear of tire rubbers do not indicate anything like such large effects as are shown by the du Pont machine. This throws some doubt on the value of this machine for testing tire tread rubbers, a conclusion which is confirmed by information obtained from other workers.

Variation in Skin Cancer Pattern in the Southwestern Region of Pakistan

2021 ◽  
Vol 15 (12) ◽  
pp. 3402-3404
Author(s):  
Hina , Manzoor ◽  
Najeeb Ahmad ◽  
Zafar H Tanveer ◽  
Khush Naseed Ahmed ◽  
Munir , Ahmed ◽  
...  
Keyword(s):  
Squamous Cell Carcinoma ◽  
Skin Cancer ◽  
Cell Carcinoma ◽  
Squamous Cell ◽  
Published Data ◽  
Non Melanoma Skin Cancer ◽  
Broad Term ◽  
The Difference ◽  
Field Workers ◽  
Melanoma Skin

Background: Skin cancer is a broad term that refers to a variety of different types of cancer. It is usually recognized as non-melanoma and melanoma skin cancer. In many parts of the world, the prevalence is high, with significant ecological and ethical variation. Objectives: Objective was to determine demographic and histological features of skin cancer in Southwest region of Pakistan. Methodology: This retrospective study was carried out on skin cancer 1169 cases of Centre for Nuclear Medicine and Radiotherapy (CENAR) in Quetta. The data from January 2000 to December 2009 (10Years) was retrieved from record. The aim was to determine the importance of skin cancer in this area, its gender wise distribution and its pathological types. Results: Record of total 9308 cancer patients was retrieved from patients presenting to CENAR Quetta. From 9308 case, 1169(12.5%) patients were of skin cancer which was second most prevalent category of cancer in this area. Prevalence was higher in males with 713(61%) cases as compared to females. Pathologically with 634(54%) cases, the most prevalent category was Squamous cell carcinoma (SCC). Conclusion: Skin cancer is wide-spread type of cancer in patients of south-west region of Pakistan. The findings of this study are not aligned with published data. The difference is because of high altitude of the study area, dry climate and long skin exposure particularly in low socio-economic field workers. Keywords: Skin cancer, gender, Melanoma skin cancer (MSC), Squamous cell carcinoma (SCC), Non-melanoma skin cancer (NMSC), Basal cell carcinoma (BCC),

scholarly journals Establishment of a Colony of Phlebotomus argentipes under Laboratory Conditions and Morphometric Variation between Wild-Caught and Laboratory-Reared Populations

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Tharaka Wijerathna ◽  
Nayana Gunathilaka ◽  
Kithsiri Gunawardena
Keyword(s):  
Sand Flies ◽  
Morphometric Variation ◽  
Essential Step ◽  
Laboratory Conditions ◽  
Phlebotomus Argentipes ◽  
Successful Attempt ◽  
Standard Procedures ◽  
Population Sizes ◽  
Laboratory Colonies ◽  
The Difference

The field-based studies on sand flies are not adequate to uncover information required for the control of the leishmaniasis through reduction of vector populations. Therefore, establishment and maintenance of laboratory colonies of sand flies is an essential step in leishmaniasis research. In the current study, a colony of P. argentipes was established from wild-caught sand flies following standard procedures from the published literature. Morphological measurements of laboratory-reared and wild-caught individual sand flies were compared to assess the difference between two groups. The colony was successfully established under confined laboratory conditions. The comparison of morphometric parameters revealed that the laboratory-reared sand flies are significantly larger than those caught from wild, suggesting a possibility of increased fitness of sand flies under favorable environmental conditions which may cause higher prevalence in the disease. The current study reports the first successful attempt in colonizing sand flies under laboratory conditions. However, the colony data suggest that the conditions extracted from the published literature need to be optimized to suit local settings in order to achieve maximum population sizes within the available amount of resources.

Test of Strain-Time Correspondence Principle with Gel-Containing Elastomers

1986 ◽  
Vol 59 (2) ◽  
pp. 305-314 ◽  
Author(s):  
N. Nakajima ◽  
E. R. Harrell
Keyword(s):  
Large Deformation ◽  
Correspondence Principle ◽  
Small Deformation ◽  
Complex Viscosity ◽  
Shear Stresses ◽  
Growth Data ◽  
Stress Growth ◽  
Linear Viscoelastic ◽  
The Difference ◽  
Linear Viscoelastic Theory

Abstract With four NBR samples and one EPR, oscillatory measurements and stress-growth measurements were performed, the former being at very small deformation and the latter leading to large deformation. The Rheometrics mechanical spectrometer was used with a cone-plate fixture. The temperature was 100°C. The stress-growth data of NBR's, converted to complex viscosity-frequency data through the application of stress-time correspondence principle, were in good agreement with those observed in the oscillatory measurement. Thus, the stress-growth data including the large deformation were “linearized” to form a master curve. With the EPR sample, such a linearization was not necessary. The stress-growth data were adequately treated with the linear viscoelastic theory up to shear stresses approaching the steady state. The difference in behavior between the NBR's and EPR is caused by differences in type and extent of long branching and gel present in the samples.

scholarly journals Anterior Cervical Corpectomy and the Operating Team: A Controversy?

2018 ◽  
Vol 07 (01) ◽  
pp. 008-015
Author(s):  
Alexandrina Nikova ◽  
Theodossios Birbilis
Keyword(s):  
Cervical Myelopathy ◽  
Postoperative Outcome ◽  
Published Data ◽  
Multifactorial Disease ◽  
Surgical Team ◽  
Cervical Corpectomy ◽  
Operating Team ◽  
Anterior Corpectomy ◽  
The Difference ◽  
Anterior Cervical Corpectomy

AbstractCervical myelopathy is multifactorial disease that can lead to many dysfunctions. Surgical treatment is believed to be the best healing choice. The authors searched the published data on Medline on this subject and found a difference between the neurosurgeons and orthopaedics on the topic of anterior corpectomy for cervical myelopathy. The difference between the orthopaedics and neurosurgeons is not big, but it could be relevant to the final outcome, which appears to be better in the neurosurgeons. The complication rate is also variable between the groups, with lower rates of complication reported by the neurosurgeons. Therefore, despite the fact that the postoperative outcome depends on many factors, such as preoperative condition, additional comorbidities, age, and lifestyle, this article also finds that the surgical team, after comparing basic techniques that the team used for anterior cervical corpectomy (ACC), is also responsible to some extent. This, however, is not a competition, and future cooperation between the teams might be beneficial for all.

scholarly journals On the Non-Specific Stimulation of Agglutinins. With Especial Reference to the Enteric Fevers and Typhus Fever

1929 ◽  
Vol 28 (4) ◽  
pp. 418-448 ◽  
Author(s):  
A. Felix
Keyword(s):  
Qualitative Method ◽  
Published Data ◽  
Enteric Infection ◽  
Widal Test ◽  
Enteric Infections ◽  
The Difference ◽  
Specific Stimulation ◽  
Enteric Group ◽  
Typhus Fever ◽  
Stimulation Of

(1) The review of the published data furnishes additional evidence in support of the view that no technique whatsoever, Dreyer's technique included, based on the quantitative method of the agglutination reaction hitherto used, is capable of affording a differentiation between inoculation and infection agglutinins.(2) These techniques are concerned always exclusively in the demonstration of the labilotropic H agglutinins ofB. typhosusandB. paratyphosusA. and B. and it is the behaviour of these agglutinins that is the responsible factor in producing the phenomena.(3) In various febrile conditions in inoculated individuals these H agglutinins undergo a re-stimulation resulting in a curve of agglutination which is indistinguishable from that due to specific stimulation. The re-stimulation of the labilotropic inoculation agglutinins is of the same nonspecific character (i.e.heterologous) in the course of enteric infections as in the course of other febrile diseases.(4) The observation of this non-specific re-stimulation is independent of the technique used; living bacilli and suspensions preserved with phenol or formalin (Dreyer's technique included) do not in this respect behave differently.(5) The proposed qualitative method for the Widal test depends, in inoculated individuals, exclusively upon the behaviour of the stabilotropic O agglutinins. In their presence it is capable of affording the certain diagnosis of an enteric infection; in their absence the negative result of the test is not conclusive; if T.A.B. vaccine has been used it is only possible to diagnose enteric group without being able to differentiate typhoid from paratyphoid A. or B.; if T. vaccine has been used then A. or B. infection can be differentiated but not T.(1) The conclusions previously arrived at by means of the qualitative method of the Widal test were fully confirmed. By eliminating the labilotropic H agglutinins from any consideration—in the case of previously sensibilised individuals—agglutination due to the specific stimulation in active enteric infection can be distinguished definitely from that due to the nonspecific re-stimulation by various febrile diseases.(2) Normal and immune O agglutinins forB. typhosusandB. paratyphosusA. and B., as well as those forB. proteusX 19, are not liable to non-specific stimulation in the course of various febrile diseases.(3) One more of the supposed differences in nature between the Widal test and the Weil-Felix test is thereby eliminated.(4) The difference in the response to non-specific stimulation shown to exist in stabilotropic and labilotropic agglutination seems more likely to be one of degree than one in nature and needs further investigation.

Should immunocontraception be used for wildlife population management?

2004 ◽  
Vol 26 (1) ◽  
pp. 61 ◽  
Author(s):  
DW Cooper
Keyword(s):  
Immune Response ◽  
New Zealand ◽  
Immune Responses ◽  
Fundamental Problem ◽  
Public Perceptions ◽  
Published Data ◽  
Red Foxes ◽  
European Rabbits ◽  
Selection For ◽  
Self Antigens

Immunocontraception involves eliciting an immune response against eggs, sperm or hormones so that successful reproduction is prevented. Work in Australasia is aimed at European rabbits (Oryctolagus cuniculus), red foxes (Vulpes vulpes), house mice (Mus musculus), common brushtail possums (Trichosurus vulpecula), koalas (Phascolartcos cinereus) and kangaroos (Macropus spp.), with the vaccines involved all containing self antigens or their relatives. Two fundamental problems have been inadequately addressed in this research. The first problem is that it is difficult to obtain strong immune responses against self antigens and so the vaccines may be ineffective. Most published data on the effect of immunocontraceptives on reproduction involve the use of an adjuvant of which there are many kinds. The materials enhance the immune response greatly. The most frequently used is Freund?s adjuvant which can cause chronic suffering. Its use on wildlife will lead to very negative public perceptions. There has been no convincing demonstration that successful immunocontraception is possible with any method of vaccination likely to be used in the field, if success is defined as contraception of a proportion of the population high enough for management requirements. If it is assumed that success can be achieved, the second fundamental problem arises with two potential consequences. Even with adjuvant, a substantial minority of the vaccinated animals remains fertile. The first consequence is that since failure to be contracepted is likely to be in part genetic, there is likely to be rapid selection for these non-responders. The method will become ineffective in a few generations. The second problem is that the offspring of the animals which breed will have altered immune responses. Their capacities to respond to their own pathogens or to harbor pathogens of other species in the same ecosystem are likely to be changed. The presence of chlamydia in P. cinereus and bovine tuberculosis in New Zealand T. vulpecula means that responses to these pathogens would have to be studied in offspring of immunocontracepted parents to ensure that the offspring were not more susceptible to them. New Zealand intentions to put an immunocontraceptive into a T. vulpecula gut worm must be viewed with caution by Australia. The eggs of transgenic worms will be easily transplanted either accidentally or deliberately back into Australia, and so infect T. vulpecula in Australia.

scholarly journals Comparison of direct and geodetic mass balances on a multi-annual time scale

2010 ◽  
Vol 4 (3) ◽  
pp. 1151-1194
Author(s):  
A. Fischer
Keyword(s):  
Mass Balance ◽  
Direct Method ◽  
Mean Difference ◽  
Published Data ◽  
Glacier Mass Balance ◽  
Mass Balances ◽  
Direct Data ◽  
The Mean ◽  
The Difference ◽  
Geodetic Mass Balance

Abstract. Glacier mass balance is measured with the direct or the geodetic method. In this study, the geodetic mass balances of six Austrian glaciers in 19 periods between 1953 and 2006 are compared to the direct mass balances in the same periods. The mean annual geodetic mass balance for all periods is −0.5 m w.e./year. The mean difference between the geodetic and the direct data is −0.7 m w.e., the minimum −7.3 m w.e. and the maximum 5.6 m w.e. The accuracy of geodetic mass balance resulting from the accuracy of the DEMs ranges from 2 m w.e. for photogrammetric data to 0.002 m w.e. for LIDAR data. Basal melt, seasonal snow cover and density changes of the surface layer contribute up to 0.7 m w.e. for the period of 10 years to the difference to the direct method. The characteristics of published data of Griesgletscher, Gulkana Glacier, Lemon Creek glacier, South Cascade, Storbreen, Storglaciären, and Zongo Glacier is similar to these Austrian glaciers. For 26 analyzed periods with an average length of 18 years the mean difference between the geodetic and the direct data is −0.4 m w.e., the minimum −7.2 m w.e. and the maximum 3.6 m w.e. Longer periods between the acquisition of the DEMs do not necessarily result in a higher accuracy of the geodetic mass balance. Specific glaciers show specific trends of the difference between the direct and the geodetic data according to their type and state. In conclusion, geodetic and direct mass balance data are complementary, but differ systematically.

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