Ring size of somatostatin analogues (ODT-8) modulates receptor selectivity and binding affinity

The synthesis, biological testing, and NMR studies of several analogues of H-c[Cys (3)-Phe (6)-Phe (7)-DTrp (8)-Lys (9)-Thr (10)-Phe (11)-Cys (14)]-OH (ODT-8, a pan-somatostatin analogue, 1) have been performed to assess the effect of changing the stereochemistry and the number of atoms in the disulfide bridge on binding affinity. Cysteine at positions 3 and/or 14 (somatostatin numbering) were/was substituted with d-cysteine, norcysteine, D-norcysteine, homocysteine, and/or D-homocysteine. The 3D structure analysis of selected partially selective, bioactive analogues (3, 18, 19, and 21) was carried out in dimethylsulfoxide. Interestingly and not unexpectedly, the 3D structures of these analogues comprised the pharmacophore for which the analogues had the highest binding affinities (i.e., sst 4 in all cases).

Experimental arthritis: effect on growth parameters and total skeletal calcium

Aim of the study was to investigate the possible mechanisms leading to stunted growth and osteoporosis in experimental arthritis. Fourty-two female rats of 7-8 weeks of age were randomly assigned to three groups of 14 animals each: (a) controls; (b) adjuvant-inoculated (AA); and (c) adjuvant-inoculated rats receiving 10 mg cyclosporin A (CsA) orally for 30 days. Biological parameters studied were: hindpaw swelling; vertebral length progression expressed as Delta increments between days 1 and 30 as a parameter of skeletal growth, and estimation of total skeletal mineral content by dual energy X-ray absorptiometry (n=10 each group) on day 30. Endocrine parameters measured were pulsatile release of growth hormone (rGH) on day 30 following jugular cannulation and measurement of insulin-like growth factor (IGF-1) in pooled plasma from rGH profiles. Results can be summarized as follows: Untreated AA rats exhibited local signs of inflammation in comparison with controls (hindpaw diameter 8.1-8.9 mm vs. 5.3-5.6 mm in controls). Treatment with CsA normalized this parameter (4.9-5.6 mm). Vertebral growth was significantly retarded in AA rats in comparison with controls (214+/-32 vs. 473+/-33 microm; p<0.001). Administration of CsA normalized vertebral size increment with a clear tendency to overgrowth (523+/-43 microm, n.s.). There was also a marked reduction in total skeletal mineral content in diseased (AA) rats as compared to controls (5.8+/-0.1 vs. 7.5+/-0.1g [OH-apatite]; p<0.001), and a moderate but significant increment above controls in the group receiving CsA (8.0+/-0.1 vs. 7.5+/-0.1g [OH-appatite]; p<0.04). Integrated rGH profiles exhibited a significant fall in arthritic rats and were completely restored to normal under CsA treatment. A trend toward higher rGH values was observed in the latter group (2908+/-554 in AA vs. 8317+/-1492 ng/ml/240 min in controls; p<0.001, and 10940+/-222 ng/ml/240 min, n.s. in the CsA group). There was a good correlation between skeletal growth and rGH pulsatility (r=0.81; p<0.001). IGF-1 followed a similar pattern (630+/-44 in AA vs. 752+/-30 ng/ml in controls; p<0.04, and 769+/-59 ng/ml in the CsA group, n.s. vs. controls). Thus, a clear tendency to skeletal overgrowth following treatment was observed in agreement with the hormonal data. It can therefore be concluded that, in experimental arthritis, attenuated GH-spiking and reduced circulating IGF-1 appear to be causally related to growth retardation, probably mimicking signs and symptoms observed in juvenile arthritis. Therapy with CsA is followed by normalization of hormonal and biological parameters accompanied by a catch up phenomenon in skeletal growth which is also observed clinically in juvenile arthritis. Generalized osteopenia is a prominent feature seemingly connected with the growth abnormalities as they parallel each other during the evolution of the disease and respond equally to therapy.

Investigation of the effect of using data collection technology on students' attitudes to science instruction

The purpose of this project was to investigate the effect of using of data collection technology on student attitudes towards science instruction. The study was conducted over the course of two years at Madison High School in Adrian, Michigan, primarily in college preparatory physics classes, but also in one college preparatory chemistry class and one environmental science class. A preliminary study was conducted at a Lenawee County Intermediate Schools student summer environmental science day camp. The data collection technology used was a combination of Texas Instruments TI-84 Silver Plus graphing calculators and Vernier LabPro data collection sleds with various probeware attachments, including motion sensors, pH probes and accelerometers. Students were given written procedures for most laboratory activities and were provided with data tables and analysis questions to answer about the activities. The first year of the study included a pretest and posttest measuring student attitudes towards the class they were enrolled in. Pre-test and post-test data were analyzed to determine effect size, which was found to be very small (Coe, 2002). The second year of the study focused only on a physics class and used Keller’s ARCS model for measuring student motivation based on the four aspects of motivation: Attention, Relevance, Confidence and Satisfaction (Keller, 2010). According to this model, it was found that there were two distinct groups in the class, one of which was motivated to learn and the other that was not. The data suggest that the use of data collection technology in science classes should be started early in a student’s career, possibly in early middle school or late elementary. This would build familiarity with the equipment and allow for greater exploration by the student as they progress through high school and into upper level science courses.

Granulocyte colony stimulating factor supports liver regeneration in a surgical small for size liver remnant mouse model

ntense liver regeneration and almost 100% survival follows partial hepatectomy of up to 70% of liver mass in rodents. More extensive resections of 70 to 80% have an increased mortality and partial hepatectomies of >80% constantly lead to acute hepatic failure and death in mice. The aim of the study was to determine the effect of systemically administered granulocyte colony stimulating factor (G-CSF) on animal survival and liver regeneration in a small for size liver remnant mouse model after 83% partial hepatectomy (liver weight <0.8% of mouse body weight). Methods: Male Balb C mice (n=80, 20-24g) were preconditioned daily for five days with 5μg G-CSF subcutaneously or sham injected (aqua ad inj). Subsequently 83% hepatic resection was performed and daily sham or G-CSF injection continued. Survival was determined in both groups (G-CSF n=35; Sham: n=33). In a second series BrdU was injected (50mg/kg Body weight) two hours prior to tissue harvest and animals euthanized 36 and 48 hours after 83% liver resection (n=3 each group). To measure hepatic regeneration the BrdU labeling index and Ki67 expression were determined by immunohistochemistry by two independent observers. Harvested liver tissue was dried to constant weight at 65 deg C for 48 hours. Results: Survival was 0% in the sham group on day 3 postoperatively and significantly better (26.2% on day 7 and thereafter) in the G-CSF group (Log rank test: p<0.0001). Dry liver weight was increased in the G-CSF group (T-test: p<0.05) 36 hours after 83% partial hepatectomy. Ki67 expression was elevated in the G-CSF group at 36 hours (2.8±2.6% (Standard deviation) vs 0.03±0.2%; Rank sum test: p<0.0001) and at 48 hours (45.1±34.6% vs 0.7±1.0%; Rank sum test: p<0.0001) after 83% liver resection. BrdU labeling at 48 hours was 0.1±0.3% in the sham and 35.2±34.2% in the G-CSF group (Rank sum test: p<0.0001) Conclusions: The surgical 83% resection mouse model is suitable to test hepatic supportive regimens in the setting of small for size liver remnants. Administration of G-CSF supports hepatic regeneration after microsurgical 83% partial hepatectomy and leads to improved long-term survival in the mouse. G-CSF might prove to be a clinically valuable supportive substance in small for size liver remnants in humans after major hepatic resections due to primary or secondary liver tumors or in the setting of living related liver donation.

Experimental and theoretical study of microstructure effect on piezoelectric property of one dimensional ZnO nanostructures

Emerging nanogenerators have attracted the attention of the research community, focusing on energy generation using piezoelectric nanomaterials. Nanogenerators can be utilized for powering NEMS/MEMS devices. Understanding the piezoelectric properties of ZnO one-dimensional materials such as ZnO nanobelts (NBs) and Nanowires (NWs) can have a significant impact on the design of new devices. The goal of this dissertation is to study the piezoelectric properties of one-dimensional ZnO nanostructures both experimentally and theoretically. First, the experimental procedure for producing the ZnO nanostructures is discussed. The produced ZnO nanostructures were characterized using an in-situ atomic force microscope and a piezoelectric force microscope. It is shown that the electrical conductivity of ZnO NBs is a function of applied mechanical force and its crystalline structure. This phenomenon was described in the context of formation of an electric field due to the piezoelectric property of ZnO NBs. In the PFM studies, it was shown that the piezoelectric response of the ZnO NBs depends on their production method and presence of defects in the NB. Second, a model was proposed for making nanocomposite electrical generators based on ZnO nanowires. The proposed model has advantages over the original configuration of nanogenerators which uses an AFM tip for bending the ZnO NWs. Higher stability of the electric source, capability for producing larger electric fields, and lower production costs are advantages of this configuration. Finally, piezoelectric properties of ZnO NBs were simulated using the molecular dynamics (MD) technique. The size-scale effect on piezoelectric properties of ZnO NBs was captured, and it is shown that the piezoelectric coefficient of ZnO NBs decreases by increasing their lateral dimensions. This phenomenon is attributed to the surface charge redistribution and compression of unit cells that are placed on the outer shell of ZnO NBs.

SIZE OPTIMIZATION OF A BIOMASS TO LIQUID FUEL CONVERSION FACILITY WITHIN A BIOMASS SUPPLY CHAIN

Bioenergy and biobased products offer new opportunities for strengthening rural economies, enhancing environmental health, and providing a secure energy future. Realizing these benefits will require the development of many different biobased products and biobased production systems. The biomass feedstocks that will enable such development must be sustainable, widely available across many different regions, and compatible with industry requirements. The purpose of this research is to develop an economic model that will help decision makers identify the optimal size of a forest resource based biofuel production facility. The model must be applicable to decision makers anywhere, though the modeled case analysis will focus on a specific region; the Upper Peninsula (U.P.) of Michigan. This work will illustrate that several factors influence the optimal facility size. Further, this effort will reveal that the location of the facility does affect size. The results of the research show that an optimal facility size can be determined for a given location and are based on variables including forest biomass availability, transportation cost rate, and economy of scale factors. These variables acting alone and interacting together can influence the optimal size and the decision of where to locate the biofuel production facility. Further, adjustments to model variables like biomass resource and storage costs have no effect on facility size, but do affect the unit cost of the biofuel produced.

Effect of two bioabsorbable barrier membranes on bone regeneration of standardized defects in calvarial bone: a comparative histomorphometric study in pigs

BACKGROUND: The effect of two different bioabsorbable collagen membranes on bone regeneration was assessed in standardized, membrane-protected calvarial defects in pigs. METHODS: Two standardized defect types (6 x 6 x 6 mm and 9 x 9 x 9 mm) were produced in the calvaria of pigs: empty defects without a membrane (group 1; eight defects per size); defects filled with deproteinized bovine bone mineral (DBBM) without a membrane (group 2; eight defects per size); defects filled with DBBM and covered by a collagen membrane (group 3; eight defects per size); and defects filled with DBBM and covered by a cross-linked collagen membrane (CCM) (group 4; eight defects per size). Sacrifice took place 16 weeks after surgery, and the following parameters were analyzed: descriptive histology; semiquantitative histology (SQH), assessing bone regeneration in the whole defect area; and histomorphometric analysis of the percentage of bone and DBBM in the regenerated area at three different depth levels of the defect. RESULTS: Using SQH, both membrane types resulted in significantly better bone regeneration compared to groups 1 and 2, irrespective of the defect size (P <0.005), with no difference between the two membranes. In the histomorphometric analysis, the layer immediately below the surface exhibited a significantly higher percentage of bone in groups 3 (27%) and 4 (36%) versus the two other groups for the 9 x 9 x 9-mm defects. No such differences were apparent for the 6 x 6 x 6-mm defects or the other two depth levels (bottom and middle layer) for either defect size. CONCLUSIONS: The two collagen membranes tested significantly enhanced bone regeneration, especially in the superficial level of the calvarial bone defects. The prototype CCM did not provide any further advantage in the present animal model.

Effect of animal species and age on plate-induced vascular damage in cortical bone

Plates used for fracture fixation produce vascular injury to the underlying cortical bone. During the recovery of the blood supply, temporary osteoporosis is observed as a result of Haversian remodeling of the necrotic bone. This process temporarily reduces the strength of the bone. We tackled the postulate that quantitative differences exist between animal species, and in different bones within the same species, due to variations in the relative importance of the endosteal and periosteal blood supplies. Using implants scaled to the size of the bone, we found comparable cortical vascular damage in the sheep and in the dog, and in the tibia and femur of each animal. We observed a significant reduction in cortical vascular damage using plates that had a smaller contact area with the underlying bone. No significant difference in cortical vascular damage was noted in animals of different ages.

Judgments of duration, figure-ground contrast, and size for words and nonwords

Does the word-superiority effect on letter discrimination result in a word-superiority effect on duration judgments? We examined this question in five experiments. In the first four experiments, we have demonstrated that (1) words shown for 32-80 msec were judged as presented longer than non-words shown for the same duration; (2) this word-superiority effect persists if the stimuli are shown for an objective duration of up to 250 msec; and (3) these effects can be extended to judgments of figure-ground contrast and letter size. These findings extend existing data on effects of processing fluency on perceptual judgments. In Experiment 5, we found that duration judgments were higher for words than for pronounceable nonwords, and duration judgments were higher for pronounceable non-words than for nonpronounceable nonwords. We discuss the implications of this finding for the discrepancy-attribution hypothesis.

Light curing through glass ceramics: effect of curing mode on micromechanical properties of dual-curing resin cements

OBJECTIVES The aim of this study was to investigate micromechanical properties of five dual-curing resin cements after different curing modes including light curing through glass ceramic materials. MATERIALS AND METHODS Vickers hardness (VH) and indentation modulus (Y HU) of Panavia F2.0, RelyX Unicem 2 Automix, SpeedCEM, BisCem, and BeautiCem SA were measured after 1 week of storage (37 °C, 100 % humidity). The resin cements were tested following self-curing or light curing with the second-generation light-emitting diode (LED) curing unit Elipar FreeLight 2 in Standard Mode (1,545 mW/cm(2)) or with the third-generation LED curing unit VALO in High Power Mode (1,869 mW/cm(2)) or in XtraPower Mode (3,505 mW/cm(2)). Light curing was performed directly or through glass ceramic discs of 1.5 or 3 mm thickness of IPS Empress CAD or IPS e.max CAD. VH and Y HU were analysed with Kruskal-Wallis tests followed by pairwise Wilcoxon rank sum tests (α = 0.05). RESULTS RelyX Unicem 2 Automix resulted in the highest VH and Y HU followed by BeautiCem SA, BisCem, SpeedCEM, and finally Panavia F2.0. Self-curing of RelyX Unicem 2 Automix and SpeedCEM lowered VH and Y HU compared to light curing whereas self-curing of Panavia F2.0, BisCem, and BeautiCem SA led to similar or significantly higher VH and Y HU compared to light curing. Generally, direct light curing resulted in similar or lower VH and Y HU compared to light curing through 1.5-mm-thick ceramic discs. Light curing through 3-mm-thick discs of IPS e.max CAD generally reduced VH and Y HU for all resin cements except SpeedCEM, which was the least affected by light curing through ceramic discs. CONCLUSIONS The resin cements responded heterogeneously to changes in curing mode. The applied irradiances and light curing times adequately cured the resin cements even through 1.5-mm-thick ceramic discs. CLINICAL RELEVANCE When light curing resin cements through thick glass ceramic restorations, clinicians should consider to prolong the light curing times even with LED curing units providing high irradiances.

Effects of Initial Body Condition, Frame Size and Concentration of Dietary Energy on Carcass Value of Finished Steers

Yearling steers were sorted into four groups based on hip height and fat cover at the start of the finishing period. Each group of sorted steers was fed diets containing 0.59 or 0.64 Mcal NEg per pound of diet. The value of each carcass was determined by use of the Oklahoma State University Boxed Beef Calculator. Sorting to increase hip height decreased the percentage of Choice carcasses and fat cover, increased ribeye area, and had no effect on carcass weight or yield grades 1 and 2. Sorting to decrease initial fat cover decreased carcass weight, carcass fat cover, and percentage of choice carcasses and increased the proportion of yield grades 1 and 2 carcasses. Concentration of energy in the finishing diet had no effect on carcass measurements. Increasing the percentage of yield grades 1 and 2 carcasses did not result in increased economic value of the carcasses when quality grades were lower and when there was a wide spread between Choice and Select carcasses, as occurred in 1996. With less spread between Choice and Select, as in 1997, sorting the cattle to increase yield grades 1 and 2 resulted in increased value, especially for close-trim boxed beef. The results of this study emphasize the importance of knowing how carcasses will grade before selecting a valuebased market for selling cattle.

Effect of Parenteral Vitamin E and/or A on Reproductive Performance of Ewes Mated on Pasture or in Drylot

Forty-four Hampshire (H) and 41 Suffolk (S) ewes were allotted within breed to one of four treatment groups (VitA, VitE, VitAE, and Control) to evaluate the effect of supplemental vitamin E and A on reproductive performance of ewes mated on pasture or in drylot. Beginning two weeks before the mating period, ewes received 0 or 300 IU of vitamin E every 14 days and 0 or 250,000 IU of vitamin A every 28 days. Hampshire ewes remained on pasture during the mating period, whereas S ewes were moved to drylot. Treatment did not affect ovulation rate (OR), embryonic loss (EL), fetal loss (FL) or litter size (LS) of H ewes. Embryonic loss was higher (P<.05) in the H yearlings and two-year olds than in older ewes. Litter size was lower (P<.01) for H yearlings compared with other age groups. Suffolk ewes in the VitE group exhibited a lower (P<.01) OR than S ewes in other treatment groups, but no effect of treatment was observed for EL, FL, or LS. Although S yearling ewes did not differ from ewes of other age groups for OR and EL, they did produce fewer (P<.05) lambs. Analysis of serum samples revealed that H yearling ewes exhibited lower (P<.05) serum a-tocopherol levels than older H ewes. In addition, H ewes had a higher (P<.05) serum a-tocopherol level than S ewes at the beginning of study when they were managed as one group. Even though age and breed influenced certain reproductive parameters, results of this study indicate little effect of supplemental vitamin E and A on the overall reproductive efficiency of ewes mated on pasture or in drylot.

Effect of Supplemental Vitamin E and A on Reproductive Performance and Serological Profiles of Ewes Managed in Drylot

Forty Hampshire and 40 Suffolk ewes were allotted to one of four groups (VitA, VitE, VitA&E, Control) in a 2 x 2 factorial treatment arrangement to evaluate the effect of supplemental vitamin E (0 or 300 IU) and vitamin A (0 or 250,000 IU) on reproductive performance. Laparoscopy and ultrasonography were used to measure ovulation rate, embryonic loss, and fetal loss. Serum profiles of a-tocopherol (vitamin E) and retinol (vitamin A) also were monitored. There were no differences (P>.05) among treatment groups in any reproductive trait. Suffolk ewes exhibited a higher (P<.02) ovulation rate than Hampshire ewes, and yearling ewes incurred higher (P<.001) embryonic loss than other age groups, resulting in a lower (P<.001) litter size. Serum levels of a-tocopherol were higher (P<.05) for Hampshire than for Suffolk ewes and were lower (P<.001) in yearling ewes versus ewes two years of age and older. Serum levels of a-tocopherol declined (P<.01) throughout the study in VitA and Control ewes but remained unchanged in VitE and VitA&E ewes. Serum level of retinol remained unchanged in VitA ewes, whereas the level increased (P<.01) initially in VitE, VitA&E, and Control ewes before declining toward initial levels. Correlations were detected between ovulation rate and the change of pre-mating a-tocopherol serum level (r=-.29; P<.02), the change in pre-mating retinol serum level (r=-.50; P<.02) and the interval from vitamin A injection (r=-.60; P<.05). These data indicate significant influences of breed, age, and treatment on a-tocopherol and retinol serum levels in ewes and suggest that the timing of vitamin A administration may influence ovulation rate; however, vitamin supplementation, administered at random stages of the estrous cycle, was unable to alter flock reproductive performance.

Alternative Cow Herd Investment Strategies: Constant Size and Constant Investment

Two heifer replacement strategies were compared over a 25-year period. One strategy retained the same number of heifers each year to maintain a constant herd size. The second strategy retained the same dollar value of heifer calves each year based on their opportunity cost as feeder calves. The constant investment strategy herd size varied throughout the period, but generated higher average profit and higher net worth than did the constant herd size strategy. Constant investment is a simple strategy to adjust the level of investment in beef cows and the resource base (pasture, labor, winter feed) in response to market signals driven by the cattle cycle. This strategy automatically increases heifer retention when the opportunity cost is low and reduces the number retained when cost is high. The effect is a lower average cost of cows in the herd, lower overall investment, and a higher net return on investment. Iowa producers, who often have greater flexibility in land use than producers in other major beef cow regions, can better utilize this strategy that generates greater profits and net worth growth.

Optical pen-size reflectometer for monitoring of early dental erosion in native and polished enamels

Application of the specular reflection intensity was previously reported for the quantification of early dental erosion. Further development of the technique and assembly of the miniaturized pen-size instrument are described. The optical system was adjusted to fit into a handy device which could potentially access different positions in the oral cavity. The assembled instrument could successfully detect early erosion progression in both polished (n=70) and native (n=20) human enamels. Different severities of enamel erosion were induced by varying incubation time of polished enamel in 1% citric acid (pH=3.60, 0.5 to 10 min), while the native incisors were treated in the commercial orange juice (Tropicana Pure Premium®, pH=3.85, 10 to 60 min). The instrument provided a good differentiation between various severities of the erosion in vitro. The size of the measurement spot affected the erosion monitoring in native enamel (human incisors). The erosion measurement in the 0.7-mm (diameter) cervical spots showed systematically lower reflection intensities compared with the analysis of central and incisal small spots. The application of larger spot areas (2.3 mm) for the erosion monitoring revealed no effect (p>0.05) of the spot position on the reflection signal. High variation of the teeth susceptibility toward in vitro erosion was detected in native enamel.