Effect of laser pulse propagation on ultrafast magnetization dynamics in a birefringent medium.

Light propagation effects can strongly influence the excitation and the detection of laser-induced magnetization dynamics. We investigated experimentally and analytically the effects of crystallographic linear birefringence on the excitation and detection of ultrafast magnetization dynamics in the rare-earth orthoferrites (Sm0.5Pr0.5)FeO3 and (Sm0.55Tb0.45)FeO3, which possess weak and strong linear birefringence, respectively. Our finding is that the effect of linear birefringence on the result of a magneto-optical pump-probe experiment strongly depends on the mechanism of excitation. When magnetization dynamics, probed by means of the Faraday effect, is excited via a rapid, heat-induced phase transition, the measured rotation of the probe pulse polarization is strongly suppressed due to the birefringence. This contrasts with the situation for magnetization dynamics induced by the ultrafast inverse Faraday effect, where the corresponding probe polarization rotation values were larger in the orthoferrite with strong linear birefringence. We show that this striking difference results from an interplay between the polarization transformations experienced by pump and probe pulses in the birefringent medium.

Stability of four commercial phytase products under increasing thermal conditioning temperatures.

Phytase is a feed-grade enzyme frequently added to swine diets to help improve the digestibility of phytate phosphorus. However, like any enzyme, it may be subject to heat damage when exposed to thermal processing. Therefore the objective of this experiment was to determine the stability of 4 commercial phytase products exposed to increasing thermal conditioning temperatures in the pelleting process. The 4 commercial products used were: Quantum Blue G (AB Vista, Plantation, FL); Ronozyme Hi Phos GT (DSM Nutritional Products, Parsippany, NJ); Axtra Phy TPT (Dupont, Wilmington, DE), and Microtech 5000 Plus (Guangdong Vtr Bio-Tech Co., Ltd., Guangdong, China). The phytase products were mixed as part of a corn-soybean meal-based swine diet at a concentration recommended by the manufacturer to provide a 0.12% aP release. Diets were exposed to each of 4 thermal conditioning temperatures (65, 75, 85, and 95°C) and the entire process repeated on 4 consecutive days to create 4 replicates. Samples were taken while feed exited the conditioner and before entering the pellet die. Samples were cooled to room temperature before being stored in plastic bags until analysis. Phytase stability was measured as the residual phytase activity (% of initial) at each conditioning temperature. There were no product × temperature interactions observed for conditioning temperature, conditioner throughput, or residual phytase activity. As target temperature increased, conditioner throughput decreased (linear; P < 0.001) and phytase activity decreased (linear; P < 0.001) for each product. Residual phytase activity decreased as conditioning temperature increased from 65 to 95°C at a rate of -1.9% for every 1°C increase in conditioning temperature. There was a significant phytase product (P < 0.001) main effect which was mainly driven by Microtech 5000 Plus having decreased (P < 0.05) phytase activity when compared to all other products at 65, 75, and 85°C. However at 95°C Axtra Phy TPT had greater (P < 0.05) residual phytase activity compared with Microtech 5000 Plus, with Quantum Blue G and Ronozyme Hi Phos intermediate. Increasing target conditioning temperatures decreased phytase stability regardless of product. In addition, Microtech 5000 Plus had decreased residual phytase activity (% of initial) when compared to all other products at 65, 75, and 85°C.

Evaluating pellet and meal feeding regimens on finishing pig performance, stomach morphology, and carcass characteristics.

A total of 2,100 pigs (PIC 327 × 1050; initially 31.2 kg BW) were used in a 118-d trial to determine the effects of pellet or meal feeding regimens on finishing pig growth performance, stomach morphology, and carcass characteristics. Pens of pigs were balanced by initial BW and randomly allotted to 1 of 6 dietary treatments (14 pens/treatment with 25 pigs/pen). Pens were sorted by gender allowing for 7 barrow pens and 7 gilt pens per treatment. The same corn-soybean meal-based diets containing 15% dried distillers' grains with solubles were used for all treatments and fed in 5 phases. Phases were fed from d 0 to 28, 28 to 56, 56 to 84, 84 to 98, and 98 to 118. The 6 treatments included a meal or pelleted diet fed from d 0 to 118, a meal diet fed from d 0 to 70 followed by pellets from d 70 to 118, a pelleted diet fed from d 0 to 70 followed by a meal diet from d 70 to 118, or pellets and meal rotated every 2 wk starting with meal or pellets. On d 110, 4 pigs from each pen were harvested and stomachs collected, from which a combined ulcer and keratinization score was determined for each pig. Overall, there were no differences in ADG across feeding regimens. Pigs fed meal throughout had the greatest ( < 0.05) ADFI, whereas pigs fed pellets throughout had the lowest ( < 0.05), with all other treatments intermediate ( < 0.05). Pigs fed pelleted diets throughout had the greatest ( < 0.05) G:F, whereas pigs fed meal throughout had the worst G:F ( < 0.05), with all other treatments intermediate ( < 0.05). When pelleted diets were fed for the last 58 d or for the entire trial, the incidence of ulceration and keratinization increased ( < 0.05), whereas pigs fed meal for the last 58 d had a lower incidence ( < 0.05), with all other treatments intermediate ( < 0.05). Feeding pellets throughout increased ( < 0.05) the number of pigs removed per pen compared with all other treatments. Pig removals were determined by an on-site farm manager when pigs were at risk due to weight loss, health, or animal welfare concerns and needed to be separated from the general population. There were no differences for any carcass characteristics measured including HCW, carcass yield, backfat depth, loin depth, and percentage lean. In conclusion, feeding pelleted diets improved G:F but increased stomach ulceration and pig removals; however, rotating pellets and meal diets provided an intermediate G:F response and moderated stomach ulcerations compared with feeding only pellets.

Effects of wheat source and particle size in meal and pelleted diets on finishing pig growth performance, carcass characteristics, and nutrient digestibility.

Two experiments were conducted to test the effects of wheat source and particle size in meal and pelleted diets on finishing pig performance, carcass characteristics, and diet digestibility. In Exp. 1, pigs (PIC 327 × 1050; = 288; initially 43.8 kg BW) were balanced by initial BW and randomly allotted to 1 of 3 treatments with 8 pigs per pen (4 barrows and 4 gilts) and 12 pens per treatment. The 3 dietary treatments were hard red winter wheat ground with a hammer mill to 728, 579, or 326 µm, respectively. From d 0 to 40, decreasing wheat particle size decreased (linear, < 0.033) ADFI but improved (quadratic, < 0.014) G:F. From d 40 to 83, decreasing wheat particle size increased (quadratic, < 0.018) ADG and improved (linear, < 0.002) G:F. Overall from d 0 to 83, reducing wheat particle size improved (linear, < 0.002) G:F. In Exp. 2, pigs (PIC 327 × 1050; = 576; initially 43.4 ± 0.02 kg BW) were used to determine the effects of wheat source and particle size of pelleted diets on finishing pig growth performance and carcass characteristics. Pigs were randomly allotted to pens, and pens of pigs were balanced by initial BW and randomly allotted to 1 of 6 dietary treatments with 12 replications per treatment and 8 pigs/pen. The experimental diets used the same wheat-soybean meal formulation, with the 6 treatments using hard red winter or soft white winter wheat that were processed to 245, 465, and 693 µm and 258, 402, and 710 µm, respectively. All diets were pelleted. Overall, feeding hard red winter wheat increased ( < 0.05) ADG and ADFI when compared with soft white winter wheat. There was a tendency ( < 0.10) for a quadratic particle size × wheat source interaction for ADG, ADFI, and both DM and GE digestibility, as they were decreased for pigs fed 465-µm hard red winter wheat and were greatest for pigs fed 402-µm soft white winter wheat. There were no main or interactive effects of particle size or wheat source on carcass characteristics. In summary, fine grinding hard red winter wheat fed in meal form improved G:F and nutrient digestibility, whereas reducing particle size of wheat from approximately 700 to 250 µm in pelleted diets did not influence growth or carcass traits. Finally, feeding hard red winter wheat improved ADG and ADFI compared with feeding soft white winter wheat.

Modeling of thermoacoustic systems using the nonlinear frequency domain method.

When modeling thermoacoustic (TA) devices at high amplitude, nonlinear effects such as time-average mass flows, and the generation of higher harmonics can no longer be neglected. Thus far, modeling these effects in TA devices required a generally computationally costly time integration of the nonlinear governing equations. In this paper, a fast one-dimensional nonlinear model for TA devices is presented, which omits this costly time integration by directly solving the periodic steady state. The model is defined in the frequency domain, which eases the implementation of phase delays due to viscous resistance and thermoacoustic heat exchange. As a demonstration, the model is used to solve an experimental standing wave thermoacoustic engine. The obtained results agree with experimental results, as well as with results from a nonlinear time domain model from the literature. The low computational cost of this model opens the possibility to do optimization studies using a nonlinear TA model.

Effects of dietary wheat middlings, corn dried distillers grains with solubles, and net energy formulation on nursery pig performance.

Four experiments were conducted to examine effects of dietary wheat middlings (midds), corn dried distillers grains with solubles (DDGS), and NE formulation on nursery pig performance and caloric efficiency. In Exp. 1, 180 nursery pigs (11.86 ± 0.02 kg BW and 39 d of age) were fed 1 of 5 diets for 21 d, with 6 pigs per pen and 6 replications per treatment. Diets were corn-soybean meal based and included 0, 5, 10, 15, or 20% wheat midds. Increasing wheat midds decreased (linear; P < 0.05) ADG and ADFI. Caloric efficiency improved (linear; P < 0.05) on both an ME (NRC, 1998) and NE (Sauvant et al., 2004) basis as dietary wheat midds increased. In Exp. 2, 210 pigs (6.85 ± 0.01 kg BW and 26 d of age) were fed 1 of 5 diets for 35 d, with 7 pigs per pen and 6 replications per treatment. Diets were corn-soybean meal based and contained 0, 5, 10, 15, or 20% wheat midds. Increasing wheat midds did not affect overall ADG or ADFI but decreased (quadratic; P < 0.013) G:F at 20%. Caloric efficiency for both ME and NE improved (quadratic; P < 0.05) as dietary wheat midds increased. In Exp. 3, 180 pigs (12.18 ± 0.4 kg BW and 39 d of age) were fed 1 of 6 experimental diets arranged in a 2 × 3 factorial with main effects of DDGS (0 or 20%) and wheat midds (0, 10, or 20%) for 21 d, with 6 pigs per pen and 5 replications per treatment. No DDGS × wheat midds interactions were observed, and DDGS did not influence ADG, ADFI, or G:F, but increasing dietary wheat midds decreased (linear; P < 0.05) ADG, G:F, and final BW. In Exp. 4, 210 pigs (6.87 kg BW and 26 d of age) were allotted to 1 of 5 dietary treatments, with 7 pigs per pen and 6 replications per treatment. Wheat middlings (0, 10, or 20%) were added to the first 3 diets without balancing for energy. In diets 4 and 5, soybean oil was added (1.4 and 2.8%) to 10 and 20% wheat midds diets to balance to the same NE as the positive control (0% wheat midds). Overall, no wheat midds × fat interactions occurred. Regardless of formulated energy value, caloric efficiency and G:F were poorer (P < 0.05) on an ME basis as wheat midds increased from 10 to 20% of the diet but did not change when calculated on an NE basis. Results of these experiments indicate that wheat midds may be fed up to 10 to 15% of the diet without negatively affecting nursery pig performance and with no interactive effects when fed in combination with DDGS. Also, formulating on an NE basis provided for similar performance with increasing dietary wheat midds compared with a corn-soybean meal control diet.

A one-dimensional heat transfer model for parallel-plate thermoacoustic heat exchangers.

A one-dimensional (1D) laminar oscillating flow heat transfer model is derived and applied to parallel-plate thermoacoustic heat exchangers. The model can be used to estimate the heat transfer from the solid wall to the acoustic medium, which is required for the heat input/output of thermoacoustic systems. The model is implementable in existing (quasi-)1D thermoacoustic codes, such as DeltaEC. Examples of generated results show good agreement with literature results. The model allows for arbitrary wave phasing; however, it is shown that the wave phasing does not significantly influence the heat transfer.

Coherent control of the route of an ultrafast magnetic phase transition via low-amplitude spin precession.

Time-resolved magneto-optical imaging of laser-excited rare-earth orthoferrite (SmPr)FeO3 demonstrates that a single 60 fs circularly polarized laser pulse is capable of creating a magnetic domain on a picosecond time scale with a magnetization direction determined by the helicity of light. Depending on the light intensity and sample temperature, pulses of the same helicity can create domains with opposite magnetizations. We argue that this phenomenon relies on a twofold effect of light which (i) instantaneously excites coherent low-amplitude spin precession and (ii) triggers a spin reorientation phase transition. The former dynamically breaks the equivalence between two otherwise degenerate states with opposite magnetizations in the high-temperature phase and thus controls the route of the phase transition.

Small-incision versus open cholecystectomy for patients with symptomatic cholecystolithiasis.

BACKGROUND: Cholecystectomy is one of the most frequently performed operations. Open cholecystectomy has been the gold standard for over 100 years. Small-incision cholecystectomy is a less frequently used alternative. OBJECTIVES: To compare the beneficial and harmful effects of small-incision versus open cholecystectomy for patients with symptomatic cholecystolithiasis. SEARCH STRATEGY: We searched TheCochrane Hepato-Biliary Group Controlled Trials Register (6 April 2004), The Cochrane Library (Issue 1, 2004), MEDLINE (1966 to January 2004), EMBASE (1980 to January 2004), Web of Science (1988 to January 2004), and CINAHL (1982 to January 2004) for randomised trials. SELECTION CRITERIA: All published and unpublished randomised trials in patients with symptomatic cholecystolithiasis comparing any kind of small-incision or other kind of minimal incision cholecystectomy versus any kind of open cholecystectomy. No language limitations were applied. DATA COLLECTION AND ANALYSIS: Two authors independently performed selection of trials and data extraction. The methodological quality of the generation of the allocation sequence, allocation concealment, blinding, and follow-up was evaluated to assess bias risk. Analyses were based on the intention-to-treat principle. Authors were requested additional information in case of missing data. Sensitivity and subgroup analyses were performed if appropriate. MAIN RESULTS: Seven trials randomised 571 patients. Bias risk was high in the included trials. No mortality was reported. The total complication proportions are respectively 9.9% and 9.3% in the small-incision and open group, which is not significantly different (risk difference all trials, random-effects 0.00, 95% confidence interval (CI) -0.06 to 0.07). There are also no significant differences considering severe complications and bile duct injuries. However, small-incision cholecystectomy has a shorter hospital stay (weighted mean difference, random-effects -2.8 days (95% CI -4.9 to -0.6)) compared to open cholecystectomy. AUTHORS' CONCLUSIONS: Small-incision and open cholecystectomy seem to be equivalent regarding risks of complications, but the latter method is associated with a significantly longer hospital stay. The quicker recovery of small-incision cholecystectomy compared with open cholecystectomy confirms the existing preference of this technique over open cholecystectomy.

Laparoscopic versus open cholecystectomy for patients with symptomatic cholecystolithiasis.

BACKGROUND: Cholecystectomy is one of the most frequently performed operations. Open cholecystectomy has been the gold standard for over 100 years. Laparoscopic cholecystectomy was introduced in the 1980s. OBJECTIVES: To compare the beneficial and harmful effects of laparoscopic versus open cholecystectomy for patients with symptomatic cholecystolithiasis. SEARCH STRATEGY: We searched TheCochrane Hepato-Biliary Group Controlled Trials Register (April 2004), The Cochrane Library (Issue 1, 2004), MEDLINE (1966 to January 2004), EMBASE (1980 to January 2004), Web of Science (1988 to January 2004), and CINAHL (1982 to January 2004) for randomised trials. SELECTION CRITERIA: All published and unpublished randomised trials in patients with symptomatic cholecystolithiasis comparing any kind of laparoscopic cholecystectomy versus any kind of open cholecystectomy. No language limitations were applied. DATA COLLECTION AND ANALYSIS: Two authors independently performed selection of trials and data extraction. The methodological quality of the generation of the allocation sequence, allocation concealment, blinding, and follow-up was evaluated to assess bias risk. Analyses were based on the intention-to-treat principle. Authors were requested additional information in case of missing data. Sensitivity and subgroup analyses were performed when appropriate. MAIN RESULTS: Thirty-eight trials randomised 2338 patients. Most of the trials had high bias risk. There was no significant difference regarding mortality (risk difference 0,00, 95% confidence interval (CI) -0.01 to 0.01). Meta-analysis of all trials suggests less overall complications in the laparoscopic group, but the high-quality trials show no significant difference ('allocation concealment' high-quality trials risk difference, random effects -0.01, 95% CI -0.05 to 0.02). Laparoscopic cholecystectomy patients have a shorter hospital stay (weighted mean difference (WMD), random effects -3 days, 95% CI -3.9 to -2.3) and convalescence (WMD, random effects -22.5 days, 95% CI -36.9 to -8.1) compared to open cholecystectomy. AUTHORS' CONCLUSIONS: No significant differences were observed in mortality, complications and operative time between laparoscopic and open cholecystectomy. Laparoscopic cholecystectomy is associated with a significantly shorter hospital stay and a quicker convalescence compared with the classical open cholecystectomy. These results confirm the existing preference for the laparoscopic cholecystectomy over open cholecystectomy.

Laparoscopic versus small-incision cholecystectomy for patients with symptomatic cholecystolithiasis.

BACKGROUND: Cholecystectomy is one of the most frequently performed operations. Open cholecystectomy has been the gold standard for over 100 years. Small-incision cholecystectomy is a less frequently used alternative. Laparoscopic cholecystectomy was introduced in the 1980s. OBJECTIVES: To compare the beneficial and harmful effects of laparoscopic versus small-incision cholecystectomy for patients with symptomatic cholecystolithiasis. SEARCH STRATEGY: We searched TheCochrane Hepato-Biliary Group Controlled Trials Register (6 April 2004), The Cochrane Library (Issue 1, 2004), MEDLINE (1966 to January 2004), EMBASE (1980 to January 2004), Web of Science (1988 to January 2004), and CINAHL (1982 to January 2004) for randomised trials. SELECTION CRITERIA: All published and unpublished randomised trials in patients with symptomatic cholecystolithiasis comparing any kind of laparoscopic cholecystectomy versus small-incision or other kind of minimal incision open cholecystectomy. No language limitations were applied. DATA COLLECTION AND ANALYSIS: Two authors independently performed selection of trials and data extraction. The methodological quality of the generation of the allocation sequence, allocation concealment, blinding, and follow-up was evaluated to assess bias risk. Analyses were based on the intention-to-treat principle. Authors were requested additional information in case of missing data. Sensitivity and subgroup analyses were performed if appropriate. MAIN RESULTS: Thirteen trials randomised 2337 patients. Methodological quality was relatively high considering the four quality criteria. Total complications of laparoscopic and small-incision cholecystectomy are high: 26.6% versus 22.9%. Total complications (risk difference, random-effects -0.01, 95% confidence interval (CI) -0.07 to 0.05), hospital stay (weighted mean difference (WMD), random-effects -0.72 days, 95% CI -1.48 to 0.04), and convalescence were not significantly different. High-quality trials show a quicker operative time for small-incision cholecystectomy (WMD, high-quality trials 'blinding', random-effects 16.4 minutes, 95% CI 8.9 to 23.8) while low-quality trials show no significant difference. AUTHORS' CONCLUSIONS: Laparoscopic and small-incision cholecystectomy seem to be equivalent. No differences could be observed in mortality, complications, and postoperative recovery. Small-incision cholecystectomy has a significantly shorter operative time. Complications in elective cholecystectomy are prevalent.

Paternal lineage of alcoholism, cohort effects, and alcoholism criteria.

Adoption studies have led to the suggestion that there may be two distinct subgroups of alcoholics with differing genetic contributions. Among 249 male alcoholics we used discriminant analysis to relate the features of type 1 and type 2 alcoholism to the presence or absence of a family history of alcoholism in male paternal relatives. We found that guilt and binging, features usually attributed to type 1 (milieu-limited) alcoholism, were in fact more prevalent in the family history positive group. An additional cohort analysis found cohort-related variations in type 1/type 2 characteristics. The possible implications of these findings are discussed.

Relationship of cognitive factors to CSF corticotropin-releasing hormone in depression.

The authors investigated the relationship between items on the Beck Depression Inventory and CSF levels of corticotropin-releasing hormone (CRH) in 17 depressed patients. Linear regression analysis showed that self-accusation, expectation of punishment, and crying accounted for 82% of CRH variance.

Relations between tablet properties.

With the aid of simple mathematical models the relations between specific crushing strength (i.e. crushing strength divided by the breaking surface), friability and disintegration time of a tablet can be given. The friability is related to the porosity of the tablets and the specific crushing strength, independent of the process conditions. For the disintegration time two models have been used, depending on the disintegration mechanism. In the first one the disintegration time is only dependent on the porosity, in the second on the specific surface by weight of the granules of which the tablets are made. The theoretical relationships were verified for two tablet formulations, made under varying process conditions.

Molecular cloning and expression of Treponema pallidum DNA in Escherichia coli K-12.

A gene bank of Treponema pallidum DNA in Escherichia coli K-12 was constructed by cloning SauI-cleaved T. pallidum DNA into the cosmid pHC79. Sixteen of 800 clones investigated produced one or more antigens that reacted with antibodies from syphilitic patients. According to the separation pattern of the antigens produced on sodium dodecyl sulfate-polyacrylamide gels, six different phenotypes were distinguished among these 16 clones. These antigens reacted also with anti-T. pallidum rabbit serum. No antibodies against the cloned antigens were found in normal rabbit serum and in nonsyphilitic human serum. The antigens produced by the E. coli K-12 recombinant DNA clones comigrated in sodium dodecyl sulfate-polyacrylamide gels with antigens extracted from T. pallidum bacteria, suggesting that the treponemal DNA is well expressed in E. coli K-12. Several of the cosmid recombinant plasmids have been subcloned, resulting in smaller T. pallidum recombinant plasmids which are more stably maintained in the cell and produce more treponemal antigen. Monoclonal antibodies were raised against T. pallidum, and one hybridoma produced antibodies that reacted not only with an antigen from T. pallidum but also with the antigen produced by one of the E. coli clones.