SMARTWheels: development and testing of a system formeasuring manual wheelchair propulsion dynamics

The purpose of this project was to develop a system for dynamically sensing pushrim propulsion forces and torques and to collect kinetic data with the device. A system was developed to detect the forces and torques applied to the wheelchair pushrim, record, store, and process the measured data, and display the kinetic information for analysis. Ten adults, including four male wheelchair users, three ambulatory men, and three ambulatory women, pushed a wheelchair with the SMART^Wheel on a dynamometer while their kinematics were videotaped. The kinetic data collected with the authors' wheel were correlated with stick figure representations of digitized kinematic data obtained through video analysis. The close agreement between the kinetic results and the kinematic results provided a temporal validation of the ability of the wheel to detect forces and torques applied to the wheelchair pushrim. The recorded forces and torques were in agreement with previously reported magnitudes     

Minimizing worst-case and average-case makespan over scenarios

We consider scheduling problems over scenarios where the goal is to find a single assignment of the jobs to the machines which performs well over all scenarios in an explicitly given set. Each scenario is a subset of jobs that must be executed in that scenario. The two objectives that we consider are minimizing the maximum makespan over all scenarios and minimizing the sum of the makespans of all scenarios. For both versions, we give several approximation algorithms and lower bounds on their approximability. We also consider some (easier) special cases. Combinatorial optimization problems under scenarios in general, and scheduling problems under scenarios in particular, have seen only limited research attention so far. With this paper, we make a step in this interesting research direction.     

Shelf life of pork from five different quality classes

A total of 117 loins were selected on the cutting line at 24 h post-mortem to study the long term shelf life (35 days, 4 °C) of vacuum packaged pork from five different quality classes (PSE: pale, soft, exudative; PFN: pale, firm, non-exudative; RSE: red, soft, exudative; RFN: red, firm, non-exudative; and DFD: dark, firm, dry). The microbial load at 0 d was not significantly different (P > 0.05) among the pork quality classes, indicating that the initial microflora was influenced by the dressing conditions at the plant, not by the meat quality class. But after 35 d of storage, total aerobic mesophilic and presumptive lactic acid bacteria counts were higher (P < 0.05) in DFD pork due to its higher ultimate pH. RSE was the second quality class most susceptible to spoilage, whereas PFN, RFN and PSE pork had similar microbial loads. Further research is needed to elucidate the causes of the shorter shelf life in RSE pork.     

SMARTWheels: development and testing of a system for measuring manual wheelchair propulsion dynamics

The purpose of this project was to develop a system for dynamically sensing pushrim propulsion forces and torques and to collect kinetic data with the device. A system was developed to detect the forces and torques applied to the wheelchair pushrim, record, store, and process the measured data, and display the kinetic information for analysis. Ten adults, including four male wheelchair users, three ambulatory men, and three ambulatory women, pushed a wheelchair with the SMARTWheel on a dynamometer while their kinematics were videotaped. The kinetic data collected with our wheel were correlated with stick figure representations of digitized kinematic data obtained through video analysis. The close agreement between the kinetic results and the Kinematic results provided a temporal validation of the ability of the wheel to detect forces and torques applied to the wheelchair pushrim. The recorded forces and torques were in agreement with previously reported magnitudes.     

Effect of postcalving serum nonesterified fatty acids concentration on the functionality of bovine immune cells

The periparturient period is marked by metabolic, hormonal, and immunological changes, which have an effect on the incidence of infectious and metabolic diseases. In a previous study, a slower increase in milk production was induced by milking cows once daily during the first week of lactation, leading to an improvement in levels of several metabolites, including nonesterified fatty acids (NEFA) and β-hydroxybutyrate (BHBA). The aim was to determine the influence of serum collected on d 2, 5, and 61 postpartum from cows milked once or twice daily on immune cell functions and to determine which of the constituents were responsible for these effects. Peripheral blood mononuclear cells (PBMC) and polymorphonuclear leukocytes were collected from healthy midlactation cows and their immune functions (i.e., proliferation and interferon-γ production and chemotaxis, phagocytosis, and oxidative burst, respectively), were evaluated in presence of serum, NEFA, and BHBA. Proliferation of PBMC was greater with d-61 (65.1±1.6%) serum than with d-2 (37.3±2.4%) or d-5 (48.4±1.6%) serum and greater with d-2 and -5 serum from cows milked once (42.2±3.7 and 54.0±2.5) compared with cows milked twice daily (32.4±3.0 and 42.9±2.1). Proliferation was inversely correlated with the concentration of NEFA and BHBA in the serum (r=-0.86). Adding NEFA to d-61 serum to reach the level present in d-5 serum decreased proliferation to the level observed with d-5 serum. No effect of BHBA addition was observed. The release of interferon-γ by PBMC was lower in d-5 serum (766±63 pg/mL) than in d-61 serum (1,187±90 pg/mL) and by NEFA. Milking frequency did not affect chemotaxis, phagocytosis, or oxidative burst of polymorphonuclear leukocytes. Phagocytosis decreased over time in serum from d 2 to 61. Similarly, oxidative burst was greater with d-5 serum (12.7×10(8) ± 1.6×10(8) relative light units) than with d-61 serum (9.0×10(8) ± 1.6×10(8) relative light units). The NEFA had a negative effect on oxidative burst, but BHBA did not. In conclusion, several immune cell functions appear affected by the NEFA concentration. Therefore, strategies that prevent increases in blood NEFA during the transition period may limit postpartum immunosuppression.     

Efficacy of a lactoferrin-penicillin combination to treat {beta}-lactam-resistant Staphylococcus aureus mastitis

The efficacy of intramammary (IM) treatments containing penicillin G (PG) alone or a combination of PG and bovine lactoferrin (bLF) was evaluated using a model of experimentally induced chronic bovine mastitis caused by a clinical isolate of Staphylococcus aureus highly resistant to β-lactam antibiotics. First, we confirmed that this strain could cause mastitis and infection could not be cured with PG alone. In a second trial, chronic mastitis was induced in 19 late-lactating cows by injecting a low dose of Staph. aureus through the teat canal of all quarters. After 15 d, cows with stable infections in their 4 quarters had their mammary quarters randomly assigned, within cow, to 1 of 4 IM treatments as follows: 1) citrate buffer, 2) 100,000 IU of PG, (3) 1 g of bLF, or 4) 1 g of bLF + 100,000 IU of PG. Treatments were repeated twice a day for 5 d. A third trial was undertaken to investigate the effect of an extended therapy on chronic mastitis acquired in a previous lactation. One month before dry-off, 20 gravid cows regrouped by dates of calving were infected in their 4 quarters. Once infections were established, cows were dried off abruptly. After calving, aseptic milk samples were collected separately from all quarters for 4 wk to monitor infection. Mammary quarters from enrolled cows were then randomly assigned, within cow, to 1 of 2 treatments as follows: 1) 100,000 IU of PG or 2) 250 mg of bLF + 100,000 IU of PG. Treatments were administered IM twice a day for 7 d. For all trials, milk samples were taken to monitor bacterial concentration and somatic cell count. Bacteriological cure rate was determined using milk samples taken 3 and 4 wk after initiation of treatments. For the second trial, cure rate was null for control quarters, 11.1% for bLF, 9.1% for PG, and 45.5% for the bLF + PG combination. For cows infected in their previous lactation, cure rate was higher for the bLF + PG combination (33.3%) compared with PG alone (12.5%). In conclusion, bLF added to PG is an effective combination (i.e., 3- to 5-times higher cure rate) for the treatment of stable Staph. aureu infections highly resistant to β-lactam antibiotics.