Effect of backpack load on the head, cervical spine and shoulder postures in children during gait termination

Twelve boys with an average age of 9.9 years were instructed to carry backpacks that weighed 0%, 10% and 15% of their body weights (BWs) to complete planned and unplanned gait termination experiments. The craniohorizontal, craniovertebral and sagittal shoulder posture angles at the sagittal plane as well as the anterior head alignment and coronal shoulder posture angles at the coronal plane were analysed. Results revealed significantly smaller craniohorizontal and sagittal shoulder posture angles during planned gait termination and a significantly smaller sagittal shoulder posture angle during unplanned gait termination under loaded conditions compared with those at 0% BW backpacks. Furthermore, the coronal shoulder posture angles at 10% and 15% BW during planned and unplanned gait terminations were significantly larger than those at 0% BW. Therefore, subjects were more likely to have a forward head posture, rounded shoulder posture and increased lateral tilting of the shoulders during gait termination as backpack loads were increased. However, gait termination, whether planned or unplanned, did not elicit a remarkable effect on posture.

New proposed conceptual mathematical models for biomass viability and membrane fouling of membrane bioreactor

The production and accumulation of soluble microbial products (SMP), extracellular polymeric substances (EPS) and colloidal inert compounds within a membrane bioreactor (MBR) may greatly affect the biomass viability and subsequently the permeability of the membrane. This paper aims at presenting new mathematical models of biomass viability and membrane fouling that has been conceptually developed through establishing links between these biomass parameters and operating parameters of the MBR. The proposed models can be used to predict the biomass viability and membrane fouling at any state of operation of MBR. Meanwhile, easily measurable parameters of the proposed model can also serve to estimate SMP/EPS concentration in the supernatant of MBR without the tedious and expensive measurement.

Effects of maternal subclinical hypothyroidism on obstetrical outcomes during early pregnancy

BACKGROUND

Maternal hypothyroidism [overt hypothyroidism and subclinical hypothyroidism (SCH)] during early pregnancy is suspected to associate with adverse obstetrical outcomes.

AIM

The aim of the present study was to investigate whether maternal SCH during the early stage of pregnancy increase obstetrical complications and whether treatment results in an improvement in these outcomes.

SUBJECTS AND METHODS

A total of 756 women in the 1st trimester (≤12 weeks) of pregnancy were enrolled through 10 hospitals in Shenyang from 2007 to 2009. All participants underwent thyroid function testing in early pregnancy and their obstetrical outcomes were studied following delivery.

RESULTS

The incidence of spontaneous abortions in the SCH group was higher than the normal TSH group (15.48% vs 8.86%, p=0.03). No significant association was observed between SCH and other obstetrical complications including gestational hypertension, premature delivery, anemia, post-partum hemorrhage, low neonatal Apgar scores and low birth weight. Although levo-T4 (L-T4) treatment decreased the incidence of spontaneous abortions in women with SCH, it was not statistically significant when compared to women who did not receive treatment in the SCH group. None of the 28 women who received L-T4 treatment had premature delivery, low birth weight, hemorrhage, and low Apgar score.

CONCLUSIONS

The incidence of spontaneous abortion in pregnant women with SCH increases in early pregnancy.

Occurrence of fipronil and its biologically active derivatives in urban residential runoff

Insecticides are commonly used around homes for controlling insects such as ants, termites, and spiders. Such uses have been linked to pesticide contamination and toxicity in urban aquatic ecosystems. Fipronil is a relatively new and popular urban-use insecticide that has acute toxicity to arthropods at low-ppb levels. In this study, we collected runoff water from 6 large communities, each consisting of 152 to 460 single-family homes, in Sacramento County and Orange County, California, and evaluated the occurrence of fipronil and its biologically active derivatives over 26 months under dry weather conditions. Statistical modeling showed that the levels of fipronil and derivatives in the runoff water were both spatially and temporally correlated. More than 10-fold differences were observed between the Sacramento and Orange County sites, with the much higher levels for Orange County (southern California) coinciding with heavier use. The median concentrations of combined fipronil and derivatives for the Orange County sites were 204-440 ng L(-1), with the 90th percentile levels ranging from 340 to 1170 ng L(-1). These levels frequently exceeded the LC50 values for arthropods such as mysid shrimp and grass shrimp. The highest levels occurred from April to October, while decreases were seen from October to December and from January to March, likely reflecting seasonal use patterns and the effect of rain-induced washoff. Fipronil and fipronil sulfone (oxidation derivative) each accounted for about 35% of the total concentrations, with desulfinyl fipronil (a photolytic product) contributing about 25%. Results of this study clearly established residential drainage as a direct source for pesticide contamination in urban waterways, and for the first time, identified fipronil as a new and widespread contaminant with potential ecotoxicological significance.

Fracture resistance of root filled premolar teeth restored with direct composite resin with or without cusp coverage

AIM

To evaluate the fracture resistance and fracture patterns of root filled maxillary first premolar teeth (with mesio-occlusal cavity preparation) restored with several composite restoration designs.

METHODOLOGY

One hundred extracted sound human maxillary first premolars were randomly divided into five groups. Group 1 remained untreated (negative control). Conventional root canal treatment with additional mesial-occlusal cavity preparation was carried out on teeth in groups 2-5. In group 2, the teeth were restored intra-coronally with direct composite resin (positive control). In group 3, the palatal cusps of the teeth were reduced, and the cavities were restored with composite resin covering the palatal cusp (partial coverage). In group 4, the buccal and palatal cusps along with the distal marginal ridges were reduced; the cavities and cusps were restored with composite resin (conventional full coverage). In group 5, the buccal and palatal cusps were reduced but the distal marginal ridges were conserved. The cavities and the cusps were restored with composite resin (modified full coverage). All teeth were subjected to a progressive compressive loading parallel to their longitudinal axis until fracture. Fracture resistance was analysed using the one-way ANOVA and Fisher's LSD test. Fracture patterns were analyzed with chi-square test. The significance level was set at 0.05.

RESULTS

The fracture resistance (mean ± SD) of groups 1-5 was 1131 ± 207N, 904 ± 184N, 927 ± 224N, 1095 ± 289N and 1085 ± 243N, respectively (groups 1, 4, 5 > groups 2, 3; P = 0.004). Cusp fractures were recorded as the fracture pattern in 20 (100%), 19 (95%), 16 (80%), 8 (40%) and 12 (60%) premolars in groups 1-5, respectively (groups 1, 2 > groups 4, 5; group 3 > group 4; P < 0.001).

CONCLUSIONS

When direct composite resin was used to restore root filled maxillary first premolar teeth involving a proximal surface, those restored with full-coverage designs had greater fracture resistance.

The effect of school bag design and load on spinal posture during stair use by children

Thirteen male children ascending and descending stairs with loads that equalled 0%, 10%, 15% and 20% of their body weight were the subject of our research: the boys were wearing an asymmetrical single-strap athletic bag or a symmetrical double-strap backpack during our experiments with them. The maximum spinal tilt to the loading side and to the support side, and the range of spinal motions, were obtained by using a motion analysis system. Our results showed that symmetry of spinal posture was observed both when they ascended staircase with all loads and descended in a backpack. When carrying an athletic bag with 15% and 20% of their body weight while ascending the staircase, the lateral spinal tilt to the supporting side was significantly increased. We concluded that a symmetrical backpack with a load not exceeding 20% or an asymmetrical single-strap athletic bag with a load not exceeding 10% should be recommended for school children in order to promote safer staircase use. STATEMENT OF RELEVANCE: Children carrying heavy school bags may develop spinal problems. This study suggested that when they are using stairs, a symmetrical backpack with a load within 20% body weight is acceptable for them. When they are carrying an asymmetrical single-strap athletic bag, the bag's weight should not exceed 10% of the body weight in order to avoid excessive spinal tilt.

Gender differences in foot shape: a study of Chinese young adults

One important extrinsic factor that causes foot deformity and pain in women is footwear. Women's sports shoes are designed as smaller versions of men's shoes. Based on this, the current study aims to identify foot shape in 1,236 Chinese young adult men and 1,085 Chinese young adult women. Three-dimensional foot shape data were collected through video filming. Nineteen foot shape variables were measured, including girth (4 variables), length (4 variables), width (3 variables), height (7 variables), and angle (1 variable). A comparison of foot measures within the range of the common foot length (FL) categories indicates that women showed significantly smaller values of foot measures in width, height, and girth than men. Three foot types were classified, and distributions of different foot shapes within the same FL were found between women and men. Foot width, medial ball length, ball angle, and instep height showed significant differences among foot types in the same FL for both genders. There were differences in the foot shape between Chinese young women and men, which should be considered in the design of Chinese young adults' sports shoes.

Preparation and lithium storage performances of mesoporous Fe₃O₄@C microcapsules

Fe(3)O(4)@C microcapsules were prepared using carbon-coated α-FeOOH nanorods as precursors, which were synthesized via two-step hydrothermal reactions. During the subsequent sintering procedure, α-FeOOH was reduced to Fe(3)O(4) by carbon, accompanied by the formation of mesopores. In Fe(3)O(4)@C microcapsules, mesoporous Fe(3)O(4) nanorods are coated with amorphorous carbon layers. The Fe(3)O(4)/C composites with such special structures demonstrate high specific capacity and good cyclic stability as anode materials in Li test cells.

Kinetics and thermodynamics of adsorption of ionizable aromatic compounds from aqueous solutions by as-prepared and oxidized multiwalled carbon nanotubes

The adsorption of 1-naphthylamine, 1-naphthol and phenol on as-prepared and oxidized multiwalled carbon nanotubes (MWCNTs) has been investigated. The results illustrated that both as-prepared and oxidized MWCNTs showed high adsorption capacity for the three ionizable aromatic compounds (IACs) studied. Oxidation of MWCNTs increased the surface area and the pore volume, and introduced oxygen-containing functional groups to the surfaces of MWCNTs, which depressed the adsorption of IACs on MWCNTs. Both Langmuir and Freundlich models described the adsorption isotherms very well and the adsorption thermodynamic parameters (DeltaG degrees, DeltaH degrees and DeltaS degrees) were measured. The adsorption for 1-naphthylamine, 1-naphthol and phenol is general spontaneous and thermodynamically favorable. The adsorption of phenol is an exothermic process, whereas the adsorption of 1-naphthylamine and 1-naphthol is an endothermic process. Results of this work are of great significance for the environmental application of MWCNTs for the removal of IACs from large volume of aqueous solutions.

Monitoring of CaSO(4) deposition behaviors on biofilm during nanofiltration via ultrasonic time-domain reflectometry (UTDR)

The ultrasonic time-domain reflectometry (UTDR) as a non-destructive real-time method was employed to monitor the CaSO(4) deposition behaviors on biofilm during nanofiltration (NF). Two parallel experiments were performed to compare the different behaviors of CaSO(4) deposition with and without biofilm on the membrane. Results showed that the flux decline during combined fouling was slower than that in case of CaSO(4) fouling alone. The Ca(2 + ) rejection obtained with biofilm was higher than that without. A larger acoustic differential signal obtained by UTDR in the combined fouling revealed a denser and thicker layer formed on the membrane surface. Furthermore, the amount of CaSO(4) deposition on the biofouled membrane was more than that on non-biofouled membrane as a result of microorganisms as crystal nucleus to induce CaSO(4) crystallization and deposition. SEM images indicate that the CaSO(4) crystals deposited in order on the non-biofouled membrane, whereas on the biofouled membrane they were embedded in the biofilm. The denser and thicker fouling layer formed with biofilm was impermeable, resulting in a high Ca(2 + ) rejection. The complexation of Ca with polysaccharide in biofilm would eliminate the cake-enhanced osmotic pressure effect leading to a slow flux decline. To sum up, the independent measurements corroborate the ultrasonic measurements.

Heritability of metabolic syndrome traits among healthy younger adults: a population based study in China

OBJECTIVE To estimate heritability of metabolic syndrome traits among healthy younger adults in a human population in China, and examine potential sex differences in heritability and parental effect on metabolic syndrome traits. METHODS Using offspring-parent regression, we estimated heritability (h(2)) of metabolic syndrome traits based on 452 child-parent triads identified from a population based random survey on metabolic syndrome among people over 15 years of age in Guangzhou, China. RESULTS Body mass index (BMI), cholesterol, high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), fasting plasma glucose (FPG) and waist circumference (waist-C) were more heritable (h(2), 0.42-0.545), whereas systolic blood pressure (SBP), diastolic blood pressure (DBP), and triglycerides (TG) were less heritable (h(2), 0.14-0.28). Sons had pronounced increases in heritability for all traits over daughters, particularly for cholesterol (0.653 vs 0.356), FPG (0.602 vs 0.313), LDL-C (0.521 vs 0.329), and TG (0.395 vs 0.187). Offspring-mother seemed to have a higher heritability in every trait except FPG (0.67 vs 0.794) than offspring-father, most notably for DBP (0.308 vs 0.122), SBP (0.288 vs 0.146), TG (0.387 vs 0.239) and waist-C (0.581 vs 0.354). CONCLUSION We estimated the heritability of metabolic syndrome traits in a human population based on a unique population based offspring-parent sample from China, and found important evidence that the maternal and paternal effects on these traits are different and the sex difference in heritability is pronounced.

Sorption of Eu(III) on attapulgite studied by batch, XPS, and EXAFS techniques

The effects of pH, ionic strength, and temperature on sorption of Eu(III) on attapulgite were investigated in the presence and absence of fulvic acid (FA) and humic acid (HA). The results indicated that the sorption of Eu(III) on attapulgite was strongly dependent on pH and ionic strength, and independent of temperature. In the presence of FA/HA, Eu(III) sorption was enhanced at pH < 4, decreased at pH range of 4-6, and then increased again at pH > 7. The X-ray photoelectron spectroscopy (XPS) analysis suggested that the sorption of Eu(III) might be expressed as is identical to X3Eu0, is identical to S(w)OHEu3+, and is identical to SOEu-OOC-/HA in the ternary Eu/HN/attapulgite system. The extended X-ray absorption fine structure (EXAFS) analysis of Eu-HA complexes indicated that the distances of d(Eu-O) decreased from 2.415 to 2.360 angstroms with increasing pH from 1.76 to 9.50, whereas the coordination number (N) decreased from approximately 9.94 to approximately 8.56. Different complexation species were also found for the different addition sequences of HA and Eu(III) to attapulgite suspension. The results are important to understand the influence of humic substances on Eu(III) behavior in the natural environment.

Changes in muscle strength, endurance, and reaction of the lower extremities with Tai Chi intervention

This study examines the effects of a 16-week Tai Chi (TC) training program on the muscle strength, endurance, and reaction time of the lower extremities of elderly people. A total of 40 elderly individuals (aged 60 years) completed the study. They were divided into two groups: the TC group (11 men and 11 women) underwent a supervised TC exercise program for 16 weeks, while the control group (9 men and 9 women) received general education for a comparable time period. Pre- and post-intervention measurements were conducted. An isokinetic dynamometer was used to measure the maximum concentric strength and dynamic endurance of the knee flexors and the extensors, and the maximum concentric strength of the ankle plantarflexors and dorsiflexors. The neuromuscular response of the rectus femoris, semitendinosus, gastrocnemius, and anterior tibialis muscles was measured by the onset latency to sudden perturbations using an electromyography system. After 16 weeks, the TC group showed a 19.9% increase in muscle strength of the knee flexors (p<.000) that was significantly greater than that in the control group (p=.046). There was also a significant decrease in semitendinosus muscle latency (6.6%, p=.014) that was significantly shorter than that in the control group (p=.042). No significant training effects were found in other measures. These results suggest that improving biomechanical characteristics of lower extremity muscles may need longer TC intervention for elderly people.

Kinematic and electromyographic analysis of the trunk and lower limbs during walking in negative-heeled shoes

BACKGROUND

We investigate kinematic adaptation and muscle activities in the trunk and lower extremities of healthy subjects during treadmill walking in negative-heeled sports shoes versus normal sports shoes.

METHODS

Thirteen healthy female university students participated in the study. We analyzed sagittal-movement kinematics and electromyographic findings from the erector spinae, rectus abdominus, rectus femoris, biceps femoris, tibialis anterior, and lateral gastrocnemius muscles of the dominant side in two shod conditions.

RESULTS

Negative-heeled gait is characterized by faster cadence, shorter stride length, increased maximal extension angles in the trunk and hip, increased flexion angle in the knee, larger dorsiflexion in the stance phase, and a larger range of motion of the ankle joint. Negative-heeled gait resulted in a significantly larger integrated electromyographic value, a longer duration of electromyographic activity, and a higher mean amplitude of electromyographic activity in the tibialis anterior, lateral gastrocnemius, and biceps femoris muscles.

CONCLUSIONS

Negative-heeled gait compared with normal gait places a higher physiologic demand on the tibialis anterior, lateral gastrocnemius, and biceps femoris muscles when walking on a level surface. Thus, negative-heeled shoes could be of value if used in an exercise rehabilitation or training program where inclined walking is not available owing to a flat terrain.

Proprioception of ankle and knee joints in obese boys and nonobese boys

BACKGROUND

The objective of this study was to examine if there was any difference in the proprioception of the ankle and knee joints between pre-pubertal obese boys and non-obese boys.

MATERIAL/METHODS

A cross-sectional experimental design was used in the study between two groups. Within the group, repetitions were performed to verify the differences in several passive motion senses in the ankle or knee. A total of 53 boys aged 7 to 12 served as the study subjects. Among them, there were 27 obese boys with an average body mass index (BMI) of 25.14+/-3.51 kg/m2 and 26 non-obese boys with BMI of 16.28+/-1.45 kg/m2. The study used custom-made apparatus to test any proprioception that was indicated by a kinaesthesis of the ankle and knee.

RESULTS

The obese boys showed significantly poorer proprioception in knee flexion movement (P=0.041). However, they showed none in the knee extension and ankle movements.

CONCLUSIONS

The obese boys showed a deficit in proprioception in knee flexion. Such alterations in their proprioception would be associated with decreased postural control capacity in obese boys as reported in published works since proprioceptive function is one important component that contributes to postural control.

Tai Chi exercise and muscle strength and endurance in older people

The purpose of the study was to investigate the influence of regular Tai Chi (TC) practice on muscle strength and endurance of the lower extremities in older people. Twenty-one long-term older TC practitioners were compared with 18 regular older joggers and 22 sedentary counterparts. Maximum concentric strength of knee flexors and extensors was tested at angular velocities of 30 degrees and 120 degrees /s. Ankle dorsiflexors and plantar flexors were tested at 30 degrees /s. Moreover the dynamic endurance of the knee flexors and extensors was assessed at the speed of 180 degrees /s. The strength of knee extensors and flexors in the sedentary group was significantly lower than that in the jogging group and marginally lower than that in the TC group at the higher velocity. For ankle joint, the subjects in both the TC group and the jogging group generated more torque in their ankle dorsiflexors. In addition, the muscle endurance of knee extensors was more pronounced in TC practitioners than the controls. Regular older TC practitioners and joggers showed better scores than the sedentary controls on most of the muscle strength and endurance measures. However, the magnitude of the exercise effects on muscles might depend on the characteristics of different types of exercise.

Tai Chi exercise and proprioception behavior in old people

Eighty subjects aged over 60 participated in this study. Ankle and knee joint kinesthesia were measured in 21 long-term TC practitioners (TC group), 20 long-term swimming/running exercisers (S/R group), and 27 sedentary controls (control group). The results showed that ankle joint kinesthesia significantly differed among the three groups (p= 0.001). TC practitioners could detect a significantly smaller amount of motion than could the S/R exercisers (p = 0.022) and sedentary counterparts (p = 0.001). No significant difference was found between the S/R group and the sedentary control group (p = 0.701). For the knee joint, the threshold for detection of passive motion was significantly different in knee extension and flexion. For knee flexion, the TC group showed a significantly smaller mean threshold for detection of passive motion than did the subjects in the control group (p = 0.026). There were no significant differences between the S/R group and the control group (p = 0.312), the TC group and S/R group (p = 0.533). For knee extension, no significant difference was noted among the three groups (p = 0.597).

Temporal characteristics of foot movement in Tai Chi exercise

The concept of proper foot movement is always emphasized in the practice of Tai Chi. Sixteen experienced Tai Chi practitioners participated in this study. Each subject practiced the whole set of 42-form Tai Chi movements and the performance was video-recorded and analyzed. The study found that Tai Chi is performed with the interchange of seven support patterns and six step directions of the foot. Compared with normal walking, there is a bigger percentage of time spent performing double support and less percentage of time spent performing single support movements in Tai Chi. However, the average duration of each support movement is longer and the change from one type of support to another is slower. In Tai Chi, the duration of steps in each direction is short and there are frequent changes from one direction to another. Tai Chi was found to be more effective than walking in simulating the gait challenges that are encountered in daily activities.