Environmental factors associated with incidence of developmental dysplasia of the hip: a systematic review and meta-analysis

BACKGROUND

Established associated factors for DDH include female sex, breech presentation, family history, congenital malformations, oligohydramnios, and maternal hyperthyroidism. However, evidence for environmental factors that may contribute to DDH is limited and inconsistent.

METHODS

A systematic review of medical literature was conducted to collect data on environmental factors, including latitude, longitude, average yearly precipitation, average yearly temperature, minimum monthly temperature, and maximum monthly temperature, from all institutions that published articles on DDH. Univariate linear regression analysis was used to examine the correlation between environmental factors and DDH incidence, while multiple regression analysis was conducted to identify significant associated factors for DDH incidence.

RESULTS

Data from a total of 93 unique manuscripts were analyzed, revealing a significant negative correlation between DDH incidence and temperature, including average yearly temperature (r = -0.27, p = 0.008), minimum monthly temperature (r = -0.28, p = 0.006), and maximum monthly temperature (r = -0.23, p = 0.029). Additionally, there was a significant positive correlation between DDH incidence and latitude (r = 0.27, p = 0.009), and a significant negative correlation between DDH incidence and average yearly precipitation (r = -0.29, p = 0.004). In the final multiple regression analysis, temperature, including average yearly temperature, minimum monthly temperature, and maximum monthly temperature, were identified as significant associated factors for DDH incidence.

CONCLUSION

The findings of this study suggest an association between cold weather and DDH incidence. Further research should explore the link between cold weather and DDH incidence, offering insights into potential interventions for cold climates.

Soft Tissue Releases With Simultaneous Guided Growth Decrease Risk of Spastic Hip Displacement Recurrence

BACKGROUND

Soft tissue release (STR) is an established treatment for spastic hip displacement, but recurrence of hip displacement is not uncommon. This study aims to (1) evaluate the recurrence of hip displacement after STR, (2) define associated factors of recurrence, and (3) elucidate the effects of guided growth on hip displacement recurrence.

METHODS

The study subjects included 66 individuals with spastic cerebral palsy treated by STR with or without guided growth for hip displacement. The treatment goal was the maintenance of migration percentage (MP) to <40%. Recurrence was defined by a rebound of the MP by 5% or more after the first postoperative year. Children with recurrence were compared with those without recurrence using the Mann-Whitney U test and the χ 2 test. The risk factors for recurrence were evaluated using multiple logistic regression analysis.

RESULTS

Nineteen individuals (29%) had a recurrence of hip displacement after the first postoperative year. They sustained a 2-fold increase in the rate of treatment failure ( P < 0.001) and reoperation ( P = 0.04). Age, sex, motor function, and preoperative radiographic parameters were comparable between individuals with and without recurrence. The use of guided growth was associated with less risk of recurrence than without (5% and 39%, respectively, odds ratio = 0.01 to 0.45, respectively) despite the similar risk of failure (35% and 48%, respectively, odds ratio = 0.15 to 4.82).

CONCLUSIONS

Recurrence of the MP >5% after the first postoperative year is an important early indicator for failure to control MP to <40% and reoperation. Guided growth not only decreases coxa valga but also reduces the risk of recurrent hip displacement after STR.

LEVEL OF EVIDENCE

Level III; case-control study.

LED-pumped eye-safe pulse laser with an extracavity optical parametric oscillator

An LED-side-pumped Nd:YAG/Cr⁴⁺:YAG passively Q-switched (PQS) laser containing an extracavity optical parametric oscillator (EOPO) is demonstrated. As far as we know, it is the first LED-pumped eye-safe laser. The Nd:YAG pump module is optimized to increase the PQS pulse energy to 24 mJ at 1064 nm. By using a single-pass EOPO design, the output energy of the signal pulse at 1573 nm is 7.44 mJ with a pulse width of 16 ns, the peak power is 434 kW, and the pump-to-signal conversion efficiency is 31%. For double-pass EOPO operation, the pump-to-signal conversion efficiency increases to 45.8%, the output energy of signal pulse is up to 10.98 mJ with a pulse width of 23.5 ns, and the peak power is 459 kW.

Congenital radioulnar synostosis: is prenatal diagnosis possible? - A case report

OBJECTIVES

The main objectives of this case report are to discuss prenatal ultrasound findings of congenital radioulnar synostosis and to review the literature.

CASE REPORT

A patient was diagnosed with congenital radioulnar synostosis at eight months old when parents noticed limited motions in the child's left forearm. The parent denied any traumatic or family history of bony malformations. Physical examination by a pediatric orthopedics specialist and digital radiography revealed proximal radioulnar synostosis. The case report includes perinatal course, comparison between the postnatal radiography and fetal ultrasound images.

CONCLUSION

Congenital radioulnar synostosis is often associated with sex chromosome abnormalities and congenital musculoskeletal disorders or syndromes affecting limbs. Isolated congenital radioulnar synostosis is hardly diagnosed before birth, in some cases even have been neglected postnatally. Knowing the developmental milestones of the forearm and specified high-risk groups might help develop a targeted screening strategy to increase the possibility of early detection and intervention.

The Resolution Rate of Pulmonary Embolism on CT Pulmonary Angiography: a Prospective Study

PURPOSE

To prospectively assess the rate of clot resolution from CT pulmonary angiography (CTPA) in patients with acute pulmonary embolism (PE).

MATERIALS AND METHODS

This prospective cohort study included 290 patients (136 men, 154 women; mean age, 51.9 years) with acute PE. All patients had a CTPA at the presentation and had at least one follow-up within 6 months (mean 72.7 days). Sixty-four percent of patients had follow-up scans for research purposes within a pre-determined period (between 28 and 184 days; mean, 78.27 days) and 36 % had (between 2 and 184 days; mean, 62.78 days) for a clinical indication. The volume of each clot was measured using a semi-automated quantification program. The resolution rate was evaluated by interval-censored analysis.

RESULTS

The overall estimated probability of complete resolution was 42 % at 7 days, 56 % at 10 days, and 71 % at 45 days. Achieving complete resolution was significantly faster in patients with peripheral clots (HR: 1.78; CI: 1.05-3.03, p = 0.032) but slower in patients with consolidation and history of venous thromboembolism (VTE), (HR: 0.37; CI: 0.18-0.79, p = 0.01 and HR: 0.57; CI: 0.35-0.91, p = 0.019, respectively). Although the patients with cancer showed a faster resolution rate (HR: 1.67; CI: 1.05-2.68, p = 0.032), the mortality rate was significantly higher than non-cancer patients.

CONCLUSION

The resolution rate of clot burden in acute PE was associated with patients' clinical presentation variables and CTPA imaging biomarkers. This information may be incorporated into designing a prediction rule and determining the appropriate duration of anticoagulation therapy in patients with acute PE.

Development and verification of the coaxial heterogeneous hyperspectral imaging system

A hyperspectral imaging system (HIS) is a helpful tool that acquires spatial and spectral information from a target. This study developed a coaxial heterogeneous HIS (CHHIS) to collect spectral images with wavelengths ranging from 400 to 1700 nm. In this system, a visible (VIS) spectrometer and a short-wave infrared (SWIR) spectrometer are combined with a coaxial optical path to share the same field of view. This structure reduces the complexity of spatial registration and maintains the scanning duration of two spectrometers as that of a single spectrometer. The spectrometers are also replaceable for extending the detecting spectral range of the system. The calibration methodologies, including spatial correction, spectral calibration, and reflectance calibration, were developed for this system. The signal-to-noise ratio of VIS and SWIR spectrometers in the CHHIS was up to 40 and 60 dB when the exposure time of the VIS and SWIR imaging sensors was 1000 and 10 ms, respectively. When the target distance was at 600 mm, the spatial error of VIS and SWIR images in the scanning direction was less than 1 pixel; these results proved that the system was stable.

Genu Valgum After Distal Femur Extension Osteotomy in Children With Cerebral Palsy

BACKGROUND

Distal femur extension osteotomy (DFEO) is a common treatment for knee flexion contracture and crouch gait in patients with cerebral palsy (CP), but skeletally immature patients tend to develop genu valgum deformities after DFEO. This study aimed to report the tendency of valgus changes after DFEO and determine the risk factors for subsequent surgery for excessive genu valgum.

METHODS

This retrospective case-control study included 25 children with CP who underwent DFEO in 44 limbs for knee flexion contractures ≥15 degrees at a mean age of 11.0 years. Radiologic measurements included the anatomic lateral distal femoral angle (aLDFA), anatomic tibiofemoral angle (aTFA), medial proximal tibia angle, and plate-condyle angle, postoperatively and at the latest follow-up. Age, sex, preoperative knee flexion contracture angle, Gross Motor Function Classification System level, and radiographic measurements were compared between children with and without subsequent guided growth for genu valgum.

RESULTS

A significant valgus change was observed at the distal femur in the first postoperative year (aLDFA from 83.6 to 80.1 degrees, P<0.001; aTFA from 176.1 to 172.5 degrees, P<0.01; plate-condylar angle from 5.3 to 9.5 degrees, P<0.001). Valgus changes occurred in 36 of the 44 limbs (82%) by an average of -4.6 degrees in the aLDFA, and subsequent guided growth was performed in 5 patients (20%). Guided growth for genu valgum was associated with a greater postoperative valgus angle (aLDFA: 78.0 vs. 84.9 degrees, P<0.01) but not with age, Gross Motor Function Classification System level, or preoperative flexion contracture.

CONCLUSIONS

Distal metaphyseal osteotomies and distally placed angled plates near the physis are associated with valgus changes following growth. We recommend making a slight varus alignment during DFEO to compensate for subsequent valgus changes.

LEVEL OF EVIDENCE

Level III-therapeutic, retrospective comparative study.

Buschke-Ollendorff syndrome presenting with asymptomatic yellowish papules and leg length discrepancy: A case report

Buschke-Ollendorff syndrome (BOS) is a rare, usually benign, autosomal dominant genetic disease affecting about 0.005% globally. BOS commonly manifests with asymptomatic connective tissue nevi, sometimes with sclerotic bone lesions like osteopoikilosis or melorheostosis. However, BOS may develop severe, symptomatic complications that require surgical intervention. Here we report a 9-year-8-month girl presenting with multiple nonpruritic, nonpainful skin plaques scattered around the trunk, buttocks, and bilateral legs. She had a history of right varus foot with inadequate plantar flexion. Upon visiting, obvious leg length discrepancy (LLD) was noted. Lesional biopsy revealed increased fibroblasts within dermal collagen bundles. Verhoeff-van Gieson stain revealed scattered foci of thickened elastic fibers between collagen fibers, especially in the mid-dermis. Radiographic examination of the lower extremities showed multiple small, round-to-oval shaped, radiopaque spots on the pelvic bones, femurs, tibiae, and both feet. Hyperostosis along the long axis with "dripping candle wax" appearance was characteristic of osteopoikilosis and melorheostosis. Genetic analysis showed heterozygous point mutation in exon 1 of LEMD3 gene (c.1323C>A, p.Y441X), confirming diagnosis of BOS. Sequential and epiphyseodesis were performed to correct LLD with a favorable outcome at 2-year follow-up. BOS associated with severe bone abnormalities is rare, but orthopedic surgical intervention can provide satisfactory outcome.

Would foot arch development in children characterize a body maturation process? a prospective longitudinal study

BACKGROUND

Flatfoot (Pes Planus), often regarded as a physiological deviation in children, is of concern to parents because there is no test to predict the development of foot arch. This study aimed to use a new diagnostic flatfoot criterion to determine 1) how the footprint index changes during the development of foot arches, 2) what factors can predict a foot arch development, and 3) whether foot arch development could be a process of body growth.

MATERIALS AND METHODS

572 children were enrolled in a prospective longitudinal study of anthropometrical parameters and physical fitness twice at age of 6.7 and 8.2 years. The bimodal frequency distribution of the Chippaux-Smirak index (CSI) of the footprint was used to define flatfoot as CSI <0.58 and non-flatfoot as CSI >0.61. Body measurements and physical fitness tests were compared between children with flatfeet who developed foot arches and children who did not.

RESULTS

Of 263 children with flatfeet, the CSI significantly changed from 0.72 to 0.46 in 70 children who developed foot arches over 1.5 years and the others had minimal change in the index. Children with foot arch development had a lower initial CSI, improved boys' performance in one-leg balance, and less increase in girls' body height than children who remained flatfooted, whereas sex and weight were similar in both groups.

CONCLUSION

This longitudinal study with the bimodal distribution of the CSI investigated how the development of foot arch advances in children around age 7. A significant and unique pattern in change of the CSI suggests involvement of a maturational stage in foot arch development. Along with the improved performance in one-leg balance, the unidirectional transition from flatfoot to non-flatfoot is associated with improvement in motor control of the ankle.

Increased Loading Rates During Gait Correlate With Morphology of Unaffected Hip in Juveniles With Treated Developmental Hip Dysplasia

Long-term follow-up studies on children with surgically treated developmental dysplasia of the hip (DDH) have shown that not only the affected side progresses to premature osteoarthritis, but the unaffected side may also suffer from insidious hip dysplasia or osteonecrosis. The current gait analysis study identified the loading and unloading rates of the ground reaction forces (GRF) and lower limb joint axial forces during gait, and their correlations with the hip morphology in twenty juvenile patients with surgically treated unilateral DDH during toddlerhood. In a gait laboratory, each subject walked at preferred speed on a 10-m walkway while the kinematics and the GRF were measured. Loading and unloading rates of the vertical GRF and the joint axial forces were obtained as the maximum instantaneous slope of these force curves. Radiographic measurements of the hips were taken, and the correlations between the morphological parameters and the loading and unloading rates were obtained. The patients showed greater-than-normal peak loading rates of the joint axial forces, and the loading rates on both the affected and unaffected sides were strongly correlated to the acetabular index on the unaffected side, which was also significantly correlated with the peak unloading rates on the affected side. These results suggest that apart from regular follow-up of the affected hip, routine assessment of the morphological changes and/or increased loading rates on the unaffected hip is also important for early identification of any signs of insidious hip dysplasia and risk of premature degeneration of the cartilage.

Tension band plates have greater risks of complications in temporary epiphysiodesis

PURPOSE

This study aimed to compare the efficacy of decreasing leg-length discrepancy (LLD) and postoperative complications between tension band plates (TBP) and percutaneous transphyseal screws (PETS).

METHODS

This retrospective study reviewed LLD patients who underwent temporary epiphysiodesis at the distal femur and/or proximal tibia from 2010 to 2017 (minimum two years follow-up). Efficacy of decreasing LLD was assessed one and two years postoperatively. Complications were classified with the modified Clavien-Dindo-Sink complication classification system. Knee deformities were assessed by percentile and zone of mechanical axis across the tibial plateau.

RESULTS

In total, 53 patients (25 boys, 28 girls) underwent temporary epiphysiodesis (mean age, 11.4 years). The efficacy of decreasing LLD at two years between the TBP (n = 38) and PETS (n = 15) groups was comparable. Seven grade III complications were recorded in six TBP patients and in one PETS patient who underwent revision surgeries for knee deformities and physis impingement. Four grade I and two grade II complications occurred in the TBP group. The mechanical axis of the leg shifted laterally in the PETS group and medially in the TBP groups (+7.1 percentile versus -4.2 percentile; p < 0.05). Shifting of the mechanical axis by two zones was noted medially in four TBP patients and laterally in two PETS patients.

CONCLUSION

More implant-related complications and revision surgeries for angular deformities were associated with TBP. A tendency of varus and valgus deformity after epiphysiodesis using TBP and PETS was observed, respectively. Patients and families should be informed of the risks and regular postoperative follow-up is recommended.

LEVEL OF EVIDENCE

Level III.

Spontaneous decrease in gastrocnemius spasticity after correction of knee flexion gait in children with cerebral palsy

PURPOSE

Synergistic neuro-excitability in the lower extremities may be related to gait disorders. This study aimed to report spontaneous changes after correcting knee flexion gait and discuss the underlying mechanisms.

METHODS

A prospective study of 23 children with cerebral palsy was conducted to assess postoperative changes in gross motor function, joint range of motion (ROM), and spasticity. Characteristics of children/limbs with spontaneous decrease in gastrocnemius spasticity were assessed.

RESULTS

In 10 patients (19 limbs) without gastrocnemius release, the Modified Ashworth scores in the gastrocnemius decreased in 6 limbs after 3 months and in 10 limbs after 6 months. Those limbs with spontaneous changes had worse preoperative knee flexion contracture than the limbs without spasticity changes (knee ROM limitation score 5.4 vs. 3.7, p = 0.026).

CONCLUSIONS

Patients with knee flexion contracture recruited greater plantar flexion-knee extension couple to balance knee flexion gait, and synergistic neuro-excitability of the gastrocnemius was enhanced. Our early results suggest preservation of the gastrocnemius in treating knee flexion gait, especially for patients with knee flexion contracture.

Association of age in motor function outcomes after multilevel myofascial release in children with cerebral palsy

BACKGROUND

Many recommend deferring orthopedic surgery for cerebral palsy-related disorders in young children. However, age is correlated with musculoskeletal deterioration, and deferral may affect surgical outcomes. We aimed to clarify the relationships among age, degree of musculoskeletal disorder, and postoperative motor function change in children with cerebral palsy.

METHODS

We prospectively evaluated children with cerebral palsy and a knee flexion gait disorder who underwent multilevel myofascial release between June 2010 and July 2014. The children were divided into younger (<10 years of age) and older (>10 years of age) groups. Outcome measures included the Gross Motor Function Measure (GMFM), range of motion, spasticity, and physical capacity. Preoperative factors and postoperative changes were compared between the groups using the chi-squared, independent t-, and Mann-Whitney tests. Significant factors were plotted by participant age to identify the relationships between age and other variables.

RESULTS

We analyzed 20 patients who underwent multilevel myofascial release (12 and 8 in the younger and older groups, respectively). Whereas most preoperative factors were comparable between the two groups, the older group had a higher range of motion limitation score (44.4 vs. 36.1, p < 0.05). The older group also showed less improvement in the GMFM (-0.3 vs. +3.0, p < 0.05) and physical capacity (+0 vs. +1, p < 0.05) scores after 6 months of postoperative rehabilitation.

CONCLUSIONS

Age was positively correlated with the range of motion limitation and negatively correlated with postoperative GMFM improvement. The less favored postoperative rehabilitation course in older children needs to be considered for parents whose children are amenable to surgeries.

Examining the association between oral health status and dementia: A nationwide nested case-controlled study

Alzheimer’s disease as a consequence of chronic brain inflammation mediated by infectious microbes including the oral microbiome continues to attract support. Taiwan’s National Insurance database was used to evaluate associations between dental health and Alzheimer’s disease; 209,112 new cases of Alzheimer’s disease were matched 1:4 with 836,448 dementia-free controls to test the hypothesis that better dental health would be associated with less occurrence of dementia. Ten year dental records and conditional logistic regression models were used to estimate the odds ratios associated with Alzheimer’s disease. Subgroup analyses compared vascular Alzheimer’s disease and sporadic Alzheimer’s disease. As the population aged, Alzheimer’s disease diagnoses were more frequent with a 10 fold upward inflection after 60. Nearly 56% of sporadic Alzheimer’s disease patients were women but less than 50% had vascular Alzheimer’s disease. Comorbidities were 10–20% higher in the Alzheimer’s disease patients than in controls, but stroke, chronic infection, and pneumonia were 40–45% more common in the vascular Alzheimer’s disease patients. Heart disease, hypertension, diabetes, stroke, peripheral artery disease, pneumonia, and herpetic disease (HSV) were all associated with higher odds of Alzheimer’s disease. HSV was not a factor in the vascular Alzheimer’s disease. Routine dental procedures tended to lower odds ratios. Root canals and extractions that restore oral homeostasis were associated with lower odds of dementia. However, when extractions exceeded four, the odds of Alzheimer’s disease rose. The fact that Alzheimer’s disease was not associated with periodontal procedures per se but with more frequent periodontal emergencies suggested again a chronic issue. Dental health costs suggest that good dental care was associated with lower odds of Alzheimer’s disease except for radiographic costs which were consistently associated with higher odds, independent of oral health. Common comorbid conditions were associated with higher odds of Alzheimer’s disease and oral health care was associated with lower odds, providing support for the hypothesis that the oral microbiome is a factor in the development of Alzheimer’s disease.

Impact statement

This study clearly demonstrates the power and value of a nationally applied digital medical record. Longitudinal studies of gradually developing pathologies like dementia have often been limited by sample size and narrow and incomplete medical histories. The Taiwan National Insurance database provides an unparalleled opportunity for detailed analyses of associations between current medical conditions and a spectrum of prior medical and dental events. The temporal impact of the database will only become more important as the past historical record progressively expands going forward. The inclusion of dental records in assessing the relationship with subsequent dementia is very important because this information is often unavailable or dependent on subject recall. This study clearly establishes associations between a variety of suspected cardiovascular and metabolic factors and the odds of dementia. A critical outcome should include the design of targeted interventions and the subsequent assessment of their efficacy.

Ultrasound screening for developmental dysplasia of the hip after 4 weeks increases exam accuracy and decreases follow-up visits

BACKGROUND

Developmental dysplasia of the hip (DDH) is a preventable and treatable disorder in children. Hip ultrasound is recommended for early detection of affected hips. The timing of the initial hip ultrasound and the frequency of subsequent ultrasounds are controversial topics when considering costs and efficiency.

METHODS

Registry data from the Taiwanese Screening and Audit System for Developmental Dysplasia of the Hip were obtained for biometry of hip ultrasounds using the Graf classification and relevant demographic data from 2016. Initial screening results and final case management outcomes were compared to determine screening accuracy and the number of visits needed to determine final outcomes.

RESULTS

In total, we screened 1683 newborns in 2016. Of the initial cases screened within 28 days (n = 1168), 86.6% were negative, 10.1% positive, and 3.3% intermediate, while of the cases screened after 28 days (n = 515), 97.3% were negative, 0.8% positive, and 1.9% intermediate. Screening of the newborns' final hip outcomes revealed that 1641 (97.6%) were negative, treatment was administered in 8 cases (0.4%), and 34 (2.0%) cases were lost to follow-up. When comparing screening times, screening after 28 days improved specificity (89%-97%), and later screenings were associated with fewer visits needed to confirm hip outcomes (aOR = 0.19, CI95% = 0.10-0.38, p < 0.001) and improved accuracy (aOR = 13.84, CI95% = 4.23-45.26, p < 0.001).

CONCLUSION

This study provides evidence of the benefits of screening for DDH after 28 days, namely: reduced false positives, improved screening accuracy, and a reduced requirement for follow-up visits. Delaying screening can also potentially reduce unnecessary parental anxiety, eliminate unnecessary healthcare burdens, and reduce costs. We recommend performing hip ultrasound screening for newborns after 28 days.

Endothelial Cell-Targeted Deletion of PPARγ Blocks Rosiglitazone-Induced Plasma Volume Expansion and Vascular Remodeling in Adipose Tissue

Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor γ (PPARγ) agonists that represent an effective class of insulin-sensitizing agents; however, clinical use is associated with weight gain and peripheral edema. To elucidate the role of PPARγ expression in endothelial cells (ECs) in these side effects, EC-targeted PPARγ knockout (Pparg ΔEC) mice were placed on a high-fat diet to promote PPARγ agonist-induced plasma volume expansion, and then treated with the TZD rosiglitazone. Compared with Pparg-floxed wild-type control (Pparg f/f) mice, Pparg ΔEC treated with rosiglitazone are resistant to an increase in extracellular fluid, water content in epididymal and inguinal white adipose tissue, and plasma volume expansion. Interestingly, histologic assessment confirmed significant rosiglitazone-mediated capillary dilation within white adipose tissue of Pparg f/f mice, but not Pparg ΔEC mice. Analysis of ECs isolated from untreated mice in both strains suggested the involvement of changes in endothelial junction formation. Specifically, compared with cells from Pparg f/f mice, Pparg ΔEC cells had a 15-fold increase in focal adhesion kinase, critically important in EC focal adhesions, and >3-fold significant increase in vascular endothelial cadherin, the main component of focal adhesions. Together, these results indicate that rosiglitazone has direct effects on the endothelium via PPARγ activation and point toward a critical role for PPARγ in ECs during rosiglitazone-mediated plasma volume expansion.

Reversible Spasticity Suppression and Locomotion Change After Pulsed Radiofrequency on the Dorsal Root Ganglia of Rats With Spinal Cord Injury

OBJECTIVES

Radiofrequency has been used to suppress spasticity affecting motion in patients with cerebral palsy and spinal cord injury. This study tested spasticity suppression and locomotion change after pulsed radiofrequency (PRF) at the dorsal root ganglion of rats with spasticity.

MATERIALS AND METHODS

Twenty-four rats that survived for 28 days after thoracic spinal cord injury and showed spasticity in the right hind limb were separated randomly to a PRF group or Sham operation group. PRF consisted of 2 Hz biphasic 25 msec trains of PRF (500 kHz, 5 V intensity) applied on the right L5 dorsal root ganglion for 300 sec. Muscle tension of the right triceps surae was measured at 450 deg/sec of passive ankle dorsiflexion on the day before and 3, 7, and 14 days after PRF or sham operation. Locomotive function was evaluated by obtaining Basso, Beattie, and Bresnahan (BBB) scores.

RESULTS

Muscle tension of the triceps surae decreased significantly three days after PRF, and gradually returned to baseline 14 days later. In the sham operation group, muscle tension increased significantly more than 14 days. The BBB scores declined from 10 to 8 after PRF and returned to pre-PRF levels 14 days later, while scores remained constant after sham operation.

CONCLUSIONS

PRF produced significant and reversible suppression in spasticity, but this was accompanied by deterioration in locomotive function. Thus, caution should be exercised in considering the benefits and costs in suppressing spasticity in ambulatory patients, and implanted devices that apply titratable doses of PRF may be best to optimize patients' needs.

Potential human exposures to neonicotinoid insecticides: A review

Due to their systemic character and high efficacy to insect controls, neonicotinoid insecticides (neonics) have been widely used in global agriculture since its introduction in early 1990. Recent studies have indicated that neonics may be ubiquitous, have longer biological half-lives in the environment once applied, and therefore implicitly suggested the increasing probability for human exposure to neonics. Despite of neonics' persistent characters and widespread uses, scientific literature in regard of pathways in which human exposure could occur is relatively meager. In this review, we summarized results from peer-reviewed articles published prior to 2017 that address potential human exposures through ingestion and inhalation, as well as results from human biomonitoring studies. In addition, we proposed the use of relative potency factor approach in order to facilitate the assessment of concurrent exposure to a mixture of neonics with similar chemical structures and toxicological endpoints. We believe that the scientific information that we presented in this review will aid to future assessment of total neonic exposure and subsequently human health risk characterization.

Elevated Aminotransferases are Predictors of Hepatic Injury in Blunt Abdominal Trauma Patients

Objective

Computed tomography (CT) scan is currently the most commonly used tool for evaluating solid-organ injuries in trauma management. However, liberal use of CT scanning increases the risk of excess radiation exposure and toxicity from contrast material. Animal studies and clinical research on the paediatric population indicated that liver enzymes elevations were related to hepatic injury. The present study was undertaken to determine whether elevated liver enzymes were associated with the occurrence of hepatic injury in adult patients with blunt abdominal trauma.

Methods

This is a cross-sectional study from August 2003 to October 2006. All adult patients with blunt injury to abdomino-pelvic organs documented by CT or surgery who were admitted to Chi-Mei Medical Centre in the captioned period were included. The study population sorted to hepatic injury (HI) and no hepatic injury (NHI) groups according to the presence or absence of hepatic injury. Variables including liver enzymes were compared between the groups.

Results

Totally 419 patients were included, including 150 patients in the HI group and 269 patients in the NHI group. The HI group was younger and had a lower rate of laparotomy (36.3 years old vs 41.4 years old; 26% vs 42%, respectively). The mean levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the HI group were significantly higher than levels in the NHI group (439.6 IU/L vs 104.7 IU/L; 353.5 IU/L vs 76.6 IU/L, p<0.01). We define AST >200 IU/L or ALT level >125 IU/L as abnormal according to previous studies. The diagnostic characteristics of hepatic injury were 87.3% sensitivity, 80.3% specificity, 71.2% positive predictive value, and 91.9% negative predictive value.

Conclusion

In adults who have experienced blunt abdominal trauma, AST >200 U/L or of ALT >125 U/L are practical predictors of hepatic injury. Screening serum aminotransferases will have a role in detecting occult hepatic injury and may reduce the hazards of excessive CT scanning. (Hong Kong j.emerg.med. 2013;20:337-342)

An Evaluation of the ACEP Guideline for Mild Head Injuries in Taiwan

Introduction

Traumatic brain injury (TBI) is an important issue in the emergency department. In the United States, the American College of Emergency Physicians (ACEP) published clinical guideline to select patients with mild head injuries for head computed tomography (CT) scans in 2008. The aim of this study was to identify the possible benefits of compliance with these guidelines for mild head injury patients in Taiwan.

Method

This was a secondary analysis on our previous study published for association of hypertension and head injuries. In our previous study, we collected data about 1290 patients with head injuries who received brain CT scans in the emergency department from September 2012 to August 2013 for a study regarding the association between head injury and hypertension. In present study, we subjected this data to further analysis to try to validate the ACEP clinical policy for mild head injuries.

Results

Of these 1,290 patients, 154 were found to have brain haemorrhage on the initial brain CT scan, and 5 were in need of neurosurgical intervention. A total of 859 patients met the ACEP guideline criteria, and 117 of these had brain haemorrhages. The sensitivity and specificity of the ACEP guideline to predict brain haemorrhage were 75.97% (95% confidence interval [CI], 68.44% to 82.48%) and 34.68% (95% CI, 31.91% to 37.53%), respectively. In predicting neurosurgical intervention, the sensitivity and specificity of the guideline were 100% (95% CI, 47.82% to 100%) and 33.54% (95% CI, 30.96% to 36.2%), respectively.

Conclusion

Although adoption of the ACEP clinical policy may reduce the number of brain CT scans in mild head injury patients who may need neurosurgical interventions, it is not a good selection tool in Taiwan.

Limits of Calcaneal Lengthening for Treating Planovalgus Foot Deformity in Children With Cerebral Palsy

BACKGROUND

Calcaneal lengthening is used to correct symptomatic planovalgus foot deformity, but outcomes have been less satisfactory in children with cerebral palsy. This study aimed to define limits of calcaneal lengthening by analyzing the risk factors for undercorrection of deformity.

METHODS

We retrospectively reviewed 20 cases of children with cerebral palsy who underwent calcaneal lengthening of 30 planovalgus feet at a mean age of 11.9 years. Foot deformities were evaluated by the anteroposterior talo-first metatarsal angle (normal, 10 ± 7.0 degrees), lateral talo-first metatarsal angle (normal, 13 ± 7.5 degrees), and lateral calcaneal pitch angle (normal, 17 ± 6.0 degrees) on standing foot radiographs. Among these parameters, a corrected foot was defined as 2 or 3 parameters being corrected to within a normal range, and an undercorrected foot was only 1 or no parameter being corrected to within a normal range. Factors were compared between the corrected group and undercorrected group for significant predictors, and cutoff values of predictors were calculated for use as a clinical guideline.

RESULTS

Seventeen planovalgus feet were corrected satisfactorily by calcaneal lengthening, while the other 13 feet were undercorrected. Undercorrected feet had a greater preoperative anteroposterior talonavicular angle (33.7 vs 22.8 degrees, P = .001) and a smaller lateral calcaneal pitch (-1.7 vs 5.6 degrees, P = .03). A talonavicular angle of more than 24 degrees and calcaneal pitch less than -5 degrees were identified as cutoff values using a receiver operating characteristic curve. The predicted probability of undercorrection was 100% (9/9 feet) for 2 positive predictors, 50% (8/16 feet) for 1 positive predictor, and 0 (0/5 feet) for zero predictors.

CONCLUSION

A talonavicular lateral subluxation of more than 24 degrees on the anteroposterior radiograph and a calcaneal pitch angle less than -5 degrees on the lateral radiograph were 2 independent predictors that could be used to identify a planovalgus deformity that would be beyond the corrective capacity of calcaneal lengthening to restore normal alignment. Level of Evidence Retrospective case control study, level III.

Gross motor function change after multilevel soft tissue release in children with cerebral palsy

Background

Improving motor function is a major goal of therapy for children with cerebral palsy (CP). However, changes in motor function after orthopedic surgery for gait disorders are seldom discussed. This study aimed to evaluate the postoperative changes in gross motor function and to investigate the prognostic factors for such changes.

Methods

We prospectively studied 25 children with CP (4–12 years) who were gross motor function classification system (GMFCS) level II to IV and and underwent bilateral multilevel soft-tissue release for knee flexion gait. Patients were evaluated preoperatively and at 6 weeks and 3 and 6 months postoperatively for Gross Motor Function Measure (GMFM-66), range of motion, spasticity, and selective motor control. The associations between change in GMFM-66 score and possible factors were analyzed.

Results

25 children with gross motor function level II to IV underwent surgery at a mean age of 8.6 years (range, 4–12 years). Mean GMFM-66 score decreased from 55.9 at baseline to 54.3 at 6-weeks postoperatively and increased to 57.5 at 6-months postoperatively (p < 0.05). Regression analysis revealed better gross motor function level and greater surgical reduction of spasticity were predictors for decreased GMFM-66 score at 6-weeks postoperatively. Younger age was a predictor for increased GMFM-66 score at 6-months postoperatively.

Conclusion

Reduction of contracture and spasticity and improvement of selective motor control were noted after surgery in children with CP. However, a down-and-up course of GMFM-66 score was noted. It is emphasized that deterioration of motor function in children with ambulatory ability and the improvement in young children after orthopedic surgery for gait disorders.

Level of evidence

case series, therapeutic study, level 4.

Treatment of displaced flexion-type pediatric supracondylar humeral fractures in the prone position

PURPOSE

This study is to report a new method to reduce and fix the displaced flexion-type pediatric supracondylar fracture in the prone position.

METHODS

Ten children with displaced flexion-type supracondylar humeral fractures treated between 2007 and 2013 were reviewed. There were three girls and seven boys, with a mean age of 9.5 years. The fracture was reduced by gentle traction of the forearm and gradual extension of the elbow in the prone position. Two or three crossed Kirschner wires (K-wires) were inserted percutaneously to secure the fracture reduction. Radiographic evaluation included the Baumann's angle and the lateral humerocapitellar angle. Clinical outcomes were assessed using the Flynn's criteria.

RESULTS

Eight children had closed reduction and percutaneous K-wire fixation. The other two children required open reduction through a posterior triceps splitting approach. The mean Baumann's angle was 70.2° immediately after K-wires fixation and 69.5° after 3 months later. The mean lateral humerocapitellar angle was 38° immediately after K-wires fixation and 35.5° after 3 months later. The clinical outcome was excellent in nine children and poor in one child by the Flynn's criteria.

CONCLUSION

Reduction of displaced flexion-type pediatric supracondylar humeral fractures by traction and gradual extension in the prone position is an effective and safe method. When reduction is still impossible or nerve incarceration is suspected, open reduction and release of the trapped nerve through a posterior triceps splitting approach are simply accessible.

Clinical significance of anterior humeral line in supracondylar humeral fractures in children

INTRODUCTION

Anterior humeral line (AHL) location is commonly used to evaluate sagittal alignment after fracture reduction in children with supracondylar humeral fractures. However, the position of the AHL for acceptable fracture reduction has not been validated by clinical outcome. The purpose of this study was to investigate the relationship between the location of AHL and range of elbow motion.

PATIENTS AND METHODS

We retrospectively reviewed 101 children who underwent closed reduction and percutaneous pinning for Gartland type III supracondylar humeral fractures between January 2009 and June 2014. There were 67 boys and 34 girls, with a mean age of 7 years. The children were classified according to the location of the AHL three months postoperatively into five groups: anteriorly loss (n=6), anterior third (n=25), middle third (n=47), posterior third (n=21), and posteriorly loss (n=2). Range of elbow motion was measured by attending paediatric orthopaedic surgeons with a goniometer. Clinical and radiographic outcomes were compared among the five groups.

RESULTS

The mean elbow extension angle was not significantly different among the groups (p=0.21). However, children with AHL anterior to the capitellum had less elbow flexion angle (125.8° vs. 131.2°, p=0.046) and less total range of elbow motion (128.3° vs. 135.7°, p=0.048) than children with AHL crossing the capitellum. When the AHL crossed the capitellum, the elbow flexion angle and total range of elbow motion were significantly decreased in children with AHL crossing the anterior third of the capitellum. The Flynn criteria were not significantly different among the central three groups (p=0.131). However, the Flynn criteria were significantly worse in children whose AHL missed the capitellum (p<0.001). The mean Baumann angle measured 3 months postoperatively was not significantly different among the groups (p=0.12).

CONCLUSIONS

These findings demonstrate that children with AHL crossing the middle and posterior thirds of the capitellum appear to have slightly better early elbow flexion and total range of elbow motion. AHL crossing the anterior third of the capitellum can be an underreduction that has similar elbow motion as AHL anterior to the capitellum. AHL posterior to the capitellum is a warning sign of overreduction and should be avoided.

Immunological impression cytology of the conjunctival epithelium in patients with thyroid orbitopathy-related dry eye

Thyroid orbitopathy (TO) is an autoimmune disease that is complicated by ocular surface disorders, leading to discomfort. Dry eye is very prevalent in patients with TO. Recent studies on the pathogenesis of dry eye have focused on the inflammatory process, and some supporting evidence has been discovered. Because TO is a disorder of autoimmune origin, we assumed that the association between TO and dry eye is related to inflammation. Inflammation of the ocular surface in TO-related dry eye has not been well studied. In this study, we assessed cellular inflammation of the ocular surface and the cytokine profiles in patients with TO-related dry eye. Conjunctival impression cytology (CIC) was assessed with an immunofluorescent assay. TO-related dry eye was diagnosed by using the Schirmer test, tear break-up time, thyroid function, and clinical signs. CIC was combined with immunological staining of interleukin-1a (IL-1a), IL-1b, and IL- 6. The immunological impression cytology (IC) grade was compared to the clinical activity score of TO. All TO patients with dry eye were positive for IL-1a, IL-1b, and IL-6. However, the normal controls were also positive for IL-1a. A trend was observed between the clinical inflammatory score and immunological IC grade. This study was the first to delineate the immunological IC of TO-related dry eye. Our study aimed to investigate the pathogenesis of dry eye in TO. Our findings suggest that the conjunctival cytokines IL-1a, IL-1b, and IL-6 may play a role. The results of this study will be useful for future studies of additional inflammatory cytokines, and the levels of these cytokines could be used as an outcome to assess the efficacy of treatment, such as anti-cytokine or immunosuppression therapy, in patients with TO-related dry eye or other ocular surface inflammatory disorders.

Econazole induces increases in free intracellular Ca2+ concentrations in human osteosarcoma cells

Econazole is an antifungal drug with different in vitro effects. However, econazole's effect on osteoblast like cells is unknown. In human MG63 osteosarcoma cells, the effect of econazole on intracellular Ca2+ concentrations ([Ca2+]i) was explored by using fura-2. At a concentration of 0.1 μM, econazole started to cause a rise in [Ca2+]i in a concentration-dependent manner. Econazole-induced [Ca2+]i rise was reduced by 74% by removal of extracellular Ca2+. The econazole-induced Ca2+ influx was mediated via a nimodipine-sensitive pathway. In Ca2+ free medium, thapsigargin, an inhibitor of the endoplasmic reticulum Ca2+ ATPase, caused a [Ca2+]i rise, after which the increasing effect of econazole on [Ca2+]i was abolished. Pretreatment of cells with econazole to deplete Ca2+ stores totally prevented thapsigargin from releasing Ca2+. U73122, an inhibitor of phospholipase C, abolished histamine (an inositol 1,4,5-trisphosphate dependent Ca2+ mobilizer)-induced, but not econazoleinduced, [Ca2+]i rise. Econazole inhibited 76% of thapsigargin-induced store-operated Ca2+ entry. These findings suggest that in MG63 osteosarcoma cells, econazole increases [Ca2+]i by stimulating Ca2+ influx and Ca2+ release from the endoplasmic reticulum via a phospholipase C-independent manner. In contrast, econazole acts as a potent blocker of store-operated Ca2+ entry.

Designing a stronger interface through graded structures in amorphous/nanocrystalline ZrCu/Cu multilayered films

Many multilayered nano-structures appear to fail due to brittle matter along the interfaces. In order to toughen them, in this study, the microstructure and interface strength of multilayered thin films consisting of amorphous ZrCu and nanocrystalline Cu (with sharp or graded interfaces) are examined and analyzed. The interface possesses a gradient nature in terms of composition, nanocrystalline phase size and volume fraction. The bending results extracted from the nano-scaled cantilever bending samples demonstrate that multilayered films with graded interfaces would have a much higher interface bending strength/strain/modulus, and an overall improvement upgrade of more than 50%. The simple graded interface design of multilayered thin films with improved mechanical properties can offer much more promising performance in structural and functional applications for MEMS or optical coating.

Influence of obesity on surgical outcomes in type III paediatric supracondylar humeral fractures

INTRODUCTION

Obesity was associated with poor treatment outcome in paediatric supracondylar humeral fractures. It is controversial about the association is related to more severe fractures in obese children or obesity directly affects treatment. The purpose of this study was to evaluate the influence of obesity on surgical outcomes after control of fracture severity.

PATIENTS AND METHODS

This is a retrospective comparative study of 107 children treated for type III supracondylar humeral fractures between January 2009 and December 2013. Children were classified according to sex-specific body mass index (BMI)-for-age growth chart into 4 groups: underweight group (n=10); normal-weight group (n=71); overweight group (n=13); and obese group (n=13). Clinical outcomes were assessed using the Flynn criteria. Radiographic evaluation included the Baumann angle and the lateral humerocapitellar angle. Loss of reduction was defined by Skaggs' criteria.

RESULTS

The mean age, sex, and Flynn criteria were comparable among the four BMI groups. Obese children were more likely to develop a varus change in the Baumann angle (p=0.017) and loss of reduction in varus (p=0.059) postoperatively. The risk for pin-related complications was significantly higher in overweight and obese children (p=0.013).

CONCLUSIONS

Obesity was associated with more postoperative varus deformation and pin-related complications after surgical fixation for type III supracondylar fracture. These findings underline the importance of stable fixation and close post-operative monitoring in obese children.

Effects of low amplitude pulsed radiofrequency stimulation with different waveform in rats for neuropathic pain

Pulsed-radiofrequency (PRF) electrical stimulation has been widely used for chronic pain treatment. It has been demonstrated with advantages of low temperature over traditional continuous radiofrequency (CRF) lesions with higher amplitude and mono polar electrode to treat pain in clinics (frequency 500 KHz, Pulse duration 20 msec, Amplitude 45 V, Treatment 2 min). We compare the effects of different pulse waveforms and PRF parameters (Pulse duration 25 ms, Treatment duration 5 min, low amplitude of 2.5/1.25 V) with a miniature bi-polar electrode on Dorsal root ganglion (DRG). The pain relief effect due to PRF is evaluated by using Von Frey method for the pain threshold index based on behavior response to mechanical stimulus of various strengths. Experimental results of Von Frey Score show that the sinusoidal group has higher responses than the square wave one. Both fast and secondary expressed proteins of c-fos and pp38 are measured from spinal cord tissue sectioning slides to characterize the pain associated inflammatory responses and their responses due to PRF stimulation.

Superradiant modes in resonant quasi-periodic double-period quantum wells

This paper firstly proposes the existence of superradiant modes in resonant quasi-periodic double-period quantum wells (QWs), which has not been observed from analyzing the structure factor by traditional methods. Using the gap map method, the reflection spectra under the relevant conditions show that there are dips in the middle and the linewidth grows linearly, despite the dips, as the number of QWs increases, which is a direct demonstration of superradiance. It is also found that the relevant conditions are divided into three regions, each of which has a different width of bandgaps.

Influence of lumbar curvature and rotation on forward flexibility in idiopathic scoliosis

BACKGROUND

Lumbar spine facet joints are arranged sagittally and mainly provide forward flexibility. Rotation of the lumbar vertebral body and coronal plane deformity may influence the function of lumbar forward flexibility. We hypothesize that the more advanced axial and coronal plane deformity could cause more limitation on forward flexibility in patients with idiopathic scoliosis.

METHODS

Between January 2011 and August 2011, 85 patients with adolescent idiopathic scoliosis were enrolled in this study. The proximal thoracic, major thoracic, thoracolumbar/lumbar (TL/L), and lumbar (L1/L5) curves were measured by Cobb's method. Lumbar apical rotation was graded using the Nash-Moe score. Lumbar forward flexibility was measured using the sit and reach (S and R) test. Statistical analysis was performed using one-way analysis of variance (ANOVA), Spearman's and Pearson's correlation coefficients.

RESULTS

The mean age was 16.1 ± 2.84 years. The mean proximal thoracic, major thoracic, TL/L, and L1/L5 curves were 17.61° ± 8.92, 25.56° ± 11.61, 26.09° ± 8.6, and 15.10° ± 7.85, respectively. The mean S and R measurement was 25.56 ± 12.33 cm. The magnitude of the TL/L and L1/L5 curves was statistically positively related to vertebral rotation (r(s) = 0.580 and 0.649, respectively). The correlation between the S and R test and both the TL/L and L1/L5 curves was negative (r(p) = -0.371 and -0.595, respectively). Besides, the S and R test also demonstrated a significant negative relationship with vertebral rotation (rs = -0.768).

CONCLUSION

In patients with idiopathic scoliosis, spinal deformity can diminish lumbar forward flexibility. Higher lumbar curvature and rotation lead to greater restriction of lumbar flexion.

Flatfoot diagnosis by a unique bimodal distribution of footprint index in children

BACKGROUND

More than 1000 scientific papers have been devoted to flatfoot issue. However, a bimodal distribution of flatfoot indices in school-aged children has never been discovered. The purposes of this study were to establish a new classification of flatfoot by characteristic in frequency distribution of footprint index and to endue the classification with discrepancy in physical fitness.

METHODS/PRINCIPAL FINDINGS

In a longitudinal survey of physical fitness and body structure, weight bearing footprints and 3 physical fitness related tests were measured in 1228 school-aged children. Frequency distribution of initial data was tested by Kolmogorov-Smirnov test for normality and a unique bimodal distribution of footprint index was identified. The frequency distribution of footprint index manifests two distinct modes, flatfoot and non-flatfoot, by deconvolution and bootstrapping procedures. A constant intersection value of 1.0 in Staheli's arch index and 0.6 in Chippaux-Smirak index could distinguish the two modes of children, and the value was constant in different age, sex, and weight status. The performance of the one leg balance was inferior in flatfoot girls (median, 4.0 seconds in flatfoot girls vs. 4.3 seconds in non-flatfoot girls, p = 0.04, 95% CI 0.404-0.484).

DISCUSSION

The natural bimodality lends itself to a flatfoot classification. Bimodality suggests development of the child's foot arch would be a leap from one state to another, rather than a continuous growth as body height and weight. The underlying dynamics of the human foot arch and motor development will trigger research prospects.

Twin extra-high photoluminescence in resonant double-period quantum wells

Twin extra high photoluminescence (PL) in resonant quasi-periodic double-period quantum wells (DPQWs) for higher-generation orders is demonstrated. In the DPQW, the number of maxima in the maximum values of the PL intensity is two, which is different from other quasi-periodic quantum wells (QWs) and traditional periodic QWs. The maximum PL intensity in a DPQW is also stronger than that in a periodic QW under the anti-Bragg condition and that in a Fibonacci QW. Although the peaks of the squared electric field for the twin PL are both located near the QWs, their field profiles are distinct.

Pharmacokinetics and preliminary safety data of a single oral dose of bosentan, a dual endothelin receptor antagonist, in cats

The objective of this study was to evaluate the pharmacokinetic properties and adverse effect profile of single-dose oral bosentan, a dual endothelin receptor antagonist, in healthy cats. Pharmacokinetic parameters were determined following a single mean ± SD oral dose of 3.2 ± 0.6 mg/kg of bosentan in 6 adult cats. Blood was collected for quantification of bosentan via high-performance liquid chromatography with ultraviolet detection. Blood and urine were evaluated for CBC, plasma biochemical profile, and urinalysis, and repeat physical examinations were performed to evaluate for adverse effects. The mean terminal half-life of bosentan was 20.4 ± 17.2 h. The mean peak plasma concentration was 0.49 ± 0.24 g/mL, and the mean time to maximum plasma concentration was 6.8 ± 8.6 h. The area under the curve was 5.14 ± 3.81 h·μg/mL. Oral bosentan tablets were absorbed in cats, and no clinically important adverse events were noted. Further evaluation of repeat dosing, investigation into the in vivo efficacy of decreasing endothelin-1 concentrations in cats, as well as safety in conjunction with other medications is warranted.

Exciton photoluminescence in resonant quasi-periodic Thue-Morse quantum wells

This Letter investigates exciton photoluminescence (PL) in resonant quasi-periodic Thue-Morse quantum wells (QWs). The results show that the PL properties of quasi-periodic Thue-Morse QWs are quite different from those of resonant Fibonacci QWs. The maximum and minimum PL intensities occur under the anti-Bragg and Bragg conditions, respectively. The maxima of the PL intensity gradually decline when the filling factor increases from 0.25 to 0.5. Accordingly, the squared electric field at the QWs decreases as the Thue-Morse QW deviates from the anti-Bragg condition.

DSBCS modulation scheme for hybrid wireless and cable television system

This work develops and demonstrates a double sideband with optical carrier suppression (DSBCS) modulation scheme for a hybrid wireless and cable television system based on a phase modulator (PM) and a polarization beam splitter (PBS). A carrier suppression ratio greater than 20 dB is achieved between two sidebands. In addition, the values of carrier-to-noise ratio, composite second-order and composite triple beat in various channels after 25 km of transmission are higher than the threshold value, and the power penalty of microwave signal in back-to-back and 25 km transmission perform well. Additionally, the constellation diagram of upstream signal is successfully recovered. Above results demonstrate that the proposed scheme is highly promising for practical applications.

Quasi-Bragg conditions in Thue-Morse dielectric multilayers

The existence of quasi-Bragg conditions (QBCs) in Thue-Morse dielectric multilayers (TMDMs), based on high reflectance and large forbidden gap regions in its transmission spectra, is presented. In contrast to a single traditional Bragg condition (TBC) in periodic bilayers, there are three QBCs in TMDMs. The formula for each of these QBCs is derived. The results show that one of these QBCs just overlaps the TBC. However, a singular point with perfect transmission exists in this QBC at the quarter-wave stack, at which high reflection exists in the periodic bilayers.

Strong photoluminescence emission from resonant Fibonacci quantum wells

Strong photoluminescence (PL) emission from a resonant Fibonacci quantum well (FQW) is demonstrated. The maximum PL intensity in the FQW is significantly stronger than that in a periodic QW under the Bragg or anti-Bragg conditions. Moreover, the peaks of the squared electric field in the FQW are located very near each of the QWs. The optimal PL spectrum in the FQW has an asymmetrical form rather than the symmetrical one in the periodic case. The maximum PL intensity and the corresponding thickness filling factor in the FQW become greater with increasing generation order.

Erosive potential of sports beverages

BACKGROUND

Dental erosion is an increasingly prevalent problem in Australia, with the consumption of sports beverages suggested as a risk factor. The aim of this study was to compare the erosive potential of Australian sports beverages.

METHODS

Ten beverages were selected and analysed to determine their pH, titratable acidity and apparent degree of saturation with respect to apatite. The erosive potential of the beverages was measured by human enamel surface loss and surface softening following a 30-minute exposure. A taste testing panel was established to determine the palatability of the sports beverages.

RESULTS

All sports beverages except Sukkie and Endura produced substantial surface loss and surface softening. Compared with the other sports beverages, Sukkie and Endura had a higher pH, lower titratable acidity and higher calcium content. However, Sukkie and Endura were deemed to be less palatable than the other more acidic sports beverages.

CONCLUSIONS

The majority of the sports beverages tested produced dental erosion in this in vitro model. However, two new products Sukkie and Endura have lower erosive potential but also lower palatability.

Differential effects of arsenic on calcium signaling in primary keratinocytes and malignant (HSC-1) cells

Arsenic is highly toxic to living cells, especially skin, and skin cancer is induced by drinking water containing arsenic. The molecular mechanisms of arsenic-induced cancer, however, are not well understood. To examine the initial processes in the development of arsenic-induced cancer, we analyzed calcium signaling at an early stage of arsenic treatment of human primary cells and compared the effects with those observed with arsenic treatment in carcinoma-derived cells. We found that arsenic inhibited inositol trisphosphate receptor (IP3R) function in the endoplasmic reticulum by inducing phosphorylation, which led to decreased intracellular calcium levels. Blockade of IP3R phosphorylation by the serine/threonine protein kinase Akt inhibitor wortmannin rescued calcium signaling. In contrast, arsenic treatment of cells derived from a carcinoma (human squamous carcinoma; HSC-1) for 1h had no obvious effect. Taken together, these results suggest that arsenic-induced reduction in calcium signaling is one of the initial mechanisms underlying the malignant transformation in the development of skin cancer.

The optimal effect site concentration of remifentanil in combination with intravenous midazolam and topical lidocaine for awake fibreoptic nasotracheal intubation in patients undergoing cervical spine surgery

BACKGROUND

Remifentanil has been suggested as a suitable agent for conscious sedation during fibreoptic intubation. We evaluated the optimal effect site concentration (Ce) of remifentanil target-controlled infusion (TCI) for awake nasotracheal fibreoptic intubation in patients undergoing elective cervical spine surgery.

METHODS

Nineteen ASA I-II patients were enrolled. Patients were premedicated with midazolam (<70 kg 1.5 mg; >70 kg 2.0 mg) intravenously. The EC(50) and EC(95) of remifentanil Ce for smooth intubation were determined using Dixon's up-and-down method and isotonic regression. Smooth intubation was considered to have failed when patients exhibited sustained and repetitive coughing with head lift during the procedure. Intubation time, number of attempts, adverse events, and hemodynamic variables were also recorded. Patients were asked to recall the procedure and grade satisfaction at postoperative 24 h.

RESULTS

The EC(50) of remifentanil Ce for smooth intubation was 2.33±0.38 ng·mL-1 as calculated by Dixon's method. The estimated EC(95) of remifentanil Ce was 3.38 (95% confidence interval 2.90-3.46) ng·mL-1. Median intubation time (min) was longer in failed smooth intubation than in smooth intubation (8.0 vs. 6.1, P=0.048). Eleven patients (58%) recalled the procedure and 16 patients (84%) rated their satisfaction score as good or excellent.

CONCLUSION

The estimated EC(95) of remifentanil Ce for smooth nasotracheal fibreoptic intubation with conscious sedation was 3.38 (95% CI 2.90-3.46) ng·mL-1 when used in combination with midazolam and topical lidocaine. Remifentanil TCI may provide a tolerable experience of awake fibreoptic intubation despite the high incidence of recall.