Potential of Soft-Shelled Rugby Headgear to Lower Regional Brain Strain Metrics During Standard Drop Tests.

BACKGROUND: The growing concern for player safety in rugby has led to an increased focus on head impacts. Previous laboratory studies have shown that rugby headgear significantly reduces peak linear and rotational accelerations compared to no headgear. However, these metrics may have limited relevance in assessing the effectiveness of headgear in preventing strain-based brain injuries like concussions. This study used an instantaneous deep-learning brain injury model to quantify regional brain strain mitigation of rugby headgear during drop tests. Tests were conducted on flat and angled impact surfaces across different heights, using a Hybrid III headform and neck. RESULTS: Headgear presence generally reduced the peak rotational velocities, with some headgear outperforming others. However, the effect on peak regional brain strains was less consistent. Of the 5 headgear tested, only the newer models that use open cell foams at densities above 45 kg/m3 consistently reduced the peak strain in the cerebrum, corpus callosum, and brainstem. The 3 conventional headgear that use closed cell foams at or below 45 kg/m3 showed no consistent reduction in the peak strain in the cerebrum, corpus callosum, and brainstem. CONCLUSIONS: The presence of rugby headgear may be able to reduce the severity of head impact exposure during rugby. However, to understand how these findings relate to brain strain mitigation in the field, further investigation into the relationship between the impact conditions in this study and those encountered during actual gameplay is necessary.

Compliance with Headgear Evaluated by Force- and Temperature-Sensitive Monitoring Device: A Case-Control Study.

The aim was to objectively assess compliance in patients prescribed headgear and evaluate the impact of monitoring awareness, treatment duration, gender, and age on compliance levels. A total of 22 patients with Class II malocclusion wore the headgear integrated with the force and temperature sensitive Smartgear monitoring system (Smartgear, Swissorthodontics AG, Cham, Switzerland). Patients were instructed to wear the headgear for 13 h daily over a 3-month period. Randomly, 11 patients were informed that they monitored and 11 were not informed. Data were organized using Microsoft Excel and analyzed using R for statistical estimates, graphs, and hypothesis testing. Smartgear recorded an average daily compliance of 6.7 h. No statistically significant differences were found in cooperation between study group and control group over the 3 months of treatment, regardless of gender and age. However, there was slight greater cooperation in the first month than in the other months, and patients ≤10 years of age had almost 2 h more cooperation than their older counterparts. Moreover, the informed group exhibited an average of 1.1 more hours of cooperation per day than the uninformed group, which may carry clinical significance. This cooperation primarily occurred at night and was found to be statistically significant. Compliance among young patients typically remained lower than the prescribed level, regardless of their gender and psychological maturity. Although an awareness of monitoring does not seem to improve compliance, implementing such systems could still offer dentists a valuable means of obtaining objective information about their patients' adherence.

ninjaCap: a fully customizable and 3D printable headgear for functional near-infrared spectroscopy and electroencephalography brain imaging.

Accurate sensor placement is vital for non-invasive brain imaging, particularly for functional near-infrared spectroscopy (fNIRS) and diffuse optical tomography (DOT), which lack standardized layouts such as those in electroencephalography (EEG). Custom, manually prepared probe layouts on textile caps are often imprecise and labor intensive. We introduce a method for creating personalized, 3D-printed headgear, enabling the accurate translation of 3D brain coordinates to 2D printable panels for custom fNIRS and EEG sensor layouts while reducing costs and manual labor. Our approach uses atlas-based or subject-specific head models and a spring-relaxation algorithm for flattening 3D coordinates onto 2D panels, using 10-5 EEG coordinates for reference. This process ensures geometrical fidelity, crucial for accurate probe placement. Probe geometries and holder types are customizable and printed directly on the cap, making the approach agnostic to instrument manufacturers and probe types. Our ninjaCap method offers 2.7 ± 1.8 mm probe placement accuracy. Over the last five years, we have developed and validated this approach with over 50 cap models and 500 participants. A cloud-based ninjaCap generation pipeline along with detailed instructions is now available at openfnirs.org. The ninjaCap marks a significant advancement in creating individualized neuroimaging caps, reducing costs and labor while improving probe placement accuracy, thereby reducing variability in research.

Treatment of Vertical Maxillary Excess and Skeletal Class II Malocclusion: A Case Report.

Class II malocclusion is a recurrent problem that may occur at a young age. If treated initially, the malocclusion can be corrected by redirecting the growth without invasive modalities and avoiding orthognathic surgeries. A female patient aged 10 years three months came to the department of orthodontics having a complaint of upper front teeth placed forwardly, diagnosed with skeletal class II due to retrusive mandible and vertical maxillary excess with hyper divergent growth pattern with increased anterior facial height, with Angle's molar class II division 1 malocclusion, increased overjet of 13 mm and overbite of 7 mm, acute nasolabial angle, deep mentolabial sulcus, and hyperactive mentalis. It was treated using an activator with medium-high-pull headgear (modified Herren activator) passing through the maxillary center of resistance. A fixed mechanotherapy with high-pull headgear was given using the anterior inclined plane acrylic plate in the maxilla and McLaughlin, Bennett, and Trevisi (MBT). Begg's wrap was used for the retention plan. This case report shows the significance of proper treatment results obtained due to correct identification and planning in treating malocclusion. This case report shows the significance of proper treatment results obtained due to correct identification and planning in treating malocclusion.

Headgear therapy in children with Class II malocclusion and the role of compliance on treatment outcome: A nine-month randomized controlled trial.

OBJECTIVES: To evaluate three-dimensional movements of maxillary teeth during headgear treatment in Class II growing children, using digital analytical tools, and to determine the effects of compliance on these movements. MATERIALS AND METHODS: A 9-month parallel-group randomized controlled trial was carried out on 40 children with Class II malocclusion, aged 8-12 years, half assigned to receive a cervical headgear and half to a no-treatment group, using block randomization. Subjects in the treatment group were instructed to wear the headgear for 12 hours daily and monitored using an electronic module. After 9 months, the following dental outcomes were measured: first maxillary molar distalisation, rotation, tip and torque, arch depth, and interpremolar and intermolar distances. Caregivers and participants were not blinded to group assignments, but those assessing outcomes were. Linear regression models were used to detect differences between groups and correlation coefficients to find correlations between compliance and dental outcomes. RESULTS: All 40 included patients were analysed. A significant difference in molar distalisation was observed between the treatment (1.2 mm) and control groups (-0.2 mm). Arch depth change was also increased to a larger extent in the treatment groups (1.3 mm vs 0.1 mm), as was the interpremolar distance (1.9 mm vs 0.4 mm). In contrast, no significant differences in molar rotation or torque change were observed. With regard to compliance, average compliance was 55%. A significant correlation was found between molar distalisation and compliance in the treatment group. CONCLUSIONS: Headgear therapy has significant effects on molar distalisation, arch depth, and arch width. Compliance has a significant positive effect on molar distalisation.

The Impact of Headgear on Distalization in Class II Division I Malocclusion: A Case Report.

This report presents a case of a 16-year-old female patient with skeletal class II and dental class II division I malocclusion that was treated with fixed orthodontic appliances and through growth modulation. Two appliances were used: a Hyrax expander and a high-pull headgear with extraction. The treatment objectives of achieving a class I molar and canine relationship, resolving the crowding in the upper and lower arches, correcting the midline shift, and improving the patient's facial profile and lip position were achieved, resulting in a good occlusion with normal overbite and overjet.

The effects of head mounted weight on comfort for helmets and headsets, with a definition of "comfortable wear time".

BACKGROUND: There are difficult tradeoffs when designing head-mounted equipment such as helmets, lights, cameras, or virtual or augmented reality displays. Increased functionality and battery life adds weight, which in turn reduces comfort. A successful product must balance both comfort and functionality to achieve its product engagement goals. OBJECTIVE: This study defines "comfortable wear time" as a new metric, and applies it to the domain of headsets in determining the relationship between headset weight and comfort. METHODS: Sixteen study participants wore four otherwise identical headsets weighted between 500g-600 g for up to two hours each in an office environment. If participants experienced more than "mild discomfort" (>3 on an NRS-11 discomfort scale), the trial ended early, and the comfortable wear time was recorded. Intensity and location of discomfort was rated at trial conclusion, and qualitative feedback collected. RESULTS: Higher weights were associated with shorter comfortable wear times. Not everyone could wear even the lightest headset (500 g) for the full two hours. Qualitatively, discomfort took many forms beyond the expected neck fatigue or contact pressure and included symptoms commonly associated with motion sickness, such as headache and dizziness. Finally, there were pronounced gender differences with females experiencing more severe discomfort with earlier onset. CONCLUSION: Heavier headsets were less comfortable for the lower quartile of participants -yielding an average of 11 fewer minutes of comfortable wear time per 33 g of weight added. Understanding the discomfort costs from adding weight empowers product teams to find the correct balance to meet their product engagement targets.

Vertical effects of cervical headgear in growing patients with Class II malocclusion: a systematic review and meta-analysis.

BACKGROUND: Cervical headgear (cHG) has been shown to be effective in Class II correction both with dental and orthopaedic effects but has traditionally been associated with vertical adverse effects in terms of posterior mandibular rotation. OBJECTIVE: To assess the treatment effects of cHG treatment in the vertical dimension. SEARCH METHODS: Unrestricted literature search of five databases up to May 2023. SELECTION CRITERIA: Randomized/non-randomized clinical studies comparing cHG to untreated controls, high-pull headgear (hp-HG), cHG adjuncts, or other Class II treatment alternatives (functional appliances or distalisers). DATA COLLECTION AND ANALYSIS: After duplicate study selection, data extraction, and risk-of-bias assessment according to Cochrane, random-effects meta-analyses of mean differences (MD)/standardized mean diffences (SMD) and their 95% confidence intervals (CIs) were performed, followed by meta-regressions, sensitivity analyses, and assessment of certainty on existed evidence. RESULTS: Two randomized/16 non-randomized studies (12 retrospective/4 prospective) involving 1094 patients (mean age 10.9 years and 46% male) were included. Compared to natural growth, cHG treatment was not associated on average with increases in mandibular (eight studies; SMD 0.22; 95% CI -0.06, 0.49; P = 0.11) or maxillary plane angle (seven studies; SMD 0.81; 95% CI -0.34, 1.95; P=0.14). Observed changes translate to MDs of 0.48° (95% CI -0.13, 1.07°) and 1.22° (95% CI -0.51, 2.94°) in the SN-ML and SN-NL angles, respectively. No significant differences were seen in y-axis, facial axis angle, or posterior face height (P > 0.05). Similarly, no significant differences were found between cHG treatment and (i) addition of a lower utility arch, (ii) hp-HG treatment, and (iii) removable functional appliance treatment (P > 0.05 for all). Meta-regressions of patient age, sex, or duration and sensitivity analyses showed relative robustness, while our confidence in these estimates was low to very low due to the risk of bias, inconsistency, and imprecision. CONCLUSIONS: cHG on average is not consistently associated with posterior rotation of the jaws or a consistent increase in vertical facial dimensions among Class II patients. REGISTRATION: PROSPERO registration (CRD42022374603).

Cervical headgear effectiveness in distalizing molars in relation to patient compliance.

OBJECTIVES: The purpose of this study was to measure the effectiveness of the cervical headgear for distalizing first permanent maxillary molars in relation to hours of use. METHODS: This was a one-centre, prospective, clinical study conducted at the Department of Orthodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece. Participants (N = 26; 17 females, 9 males) were patients with no history of orthodontic treatment, no syndromes or clefts, and Angle's Class II malocclusion, where the treatment plan included a cervical headgear. They were instructed to wear the appliance for at least 12 h per day. A TheraMon® microsensor was embedded in the headgear's strap to objectively measure wear-time. To measure tooth movement, pre- and post-treatment digital models were superimposed, using the palate as a reference area; translation and rotation were measured along three axes. Superimposition and movement measurements were made with the Viewbox 4 software. RESULTS: Average treatment time and headgear wear were 130 days and 55 days, respectively, i.e. 10.1 h/day. During this period, distal movement averaged 1.75 mm with high variability (min 0.2 mm, max 4.5 mm). Distal tipping and rotation had an average of approximately 5 °C. Cumulative headgear wear was significantly correlated with distal movement (r2 = 0.32, P < .002), distal tipping (r2 = 0.27, P < .01), and distal rotation around the long axis of the tooth (r2 = 0.20, P < .05). CONCLUSION: Compliance is critical for having a successful clinical outcome. Distalization of the molar with a cervical headgear is correlated with the cumulative hours of appliance use, with hours per day being a weaker predictor.

A Helmet of Her Own?: A Qualitative Study of Key Stakeholder Perspectives on Headgear in Girls' Lacrosse.

Introduction: Despite the high incidence rate of concussions in women's lacrosse, there is substantial push back against the use of helmets at the secondary educational and collegiate levels in the U.S. This study examines the social factors influencing the controversy surrounding the use of protective headgear and how the recent development of headgear specific to the women's game has shaped ongoing debates. Methods: Purposeful sampling was used to recruit interviewees with research knowledge or firsthand experience with injury and protective headgear in girls' lacrosse. Semistructured interviews were conducted and subsequently coded using qualitative research software to identify key themes and patterns. Results: Sixteen respondents participated in this study; 4 players, 4 coaches, 3 researchers, and 5 administrators were represented in this sample. Overarching themes identified across these interviews included playing through pain, health consequences of concussions, concussion prevention strategies and the potential role of headgear, symbolism of headgear, gender dynamics, autonomy, and decision making. Conclusions: This qualitative study shows the importance of attention to the unique history of girls' lacrosse and current narratives surrounding headgear in the sport. There is a need for greater collaboration and consensus between all relevant groups to ensure that headgear best addresses the concerns of the people who will ultimately be using it. Future qualitative research should build on this preliminary study with a larger and more diverse sample to follow up on key themes and ultimately inform effective safety measures to protect athletes.

Conventional Twin-Block Versus Cervical Headgear and Twin-Block Combination: Therapeutic Effects on the Craniofacial Structures in Growing Subjects.

Objective: To compare the short-term effects of the conventional twin-block (TB) appliance and the cervical headgear TB (CHG-TB) appliance on craniofacial structures. Methods: The retrospective controlled study examined lateral cephalograms taken from 46 growing subjects. Individuals were divided into two groups according to the treatment. Group I consisted of 15 individuals (9 girls, 6 boys, mean age: 12.34±1.23 years) treated with the TB appliance and Group II consisted of 16 individuals (9 girls, 7 boys) treated with the CHG-TB appliance (mean age: 12.50±1.30 years). To distinguish the treatment effects of these appliances on growth, a control group of 15 untreated individuals (9 girls, 6 boys, mean age: 11.82±1.16 years) was included from the archives. Results: Significant improvements were found in the interdental and maxillo-mandibular measurements in the treatment groups (p<0.001). Significant differences were observed in the SNA, SN/PP, and SN/GoGn values in the CHG-TB group compared to other groups (p<0.05). The mandible showed a significant downward movement in both treatment groups compared with the control group (p<0.001), while the change in SNB angle was statistically significant only in the TB group compared to the control group (p<0.05). Lower incisors showed significant proclination only in the TB group (p<0.05). Conclusion: The CHG-TB appliance was found to be more effective in limiting maxillary growth and preventing lower incisor proclination compared with the TB appliance, whereas the TB appliance was more effective in anterior mandibular movement.

Effects of headgear timing on dental arch changes from 7 to 18 years of age: a follow-up study.

BACKGROUND: Dental arch effects after cervical headgear (CHG) treatment have been researched from several different perspectives. However, the long-term effects of CHG timing are still unknown. OBJECTIVES: To analyse the long-term effects of CHG timing on dental arches. MATERIAL AND METHODS: A total of 67 children with Angle Class II malocclusion comprised the study group in this trial. The participants were randomized into two equal-sized groups. In the early group (EG, n = 33), treatment was started after the eruption of the first upper molars. In the later-timed group (LG, n = 34), treatment was started 18 months later compared with the early group. Long-term effects were measured from dental casts taken at five time points between 7 and 18 years of age. RESULTS: The total maxillary dental arch length was achieved earlier, the gained length persisted better in the long term, and significantly more space was achieved in EG compared with LG (P = .048). The intermolar width in the maxillary dental arch was more stable and was reached earlier in EG compared with LG (P = .002). The results showed that in terms of total mandibular arch length increases, EG males benefited the most and LG females the least from CHG treatment (P = .031). CONCLUSIONS: Both genders benefited from earlier CHG treatment. The maxillary dental arches remained longer, and the final width was gained earlier in EG compared with LG.

Effects of Alt-RAMEC protocol with facemask therapy in cleft lip palate patients in a sample of Pakistani population.

OBJECTIVE: The objective of the study is to evaluate the skeletal, dentoalveolar and soft tissue changes before and after treatment with Alt-RAMEC protocol and protraction headgear in comparison to the controls. MATERIAL AND METHODS: A quasi experimental study was conducted in the orthodontic department on 60 patients of cleft lip and palate. These patients were divided into two groups. Group I was the Alt-RAMEC group that underwent Alt-RAMEC protocol followed by facemask therapy while group II was the control group that underwent RME and facemask therapy. Total treatment time in both the groups was approximately 6 to 7 months. Mean and standard deviation was calculated for all the quantitative variables. Pre and post treatment changes between treatment and control groups were made using paired t-test. Intergroup comparison between treatment and control group was analyzed using independent t-test. Significance for all tests was predetermined at a P-value of ≤ 0.05. RESULTS: The Alt-RAMEC group showed significant forward movement of maxilla and improvement in the maxillary base. A remarkable improvement in SNA was seen. The overall outcome was better maxillo-mandibular relationship as shown by positive ANB values and angle of convexity. More effect on maxilla and least effect on mandible was notified with Alt-RAMEC protocol and facemask therapy. Improvement in transverse relationship was also evident in the Alt-RAMEC group. CONCLUSION: Alt-RAMEC protocol in combination with protraction headgear is a better alternative to treat cleft lip and palate patients in comparison to the conventional protocol.

Third molar position after completion of orthodontic treatment: a prospective follow-up.

OBJECTIVES: To prospectively follow up a previously reported sample, analyzing (1) changes in third molar (M3) position after completion of 2 different types of orthodontic treatment: (2) non-extraction treatment with (HG) vs without cervical headgear (non-HG) and (3) first or second premolar extractions (PM1-2) compared to a non-extraction group (NE). METHODS: A total of 474 patients were prospectively followed up. Panoramic radiographs were taken pre- (T1), post-treatment (T2) and at follow-up (T3). T3 records (a mean of three years after treatment) were available for 135 (HG vs non-HG) and 134 patients (PM1-2 vs NE), respectively. Angulation, vertical position, relation with the mandibular canal and mineralization status of M3 at T2 and T3 were statistically compared. RESULTS: The HG group presented more M3 with ideal vertical orientation at T3. In NE-cases, further improvement in angulation and orientation can be expected after debonding, as well as a deterioration in the relationship with the mandibular canal. Extractions accelerated upper M3 vertical eruption and PM2 extractions led to long-term larger lower retromolar spaces. CONCLUSIONS: The use of cervical headgear increased upper M3 uprighting three years after debonding, while little changes in M3 position were found after orthodontic treatment with extractions. However, PM2 extractions led to larger retromolar spaces and better M3 angulation in the long term.

Long-term stability after high-pull headgear combined with fixed appliances: A retrospective cohort study of growing class II patients.

BACKGROUND: High-pull headgear with fixed appliances is a common therapeutic plan in class II growing individuals, especially in those with a tendency to hyperdivergence. The stability of this approach has not been adequately assessed in the long-term. The aim of this retrospective study was to assess that long-term stability by means of lateral cephalograms. Seventy-four consecutive patients were included and examined at three time-points: pre-treatment (T1), end of treatment (T2), and at least five years post-treatment (T3). RESULTS: The average initial age of the sample was 9.3 years (standard deviation, SD: 1.6). At T1, the mean ANB was 5.1 degrees (SD: 1.6), the mean SN-PP 5.6 (SD: 3.0) and the mean MP-PP 28.7 degrees (SD: 4.0). The median follow-up time was 8.6 years with an interquartile range of 2.7. A statistically significant, but of small magnitude increase in the SNA angle was noted at T3 compared to T2 after adjusting for the pre-treatment SNA value (mean difference (MD): 0.75; 95% CI: 0.34, 1.15; P<0.001). The inclination of the palatal plane appeared stable in the post-treatment period, while the MP-PP angle showed scarce evidence of decrease during the post-treatment period after adjusting for sex, pre-treatment SNA and SN-PP angles (MD: -2.29; 95% CI: -2.85, -1.74; P<0.001). CONCLUSIONS: The sagittal position of the maxilla and the inclination of the palatal plane appeared to be stable after treatment with high-pull headgear and fixed appliances in the long-term. Continuous mandibular growth, both sagittaly and vertically, contributed to the stability of class II correction.

Padded Helmet Shell Covers in American Football: A Comprehensive Laboratory Evaluation with Preliminary On-Field Findings.

Protective headgear effects measured in the laboratory may not always translate to the field. In this study, we evaluated the impact attenuation capabilities of a commercially available padded helmet shell cover in the laboratory and on the field. In the laboratory, we evaluated the padded helmet shell cover's efficacy in attenuating impact magnitude across six impact locations and three impact velocities when equipped to three different helmet models. In a preliminary on-field investigation, we used instrumented mouthguards to monitor head impact magnitude in collegiate linebackers during practice sessions while not wearing the padded helmet shell covers (i.e., bare helmets) for one season and whilst wearing the padded helmet shell covers for another season. The addition of the padded helmet shell cover was effective in attenuating the magnitude of angular head accelerations and two brain injury risk metrics (DAMAGE, HARM) across most laboratory impact conditions, but did not significantly attenuate linear head accelerations for all helmets. Overall, HARM values were reduced in laboratory impact tests by an average of 25% at 3.5 m/s (range: 9.7 to 39.6%), 18% at 5.5 m/s (range: - 5.5 to 40.5%), and 10% at 7.4 m/s (range: - 6.0 to 31.0%). However, on the field, no significant differences in any measure of head impact magnitude were observed between the bare helmet impacts and padded helmet impacts. Further laboratory tests were conducted to evaluate the ability of the padded helmet shell cover to maintain its performance after exposure to repeated, successive impacts and across a range of temperatures. This research provides a detailed assessment of padded helmet shell covers and supports the continuation of in vivo helmet research to validate laboratory testing results.

Evaluation of the Patient-Reported Outcome Measures (PROMs) With Temporary Skeletal Anchorage Devices in Fixed Orthodontic Treatment: A Systematic Review.

Analysis of patient-reported outcome measures (PROMs) is essential to ensure that the skeletal and traditional anchoring methods are appropriately and effectively utilized in the context of patient acceptance and satisfaction. This review's objective was to assess the available data on the levels of discomfort, soft-tissue irritation, functional impairment, and other patient-reported outcomes related to the usage of mini-implants in the context of fixed orthodontic treatment for adult patients. A total of seven electronic bibliographic databases were searched between January 1995 and February 2022. Moreover, a manual search was done in the selected orthodontic journals. This systematic review (SR) covered cohort studies, retrospective studies, randomized clinical trials (RCTs), and controlled clinical trials (CCTs) that studied the use of mini-implants, mini-plates, or onplants as anchorage devices on patients receiving orthodontic treatment. The risk of bias was assessed using Cochrane's risk of bias tool (RoB2 tool). Three RCTs and two cohorts were included in this SR with a total of 468 patients. Three of the four included studies were at high risk of bias. The pain level was in the "mild-to-moderate" category on the first day following the insertion of mini-implants, then decreased to a mild level from the fifth day to the seventh day of insertion (mean values are 36.61, 16.36, and 11.33, respectively). The levels of functional impairments were found to be located between the "mild-to-moderate" and "moderate" categories after the placement of mini-plates and intermaxillary fixation screws, while they experienced a mild level with mini-implants. The greatest pain levels were found after the insertion of the temporary anchorage devices (TADs) and then decreased until they became mild or disappeared completely after one month. Speaking, chewing, and cleaning difficulties were more problematic when using TADs compared to conventional anchorage. To obtain good evidence in this area, more high-quality RCTs are needed.

Topologically associating domains in the POLLED region are the same for Angus- and Brahman-specific Hi-C reads from F1 hybrid fetal tissue.

Horns, a form of headgear carried by Bovidae, have ethical and economic implications for ruminant production species such as cattle and goats. Hornless (polled) individuals are preferred. In cattle, four genetic variants (Celtic, Friesian, Mongolian and Guarani) are associated with the polled phenotype, which are clustered in a 300-kb region on chromosome 1. As the variants are intergenic, the functional effect is unknown. The aim of this study was to determine if the POLLED variants affect chromatin structure or disrupt enhancers using publicly available data. Topologically associating domains (TADs) were analyzed using Angus- and Brahman-specific Hi-C reads from lung tissue of an Angus (Celtic allele) cross Brahman (horned) fetus. Predicted bovine enhancers and chromatin immunoprecipitation sequencing peaks for histone modifications associated with enhancers (H3K27ac and H3K4me1) were mapped to the POLLED region. TADs analyzed from Angus- and Brahman-specific Hi-C reads were the same, therefore, the Celtic variant does not appear to affect this level of chromatin structure. The Celtic variant is located in a different TAD from the Friesian, Mongolian, and Guarani variants. Predicted enhancers and histone modifications overlapped with the Guarani and Friesian variants but not the Celtic or Mongolian variants. This study provides insight into the mechanisms of the POLLED variants for disrupting horn development. These results should be validated using data produced from the horn bud region of horned and polled bovine fetuses.

A modelling framework for local thermal comfort assessment related to bicycle helmet use.

Thermal discomfort due to accumulated sweat increasing head skin wettedness may contribute to low wearing rates of bicycle helmets. Using curated data on human head sweating and helmet thermal properties, a modelling framework for the thermal comfort assessment of bicycle helmet use is proposed. Local sweat rates (LSR) at the head were predicted as the ratio to the gross sweat rate (GSR) of the whole body or by sudomotor sensitivity (SUD), the change in LSR per change in body core temperature (Δtre). Combining those local models with Δtre and GSR output from thermoregulation models, we simulated head sweating depending on the characteristics of the thermal environment, clothing, activity, and exposure duration. Local thermal comfort thresholds for head skin wettedness were derived in relation to thermal properties of bicycle helmets. The modelling framework was supplemented by regression equations predicting the wind-related reductions in thermal insulation and evaporative resistance of the headgear and boundary air layer, respectively. Comparing the predictions of local models coupled with different thermoregulation models to LSR measured at the frontal, lateral and medial head under bicycle helmet use revealed a large spread in LSR predictions predominantly determined by the local models and the considered head region. SUD tended to overestimate frontal LSR but performed better for lateral and medial head regions, whereas predictions by LSR/GSR ratios were lower and agreed better with measured frontal LSR. However, even for the best models root mean squared prediction errors exceeded experimental SD by 18-30%. From the high correlation (R > 0.9) of skin wettedness comfort thresholds with local sweating sensitivity reported for different body regions, we derived a threshold value of 0.37 for head skin wettedness. We illustrate the application of the modelling framework using a commuter-cycling scenario, and discuss its potential as well as the needs for further research.

Protraction Headgear Compliance and Orthognathic Surgery in Patients With Cleft Lip and Palate.

Assess cephalometric parameters and the need for orthognathic surgery (OS) and its relationship with compliance in protraction headgear (PHG).Retrospective case series.Hospital cleft-craniofacial center.23 patients with nonsyndromic cleft lip and palate and history of lip and palate repair.Patients received PHG and orthodontic treatment. Compliant patients were compared to patients that were not. Protraction was applied with 170-gram elastics and patients were instructed to wear for at least 12 hours daily.Cephalometric measurements at initial (T1), post-PHG (T2), and pre-surgical or post-orthodontic treatment (T3) of at least age 15 for females and 17 for males and the presence of OS were compared.83% (19) of patients reported compliance with therapy. Of those compliant, 68% (13) had OS and 32% (6) did not (P = .99). Inter-group comparisons at T1 between compliant and noncompliant showed no significant differences and the non-OS patients started with larger nasolabial angles (P < .05). At T2, there were no significant cephalometric differences between groups. At T3, compliant patients showed significantly more upper incisor proclination than noncompliant patients. Between OS and non-OS, OS patients had significantly decreased ANB, Wits, convexity, overjet, and FMA and larger nasolabial angles (P < .05).Patients compliant with PHG showed no difference in the need for OS. However, after orthodontic treatment, compliant patients showed more upper incisor proclination and OS patients with decreased ANB, Wits, convexity, overjet, FMA, and larger nasolabial angles.