3D printable adhesive elastomers with dynamic covalent bond rearrangement.

Repairable adhesive elastomers are emerging materials employed in compelling applications such as soft robotics, biosensing, tissue regeneration, and wearable electronics. Facilitating adhesion requires strong interactions, while self-healing requires bond dynamicity. This contrast in desired bond characteristics presents a challenge in the design of healable adhesive elastomers. Furthermore, 3D printability of this novel class of materials has received limited attention, restricting the potential design space of as-built geometries. Here, we report a series of 3D-printable elastomeric materials with self-healing ability and adhesive properties. Repairability is obtained using Thiol-Michael dynamic crosslinkers incorporated into the polymer backbone, while adhesion is facilitated with acrylate monomers. Elastomeric materials with excellent elongation up to 2000%, self-healing stress recovery >95%, and strong adhesion with metallic and polymeric surfaces are demonstrated. Complex functional structures are successfully 3D printed using a commercial digital light processing (DLP) printer. Shape-selective lifting of low surface energy poly(tetrafluoroethylene) objects is achieved using soft robotic actuators with interchangeable 3D-printed adhesive end effectors, wherein tailored contour matching leads to increased adhesion and successful lifting capacity. The demonstrated utility of these adhesive elastomers provides unique capabilities to easily program soft robot functionality.

Climate warming and increasing Vibrio vulnificus infections in North America.

Vibrio vulnificus is an opportunistic bacterial pathogen, occurring in warm low-salinity waters. V. vulnificus wound infections due to seawater exposure are infrequent but mortality rates are high (~ 18%). Seawater bacterial concentrations are increasing but changing disease pattern assessments or climate change projections are rare. Here, using a 30-year database of V. vulnificus cases for the Eastern USA, changing disease distribution was assessed. An ecological niche model was developed, trained and validated to identify links to oceanographic and climate data. This model was used to predict future disease distribution using data simulated by seven Global Climate Models (GCMs) which belong to the newest Coupled Model Intercomparison Project (CMIP6). Risk was estimated by calculating the total population within 200 km of the disease distribution. Predictions were generated for different "pathways" of global socioeconomic development which incorporate projections of greenhouse gas emissions and demographic change. In Eastern USA between 1988 and 2018, V. vulnificus wound infections increased eightfold (10-80 cases p.a.) and the northern case limit shifted northwards 48 km p.a. By 2041-2060, V. vulnificus infections may expand their current range to encompass major population centres around New York (40.7°N). Combined with a growing and increasingly elderly population, annual case numbers may double. By 2081-2100 V. vulnificus infections may be present in every Eastern USA State under medium-to-high future emissions and warming. The projected expansion of V. vulnificus wound infections stresses the need for increased individual and public health awareness in these areas.

Current Siberian heating is unprecedented during the past seven millennia.

The Arctic is warming faster than any other region on Earth. Putting this rapid warming into perspective is challenging because instrumental records are often short or incomplete in polar regions and precisely-dated temperature proxies with high temporal resolution are largely lacking. Here, we provide this long-term perspective by reconstructing past summer temperature variability at Yamal Peninsula - a hotspot of recent warming - over the past 7638 years using annually resolved tree-ring records. We demonstrate that the recent anthropogenic warming interrupted a multi-millennial cooling trend. We find the industrial-era warming to be unprecedented in rate and to have elevated the summer temperature to levels above those reconstructed for the past seven millennia (in both 30-year mean and the frequency of extreme summers). This is undoubtedly of concern for the natural and human systems that are being impacted by climatic changes that lie outside the envelope of natural climatic variations for this region.

Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years.

Asian summer monsoon (ASM) variability and its long-term ecological and societal impacts extending back to Neolithic times are poorly understood due to a lack of high-resolution climate proxy data. Here, we present a precisely dated and well-calibrated tree-ring stable isotope chronology from the Tibetan Plateau with 1- to 5-y resolution that reflects high- to low-frequency ASM variability from 4680 BCE to 2011 CE. Superimposed on a persistent drying trend since the mid-Holocene, a rapid decrease in moisture availability between ∼2000 and ∼1500 BCE caused a dry hydroclimatic regime from ∼1675 to ∼1185 BCE, with mean precipitation estimated at 42 ± 4% and 5 ± 2% lower than during the mid-Holocene and the instrumental period, respectively. This second-millennium-BCE megadrought marks the mid-to late Holocene transition, during which regional forests declined and enhanced aeolian activity affected northern Chinese ecosystems. We argue that this abrupt aridification starting ∼2000 BCE contributed to the shift of Neolithic cultures in northern China and likely triggered human migration and societal transformation.

Differences in Female and Male-to-Female Transgender Facial Skin Micro-Vessel Density.

Importance: The risk of hematoma formation after rhytidectomy is gender associated and can lead to postoperative complications. The literature to help explain and elucidate the mechanism behind this gender-associated risk is poorly developed and requires further investigation. Objective: The objective of this study was to compare facial skin micro-vessel density of female and male-to-female (MTF) transgender patients undergoing rhytidectomy to better understand the mechanism of gender-correlated hematoma risk factors. The authors hypothesized that transgender patients would have higher micro-vessel density compared with female patients. Design, Setting, and Participants: This was a prospective histopathological analysis of pre- and post-auricular facial skin samples from patients undergoing primary rhytidectomy. Patient clinical data and skin samples were collected. Histopathological slides were prepared and stained with CD-31, a marker of vessel endothelium, followed by image analysis allowing for micro-vessel stained pixel counts and calculated pixel density comparisons at a single academic hospital. Female, MTF transgender, and male patients >18 years of age were studied. Exposure: Patients undergoing primary rhytidectomy between 2015 and 2018. Main Outcomes: Gender-associated pre- and post-auricular micro-vessel pixel density. Results: Forty-one patients contributed skin samples for analysis. Post-auricular micro-vessel pixel density was greater than pre-auricular density (mean difference post-pre 0.359 percentage points [p.p.], standard error [SE] = 0.135, p = 0.009). The mean post-auricular micro-vessel pixel density was 1.60% (SE = 0.13 p.p.), 2.16% (SE = 0.19 p.p.), and 2.77% (SE = 0.34 p.p.) for female, transgender, and male patients, respectively (p = 0.016). Pre-auricular micro-vessel pixel density showed no difference among females, males, and transgender patients (p = 0.30). Gender was a strong predictor of increased post-auricular micro-vessel pixel density on stepwise linear regression, but it did not predict pre-auricular micro-vessel density. Both preoperative hair removal and a history of hypertension were associated with increased pre-auricular micro-vessel density. Conclusions and Relevance: Facial skin micro-vessel density differs by gender, in addition to pre- and post-auricular locations in patients undergoing rhytidectomy.

Version 4 of the CRU TS monthly high-resolution gridded multivariate climate dataset.

CRU TS (Climatic Research Unit gridded Time Series) is a widely used climate dataset on a 0.5° latitude by 0.5° longitude grid over all land domains of the world except Antarctica. It is derived by the interpolation of monthly climate anomalies from extensive networks of weather station observations. Here we describe the construction of a major new version, CRU TS v4. It is updated to span 1901-2018 by the inclusion of additional station observations, and it will be updated annually. The interpolation process has been changed to use angular-distance weighting (ADW), and the production of secondary variables has been revised to better suit this approach. This implementation of ADW provides improved traceability between each gridded value and the input observations, and allows more informative diagnostics that dataset users can utilise to assess how dataset quality might vary geographically.

Limiting global-mean temperature increase to 1.5-2 °C could reduce the incidence and spatial spread of dengue fever in Latin America.

The Paris Climate Agreement aims to hold global-mean temperature well below 2 °C and to pursue efforts to limit it to 1.5 °C above preindustrial levels. While it is recognized that there are benefits for human health in limiting global warming to 1.5 °C, the magnitude with which those societal benefits will be accrued remains unquantified. Crucial to public health preparedness and response is the understanding and quantification of such impacts at different levels of warming. Using dengue in Latin America as a study case, a climate-driven dengue generalized additive mixed model was developed to predict global warming impacts using five different global circulation models, all scaled to represent multiple global-mean temperature assumptions. We show that policies to limit global warming to 2 °C could reduce dengue cases by about 2.8 (0.8-7.4) million cases per year by the end of the century compared with a no-policy scenario that warms by 3.7 °C. Limiting warming further to 1.5 °C produces an additional drop in cases of about 0.5 (0.2-1.1) million per year. Furthermore, we found that by limiting global warming we can limit the expansion of the disease toward areas where incidence is currently low. We anticipate our study to be a starting point for more comprehensive studies incorporating socioeconomic scenarios and how they may further impact dengue incidence. Our results demonstrate that although future climate change may amplify dengue transmission in the region, impacts may be avoided by constraining the level of warming.

Iliac crest bone grafting for mandibular reconstruction: 10-year experience outcomes.

PURPOSE: To evaluate 10-year patient data related to mandibular reconstruction with NVBG at a tertiary academic center. PATIENTS AND METHODS: Sixty patients with mandibular mandibular reconstruction were included. Patients were divided to continuity defect and non-continuity defect. Pathology lesion, immediate reconstruction, smoking habit, medical comorbidities, site and size of the defect, surgical approach, intraoperative perforation, cadaveric bone use, and maxilla-mandibular fixation use were analyzed as factors of influence on success. Success was defined as maintenance of more than 50% of graft for non-continuity defects (NCD) and bone continuity and stability for continuity defect (CD), and absence of infection on last follow up upon clinical and radiographic examination. Complications were classified as minor or major. RESULTS: The reconstruction was successful in 28 (87%) of CD patients and 23 (82.1%) of NCD patients. Analyses showed that the size of defect was significantly associated with failure. All 4 failed cases of CD had defects more than 9 cm. Four patients had major complications and 43 minor complication. CONCLUSIONS: Nonvascularized iliac crest bone grafts are highly successful in mandibular continuity reconstruction for non-Cancer patients and should be considered as first choice for defects less than 9 cm. They are less predictable for defects larger than 9 cm but can be considered in these cases with osteoconductive cribs. Symphysis involvement may or may not be associated with lower success rate if our protocol is followed.

The surgical management of cephalalgia.

PURPOSE OF REVIEW: Management of headache disorders is not part of most craniomaxillofacial surgery practices; however there are certain indications for surgical management of headaches by the craniomaxillofacial surgeon. RECENT FINDINGS: Migraine headaches are the most amenable to surgical management and while the exact mechanism of migraine is unknown, a central or peripheral trigger such as compressive neuropathy of trigeminal nerve branches leading to neurogenic inflammation has been suggested. The primary management for episodic migraine headache should be lifestyle modification and medication, whereas for chronic migraine (>15 headache days/month) use of medication and botulinum neurotoxin is effective, whereas some patients may choose to explore surgical options. Trigger site decompression for chronic migraine surgically relieves anatomic impingement at various sites and has been shown to reduce by at least 50% the frequency, intensity, and duration of headaches in over 85% and elimination of headaches in almost 60%. Trigger points may also lead to exacerbation of cluster headaches and treatment with botulinum neurotoxin may reduce attacks. SUMMARY: Trigger site decompression is an effective treatment for chronic migraine, as are botulinum neurotoxin injections in reducing attacks in cluster headaches. The craniomaxillofacial surgeon is uniquely qualified to treat these primary headache disorders.

Therapeutic applications of botulinum neurotoxins in head and neck disorders.

OBJECTIVE: The aim of this article is to review the mechanism of action, physiological effects, and therapeutic applications of botulinum neurotoxins in the head and neck area. STUDY DESIGN: An extensive literature search was performed using keywords. The resulting articles were analyzed for relevance in four areas: overview on botulinum neurotoxins, the role of botulinum neurotoxins in the management of salivary secretory disorders, the role of botulinum neurotoxins in the management of facial pain, and the role of botulinum neurotoxins in head and neck movement disorders. Institutional review board approval was not needed due the nature of the study. RESULTS: Botulinum neurotoxin therapy was demonstrated to be a valuable alternative to conventional medical therapy for many conditions affecting the head and neck area in terms of morbidly, mortality, and patient satisfaction with treatment outcomes. CONCLUSION: Botulinum neurotoxin therapy provides viable alternatives to traditional treatment modalities for some conditions affecting the head and neck region that have neurological components. This therapy can overcome some of the morbidities associated with conventional therapy. More research is needed to determine the ideal doses of botulinum neurotoxin to treat different diseases affecting the head and neck regions.

A 3,500-year tree-ring record of annual precipitation on the northeastern Tibetan Plateau.

An annually resolved and absolutely dated ring-width chronology spanning 4,500 y has been constructed using subfossil, archaeological, and living-tree juniper samples from the northeastern Tibetan Plateau. The chronology represents changing mean annual precipitation and is most reliable after 1500 B.C. Reconstructed precipitation for this period displays a trend toward more moist conditions: the last 10-, 25-, and 50-y periods all appear to be the wettest in at least three and a half millennia. Notable historical dry periods occurred in the 4th century BCE and in the second half of the 15th century CE. The driest individual year reconstructed (since 1500 B.C.) is 1048 B.C., whereas the wettest is 2010. Precipitation variability in this region appears not to be associated with inferred changes in Asian monsoon intensity during recent millennia. The chronology displays a statistical association with the multidecadal and longer-term variability of reconstructed mean Northern Hemisphere temperatures over the last two millennia. This suggests that any further large-scale warming might be associated with even greater moisture supply in this region.

Large-scale variations in the vegetation growing season and annual cycle of atmospheric CO2 at high northern latitudes from 1950 to 2011.

We combine satellite and ground observations during 1950-2011 to study the long-term links between multiple climate (air temperature and cryospheric dynamics) and vegetation (greenness and atmospheric CO(2) concentrations) indicators of the growing season of northern ecosystems (>45°N) and their connection with the carbon cycle. During the last three decades, the thermal potential growing season has lengthened by about 10.5 days (P < 0.01, 1982-2011), which is unprecedented in the context of the past 60 years. The overall lengthening has been stronger and more significant in Eurasia (12.6 days, P < 0.01) than North America (6.2 days, P > 0.05). The photosynthetic growing season has closely tracked the pace of warming and extension of the potential growing season in spring, but not in autumn when factors such as light and moisture limitation may constrain photosynthesis. The autumnal extension of the photosynthetic growing season since 1982 appears to be about half that of the thermal potential growing season, yielding a smaller lengthening of the photosynthetic growing season (6.7 days at the circumpolar scale, P < 0.01). Nevertheless, when integrated over the growing season, photosynthetic activity has closely followed the interannual variations and warming trend in cumulative growing season temperatures. This lengthening and intensification of the photosynthetic growing season, manifested principally over Eurasia rather than North America, is associated with a long-term increase (22.2% since 1972, P < 0.01) in the amplitude of the CO(2) annual cycle at northern latitudes. The springtime extension of the photosynthetic and potential growing seasons has apparently stimulated earlier and stronger net CO(2) uptake by northern ecosystems, while the autumnal extension is associated with an earlier net release of CO(2) to the atmosphere. These contrasting responses may be critical in determining the impact of continued warming on northern terrestrial ecosystems and the carbon cycle.

Anatomy of the auriculotemporal nerve: variations in its relationship to the superficial temporal artery and implications for the treatment of migraine headaches.

BACKGROUND: Clinical experience with surgical decompression of specific peripheral nerves in the head and neck for the relief of migraine headache symptoms has proven to be effective in most patients. Some patients, however, continue to have residual symptoms after these procedures. In an effort to better understand potential etiologies for failure of treatment, an investigation was performed to determine whether or not vascular-mediated peripheral trigger points exist that have heretofore been undescribed that may be contributing to persistent symptomatology. One such potential trigger point is the superficial temporal artery's interaction with the auriculotemporal nerve. A cadaveric investigation was performed to advance this anatomical understanding of this relationship. METHODS: Both sides of 25 fresh cadaveric heads were dissected in the preauricular and temporal regions. The superficial temporal artery and auriculotemporal nerve were identified and dissected both proximally and distally. Their relationship was examined, and a topographical map of their intersections was generated. RESULTS: The auriculotemporal nerve and superficial temporal artery run together in the superficial soft tissue in the preauricular and temple regions. A contiguous relationship between the two was found in 17 hemiheads (34.0 percent). CONCLUSIONS: There are variations in the relationship between the auriculotemporal nerve and the superficial temporal artery. These variations may serve as an anatomical explanation for this point as a source of migraine headaches in some patients. A topographical map of the relationship between these two structures may serve as a guide for surgeons interested in decompressing the nerve from the artery when indicated.

Phase 2, double-blind, placebo-controlled, dose-response trial of intravenous adenosine for perioperative analgesia.

BACKGROUND: Adenosine regulates pain transmission by actions at spinal, supraspinal, and peripheral sites. A few studies have suggested that administration of adenosine might be associated with anesthetic- and analgesic-sparing effects. The primary aim of this multicenter study was to determine the dose-response profile of adenosine with respect to perioperative analgesia. METHODS: Women undergoing major gynecologic surgery were enrolled. Subjects were randomly assigned to receive one of four doses of adenosine (25, 50, 100, or 200 microg x kg x min) or matching placebo. A dose-escalation cohort approach was followed. Study drug administration was started in the operating room at the time of skin incision and discontinued at the end of surgery. The anesthetic technique was standardized. Postoperative analgesia was provided with a standardized morphine patient-controlled analgesia system. Data were collected in the hospital and after discharge daily through postoperative day 7. RESULTS: A total of 166 subjects received treatment with study drug: 125 received adenosine and 41 received placebo. Except for height, there were no differences between treatment groups with respect to demographic or baseline characteristics. Cumulative opioid use during the initial 24-h period after extubation was not significantly different between treatment groups. There were also no differences between treatment groups with respect to cumulative anesthetic use, intraoperative opioid requirements, pain scores, sedation, time to readiness for discharge from the postanesthesia care unit, time to readiness for discharge from the hospital, opioid-related symptom distress scores, patient satisfaction with pain control, and occurrence of adverse events. CONCLUSIONS: There were no differences between placebo and adenosine with respect to efficacy and safety for perioperative analgesia.

Deep space neck infection: principles of surgical management.

Knowledge of the management of infections of the deep spaces of the neck is essential to the daily practice of oral and maxillofacial surgery. Timely decisions must be made through the acute course of the disease. Interventions must be performed with the appropriate surgical skill. The surgeon must decide on medical and surgical management, including antibiotic selection, how to employ supportive resuscitative care, when to operate, what procedures to perform, and how to secure the airway. To make these decisions the surgeon must understand the anatomy of the region and the etiology of infection, appropriate diagnostic workup, and medical and surgical management. This article provides a review of these pertinent topics.

Preparation of the neck for microvascular reconstruction of the head and neck.

Reconstruction of congenital, developmental, or acquired head and neck defects remains a significant challenge for the oral and maxillofacial surgeon. Microvascular free tissue transfer has several advantages over nonvascularized bone grafts and pedicled soft tissue flaps that currently make it the modality of choice for the reconstruction of extirpative defects of the head and neck. Preoperative planning must include detailed attention to the technical aspects of the microvascular procedure. This includes a thorough understanding of the vascular anatomy of the patient's neck; vascular anatomy of the various flaps including pedicle lengths; and a knowledge of how to facilitate microvascular surgery in the neck and to manage complicating factors in the difficult neck.

Computed tomographic angiography as an aid to clinical decision making in the selective management of penetrating injuries to the neck: a reduction in the need for operative exploration.

BACKGROUND: Improvements in imaging technology, particularly computed tomographic angiography (CTA), have altered the management of patients with penetrating injuries in the neck. The purpose of this retrospective study is to evaluate our 5-year experience with the management of penetrating injuries to the neck, to the further elucidate the role of CTA in clinical decision making, and to assess treatment outcome. METHODS: Clinical variables were collected and evaluated on all patients with penetrating injuries to the neck presenting to the Legacy Emanuel Hospital Trauma Service from 2000 to 2005. For comparison, the patients were divided into two groups based upon whether the patient had received a CTA before operative intervention: group 1, CTA; group 2, no CTA. A statistical analysis using the Fisher exact test and t test was performed to analyze whether the rate of neck exploration or the findings at the time of neck dissection were significantly different between the groups. RESULTS: Of the 120 consecutive patients with penetrating injuries to the neck, 55 were excluded from the study because the injury was superficial, the patient died before operative intervention, or they underwent emergent neck exploration to control hemorrhage. Sixty-five patients with neck injuries penetrating the platysma were identified that met the criteria for inclusion in the study. Group 1 (CTA) consisted of 24 patients and group 2 (no CTA) had 41 patients. Group 1 (CTA) had significantly fewer formal neck explorations (N = 6) compared with group 2 (no CTA) (N = 27) (p < 0.01). All six of the operations in the CTA group had clear indications for and positive findings on surgical exploration, and there were no clinically significant missed injuries. Of the 27 patients in group 2 who underwent neck exploration, only 14 had a positive finding, 4 of which were simply superficial bleeding vessels, yielding a rate of negative neck exploration of 48%, compared with 0% for group 1 (p < 0.01). The number of adjunctive studies such as esophagography, angiography, and various endoscopic procedures were similar in both groups. CONCLUSION: The management of stable patients with penetrating injuries to the neck that penetrate the platysma has evolved at our institution into selective surgical intervention based on clinical examination and CTA. The use of CTA has resulted in fewer formal neck explorations and virtual elimination of negative exploratory surgery.

Management of penetrating neck injuries: a new paradigm for civilian trauma.

PURPOSE: Improvements in imaging technology, particularly computed tomographic angiography (CTA), have altered the management of patients with penetrating neck injuries. Although some centers still advocate routine exploration for all zone 2 neck injuries penetrating the platysma, many civilian centers in the United States have adopted a policy of selective exploration based on clinical and radiographic examination. The purpose of this retrospective study is to evaluate our 5-year experience with the management of penetrating neck injuries, to further elucidate the role of CTA in clinical decision-making, and to assess treatment outcome. PATIENTS AND METHODS: One hundred thirty-four consecutive patients were identified from the Legacy Emanuel Trauma Registry as having sustained penetrating neck injuries from 2000 to 2005. Using data collected from the Trauma Registry, as well as individual chart notes and electronic records, variables were collected and evaluated including age, gender, mechanism of injury, number of associated injuries, and the Injury Severity Score, Glasgow Coma Scale on admission, initial hematocrit, airway management techniques, diagnostic and therapeutic modalities, missed injuries, length of hospital stay, disposition, and outcome. Descriptive statistics were used to describe demographics, treatment, and outcome. RESULTS: One hundred twenty patients met the inclusion criteria, 55 of which had only superficial injuries that did not penetrate the platysma. The primary study group consisted of 65 patients who sustained more significant injuries that violated the platysma including deep, complex, and/or avulsive wounds, vascular injuries, injuries to the aerodigestive tract, musculoskeletal system, cranial nerves, or thyroid gland. The overall mortality rate for the 65 patients with injuries penetrating the platysma was 3.0% (n = 2). Complications occurred in 7 of the surviving 63 patients (10.7%): 2 patients with zone 3 internal carotid artery injuries developed hemispheric ischemic infarcts and hemiplagia; as well as other complications including: infection (n = 2); deep venous thrombosis (n = 1); aspiration pneumonia (n = 1); and hematoma (n = 1). All surviving patients except the 2 stroke patients eventually healed uneventfully without significant functional deficit. The use of CTA as a guide to clinical decision-making led to a significant decrease in the number of neck explorations performed and a virtual elimination of negative neck explorations. CONCLUSION: The management of stable patients with neck injuries that penetrate the platysma has evolved at our institution into selective surgical intervention based on clinical examination and CTA and has resulted in minimal morbidity and mortality.