22 research outputs found
Halogens as tracers of protosolar nebula material in comet 67P/Churyumov–Gerasimenko
We report the first in situ detection of halogens in a cometary coma, that of 67P/ChuryumovGerasimenko. Neutral gas mass spectra collected by the European Space Agency’s Rosetta spacecraft during four periods of interest from the first comet encounter up to perihelion indicate that the main halogen-bearing compounds are HF, HCl and HBr. The bulk elemental abundances relative to oxygen are ~8.9 × 10⁻⁵ for F/O, ~1.2 × 10⁻⁴ for Cl/O and ~2.5 × 10⁻⁶ for Br/O, for the volatile fraction of the comet. The cometary isotopic ratios for ³⁷Cl/³⁵Cl and ⁸¹Br/⁷⁹Br match the Solar system values within the error margins. The observations point to an origin of the hydrogen halides in molecular cloud chemistry, with frozen hydrogen halides on dust grains, and a subsequent incorporation into comets as the cloud condensed and the Solar system formed
The Comet Interceptor Mission
Here we describe the novel, multi-point Comet Interceptor mission. It is dedicated to the exploration of a little-processed long-period comet, possibly entering the inner Solar System for the first time, or to encounter an interstellar object originating at another star. The objectives of the mission are to address the following questions: What are the surface composition, shape, morphology, and structure of the target object? What is the composition of the gas and dust in the coma, its connection to the nucleus, and the nature of its interaction with the solar wind? The mission was proposed to the European Space Agency in 2018, and formally adopted by the agency in June 2022, for launch in 2029 together with the Ariel mission. Comet Interceptor will take advantage of the opportunity presented by ESA’s F-Class call for fast, flexible, low-cost missions to which it was proposed. The call required a launch to a halo orbit around the Sun-Earth L2 point. The mission can take advantage of this placement to wait for the discovery of a suitable comet reachable with its minimum ΔV capability of 600 ms−1. Comet Interceptor will be unique in encountering and studying, at a nominal closest approach distance of 1000 km, a comet that represents a near-pristine sample of material from the formation of the Solar System. It will also add a capability that no previous cometary mission has had, which is to deploy two sub-probes – B1, provided by the Japanese space agency, JAXA, and B2 – that will follow different trajectories through the coma. While the main probe passes at a nominal 1000 km distance, probes B1 and B2 will follow different chords through the coma at distances of 850 km and 400 km, respectively. The result will be unique, simultaneous, spatially resolved information of the 3-dimensional properties of the target comet and its interaction with the space environment. We present the mission’s science background leading to these objectives, as well as an overview of the scientific instruments, mission design, and schedule
Bilateral cleft lip repair
Repair of a bilateral cleft lip remains a big challenge. We describe our approach based on the bilateral cleft lip repair by Fisher. In this repair, the red lip is made from the lateral lip elements only, and continuity of the orbicularis oris muscle is achieved. Tips are given to avoid a whistle notch deformity or too much fullness of the median tubercle. The nose remains the main stigma for patients with complete bilateral lips, deserving an equal amount of attention as the lip during the repair. A method for optimal primary correction is presented, while avoiding additional scars and damage that will complicate later surgery. The rotation of C-flaps from the prolabium into the nostril sill can also help define the angle between columella and lip. Proper muscle release, repositioning, and approximation are the foundation of the lip repair
The effect of various muscle transfer procedures on eye closure and blinking in longstanding facial palsy patients
Background: Facial palsy causes paralytic lagophthalmos, which remarkably deteriorates a patient's quality of life. In cases where denervation time is over 18-24 months (longstanding facial palsy), a free or pedicled muscle transfer is needed to replace the denervated orbicularis oculi muscle. Purpose: The purpose of this systematic review is to investigate the effect of various eye sphincter substitution procedures (free or pedicled muscle transfers) in longstanding facial palsy patients on eye closure and blink. Methods: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we performed a systematic review of the Embase, Medline, Web of Science and Cochrane Library databases and Google Scholar. Our literature search yielded 4322 articles. Following a full-text review, 4 retrospective cohort studies and 21 case series were selected for this review. Meta-analyses using R package meta (version 6.5-0) were conducted. Main findings: All free and pedicled muscle transfers in this review showed an improvement in the scores and measurements on eye closure and blink. The pedicled temporalis muscle transfer was the procedure most commonly performed as eye reanimation surgery and showed consistent good results. Using the random effects model, the pooled effect of mean difference in lagophthalmos after gentle eye closure post-operatively versus pre-operatively (mm) in patients who received a pedicled (temporalis) muscle transfer was −6.19 (I2 = 85%, 95% CI: −7.89; −4.49) whereas it was −4.11 (I2 = 85%, 95% CI: −7.26; −0.95) for free (gracilis or platysma) muscle transfers. The pooled proportion of patients with complete eye closure after surgery was 0.69 (I2 = 49%, 95% CI: 0.54; 0.82) in patients who received a pedicled (temporalis) muscle transfer and 0.40 (I2 = 74%, 95% CI: 0.13; 0.74) in patients who received a free (platysma) muscle transfer.Conclusions: Unlike smile reanimation, dynamic eye closure and blink restoration are rather neglected topics in facial reanimation. The pedicled temporalis muscle transfer is often recommended as the first treatment of choice for eye reanimation in longstanding facial palsy patients since it is a reliable, straightforward procedure, that does not require complex microsurgery. However, with the advancements in the field of microsurgery, free muscle transfers are promising therapies, which may regenerate voluntary and spontaneous blinking.</p
Comparison of presurgical anthropometric measures of right and left complete unilateral cleft lip and/or palate
Background: Left clefts occur twice as frequently as right ones. The sidedness has been suggested to influence certain outcomes. Some surgeons ( potter a right deft more challenging to repair. This is often attributed to their reduced prevalence. The authors question whether this may be caused by morphologic differences. The authors' hypothesis is that there are anthropometric differences between left and right complete cleft lips.
Methods: Patients with complete unilateral cleft lip, with or without cleft palate, operated on at the age of 3 to 6 months, between 2000 and 2018, by a single surgeon, were included. Eight standardized anthropometric measurements of the cleft lip, collected just before cleft lip repair, compare lip and vermillion dimensions and ratios between left and right clefts.
Results: One hundred thirty-nine left and 80 right unilateral cleft lips were compared. A significant difference was found between left and right clefts for cleft-side to non-cleft-side ratios comparing the lateral lip element vertical heights and vermillion heights.
Conclusions: Patients with right cleft lips have a greater degree of lateral lip element hypoplasia, demonstrating greater deficiencies of lateral lip element vertical height and vermillion height when compared to patients with left clefts. This has clinical implications for preoperative assessment, choice of surgical technique, and postoperative and long-term outcomes
The effect of various muscle transfer procedures on eye closure and blinking in longstanding facial palsy patients
Background: Facial palsy causes paralytic lagophthalmos, which remarkably deteriorates a patient's quality of life. In cases where denervation time is over 18-24 months (longstanding facial palsy), a free or pedicled muscle transfer is needed to replace the denervated orbicularis oculi muscle. Purpose: The purpose of this systematic review is to investigate the effect of various eye sphincter substitution procedures (free or pedicled muscle transfers) in longstanding facial palsy patients on eye closure and blink. Methods: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we performed a systematic review of the Embase, Medline, Web of Science and Cochrane Library databases and Google Scholar. Our literature search yielded 4322 articles. Following a full-text review, 4 retrospective cohort studies and 21 case series were selected for this review. Meta-analyses using R package meta (version 6.5-0) were conducted. Main findings: All free and pedicled muscle transfers in this review showed an improvement in the scores and measurements on eye closure and blink. The pedicled temporalis muscle transfer was the procedure most commonly performed as eye reanimation surgery and showed consistent good results. Using the random effects model, the pooled effect of mean difference in lagophthalmos after gentle eye closure post-operatively versus pre-operatively (mm) in patients who received a pedicled (temporalis) muscle transfer was −6.19 (I2 = 85%, 95% CI: −7.89; −4.49) whereas it was −4.11 (I2 = 85%, 95% CI: −7.26; −0.95) for free (gracilis or platysma) muscle transfers. The pooled proportion of patients with complete eye closure after surgery was 0.69 (I2 = 49%, 95% CI: 0.54; 0.82) in patients who received a pedicled (temporalis) muscle transfer and 0.40 (I2 = 74%, 95% CI: 0.13; 0.74) in patients who received a free (platysma) muscle transfer.Conclusions: Unlike smile reanimation, dynamic eye closure and blink restoration are rather neglected topics in facial reanimation. The pedicled temporalis muscle transfer is often recommended as the first treatment of choice for eye reanimation in longstanding facial palsy patients since it is a reliable, straightforward procedure, that does not require complex microsurgery. However, with the advancements in the field of microsurgery, free muscle transfers are promising therapies, which may regenerate voluntary and spontaneous blinking.</p
A novel technique for preventive lymphovenous anastomosis : anastomosing a ligated lymphatic vessel
Background:
Lymphedema is defined as a chronic condition, caused by lymphostasis. A major part in the Western world consists of iatrogenic lymphedema caused by surgery to the lymph nodes of the axilla or groin. Prophylactic lymphovenous anastomosis (LVA) could be beneficial in the prevention of lymphedema of the extremities. These procedures require experienced supramicrosurgeons and can be time consuming, which might be the reasons why prophylactic LVA has not yet been widely implemented in the treatment of cancer. Due to the small diameter of lymphatic vessels, it remains challenging to identify the lumen, and therefore, anastomoses are prone to back wall stitching. Different inventive procedures have been described making use of stents or monofilament sutures.
Methods:
In this article, we describe a newly developed and straightforward technique for LVA in 4 patients who underwent an axilla dissection and 1 patient who underwent a dissection of the groin lymph nodes. This latter approach makes use of clipping of the lymphatic vessel during lymph node dissection, and remains ligated during anastomosis. The candidate vein was the V. thoracodorsalis for the axilla and the V. circumflexa superficialis for the groin. We describe the feasibility, average duration, and complications.
Results:
Performing an end-to-side anastomosis on a clipped lymphatic vessel minimizes the problem of back wall stitching as well as the trouble of finding the lumen due to collapsing of the vessel. The turgor of the lymphatic vessel is maintained and makes anastomosing easy. Average time for LVA was 33.4 minutes and 1 minor complication was seen.
Conclusion:
We believe that this approach might be of value in popularizing LVA in the treatment or prevention of different conditions such as breast cancer-related lymphedema
Case Report: Pediatric alloplastic nose reconstruction with a 3D printed patient specific titanium implant
An 11-year-old girl presented at the emergency service with a nasal defect caused by a dog bite in the midface. Autologous nose reconstruction in the pediatric population is challenging due to donor site morbidity and remaining facial growth. Temporary prosthetic treatment is difficult to accept due to problems with retention. We present an innovative solution using a 3D printed patient specific titanium implant for support of a nasal prosthesis. With preoperative 3-dimensional planning, the implant can be designed to find fixation in the areas with the best bone quality, avoid potential damage to tooth buds and dental roots and avoid interference to soft tissues such as the nasal septum. Clear communication between the anaplastologist, surgeon and medical engineer is crucial for treatment success. The impact of facial growth is still unclear and will have to be assessed
Takotsubo cardiomyopathy induced by epinephrine infiltration for liposuction : broken heart syndrome
Broken heart syndrome, more commonly known as Takotsubo cardiomyopathy (TCM), is an acute cardiac condition. It is characterized by regional cardiac wall motion abnormalities triggered by physical or emotional stress or administration of catecholamines such as epinephrine. The initial clinical presentation is similar to an acute coronary syndrome and must be ruled out. Visualization of the characteristic wall motion will trigger the diagnosis of TCM. In this case report, we present a 50-year-old woman with additional liposuction and fat grafting after autologous breast reconstruction. Shortly after infiltration with a solution containing epinephrine to achieve vasoconstriction, hypotension and bradycardia was noticed. This escalated into full asystole for which cardiac resuscitation was required. ST-elevations and a decrease in systolic function were clear indicators for urgent coronarography and ventriculography. These confirmed the diagnosis of TCM. Infiltration with epinephrine-containing products to achieve local vasoconstriction is used routinely. Medical professionals should be aware that this can trigger a TCM with an estimated mortality rate of 5%. No evidence of a specific preventive measure currently exists. We know that women with a neurologic or psychiatric comorbidity and high levels of stress are more at risk. Reducing stress and anxiolytic medication prior to surgery could be useful. We also know that the cardiac wall motion abnormality is mainly related to beta-adrenoreceptors. The use of a selective a-adrenoreceptor agonist could be considered. Further research in the pathophysiology and incidence of TCM could improve identification of patients at risk and lead to more effective prevention and treatment