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"Badash, A."
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The complex circumstellar environment of supernova 2023ixf
2024
The early evolution of a supernova (SN) can reveal information about the environment and the progenitor star. When a star explodes in vacuum, the first photons to escape from its surface appear as a brief, hours-long shock-breakout flare
1
,
2
, followed by a cooling phase of emission. However, for stars exploding within a distribution of dense, optically thick circumstellar material (CSM), the first photons escape from the material beyond the stellar edge and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating
3
. Early serendipitous observations
2
,
4
that lacked ultraviolet (UV) data were unable to determine whether the early emission is heating or cooling and hence the nature of the early explosion event. Here we report UV spectra of the nearby SN 2023ixf in the galaxy Messier 101 (M101). Using the UV data as well as a comprehensive set of further multiwavelength observations, we temporally resolve the emergence of the explosion shock from a thick medium heated by the SN emission. We derive a reliable bolometric light curve that indicates that the shock breaks out from a dense layer with a radius substantially larger than typical supergiants.
Using ultraviolet data as well as a comprehensive set of further multiwavelength observations of the supernova 2023ixf, a reliable bolometric light curve is derived that indicates the heating nature of the early emission.
Journal Article
Resolving the explosion of supernova 2023ixf in Messier 101 within its complex circumstellar environment
2024
Observing a supernova explosion shortly after it occurs can reveal important information about the physics of stellar explosions and the nature of the progenitor stars of supernovae (SNe). When a star with a well-defined edge explodes in vacuum, the first photons to escape from its surface appear as a brief shock-breakout flare. The duration of this flare can extend to at most a few hours even for nonspherical breakouts from supergiant stars, after which the explosion ejecta should expand and cool. Alternatively, for stars exploding within a distribution of sufficiently dense optically thick circumstellar material, the first photons escape from the material beyond the stellar edge, and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating. The difficulty in detecting SN explosions promptly after the event has so far limited data regarding supergiant stellar explosions mostly to serendipitous observations that, owing to the lack of ultraviolet (UV) data, were unable to determine whether the early emission is heating or cooling, and hence the nature of the early explosion event. Here, we report observations of SN 2023ixf in the nearby galaxy M101, covering the early days of the event. Using UV spectroscopy from the Hubble Space Telescope (HST) as well as a comprehensive set of additional multiwavelength observations, we trace the photometric and spectroscopic evolution of the event and are able to temporally resolve the emergence and evolution of the SN emission.
Journal Article
Resolving the explosion of supernova 2023ixf in Messier 101 within its complex circumstellar environment
2024
Observing a supernova explosion shortly after it occurs can reveal important information about the physics of stellar explosions and the nature of the progenitor stars of supernovae (SNe). When a star with a well-defined edge explodes in vacuum, the first photons to escape from its surface appear as a brief shock-breakout flare. The duration of this flare can extend to at most a few hours even for nonspherical breakouts from supergiant stars, after which the explosion ejecta should expand and cool. Alternatively, for stars exploding within a distribution of sufficiently dense optically thick circumstellar material, the first photons escape from the material beyond the stellar edge, and the duration of the initial flare can extend to several days, during which the escaping emission indicates photospheric heating. The difficulty in detecting SN explosions promptly after the event has so far limited data regarding supergiant stellar explosions mostly to serendipitous observations that, owing to the lack of ultraviolet (UV) data, were unable to determine whether the early emission is heating or cooling, and hence the nature of the early explosion event. Here, we report observations of SN 2023ixf in the nearby galaxy M101, covering the early days of the event. Using UV spectroscopy from the Hubble Space Telescope (HST) as well as a comprehensive set of additional multiwavelength observations, we trace the photometric and spectroscopic evolution of the event and are able to temporally resolve the emergence and evolution of the SN emission.
Contemporary Review of Submandibular Gland Sialolithiasis and Surgical Management Options
2022
One of the most common disorders of the salivary glands is obstructive sialolithiasis. Salivary gland obstruction is important to address, as it can significantly impact patient quality of life and can progress to extensive cellulitis and abscess formation if left untreated. For small and accessible stones, conservative therapies often produce satisfactory outcomes. Operative management should be considered when stones are inaccessible or larger in size, and options include sialendoscopy, laser lithotripsy, extracorporeal shockwave lithotripsy, transoral surgery, and submandibular gland adenectomy. Robotic approaches are also becoming increasingly used for submandibular stone management. The purpose of this review is to summarize the modern-day management of submandibular gland obstructive sialolithiasis with an emphasis on operative treatment modalities. A total of 77 articles were reviewed from PubMed and Embase databases, specifically looking at the pathophysiology, clinical presentation, diagnosis, and management of submandibular sialolithiasis.
Journal Article
Factors associated with loss and recovery of smell and taste after COVID‐19 infection
2024
Objective To identify predictors associated with loss and recovery of smell and taste after COVID‐19 infection. Methods The Integrated Public Use Microdata Series (IPUMS) 2021 National Health Interview Series (NHIS) database was used to analyze factors associated with loss and recovery of smell and taste in respondents who had a previous COVID‐19 infection. Significant variables from univariate analysis were included in a stepwise backward regression model to identify independent predictors. Results Of the 3844 individuals who answered yes to having contracted COVID‐19, 51.1% and 48.9% reported losing smell and taste, respectively. 95.7% recovered smell and 97% recovered taste. Predictors associated with higher odds of reporting a loss of smell included younger age (odds ratio [OR] 0.98; 95% confidence interval [CI] 0.98–0.99), female sex (OR 1.38; CI 1.17–1.63), use of e‐cigarettes (OR 1.59; CI 1.25–2.02), and Mexican ethnicity (OR 1.61; CI 1.22–2.11). Predictors of taste loss were younger age (OR 0.98; CI 0.98–0.99), female sex (OR 1.31; CI 1.08–1.58), and higher BMI (OR 1.02; CI 1.00–1.04). Female sex was associated with decreased odds of reporting a recovery of smell (OR 0.74; CI 0.59–0.92) and taste (OR 0.54; CI 0.42–0.69). Black/African American race (OR 1.44; CI 1.03–2.03) and non‐Mexican Hispanic ethnicities (OR 1.55; CI 1.02–2.34) were associated with an increased likelihood of reporting the recovery of smell. Conclusion Various factors may be associated with the loss and recovery of smell and taste after COVID‐19 infections. Clinicians may use this information to better counsel patients with these symptoms. Level of evidence 4.
Journal Article
A nuclear winter's tale : science and politics in the 1980s
2009
The rise and fall of the concept of nuclear winter, played out in research activity, public relations, and Reagan-era politics.The nuclear winter phenomenon burst upon the public's consciousness in 1983.
Opioid‐limiting legislation and prescribing habits of otolaryngologists among Medicare beneficiaries
2023
Objectives To identify changes in otolaryngologists' opioid prescribing trends for Medicare beneficiaries associated with the enactment of state laws that limit the duration of prescriptions to 3–7 days in the years 2016 and 2017 in the United States. Methods Through the Centers for Medicare and Medicaid Services (CMS) database, we retrieved data on Medicare enrollment and on the total days prescribed and total number of beneficiaries for the drugs codeine/acetaminophen, hydrocodone/acetaminophen, oxycodone HCl, oxycodone/acetaminophen, and tramadol HCl, by each otolaryngologist prescriber in 13 states from January 2013 to December 2019. We modeled trends using linear spline regression models that controlled for Medicare beneficiaries' state‐level socio‐demographic characteristics' fixed effects. Results Across the 13 states, the number of days of all five opioids prescribed per beneficiary declined by 8.35 (SD = 12.61). The most commonly prescribed opioid type by otolaryngologists during the 5‐year study period was tramadol HCl (28.72 days/beneficiary) followed by oxycodone HCl (19.99 days/beneficiary). All opioids had declines in prescription days over this time window and higher rates of decline in the years following law passage. Four states experienced statistically significant declines in the prescriptions of all opioids after the year of legislation passage (p < .05). Some states that had the greatest inclines in opioid prescriptions in the years prior to law enactment also experienced the greatest reductions in the time after legislation enactment. Conclusions Opioid prescribing practices of otolaryngologists may have been affected by opioid prescription duration limiting laws passed in 13 states in 2016 and 2017. Level of Evidence Level 4. Opioid duration‐limiting laws enacted between 2016 and 2017 may have contributed to the reduced length of opioid prescriptions written by otolaryngologists in most of the states in which these laws were passed.
Journal Article
Azithromycin and Sildenafil May Have Protective Effects on Retinal Ganglion Cells via Different Pathways: Study in a Rodent Microbead Model
by
Zahavi, Alon
,
Sela, Tal Corina
,
Goldenberg-Cohen, Nitza
in
Azithromycin
,
Drug therapy
,
Glaucoma
2023
Decreased blood flow to the optic nerve (ON) and neuroinflammation are suggested to play an important role in the pathophysiology of glaucoma. This study investigated the potential neuroprotective effect of azithromycin, an anti-inflammatory macrolide, and sildenafil, a selective phosphodiesterase-5 inhibitor, on retinal ganglion cell survival in a glaucoma model, which was induced by microbead injection into the right anterior chamber of 50 wild-type (WT) and 30 transgenic toll-like receptor 4 knockout (TLR4KO) mice. Treatment groups included intraperitoneal azithromycin 0.1 mL (1 mg/0.1 mL), intravitreal sildenafil 3 µL, or intraperitoneal sildenafil 0.1 mL (0.24 μg/3 µL). Left eyes served as controls. Microbead injection increased intraocular pressure (IOP), which peaked on day 7 in all groups and on day 14 in azithromycin-treated mice. Furthermore, the retinas and ON of microbead-injected eyes showed a trend of increased expression of inflammatory- and apoptosis-related genes, mainly in WT and to a lesser extent in TLR4KO mice. Azithromycin reduced the BAX/BCL2 ratio, TGFβ, and TNFα levels in the ON and CD45 expression in WT retina. Sildenafil activated TNFα-mediated pathways. Both azithromycin and sildenafil exerted a neuroprotective effect in WT and TLR4KO mice with microbead-induced glaucoma, albeit via different pathways, without affecting IOP. The relatively low apoptotic effect observed in microbead-injected TLR4KO mice suggests a role of inflammation in glaucomatous damage.
Journal Article
Perioperative Testosterone Supplementation Increases Lean Mass in Healthy Men Undergoing Anterior Cruciate Ligament Reconstruction: A Randomized Controlled Trial
2017
Background:
Rehabilitation after repair of the anterior cruciate ligament (ACL) is complicated by the loss of leg muscle mass and strength. Prior studies have shown that preoperative rehabilitation may improve muscle strength and postoperative outcomes. Testosterone supplementation may likewise counteract this muscle loss and potentially improve clinical outcomes.
Purpose:
The purpose was to investigate the effect of perioperative testosterone administration on lean mass after ACL reconstruction in men and to examine the effects of testosterone on leg strength and clinical outcome scores. It was hypothesized that testosterone would increase lean mass and leg strength and improve clinical outcome scores relative to placebo.
Study Design:
Randomized controlled trial; Level of evidence, 1.
Methods:
Male patients (N = 13) scheduled for ACL reconstruction were randomized into 2 groups: testosterone and placebo. Participants in the testosterone group received 200 mg of intramuscular testosterone weekly for 8 weeks beginning 2 weeks before surgery. Participants in the placebo group received saline following the same schedule. Both groups participated in a standard rehabilitation protocol. The primary outcome was the change in total lean body mass at 6 and 12 weeks. Secondary outcomes were extensor muscle strength, Tegner activity score, and Knee injury and Osteoarthritis Outcome Score.
Results:
There was an increase in lean mass of a mean 2.7 ± 1.7 kg at 6 weeks postoperatively in the testosterone group compared with a decrease of a mean 0.1 ± 1.5 kg in the placebo group (P = .01). Extensor muscle strength of the uninjured leg also increased more from baseline in the testosterone group (+20.8 ± 25.6 Nm) compared with the placebo group (–21.4 ± 36.7 Nm) at 12 weeks (P = .04). There were no significant between-group differences in injured leg strength or clinical outcome scores. There were no negative side effects of testosterone noted.
Conclusion:
Perioperative testosterone supplementation increased lean mass 6 weeks after ACL reconstruction, suggesting that this treatment may help minimize the effects of muscle atrophy associated with ACL injuries and repair. This study was not powered to detect differences in strength or clinical outcome scores to assess the incidence of testosterone-related adverse events.
Clinical Relevance:
Supraphysiological testosterone supplementation may be a useful adjunct therapy for counteracting muscle atrophy after ACL reconstruction. Further investigation is necessary to determine the safety profile and effects of perioperative testosterone administration on leg strength and clinical outcomes after surgery.
Registration:
NCT01595581 (ClinicalTrials.gov).
Journal Article