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1.
Discov Educ ; 1(1): 22, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36590921

RESUMEN

One promising practice for increasing active learning in undergraduate science education is the use of a mentoring network. The Promoting Active Learning and Mentoring (PALM) Network was launched with practitioners from several professional societies and disciplines to make changes in their teaching based on evidence-based practices and to encourage the members to reflect deeply on their teaching experiences. Members of the Network interviewed seven previous Fellows, 1 to 6 years after completing their fellowship, to better understand the value of the Network and how these interactions impacted their ability to sustain change toward more active teaching practices. The interviews resulted in the creation of three personas that reflect the kinds of educators who engaged with the Network: Neil the Novice, Issa the Isolated, and Etta the Expert. Key themes emerged from the interviews about how interactions with the PALM Network sustained change toward evidence-based teaching practices allowing the members to readily adapt to the online learning environment during the COVID-19 pandemic. Understanding how the personas intersect with the ADKAR model contributes to a better understanding of how mentoring networks facilitate transformative change toward active learning and can inform additional professional development programs. Supplementary Information: The online version contains supplementary material available at 10.1007/s44217-022-00023-w.

2.
Artículo en Inglés | MEDLINE | ID: mdl-33294101

RESUMEN

A large body of data suggests that implementing active learning practices in a STEM classroom contributes to increased success in both achievement of student learning outcomes and retention of students. Despite these findings, significant barriers exist for instructors implementing active learning strategies in their undergraduate classrooms. These barriers can be effectively addressed by providing sustained support to instructors and postdoctoral trainees interested in implementing active learning strategies in their teaching practice. The Promoting Active Learning and Mentoring (PALM) network attains this objective by connecting instructors interested in learning more about active learning (Fellows) with individuals who have extensive expertise related to this practice (mentors). These facilitated connections occur in the form of active mentorship for a year or more, virtual journal clubs, and biannual gatherings of PALM Fellows and mentors. Here, we describe the foundation on which PALM was built and explain how a successful mentorship program can pave the way for educators to adapt and implement evidence-based practices like active learning in a college classroom.

3.
Brachytherapy ; 17(2): 392-398, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29128230

RESUMEN

PURPOSE: Given the limited data using an interstitial approach with 3D-based planning for definitive cervical cancer utilizing the GEC-ESTRO defined high-risk clinical target volume (HR-CTV), we reviewed our institutional experience of cervical cancer patients with HR-CTVs ≥ 30 cc to determine whether our clinical and toxicity outcomes are acceptable. METHODS: A retrospective review of 37 cervical cancer patients with high-risk clinical target volumes (HR-CTVs) ≥30 cc treated with interstitial image-guided brachytherapy (IS IGBT) was performed. All patients received external beam radiotherapy to a median dose of 45 Gy, followed by IS IGBT delivered in a single implant to a median dose of 6 Gy × 5 fractions. Median HR-CTV was 59 cc. A median HR-CTV D90 of 87.44 Gy was achieved. Kaplan-Meier method was used to evaluate local control (LC), distant control, and overall survival (OS), with stratification by overall treatment time (OTT) ≤ 7 or >7 weeks. RESULTS: Median followup was 17 months. The estimated 2-year LC, distant control, and OS were 77.6% (confidence interval [CI]: 63.8-94.5%), 56.8% (CI: 41.3-78.1%), and 54.4% (CI: 39.4-75%), respectively. The 2-year LC for OTT ≤7 weeks and >7 weeks were 100% and 58.3%, respectively (p = 0.026). The 2-year OS for OTT ≤7 weeks and >7 weeks were 77.8% and 38%, respectively (p = 0.021). DISCUSSIONS: IS IGBT can achieve a high D90 to the HR-CTV even in the setting of large-volume disease and results in a favorable LC and toxicity profile. OTT > 7 weeks is associated with significant decrease in LC and OS. CONCLUSIONS: Efforts should be made to complete whole treatment within 7 weeks as this is associated with improved clinical outcomes.


Asunto(s)
Braquiterapia/métodos , Neoplasias del Cuello Uterino/diagnóstico por imagen , Neoplasias del Cuello Uterino/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Fraccionamiento de la Dosis de Radiación , Femenino , Estudios de Seguimiento , Humanos , Persona de Mediana Edad , Planificación de la Radioterapia Asistida por Computador , Estudios Retrospectivos , Tasa de Supervivencia , Factores de Tiempo , Tomografía Computarizada por Rayos X , Resultado del Tratamiento , Adulto Joven
4.
Brachytherapy ; 14(5): 626-32, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26024784

RESUMEN

PURPOSE: To report early clinical outcomes of high-dose-rate interstitial image-guided brachytherapy (BT) in the definitive management of locally advanced cervical cancer. METHODS: We retrospectively analyzed 31 locally advanced cervical cancer patients treated at our institution between January 2010 and April 2013. About 88% had advanced disease based on the International Federation of Gynecology and Obstetrics guidelines, and 87% received concurrent chemotherapy. All patients were treated with external beam radiation therapy to a median dose of 45 Gy (range, 39.6-58 Gy) before receiving BT. High-dose-rate BT was delivered in a single implant to a median dose of 6 Gy × five fractions to a CT-defined volume. Median total equivalent 2-Gy dose, dose covered by 90% of the high-risk clinical target volume (HR-CTV D90), and HR-CTV were 84, 87.4, and 49.9 cc, respectively. Kaplan-Meier method was used for actuarial survival analysis, and toxicity was graded using Common Terminology Criteria for Adverse Events, version 4.0. RESULTS: Median followup was 19.3 months. Two-year actuarial local control, regional control, and distant metastasis (DM) were 90%, 93%, and 23.6%, respectively. Two-year disease-free survival was 55%. Genitourinary, gastrointestinal, or gynecologic Grade 3 toxicity was seen in 5 patients (3 T4a and 2 T3b) for crude rates of 13%, 7%, and 3%, respectively. Stratifying HR-CTV by <30 and >30 cc and then by HR-CTV D90 of <85, 85-90, and >90 Gy showed that 100% of the local failures, regional failures, DM, and G3 toxicity occurred in >30 cc group. The rate of DM was also significantly higher in the >30 cc group (p = 0.036). CONCLUSIONS: An interstitial approach can achieve excellent outcomes in cases where intracavitary and/or hybrid approaches are either not suitable or not available.


Asunto(s)
Braquiterapia/métodos , Tracto Gastrointestinal/efectos de la radiación , Tomografía Computarizada por Rayos X , Ultrasonografía Intervencional , Sistema Urogenital/efectos de la radiación , Neoplasias del Cuello Uterino/radioterapia , Adulto , Anciano , Anciano de 80 o más Años , Braquiterapia/efectos adversos , Supervivencia sin Enfermedad , Femenino , Humanos , Persona de Mediana Edad , Metástasis de la Neoplasia , Traumatismos por Radiación/etiología , Dosificación Radioterapéutica , Planificación de la Radioterapia Asistida por Computador , Estudios Retrospectivos , Tasa de Supervivencia , Resultado del Tratamiento , Neoplasias del Cuello Uterino/patología , Adulto Joven
5.
Radiat Oncol J ; 31(2): 104-10, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23865007

RESUMEN

PURPOSE: Intensity modulated arc therapy (IMAT) is a form of intensity modulated radiation therapy (IMRT) that delivers dose in single or multiple arcs. We compared IMRT plans versus single-arc field (1ARC) and multi-arc fields (3ARC) IMAT plans in high-risk prostate cancer. MATERIALS AND METHODS: Sixteen patients were studied. Prostate (PTV P ), right pelvic (PTV RtLN ) and left pelvic lymph nodes (PTV LtLN ), and organs at risk were contoured. PTV P , PTV RtLN , and PTV LtLN received 50.40 Gy followed by a boost to PTV B of 28.80 Gy. Three plans were per patient generated: IMRT, 1ARC, and 3ARC. We recorded the dose to the PTV, the mean dose (D MEAN ) to the organs at risk, and volume covered by the 50% isodose. Efficiency was evaluated by monitor units (MU) and beam on time (BOT). Conformity index (CI), Paddick gradient index, and homogeneity index (HI) were also calculated. RESULTS: Average Radiation Therapy Oncology Group CI was 1.17, 1.20, and 1.15 for IMRT, 1ARC, and 3ARC, respectively. The plans' HI were within 1% of each other. The D MEAN of bladder was within 2% of each other. The rectum D MEAN in IMRT plans was 10% lower dose than the arc plans (p < 0.0001). The GI of the 3ARC was superior to IMRT by 27.4% (p = 0.006). The average MU was highest in the IMRT plans (1686) versus 1ARC (575) versus 3ARC (1079). The average BOT was 6 minutes for IMRT compared to 1.3 and 2.9 for 1ARC and 3ARC IMAT (p < 0.05). CONCLUSION: For high-risk prostate cancer, IMAT may offer a favorable dose gradient profile, conformity, MU and BOT compared to IMRT.

6.
Am J Nucl Med Mol Imaging ; 2(3): 307-13, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-23133818

RESUMEN

We have previously introduced anatomic biologic contouring (ABC) with PET/CT, using a distinct "halo" to unify contouring methods in treatment planning for lung and head and neck cancers. The objective of this study is to assess the utility of PET/CT in planning and treatment response for cervical cancer. Forty-two patients with stages II-IIIB cervix cancer were planned for irradiation using PET/CT. A CT-based Gross Tumor Volume (GTV-CT) was delineated by two independent observers while the PET remained obscured. The Planning Target Volume (PTV) was obtained by adding a 1.5 cm margin around the GTV. The same volumes were recontoured using PET/CT data and termed GTV-ABC and PTV-ABC, respectively. The values of GTV-CT and GTV-ABC and the absolute differences between the two observers were analyzed. Additionally, 23 of these patients had PET/CT performed 3 months after treatment. The anatomic biologic value (ABV) was calculated using the product of maximum diameter and mean SUV of the cervical tumor. The pre- and post-treatment ABVs were compared. A "halo" was observed around areas of maximal SUV uptake. The mean halo SUV was 1.91 ± 0.56 (SD). The mean halo thickness was 2.12 ± 0.5 (SD) mm. Inter-observer GTV variability decreased from a mean volume difference of 55.36 cm(3) in CT-based planning to 12.29 cm(3) in PET/CT-based planning with a respective decrease in standard deviation (SD) from 55.78 to 10.24 (p <0.001). Comparison of mean pre-treatment and post-treatment ABV's revealed a decrease of ABV from 48.2 to 7.8 (p<0.001). PET/CT is a valuable tool in radiation therapy planning and evaluation of treatment response for cervical cancer. A clearly visualized "halo" was successfully implemented in GTV contouring in cervical cancer, resulting in decreased inter-observer variability in planning. PET/CT has the ability to quantify treatment response using anatomic biologic value.

7.
Biochemistry ; 44(49): 16054-63, 2005 Dec 13.
Artículo en Inglés | MEDLINE | ID: mdl-16331965

RESUMEN

The structure of nitrite reductase, a key enzyme in the process of nitrogen assimilation, has been determined using X-ray diffraction to a resolution limit of 2.8 A. The protein has a globular fold consisting of 3 alpha/beta domains with the siroheme-iron sulfur cofactor at the interface of the three domains. The Fe(4)S(4) cluster is coordinated by cysteines 441, 447, 482, and 486. The siroheme is located at a distance of 4.2 A from the cluster, and the central iron atom is coordinated to Cys 486. The siroheme is surrounded by several ionizable amino acid residues that facilitate the binding and subsequent reduction of nitrite. A model for the ferredoxin:nitrite reductase complex is proposed in which the binding of ferredoxin to a positively charged region of nitrite reductase results in elimination of exposure of the cofactors to the solvent. The structure of nitrite reductase shows a broad similarity to the hemoprotein subunit of sulfite reductase but has many significant differences in the backbone positions that could reflect sequence differences or could arise from alterations of the sulfite reductase structure that arise from the isolation of this subunit from the native complex. The implications of the nitrite reductase structure for understanding multi-electron processes are discussed in terms of differences in the protein environments of the cofactors.


Asunto(s)
Coenzimas/química , Hemo/análogos & derivados , Proteínas Hierro-Azufre/química , Nitrito Reductasas/química , Estructura Terciaria de Proteína , Spinacia oleracea/enzimología , Cristalografía por Rayos X , Ferredoxinas/química , Hemo/química , Hemo/metabolismo , Proteínas Hierro-Azufre/metabolismo , Modelos Moleculares , Datos de Secuencia Molecular , Complejos Multiproteicos , Nitrito Reductasas/genética , Nitrito Reductasas/metabolismo
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