37 research outputs found
Stray magnetic field imaging of thin exfoliated iron halides flakes
Magnetic van der Waals materials are often proposed for use in future spintronic devices, aiming to leverage the combination of long-range magnetic order and near-atomic thinness to produce energy-efficient components. One class of material that has been discussed in this context are the iron halides FeCl2 and FeBr2, which are A-type antiferromagnets with strong uniaxial magnetocrystalline anisotropy. However, despite characterization of the bulk materials, the possibility for sustaining the magnetic behaviors that would underpin such applications in thin flakes has not been investigated. In this work, we use nitrogen-vacancy center microscopy to quantitatively image magnetism in individual exfoliated flakes of these iron halides, revealing the absence of magnetic remanence, a weak induced magnetization under bias field, and variable behavior versus temperature. We show that our results are consistent with the antiferromagnetic behavior of the bulk material with a soft ferromagnetic uncompensated layer, indicating that extended (>1µm) ferromagnetic domains are not sustained even at low temperatures (down to 4 K). Finally, we find that the magnetic order is strongly affected by the sample preparation, with a surprising diamagnetic behavior observed in a thin, hydrated sample.<br/
Thirty- and ninety-day outcomes after sublobar resection with and without brachytherapy for non–small cell lung cancer: Results from a multicenter phase III study
ObjectiveSublobar resection (SR) is commonly used for patients considered high risk for lobectomy. Nonoperative therapies are increasingly being reported for patients with similar risk because of perceived lower morbidity. We report 30- and 90-day adverse events (AEs) from American College of Surgeons Oncology Group Z4032, a multicenter phase III study for high-risk patients with stage I non–small cell lung cancer.MethodsData from 222 evaluable patients randomized to SR (n = 114) or SR with brachytherapy (n = 108) are reported. AEs were recorded using the Common Terminology Criteria for Adverse Events, Version 3.0, at 30 and 90 days after surgery. Risk factors (age, percent baseline carbon monoxide diffusion in the lung [DLCO%], percent forced expiratory volume in 1 second [FEV1%], upper lobe vs lower lobe resections, performance status, surgery approach, video-assisted thoracic surgery vs open and extent, and wedge vs segmentectomy) were analyzed using a multivariable logistic model for their impact on the incidence of grade 3 or higher (G3+) AEs. Respiratory AEs were also specifically analyzed.ResultsMedian age, FEV1%, and DLCO% were similar in the 2 treatment groups. There was no difference in the location of resection (upper vs lower lobe) or the use of segmental or wedge resections. There were no differences between the groups with respect to “respiratory” G3+ AEs (30 days: 14.9% vs 19.4%, P = .35; 0–90 days: 19.3% vs 25%, P = .31) and “any” G3+ AEs (30 days: 25.4% vs 30.6%, P = .37; 0–90 days: 29.8% vs 37%, P = .25). Further analysis combined the 2 groups. Mortality occurred in 3 patients (1.4%) by 30 days and in 6 patients (2.7%) by 90 days. Four of the 6 deaths were thought to be due to surgery. When considered as continuous variables, FEV1% was associated with “any” G3+ AE at days 0 to 30 (P = .03; odds ratio [OR] = 0.98) and days 0 to 90 (P = .05; OR = 0.98), and DLCO% was associated with “respiratory” G3+ AE at days 0 to 30 (P = .03; OR = 0.97) and days 0 to 90 (P = .05; OR = 0.98). Segmental resection was associated with a higher incidence of any G3+ AE compared with wedge resection at days 0 to 30 (40.3% vs 22.7%; OR = 2.56; P < .01) and days 0 to 90 (41.5% vs 29.7%; OR = 1.96; P = .04). The median FEV1% was 50%, and the median DLCO% was 46%. By using these median values as potential cutpoints, only a DLCO% of less than 46% was significantly associated with an increased risk of “respiratory” and “any” G3+ AE for days 0 to 30 and 0 to 90.ConclusionsIn a multicenter setting, SR with brachytherapy was not associated with increased morbidity compared with SR alone. SR/SR with brachytherapy can be performed safely in high-risk patients with non–small cell lung cancer with low 30- and 90-day mortality and acceptable morbidity. Segmental resection was associated with increased “any” G3+ AE, and DLCO% less than 46% was associated with “any” G3+ AE and “respiratory” G3+ AE at both 30 and 90 days
American College of Surgeons Oncology Group Z4099/Radiation Therapy Oncology Group 1021: A randomized study of sublobar resection compared with stereotactic body radiotherapy for high-risk stage I non–small cell lung cancer
Location as an important predictor of lymph node involvement for pulmonary adenocarcinoma
BackgroundIncreasing data implicate histologic grade and radiographic appearance along with tumor size as key prognostic indicators for pulmonary adenocarcinoma. The impact of tumor location on prognosis has not been examined.MethodsThe records of 530 consecutive patients with pulmonary adenocarcinoma pathologically staged between June 1979 and July 2002 were reviewed. All patients had a preoperative computed tomographic scan of the chest and underwent surgical staging by mediastinoscopy, lymph node sampling, or lymph node dissection. Patients with bronchioalveolar cell carcinoma were excluded. Peripheral tumors were compared with central tumors with regard to stage and survival. A tumor was considered to be central if visualized within the inner third of the lung field or seen bronchoscopically. Patients with T1 cancers were further analyzed on the basis of tumor size. Survival was determined by the Kaplan-Meier analysis and comparisons were made by the log-rank method.ResultsCentral tumors were more advanced and demonstrated a significantly (P < .0001) poorer survival than peripheral tumors (median 18 vs 39 months). Sixty percent of patients with central tumors had stage III or stage IV disease compared with 25% of those with peripheral tumors. Central T1 tumors, however, demonstrated a 50% incidence of lymph node involvement. Although the incidence of lymph node metastases increased incrementally with the size of peripheral T1 tumors, it remained 50% for central T1 tumors irrespective of size.ConclusionTumor location for pulmonary adenocarcinoma should be considered when planning therapy. Central tumors have a high incidence of lymph node metastases (regardless of size) and a poorer prognosis
Lobar and sublobar resection with and without brachytherapy for small stage IA non–small cell lung cancer
ObjectiveComputed tomographic screening is detecting ever smaller peripheral non–small cell lung cancers. These smaller cancers are amenable to sublobar resection, but sublobar resection is not currently the treatment of choice. This study compared sublobar resection with lobar resection for stage IA non–small cell lung cancers to assess whether sublobar resection is appropriate treatment for certain lesions. The use of adjuvant brachytherapy was also evaluated.MethodsA retrospective multicenter study of 291 patients with T1 N0 disease was done. Outcomes after sublobar resection (n = 124) were compared with those after lobar resection (n = 167). Brachytherapy was used in conjunction with 60 (48%) sublobar resection operations. Analysis based on tumor diameter was performed.ResultsThere were 137 cancers smaller than 2 cm and 154 cancers ranging from 2 to 3 cm. Patients undergoing sublobar resection were older (68.4 vs 66.1 years, P = .018) with poorer pulmonary function (forced expiratory volume in 1 second of 53.1% vs 78.2%, P = .001). Mean follow-up was 34.5 months. Brachytherapy decreased local recurrence rate significantly among patients undergoing sublobar resection, from 11 (17.2%) to 2 (3.3%). For tumors smaller than 2 cm, there was no difference in survival between sublobar resection and lobar resection groups. For the larger tumors (2-3 cm), median survival was significantly better in the lobar resection group, at 70 versus 44.7 months (P = .003).ConclusionIntraoperative brachytherapy may reduce the local recurrence that is usually reported with sublobar resection. Our experience supports the further investigation of the use of sublobar resection with brachytherapy for peripheral stage IA non–small cell lung cancers smaller than 2 cm