Four annular structures in a protostellar disk less than 500,000 years old.

Annular structures (rings and gaps) in disks around pre-main-sequence stars have been detected in abundance towards class II protostellar objects that are approximately 1,000,000 years old1. These structures are often interpreted as evidence of planet formation1-3, with planetary-mass bodies carving rings and gaps in the disk4. This implies that planet formation may already be underway in even younger disks in the class I phase, when the protostar is still embedded in a larger-scale dense envelope of gas and dust5. Only within the past decade have detailed properties of disks in the earliest star-forming phases been observed6,7. Here we report 1.3-millimetre dust emission observations with a resolution of five astronomical units that show four annular substructures in the disk of the young (less than 500,000 years old)8 protostar IRS 63. IRS 63 is a single class I source located in the nearby Ophiuchus molecular cloud at a distance of 144 parsecs9, and is one of the brightest class I protostars at millimetre wavelengths. IRS 63 also has a relatively large disk compared to other young disks (greater than 50 astronomical units)10. Multiple annular substructures observed towards disks at young ages can act as an early foothold for dust-grain growth, which is a prerequisite of planet formation. Whether or not planets already exist in the disk of IRS 63, it is clear that the planet-formation process begins in the initial protostellar phases, earlier than predicted by current planet-formation theories11.

The effect of combining prewarming with intraoperative phenylephrine infusion on the prevention of hypothermia in patients undergoing urological surgery: a prospective, randomized, and controlled trial.

Background: Hypothermia is common in patients undergoing urological surgery; however, no single preventative modality is completely effective. This study evaluated the effects of combining prewarming with intraoperative phenylephrine infusion for the prevention of hypothermia in patients undergoing urological surgery. Methods: This prospective study enrolled 58 patients scheduled for urological surgery under general anesthesia. The patients were randomized into two groups (n = 29). Patients in the experimental (prewarming and phenylephrine infusion) group (PP group) received prewarming for 20 min and intraoperative phenylephrine infusion, whereas those in the control group (C group) received no active prewarming with only intermittent administration of vasoactive agents. The patient's sublingual temperatures before and after anesthesia and nasopharyngeal temperature during anesthesia were recorded as core temperatures. Results: The incidence of intraoperative hypothermia was higher in the C group than in the PP group (57.7% [15/26] vs. 23.1% [6/26], P = 0.01). The severity of intraoperative hypothermia was higher in the C group than in the PP group (P = 0.004). The nasopharyngeal temperature at the end of surgery was lower in the C group than in the PP group (35.8 ± 0.6°C vs. 36.3 ± 0.4°C, P = 0.002). The trend of core temperature decline during the first hour after anesthesia induction differed between the two groups (P = 0.003; its decline was more gradual in the PP group). Conclusions: The combination of prewarming for 20 min and intraoperative phenylephrine infusion reduced the incidence and severity of intraoperative hypothermia and modified the trend of decreasing core temperatures in patients undergoing urological surgery.

Spatially resolved magnetic field structure in the disk of a T Tauri star.

Magnetic fields in accretion disks play a dominant part during the star formation process but have hitherto been observationally poorly constrained. Field strengths have been inferred on T Tauri stars and possibly in the innermost part of their accretion disks, but the strength and morphology of the field in the bulk of a disk have not been observed. Spatially unresolved measurements of polarized emission (arising from elongated dust grains aligned perpendicularly to the field) imply average fields aligned with the disks. Theoretically, the fields are expected to be largely toroidal, poloidal or a mixture of the two, which imply different mechanisms for transporting angular momentum in the disks of actively accreting young stars such as HL Tau (ref. 11). Here we report resolved measurements of the polarized 1.25-millimetre continuum emission from the disk of HL Tau. The magnetic field on a scale of 80 astronomical units is coincident with the major axis (about 210 astronomical units long) of the disk. From this we conclude that the magnetic field inside the disk at this scale cannot be dominated by a vertical component, though a purely toroidal field also does not fit the data well. The unexpected morphology suggests that the role of the magnetic field in the accretion of a T Tauri star is more complex than our current theoretical understanding.

Patient-specific depth of endotracheal intubation-from anthropometry to the Touch and Read Method.

OBJECTIVE: Knowledge of accurate airway length (AL) enables safer placement of the endotracheal tube (ETT) in the trachea. Our objective was to check the safety of a new formula (Touch and Read method) to determine ETT depth. METHODS: AL was measured in 176 patients. Patients were divided into a normal group (AL >25 cm in men, >23 cm in women) and a risk group (AL ≤25 cm in men, ≤23cm in women). A control test (Conventional method) was performed in which the ETT was secured at a depth of 23 cm from the central incisor in men and 21 cm in women. In the experimental test (Touch and Read method), the ETT was secured at a depth equal to the distance from the angle of the mouth to the epiglottis tip plus 12.5 cm in men and 11.5 cm in women. The mean distance from the tube tip to the carina and that from the vocal cords to tube cuff were compared between the control and experimental tests in each group. RESULTS: The two distances were similar between control and experimental tests in the normal group, but differed in the risk group (Women: mean distance from tube tip to carina, 1.2 cm and from vocal cords to cuff, 2.7 cm [control test]; 1.9 and 2.0 cm, respectively [experimental test]. Men: 0.7 and 3.5 cm, respectively [control test]; 2.0 and 2.3 cm, respectively [experimental test]). CONCLUSION: Touch and Read method enables safer placement of the ETT in the trachea than the conventional method in the risk group.

Comparison of remimazolam and desflurane in emergence agitation after general anesthesia for nasal surgery: A prospective randomized controlled study.

Background: Remimazolam is an ultrashort-acting benzodiazepine. Few studies have evaluated the effects of remimazolam-based total intravenous anesthesia (TIVA) on emergence agitation (EA). This study aimed to compare the incidence and severity of EA between TIVA using remimazolam and desflurane. Methods: This prospective randomized controlled study enrolled 76 patients who underwent nasal surgery under general anesthesia. Patients were randomized into two groups of 38 each: desflurane-nitrous oxide (N2O) (DN) and remimazolam-remifentanil (RR) groups. The same protocol was used for each group from induction to emergence, except for the use of different anesthetics during maintenance of anesthesia according to the assigned group: desflurane and nitrous oxide for the DN group and remimazolam and remifentanil for the RR group. The incidence of EA as the primary outcome was evaluated using three scales: Ricker Sedation-Agitation Scale, Richmond Agitation-Sedation Scale, and Aono's four-point agitation scale. Additionally, hemodynamic changes during emergence and postoperative sense of suffocation were compared. Results: The incidence of EA was significantly lower in the RR group than in the DN group in all three types of EA assessment scales (all P < 0.001). During emergence, the change in heart rate differed between the two groups (P = 0.002). The sense of suffocation was lower in the RR group than in the DN group (P = 0.027). Conclusions: RR reduced the incidence and severity of EA in patients undergoing nasal surgery under general anesthesia. In addition, RR was favorable for managing hemodynamics and postoperative sense of suffocation.

Characterization of a novel activated Ran GTPase mutant and its ability to induce cellular transformation.

Ran (Ras-related nuclear) protein, a member of the Ras superfamily of GTPases, is best known for its roles in nucleocytoplasmic transport, mitotic spindle fiber assembly, and nuclear envelope formation. Recently, we have shown that the overexpression of Ran in fibroblasts induces cellular transformation and tumor formation in mice (Ly, T. K., Wang, J., Pereira, R., Rojas, K. S., Peng, X., Feng, Q., Cerione, R. A., and Wilson, K. F. (2010) J. Biol. Chem. 285, 5815-5826). Here, we describe a novel activated Ran mutant, Ran(K152A), which is capable of an increased rate of GDP-GTP exchange and an accelerated GTP binding/GTP hydrolytic cycle compared with wild-type Ran. We show that its expression in NIH-3T3 fibroblasts induces anchorage-independent growth and stimulates cell invasion, as well as activates signaling pathways that lead to extracellular regulated kinase (ERK) activity. Furthermore, Ran(K152A) expression in the human mammary SKBR3 adenocarcinoma cell line gives rise to an enhanced transformed phenotype and causes a robust stimulation of both ERK and the N-terminal c-Jun kinase (JNK). Microarray analysis reveals that the expression of the gene encoding SMOC-2 (secreted modular calcium-binding protein-2), which has been shown to synergize with different growth factors, is increased by at least 50-fold in cells stably expressing Ran(K152A) compared with cells expressing control vector. Knocking down SMOC-2 expression greatly reduces the ability of Ran(K152A) to stimulate anchorage-independent growth in NIH-3T3 cells and in SKBR3 cells and also inhibits cell invasion in fibroblasts. Collectively, our findings highlight a novel connection between the hyper-activation of the small GTPase Ran and the matricellular protein SMOC-2 that has important consequences for oncogenic transformation.

Strategic multimodal non-invasive assessment of cardiac performance in patients with heart failure.

AIMS: Although various non-invasive cardiac examinations are known to be predictive of long-term outcomes in patients with heart failure (HF), combining them properly would provide synergism. We aimed to show that non-invasive cardiac assessments targeting left ventricular filling pressure (LVFP), left atrial remodelling, and exercise capacity would provide better prognostication in combination. METHODS AND RESULTS: This prospective observational study included consecutive hospitalized stage A-C HF patients evaluated with N-terminal pro-B-type natriuretic peptide (NT-proBNP), echocardiography including two-dimensional speckle tracking, and cardiopulmonary exercise testing. According to NT-proBNP and echocardiographic semi-quantitative LVFP grading (Echo-LVFP), patients were classified into three LVFP groups: normal range of both Echo-LVFP and NT-proBNP (Group 1), normal range of Echo-LVFP but elevated NT-proBNP (Group 2), and elevated Echo-LVFP and NT-proBNP (Group 3). The adverse outcome was defined as a composite of cardiovascular death, non-fatal acute coronary syndrome, acute stroke, or HF-related hospitalization. Among 224 HF patients (mean age of 63.8 ± 11.6 years, 158 men) analysed, 160 (71.4%) had ischaemic aetiology. During the follow-up of 18.6 ± 9.8 months, event-free survival in Group 2 (n = 56, age of 65.4 ± 12.4) was better than that in Group 3 (n = 45, age of 68.5 ± 11.5) but worse than that in Group 1 (n = 123, mean age of 61.4 ± 10.5) (log-rank P < 0.001). Mechanical left atrial dysfunction (peak longitudinal strain <28%) (adjusted hazard ratio 5.69, 95% confidence interval 1.06-4.48) and limited exercise capacity (peak VO2 per +5 mL/kg/min) (adjusted hazard ratio 0.63, 95% confidence interval 0.46-0.87) were also predictable adverse outcomes. Serial addition of peak VO2 and left atrial strain to the model incrementally enhanced the predictive power of LVFP-based risk stratification for adverse outcomes. CONCLUSIONS: The combination of NT-proBNP and Echo-LVFP could be used to predict adverse outcomes in patients with HF of various stages. Left atrial mechanics and exercise capacity are incremental to prognostication. Non-invasive test findings could be strategically combined to provide an integrative profile of cardiac performance.

The prognostic value of cardiopulmonary exercise testing and HFA-PEFF in patients with unexplained dyspnea and preserved left ventricular ejection fraction.

BACKGROUND: HFA-PEFF and cardiopulmonary exercise testing (CPET) are comprehensive diagnostic tools for heart failure with preserved ejection fraction (HFpEF). We aimed to investigate the incremental prognostic value of CPET for the HFA-PEFF score among patients with unexplained dyspnea with preserved ejection fraction (EF). METHODS: Consecutive patients with dyspnea and preserved EF (n = 292) were enrolled between August 2019 and July 2021. All patients underwent CPET and comprehensive echocardiography, including two-dimensional speckle tracking echocardiography in the left ventricle, left atrium and right ventricle. The primary outcome was defined as a composite cardiovascular event including cardiovascular-related mortality, acute recurrent heart failure hospitalization, urgent repeat revascularization/myocardial infarction or any hospitalization due to cardiovascular events. RESULTS: The mean age was 58 ± 14.5 years, and 166 (56.8%) participants were male. The study population was divided into three groups based on the HFA-PEFF score: < 2 (n = 81), 2-4 (n = 159), and ≥ 5 (n = 52). HFA-PEFF score ≥ 5, VE/VCO2 slope, peak systolic strain rate of the left atrium and resting diastolic blood pressure were independently associated with composite cardiovascular events. Furthermore, the addition of VE/VCO2 and HFA-PEFF to the base model showed incremental prognostic value for predicting composite cardiovascular events (C-statistic 0.898; integrated discrimination improvement 0.129, p = 0.032; net reclassification improvement 1.043, p ≤ 0.001). CONCLUSIONS: CPET could be exploited for the HFA-PEFF approach in terms of incremental prognostic value and diagnosis among patients with unexplained dyspnea with preserved EF.

A study of the analgesic efficacy of rectus sheath block in single-port total laparoscopic hysterectomy: a randomized controlled study.

OBJECTIVE: To investigate the postoperative analgesic effects of rectus sheath block (RSB) in combination with patient-controlled analgesia (PCA) compared with PCA alone after single-port total laparoscopic hysterectomy (TLH). METHODS: This randomized, single-blind study enrolled female patients that underwent single-port TLH. The patients were randomized to receive either fentanyl PCA (PCA group) or RSB with the same PCA. The primary outcomes were fentanyl consumption at 8 h postoperatively and visual analogue scale (VAS) pain scores, which represented the severity of postoperative pain. RESULTS: A total of 36 patients were enrolled in the study: 18 in the PCA group and 18 in the RSB group (two patients were excluded). The primary outcome of fentanyl consumption was significantly lower at 8 h postoperatively in the RSB group than in the PCA group (148 ± 61 µg versus 222 ± 107 µg, respectively). VAS scores were significantly lower at arrival in the post-anaesthesia care unit and at 30 min after arrival in the RSB group compared with the PCA group. There were no significant differences in the nausea/vomiting score and in additional analgesic consumption between the two groups. CONCLUSIONS: RSB can be used as a multimodal approach for pain control in single-port TLH procedures.Clinical Research Information Service (no. KCT0001461).

Abdominal Wall Block Decreases Intraoperative Opioid Con-Sumption by Surgical Pleth Index-Guided Remifentanil Administration in Single-Port Laparoscopic Herniorrhaphy: A Prospective Randomized Controlled Trial.

Abdominal wall blocks (AWBs) can reduce pain during surgery and lessen opioid demand. Since it is difficult to know the exact level of intraoperative pain, it is not known how much the opioid dose should be reduced. In this study, using the surgical pleth index (SPI), which indicates pain index from sympathetic fibers, the amount of remifentanil consumption was investigated. We conducted single-port laparoscopic hernia repair in 64 patients, as follows: the regional block group (R group) was treated with AWB, while the control group (C group) was only subjected to general anesthesia. In both groups, the remifentanil concentration was adjusted to maintain the SPI score between 30 and 40 during surgery. The primary parameter was the amount of remifentanil. A total of 52 patients completed the study (24 in the R group, 28 in the C group). The remifentanil dose during surgery was decreased in the R group (29 ± 21 vs. 56 ± 36 ng/kg/min; p = 0.002). Visual analogue scale score and additional administrated analgesics were also low in the R group. As such, AWB can reduce the remifentanil dose while maintaining the same pain level.

Comparative study of pulpal responses to ProRoot MTA, Vitapex, and Metapex in canine teeth.

BACKGROUND/PURPOSE: ProRoot MTA, Vitapex, and Metapex are widely used for pulp treatment of primary tooth. The aim of this study was to compare the pulpal responses to ProRoot MTA, Vitapex, and Metapex in a canine model of pulpotomy. MATERIALS AND METHODS: Pulpotomy procedure was performed to 34 teeth (21 incisors and 13 premolars) and ProRoot MTA, Vitapex or Metapex was applicated to artificially exposed pulp tissues. After 13 weeks, the teeth were extracted and processed with hematoxylin-eosin staining for histologic evaluation. All specimens were evaluated in several categorys related to calcific barrier, inflammatory responses and the area of calcific barrier formation was measured. RESULTS: Most of the specimens in the ProRoot MTA group developed a calcific barrier at the pulp amputation site and showed a low level of inflammatory response. However, in comparison to ProRoot MTA group, a small amount of calcific barrier formed in Vitapex and Metapex groups. CONCLUSION: This in vivo study found that Vitapex and Metapex induced similar pulpal responses but showed poor outcomes compared with using ProRoot MTA. Vitapex and Metapex are therefore not good substitutes for ProRoot MTA in direct pulp capping and pulpotomy.

Single-port laparoscopic Deloyers procedure for tension-free anastomosis after extended left colectomy or subtotal colectomy: A 6-patient case series.

Right colon-to-rectal anastomosis is performed in relatively rare conditions, including after subtotal colectomy or extended left hemicolectomy. One technique of tension-free anastomosis is the Deloyers procedure that includes cranio-caudal rotation of the right colon. As with other colon surgeries, the laparoscopic approach has been adapted for the Deloyers procedure. Nevertheless, due to its rare indications and technical specificity, only a small case series have been reported. Here, we report our experience with single-port laparoscopic (SPL) Deloyers procedures.Between June 2013 and March 2018, 6 patients underwent SPL Deloyers procedures. Three patients underwent SPL subtotal colectomy with ascending colon-to-rectal anastomosis for sigmoid colon cancer with chronic ischemic colitis, sigmoid colon cancer with left colon ischemia, and synchronous transverse and sigmoid colon cancer, respectively. The other 3 patients underwent SPL Hartmann reversal using the Deloyers procedure technique for 2 transverse colon end colostomies and 1 ascending colon end colostomy state, which were the result of a previous extended left hemicolectomy and subtotal colectomy, respectively. A commercially available single port was used with conventional straight and rigid laparoscopic instruments. The surgical procedures were similar to those performed during conventional laparoscopic surgery. For the anastomosis, the mobilized remaining ascending colon was rotated 180° counter-clockwise around the axis of the ileocolic pedicle. Tension-free colorectal anastomosis was then performed between the well-vascularized ascending colon and the rectal stump.The SPL Deloyers procedure was successful in all patients. No additional incisions for trocars or conversions to open surgery were necessary. The operative time and postoperative length of stay were 210 to 470 min and 8 to 21 days, respectively. No intraoperative complications were noted. There were 3 minor postoperative complications without anastomotic leakage. All patients had 2 to 3 bowel movements per day, and 1 patient regularly took loperamide at 6 months after surgery.The SPL Deloyers procedure was feasible and allowed patients to achieve good bowel movements. This operation may be considered an additional surgical option for experienced SPL surgeons in selected patients.

Erector spinae plane block for multimodal analgesia after wide midline laparotomy: A case report.

RATIONALE: The most commonly used regional techniques for analgesia following laparotomy thoracic epidural analgesia and paravertebral blocks are technically difficult to perform and carry a risk of severe complications. Recently, the erector spinae plane block (ESPB) has been reported to effectively treat neuropathic pain. The ultrasound-guided ESPB is an easily performed fascial plane block that can provide sensory blockade from T2-4 to T12-L1. Moreover, the ESPB reportedly blocks both the ventral rami of spinal nerves and the rami communicants, which contain sympathetic nerve fibres, through spread into the thoracic paravertebral space. PATIENT CONCERNS: We report the case of a 35-year-old female patient who underwent excision of a larger ovarian mass via laparotomy with a wide, midline incision from the xiphoid process to the pubic tubercle. DIAGNOSES: They were diagnosed with mucinous cystadenoma originated from the right ovary and fallopian tube, and a right oophorectomy and salpingectomy were performed. INTERVENTIONS: The ESPB was performed for postoperative pain control at the level of the T8 transverse process. Postoperative multimodal analgesia was provided according to the acute pain service protocol of our hospital. The patient was prescribed oral acetaminophen 175 mg every 6 hours and intravenous patient-controlled analgesia (PCA) with fentanyl 7 µg/mL. A 1:1 mixture of 0.75% ropivacaine (20 mL) and saline (20 mL) with epinephrine (1: 200,000) was manually injected through the indwelling catheter every 8 hours (20 mL per side). OUTCOMES: The first demand dose of fentanyl was administered at 9 hours and 39 minutes after the surgery. There were no reported resting pain scores >4, nor were any rescue analgesics needed during the first 5 postoperative days. LESSONS: The ESPB provided highly effective analgesia as a part of multimodal analgesia after laparotomy with a wide midline incision.

Alternative way to find sacral hiatus for blind caudal block - Based on 3D pelvis CT anthropometry: A retrospective study.

The aim of this study is to develop an alternative way to locate the sacral hiatus for blind caudal block from the anthropometrical data measured on 3D pelvic CT. The intersection of the line connecting two sacral cornua and the midline is considered the ideal point (IP) for caudal block. The mean length from the coccyx tip to the IP was measured using 3D pelvic CT images in 30 men and 30 women and was 6.5 cm and 6.0 cm, respectively. For the conventional method group, we used the conventional equilateral triangle method to find the sacral hiatus, which was named conventional method group needling point (CNP). For the experimental method group, the point 6.5 cm or 6.0 cm (mean length from the coccyx tip to the IP) away from the coccyx tip was called the experimental method group needling point (ENP). Drawing the three points of the IP, CNP, and ENP on the same patient's 3D pelvic CT, we compared the distance from the IP to the CNP with the distance from the IP to the ENP. We propose that the experimental method is comparable to the conventional method in locating the sacral hiatus, which is crucial for a successful caudal block procedure. Anthropometric measurements and virtual comparative test between two methods were done on the 3D pelvis CT. In men, the distance from the CNP to the IP was 0.8 ±â€¯0.5 cm in the conventional method group, while the distance from the ENP to the IP was 0.5 ±â€¯0.4 cm in the experimental method group (p < 0.05). In women, the same distances were 1.5 ±â€¯0.8 cm and 0.7 ±â€¯0.3 cm, respectively (p < 0.05). In conclusion, finding a point of 6.5 cm from the coccyx tip in men and 6.0 cm in women could be an alternative way to find the sacral hiatus for blind caudal block.

Abdominal peripheral nerve block as the only anesthetic technique for totally extraperitoneal endoscopic inguinal hernia repair: Two case reports.

RATIONALE: Laparoscopic totally extraperitoneal (TEP) inguinal hernia repair is a rapidly evolving, minimally invasive treatment modality for inguinal hernia. Compared with open hernia repair, this method requires a smaller incision, has cosmetic advantages, and facilitates rapid recovery and early return to daily activities because of less postoperative pain. Because general anesthesia is essential for TEP hernia repair, it cannot be performed on patients who have an increased risk of developing complications when placed under general anesthesia. PATIENT CONCERNS: We report 2 cases of single-port laparoscopic TEP (SP TEP) that were performed using only an abdominal peripheral nerve block (PNB) at our institute. General anesthesia and neuraxial block were dangerous for both patients owing to severe heart failure and severe chronic obstructive pulmonary disease (COPD). DIAGNOSES: They were diagnosed with an inguinal hernia requiring surgery. INTERVENTIONS: Hence, the anesthesiologist and surgeon decided to attempt a PNB to avoid complications from general anesthesia and allow faster recovery. An ipsilateral transversus abdominis plane block as well as a rectus sheath block and inguinal canal block were administered via ultrasound guidance. OUTCOMES: The patients did not report any pain, and no rescue drug was administrated. The operation times were 65 and 62minutes in patients 1 and 2, respectively. No intraoperative complications were noted. Patient 1 was discharged the day after the surgery, whereas patient 2 was discharged on the same day as the surgery. LESSONS: TEP hernia repair using abdominal PNB anesthesia seemed to be a safe and feasible technique without causing any additional complications. However, the use of abdominal PNB anesthesia alone for TEP hernia repair as an alternative to general anesthesia requires further investigation using a larger cohort.

Differences among Endophytic Fungal Communities Isolated from the Roots of Cephalanthera longibracteata Collected from Different Sites in Korea.

Orchidaceous plants have symbiotic relationships with endophytic fungi, including mycorrhizal fungi, which play important roles in the seed germination and growth of the host plants. In this study, endophytic fungal communities isolated from the roots of Cephalanthera longibracteata collected from three different sites in Korea were analyzed, and it was determined whether fungal communities were preferentially correlated with the sites. The fungal isolates were identified by sequence analysis of the internal transcribed spacer regions of rDNA. In total, 30 species of endophytic fungi, including two species of mycorrhizal fungi belonging to the genus Tulasnella, were identified. Leptodontidium orchidicola showed the highest frequency and was isolated from all root samples. Species diversity and richness were not significantly different among sites. However, the community structure of the endophytic fungi significantly differed among sites, suggesting that the site characteristics affected the community composition of the endophytic fungi colonizing the roots of C. longibracteata. Our findings will aid in developing methods involving the use of symbiotic fungi for orchid conservation and restoration in native habitats.

Spiral density waves in a young protoplanetary disk.

Gravitational forces are expected to excite spiral density waves in protoplanetary disks, disks of gas and dust orbiting young stars. However, previous observations that showed spiral structure were not able to probe disk midplanes, where most of the mass is concentrated and where planet formation takes place. Using the Atacama Large Millimeter/submillimeter Array, we detected a pair of trailing symmetric spiral arms in the protoplanetary disk surrounding the young star Elias 2-27. The arms extend to the disk outer regions and can be traced down to the midplane. These millimeter-wave observations also reveal an emission gap closer to the star than the spiral arms. We argue that the observed spirals trace shocks of spiral density waves in the midplane of this young disk.