Are maximum magnitudes of induced earthquakes controlled by pressure diffusion?

There is an ongoing discussion about how to forecast the maximum magnitudes of induced earthquakes based on operational parameters, subsurface conditions and physical process understanding. Although the occurrence of damage caused by induced earthquakes is rare, some cases have caused significant economic loss, injuries and even loss of life. We analysed a global compilation of earthquakes induced by hydraulic fracturing, geothermal reservoir stimulation, water disposal, gas storage and reservoir impoundment. Our analysis showed that maximum magnitudes scale with the characteristic length of pressure diffusion in the brittle Earth's crust. We observed an increase in the nucleation potential of larger-magnitude earthquakes with time and explained it by diffusion-controlled growth of the pressure-perturbed part of faults. Numerical and analytical fault size modelling supported our findings. Finally, we derived magnitude scaling laws to manage induced seismic hazard of upcoming energy projects prior to operation. This article is part of the theme issue 'Induced seismicity in coupled subsurface systems'.

Nanoarchitectured peroxidase-mimetic nanozymes: mesoporous nanocrystalline α- or γ-iron oxide?

Nanozymes (nanoparticles with enzyme-like properties) have attracted considerable attention in recent years owing to their intrinsic enzyme-like properties and broad application in the fields of ELISA based immunoassay and biosensing. Herein, we systematically investigate the influence of crystal phases (γ-Fe2O3 and α-Fe2O3) of mesoporous iron oxide (IO) on their peroxidase mimetic activity. In addition, we have also demonstrated the applicability of these mesoporous IOs as nanozymes for detecting the glucose biomarker with a limit of detection (LOD) of 0.9 µM. Mesoporous γ-Fe2O3 shows high nanozyme activities (and magnetism) toward the catalytic oxidation of chromogenic substances, such as 3,3',5,5'-tetramethylbenzidine (TMB) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid)-ABTS, as well as for the colourimetric detection of glucose, compared to that of α-Fe2O3. We believe that this in-depth study of crystal structure based nanozyme activity will guide designing highly effective nanozymes based on iron oxide nanostructures for chemical sensing, biosensing and environmental remediation.

Synthesis and cytotoxic activity of 3-O-acyl/3-hydrazine /2-bromo/20,29-dibromo betulinic acid derivatives.

A series of 3-O-acyl, 3-hydrazine, 2-bromo, and 20,29-dibromo betulinic acid derivatives (1-27) have been synthesized and screened for in vitro cytotoxic activity on human cancer cell lines MOLT-4, JurkatE6.1, CEM.CM3, BRISTOL8, U937, DU145, PA-1, A549, and L132. A number of compounds have shown ED(50)<1 microg/mL against the cancer cell lines tested and have shown better cytotoxicity than betulinic acid. Compounds 13, 19, 20, 23, and 27 were the best derivatives and were selected as lead molecules for further development. The structure-activity relationship has been described.

Synthesis of 3-O-acyl/3-benzylidene/3-hydrazone/3-hydrazine/17-carboxyacryloyl ester derivatives of betulinic acid as anti-angiogenic agents.

New 3-O-acyl, 3-benzylidene, 3-hydrazone, 3-hydrazine, 17-carboxyacryloyl ester derivatives of betulinic acid (2-6, 8-11, 13, 17, 18, 21, and 22) were synthesized and evaluated in vitro for anti-angiogenic activity on endothelial cell cytotoxicity, specificity, and tube-formation ability. All derivatives reported here showed IC(50)<4 microg/mL. Compounds 3, 9, 10, 17, 21, and 22 have shown better cytotoxicity (IC(50)<1.2 microg/mL) than betulinic acid (1) and improved endothelial cell specificity (ECS>10) in some cases. Compounds 10, 17, and 18 have shown 20%, 32%, and 48% reduction in TLS, respectively, and were found better than betulinic acid (1). We have shown that 20,29-dihydrobetulinic acid derivatives have better anti-angiogenic activity as compared to betulinic acid or its other derivatives.

Betulinic acid and its derivatives as anti-angiogenic agents.

Betulinic acid (1) significantly caused cytotoxicity to endothelial cell line ECV304 (IC(50) 1.26+/-0.44 microg/mL) in a 5-day MTT assay. Novel and more potent derivatives of betulinic acid (2, 4, 6-8) have been synthesized with IC(50) less than 0.4 microg/mL. The endothelial cell specificity against human tumor cell lines DU145, L132, A549, and PA-1 were determined. Further betulinic acid (1) inhibited TLS formation of ECV304 cells on Matrigel(TM) by 5.5% while its derivatives caused an inhibition of 13.1-49.2%.

Lipoma of the cleft soft palate: a case report of a rare congenital anomaly.

OBJECTIVE: Congenital tumors of the oral cavity are extremely uncommon. The teratoid tumors (epiganthi, dermoid, and hairy polyps) account for almost all of the reported cases and are not infrequently associated with cleft of the soft palate. Of the remaining tumors in the pediatric cleft palate population, infantile lipoma of the oral cavity is exceedingly rare. A case of a congenital lipoma associated with a cleft of the soft palate is presented. The review of the literature, the description of the lesion, the diagnosis, and the management of this finding are outlined.

Increased axonal regeneration through a biodegradable amnionic tube nerve conduit: effect of local delivery and incorporation of nerve growth factor/hyaluronic acid media.

The authors emphasize the possible pharmacological enhancement of axonal regeneration using a specific growth factor/ extracellular media incorporated in a biodegradable nonneural nerve conduit material. They investigated the early effects on nerve regeneration of continuous local delivery of nerve growth factor (NGF) and the local incorporation of hyaluronic acid (HA) inside a newly manufactured nerve conduit material from fresh human amnionic membrane. Human amnionic membrane contains important biochemical factors that play a major neurotrophic role in the nerve regeneration process. The process of manufacturing a nerve conduit from fresh human amnionic membrane is described. This nerve conduit system was used in rabbits to bridge a 25-mm nerve gap over 3 months. NGF was released locally, over 28 days, at the distal end of the tube via a system of slow release, and HA was incorporated inside the lumen of the tube at the time of surgery. NGF/HA treatment promoted axonal regeneration across the amnionic tube nerve conduit (8,962 +/- 383 myelinated axons) 45% better than the nontreated amnionic tube group (6,180 +/- 353 myelinated axons). The authors demonstrate that NGF/HA media enhances additional axonal regeneration in the amnionic tube nerve conduit. This result is secondary to the effect of the amnion promoting biochemical factors, in combination with the NGF/HA effect on facilitating early events in the nerve regeneration process.

Endoscopic technique for harvesting the intercostal nerve as a nerve graft: a feasibility preliminary study in cadavers.

Endoscopic surgical procedures in plastic surgery have been applied in numerous aesthetic and reconstructive surgical techniques. The use of the endoscopic video-assisted technique in peripheral nerve surgery is one of the most recent advances in reconstructive surgery. In this preliminary report, the seventh intercostal nerve, in fresh human cadavers, was harvested with the aid of endoscopy through a single 2-cm transverse incision. The anatomy of the intercostal nerve and the endoscopic surgical technique are described in this report. Multiple intercostal nerve grafts of adequate size, number, and length could be harvested, with less donor site morbidity, and used for future reconstruction of the injured peripheral nerve. The advantages of using an endoscopic technique to harvest the intercostal nerve include a magnified, clear, and illuminated visualization; a better remote access incision site; and an atraumatic technique, which may be proven particularly applicable in clinical procedures in patients who are prone to hypertrophic scars such as in women and children.

Endoscopic-assisted temporoparietal fascial flap dissection and harvesting: a feasibility preliminary cadaveric study.

Endoscopic procedures in plastic surgery have been applied in various aesthetic and reconstructive surgical techniques. The authors describe, in this preliminary report, a new surgical technique of endoscopic dissection of the temporoparietal fascial flap. A series of 6 fresh human cadavers (12 flaps) were dissected endoscopically. The surgical incisions, flap anatomy applicable to endoscopy, endoscopic surgical technique, and type of endoscopic setup is standardized for all flaps, allowing direct identification of the temporoparietal fascial layers and the major vascular pedicle. This endoscopic manipulation of the flap, without the traditional large scalp incision, permits local and free transfer of the temporoparietal fascial flap. Exposure of the flap by means of the conventional T or Y temporal incisions has several possible disadvantages, including an increased risk of blood loss, alopecia, and facial nerve injury. Endoscopic dissection and mobilization of the temporoparietal fascial flap can obviate the direct flap incision and yield a flap accessible to dissection and mobilization for additional clinical applications. This new, innovative, and minimally invasive endoscopic procedure may prove particularly applicable to future clinical applications of this type of fascial flap.

Ultrasound in the diagnosis and management of fluid collection complications following abdominoplasty.

A 6-year prospective study of 80 abdominoplasties is reported. Type and incidence of complications are presented with particular attention toward the incidence of fluid collection following abdominoplasty, such as seroma and hematoma. Ultrasound was performed in 56 patients (70%), with normal findings in 27 patients (48%). Accurate diagnosis of fluid collection in 29 patients (51.8%), seroma in 24 (42.8%), and hematoma in 5 (9%) was confirmed with the aid of ultrasound. The advantage of early radiological diagnosis alerted the surgeon for positive findings of fluid collection areas in the abdominal wall, which resulted in close observation and early intervention whenever indicated. Ultrasound of the abdominal wall following abdominoplasty provides a noninvasive, accurate, and low-cost method of diagnosing fluid collection in the abdominal wall. This method, if performed routinely postabdominoplasty, will aid the surgeon in managing potential complications such as wound-healing problems, infection, and patient discomfort.

Endoscopic exploration of the orbital floor: a technique for transantral grafting of floor blowout fractures.

A cadaveric study was conducted with a twofold purpose--to perform diagnostic transantral endoscopy in pure blowout fractures of the orbital floor and to attempt restoration of bony defects in the orbital floor using the endoscope. Endoscopic visual access of the orbital floor allows precise determination of the fracture size and the presence and extent of entrapped periorbital fasciae. A bony defect was created surgically in the orbital floor of 6 fresh cadaver heads, and a split-thickness calvarial bone graft and an alloplast were used to repair the orbital floor. Grafting of the orbital floor with endoscopic visual access was successful, and the potential risks associated with the traditional eyelid incisions were minimized. The anatomic course of the infraorbital nerve was observed and protected. The study confirmed that endoscopy could be used successfully in obtaining visual access to the orbital floor.