Measurement Compensation for Time-Delay Seeker and Three-Dimensional Adaptive Guidance Law Design.

The time delay of seekers has grown to be a serious issue for tactical missile guidance with the development of flight vehicle technologies. To address the problem, a measurement compensation system for the seeker, with lags and delays based on predictive active disturbance rejection control, is proposed. In addition, to eliminate the effects of target maneuvers to the tactical missile guidance, an adaptive finite-time convergent sliding mode guidance law, based on super-twisting algorithm, is proposed in three-dimensional missile-target engagement kinematics. Specifically, the compensation system consists of a predictive tracking structure and an active disturbance rejection control system, which could follow a virtual measurement without lags and delays. The compensation system has advantages in disturbance rejection and model inaccuracy addressing, compared with existing compensation methods for seeker measurement. As for the sliding mode guidance law design, the proposed approach is based on an improved super-twisting algorithm with fast convergent adaptive gains, which has advantages in addressing unknown but bounded target maneuvers and avoiding chattering of the classical sliding mode control. As a result, the measurement compensation system and the adaptive sliding mode guidance law is verified robust and effective under the proposed constraints by the simulation examples.

Polybrominated diphenyl ethers in student dormitory microenvironments: Concentrations, sources, and human exposure.

Microenvironments, such as student dormitories, differ from general residential environments. They are characterized by small spaces, poor air circulation, high personnel densities, and electronic products, such as computers that are turned on for extended periods, leading to increased pollution concentrations. The limited space and poor air circulation reduce migration of contaminants, such as polybrominated diphenyl ethers (PBDEs), making it easier for PBDEs to accumulate. However, few studies have been conducted on small group dwellings, including student dormitory dwellings. We collected dust samples from student dormitories of a university to analyze the characteristics and traceability of PBDEs in dormitory microenvironments. The results showed that PBDE congeners were widely present in university dormitories and the order of median concentration of ∑10PBDEs was as follows: male old-fashioned dormitory (273 ng/g) > female four-person dormitory (132 ng/g) > female two-person dormitory (132 ng/g) > male two-person dormitory (96.2 ng/g) > female old-fashioned dormitory (91.6 ng/g) > male four-person apartment (51.8 ng/g). BDE-209 was the most abundant PBDE congener, followed by BDE-47, and BDE-28. PBDEs were also found in typical electrical appliances, with higher concentrations in laptops than in desktops, and higher concentrations in desktops than in idle ones. According to Spearman correlation and Principal Component Analysis (PCA), we also found that boards and wallpaper materials were common sources of contamination in the microenvironment of student dormitories, and that female dormitories had more sources of PBDE emissions. Human exposure to PBDEs in students is below the US Environmental Protection Agency reference dose. Although exposure to PBDEs generated in dormitories does not pose a significant health risk, the potential hazards of PBDEs to the reagent environment remain to be investigated.

Study on Penetration Performance of Rear Shaped Charge Warhead.

In guided munitions, the shaped charge jet (SCJ) warhead is located behind the simulation compartment (including the control cabin, the steering gear cabin, and the guidance cabin). Therefore, the order of penetration of the SCJ is the simulation cabin and the target. To study the penetration performance of the SCJ to the target plate, the numerical simulation method is used to study the penetration performance of the designed warhead for the steel target at different standoffs, and the depth of penetration (DOP) at the best standoff is obtained, that is, the DOP of the steel target is about 128 mm. Additionally, the penetration performance of the SCJ warhead to target is studied by numerical simulation and experimental verification. Numerical simulation and experimental results show that the DOP of the SCJ warhead to the steel target is 50 mm without the simulation cabin, and about 30 mm with the simulation cabin. The results show that the penetration performance of SCJ is greatly weakened under the condition of non-optimal standoff, but the rear shaped charge warhead still has a strong penetration performance after completing the penetration of the simulated cabin.

Sphenopalatine ganglion-targeted low-temperature plasma radiofrequency ablation in the treatment of refractory cluster headache.

INTRODUCTION: Cluster headache (CH) is a refractory headache. Low-temperature plasma radiofrequency ablation is a relatively novel technique with promising applications in neuropathic pain. It may improve the treatment of CH. AIM: To evaluate the efficacy and safety of sphenopalatine ganglion-targeted low-temperature plasma radiofrequency ablation in the treatment of patients with refractory CH. MATERIAL AND METHODS: A retrospective cohort study including seventy-five patients with refractory cluster headache who underwent computed tomography (CT)-guided sphenopalatine ganglion-targeted low-temperature plasma radiofrequency ablation between January 2015 and December 2017 at the Beijing Xuanwu Hospital was conducted. RESULTS: Effective pain relief rate 3 months after the procedure was 96% with 40 (53.3%) patients achieving complete relief; 32 (42.7%) patients obtained partial relief and 3 (4%) patients showed no relief. The effective pain relief rate two years after the procedure remained as high as 85.3% with 29 (38.6%) achieving complete relief, 35 (46.7%) partial relief and 11 (14.7%) no relief. The procedure proved equally effective for both episodic and chronic cluster headache. Complications including facial numbness, masseter weakness, facial hypoesthesia and cheek hematoma were observed, but all were mild and disappeared within 6 months. CONCLUSIONS: CT-guided low-temperature plasma radiofrequency ablation is an effective and safe strategy for refractory cluster headache. For patients who have not responded to conservative treatment, this minimally invasive intervention is a reliable alternative.

CT-guided percutaneous radiofrequency thermocoagulation for glossopharyngeal neuralgia: A retrospective clinical study of 117 cases.

OBJECTIVE: Glossopharyngeal neuralgia (GPN) is a rare disorder of the ninth cranial nerve. Percutaneous radiofrequency thermocoagulation (PRT) is an established treatment for neuropathic pain. Since PRT was first applied with GPN, only a few studies have provided detailed reports on its clinical outcomes and complications, and the number of cases was small. The aim of this study was to investigate the effects, incidence rates, and severity of adverse events of computed tomography (CT)-guided PRT in 117 patients with GPN. PATIENTS AND METHODS: A total of 117 patients with idiopathic GPN underwent CT-guided PRT from July 2004 to December 2016. A retrospective review of medical records was performed to investigate baseline characteristics and immediate outcomes after operation. Long-term outcomes were obtained via telephone interviews. Patients were followed up at 3 months, 6 months, and thereafter, every year after operation. According to Barrow Neurological Institute (BNI) pain scale, the effects of this treatment were categorized into 5 levels. Adverse events, frequencies, severity, and recovery times of complications were recorded. RESULTS: Patients who were classified into BNI class I and BNI class II experienced excellent pain relief. Ninety-six patients (82.1%) achieved "excellent" pain relief immediately after treatment. The mean follow-up period was 73.6 months (range, 13-150). With regard to long-term outcomes, the percentage of patients who experienced "excellent" pain relief was 75.9% at 1 year, 63.0% at 3 years, 54.0% at 5 years, 44.2% at 10 years, and 39.3% at 12.5 years. Complications, which included dysphagia, lingual numbness, pharynx and larynx numbness, hoarseness, and abnormal sense of taste, were graded 1 as defined by the Landriel Ibanez classification, and all complications disappeared within 12.9 ± 5.1 weeks. CONCLUSION: This study indicates that PRT is a minimally invasive procedure that leads to minor complications and is proven to have immediate and long-term effectiveness for managing GPN. It is especially suitable for patients with contraindication to surgery and patients who require recurrent treatment. We provide a detailed report of the adverse events experienced by GPN patients who underwent PRT.

Low-temperature plasma radiofrequency ablation in phantom limb pain: A case report.

Phantom limb pain (PLP) and phantom limb sensations are common complications postamputation. PLP is defined as persistent painful sensations perceived in the missing portion of the amputated limb. Low-temperature plasma radiofrequency ablation (coblation) technology is a relatively new technology that has shown promise in treating neuropathic pain. This report illustrates the use of coblation technology on cervical nerve roots for PLP. Coblation of the cervical nerve root was performed. Three 17G puncture trocars were placed near the C5-C6, C6-C7, and C7-T1 intervertebral foramen with computed tomography (CT) guidance. Then, a coblation needle attached to low-temperature plasma multifunctional operation system was placed near the C8 nerve root through the puncture trocars. To locate the target nerve, single stimulation (lasting for 5 s, at 1 intensity) in "cut" and "coagulation" model was given to serve as a sensory stimulation test. The stimulation induced radiating pain of the stimulated nerve away from the stimulation site to confirm our target nerve. The needle location was redirected based on the reproduction of the patient's symptoms with minimal intensity. A CT-guided cervical nerve root coblation was performed to obtain longer PLP relief. The patient reported pain relief in PLP after the operation. At 1-, 3-, and 6-month postoperative review, PLP relief was achieved. Overall activity was improved and there was necessarily need for pain medications. However, the doses of medicine significantly decreased. The analgesic effect was stable during the 6-month follow-up period. Our report demonstrates that coblation technology is successful treatment for PLP in this case. It will supply us a novel navigation in PLP treatments. Meanwhile, this finding still needs additional study for confirmation.

Successful treatment of refractory cancer pain with morphine and ropivacaine: A case report.

RATIONALE: Pain is one of the most common and distressing symptoms experienced by cancer patients. Cancer pain is a complex phenomenon with physical, psychological, social, and cognitive domains. Although opioids remain a cornerstone of cancer pain management, they are not effective in all patients. This case highlights the successful treatment of an opioid-refractory severe cancer pain crisis with ropivacaine infusion and subsequent rapid tapering of opioid dose. PATIENT CONCERNS: This report illustrates the use of ropivacaine for cancer pain. A 62-year-old man with metastatic lung cancer was admitted to the hospital with uncontrolled chest-back and abdominal pain. DIAGNOSES: The patient was diagnosed as refractory cancer pain. INTERVENTIONS: Successful treatment with morphine and ropivacaine was performed to obtain longer opioid refractory severe cancer pain. OUTCOMES: At 1, 3, and 6 months postoperative review, 70-75% relief of pain was achieved with overall activity was improved. The analgesic effect was stable during the 6-month follow-up period. No complications were reported during the follow-up period. LESSONS: Our report demonstrates that ropivacaine is successful treatment for cancer pain in this case. It will supply us a novel navigation in cancer pain treatments. Meanwhile, this finding still needs additional study for confirmation.