Analysis of the Effect of Limb Rehabilitation Therapy Combined with Transcranial Magnetic Stimulation Therapy on Muscle Activity in Patients with Upper Limb Dysfunction After Cerebral Infarction

Objective:To analyze the effect of limb rehabilitation therapy combined with transcranial magnetic stimulation therapy on muscle activity in patients with upper limb dysfunction after cerebral infarction(CI).Methods:320 patients with upper limb dysfunction after CI were selected,all of whom were treated in our hospital between June 2021 and June 2023.They were randomly grouped according to the lottery method into the control group(limb rehabilitation therapy,160 cases)and the intervention group(transcranial magnetic stimulation therapy+limb rehabilitation therapy,160 cases).The upper limb function scores,neuro-electrophysiological indicators,daily living ability scores,and quality of life scores of the two groups were compared.Results:Compared with the control group,upper limb function scores and daily living ability scores in the intervention group were higher after treatment,and the neuro-electrophysiological indicators of the intervention group were lower after treatment(P<0.05).Conclusion:Transcranial magnetic stimulation therapy combined with limb rehabilitation therapy has significant effects in patients with upper limb dysfunction after CI and is worthy of promotion and application.

Non-invasive physical therapy as salvage measure for ischemic skin flap:A literature review

This review focuses on the available evidence regarding the molecular mechanisms and treatment potential of several non-surgical physical therapies for managing flap ischemia to propose a non-invasive,economical,and simple treatment to improve flap survival.A review of the literature was conducted on the topics of various non-invasive methods for the treatment of ischemic necrosis of the distal end of the flap between 1988 and 2019.A total of 52 published studies were reviewed on the applications of hyperbaric oxygen therapy,electrical stimulation therapy,heat stress pretreatment,phototherapy,and vibration therapy to manage skin flap necrosis.The underlying molecular mechanisms of these physical therapies on revitalizing the dying skin flaps were discussed and preliminary clinical uses of these therapies to salvage the necrotic skin flaps were pooled and summarized for clarifying the safety and feasibility of these methods.Various physical therapy regimens have been ushered to manage necrotic development in cutaneous flaps.With the refinement of these new technologies and enhancement of related basic science research on vascular revitalization,the prevention and treatment of flap ischemia will enter a new era.

Does a combined intervention program of repetitive transcranial magnetic stimulation and intensive occupational therapy affect cognitive function in patients with post-stroke upper limb hemiparesis?

Low-frequency repetitive transcranial magnetic stimulation（LF-r TMS） to the contralesional hemisphere and intensive occupational therapy（i OT） have been shown to contribute to a significant improvement in upper limb hemiparesis in patients with chronic stroke. However, the effect of the combined intervention program of LF-r TMS and i OT on cognitive function is unknown. We retrospectively investigated whether the combined treatment influence patient＇s Trail-Making Test part B（TMT-B） performance, which is a group of easy and inexpensive neuropsychological tests that evaluate several cognitive functions. Twenty-five patients received 11 sessions of LF-r TMS to the contralesional hemisphere and 2 sessions of i OT per day over 15 successive days. Patients with right- and left-sided hemiparesis demonstrated significant improvements in upper limb motor function following the combined intervention program. Only patients with right-sided hemiparesis exhibited improved TMT-B performance following the combined intervention program, and there was a significant negative correlation between Fugl-Meyer Assessment scale total score change and TMT-B performance. The results indicate the possibility that LF-r TMS to the contralesional hemisphere combined with i OT improves the upper limb motor function and cognitive function of patients with right-sided hemiparesis. However, further studies are necessary to elucidate the mechanism of improved cognitive function.

Multifunctional hydrogel combined with electrical stimulation therapy for promoting diabetic wound healing

Diabetic wounds, as a complication of diabetes, are slow to heal and seriously affect the quality of life of patients. Functional hydrogel dressing is an effective approach to improve diabetic wound healing. Electrical stimulation (ES) therapy is conducive to promoting cell migration and wound healing. In this work, a multifunctional PPTZ hydrogel wound dressing was developed by freeze-thaw method with polyvinyl alcohol (PVA), phytic acid (PA), tannic acid (TA), and Zinc chloride. The obtained PPTZ hydrogel has good mechanical properties (stress and strain of 700.03 kPa and 575.08%), light transmittance (close to 100%) and antibacterial rate (over 75%). With good biocompatibility, antioxidant abilities and conductivity, the PPTZ hydrogel could effectively promote the healing of diabetic wounds with two weeks under the action of electric field, which provides an auxiliary treatment strategy for diabetic patients.

Neuroplasticity in post-stroke gait recovery and noninvasive brain stimulation

Gait disorders drastically affect the quality of life of stroke survivors,making post-stroke rehabilitation an important research focus.Noninvasive brain stimulation has potential in facilitating neuroplasticity and improving post-stroke gait impairment.However,a large inter-individual variability in the response to noninvasive brain stimulation interventions has been increasingly recognized.We first review the neurophysiology of human gait and post-stroke neuroplasticity for gait recovery,and then discuss how noninvasive brain stimulation techniques could be utilized to enhance gait recovery.While post-stroke neuroplasticity for gait recovery is characterized by use-dependent plasticity,it evolves over time,is idiosyncratic,and may develop maladaptive elements.Furthermore,noninvasive brain stimulation has limited reach capability and is facilitative-only in nature.Therefore,we recommend that noninvasive brain stimulation be used adjunctively with rehabilitation training and other concurrent neuroplasticity facilitation techniques.Additionally,when noninvasive brain stimulation is applied for the rehabilitation of gait impairment in stroke survivors,stimulation montages should be customized according to the specific types of neuroplasticity found in each individual.This could be done using multiple mapping techniques.

Neuromuscular Electrical Stimulation in Intensive Care Unit Patients:Integrative Review

Intensive care units’ acquired muscle weakness is present in approximately 50% of the patients. Although active muscle training can attenuate weakness, a large proportion of critical patients cannot participate in any active mobilization. Neuromuscular electrical stimulation may be an alternative strategy to reverse muscle weakness. The objective of the study was to review the scientific publications on the use of neuromuscular electrical stimulation and its parameters and the main results in patients hospitalized in intensive care units. This is an integrative review surveying studies in online databases. The studies were selected from the following descriptors: neuromuscular electrical stimulation AND parameters AND intensive care units AND muscle weakness. The inclusion criteria included articles that addressed the topic of neuromuscular electrical stimulation and the parameters used in patients admitted to intensive care units, aged 18 years or older. Exclusion criteria were studies involving animals, case reports, letters to the editor and book chapters. The search comprised articles in the Portuguese, English and Spanish languages from January 2013 to March 2019. Of the 185 articles identified, nine met the eligibility criteria. The studies were evaluated assessing the level of evidence, and the relevant information was presented in the table and discussed. The parameters of the neuromuscular electrical stimulation employed in the studies showed positive results for the maintenance of strength and muscle mass. There was evidence of benefits in the local and systemic microcirculation, potentially mobilizing endothelial stem cells, to prevent atrophy, to reduce mechanical ventilation time and stay in intensive care unit;and when incorporated into the usual physiotherapy care, proved to be more effective than usual care. Its use is safe and viable in critically ill patients.

Systematic evaluation on the clinical efficacy of acupoint stimulation therapy for treatment of premature ovarian insufficiency on the basis of network Meta-analysis

Objective To systematically evaluate the effectiveness and safety of acupoint stimulation therapy for treatment of premature ovarian insufficiency（POI）. Methods Computer retrieval was carried out in such databases as Pub Med, Embase, Cochrane Library, web of science, Chinese biomedicine database（CBM）, China National Knowledge Infrastructure（CNKI）, Wan Fang and VIP in order to collect the randomized controlled trials（RCT） concerning acupoint stimulation therapy for treatment of POI. Software R 3.40 and stata 14.0 were used for Meta-analysis and network Meta-analysis, and Rev Man 5.3 was used for plotting the risk bias diagrams. Results Fortythree RCTs were included in total, involving 3046 POI patients and 18 acupoint stimulation therapies and comprehensive therapies. Metaanalysis showed：（1） The curative effects of acupoint stimulation therapy（RR=1.25, 95%CI [1.07,1.45]）, acupoint stimulation therapy＋Chinese herbal medicine（RR=1.25, 95%CI [1.18,1.32]） and acupoint stimulation therapy＋ hormone replacement therapy（HRT）（RR=1.20, 95%CI [1.12,1.29]） were all superior to that of HRT, indicating that the differences were statistically significant（Z=2.90, P=0.04; Z=7.56, P〈0.000 01; Z=4.06, P〈0.000 01）.（2） Compared with HRT, the occurrence rate of adverse effect of acupoint stimulation therapy was lower, and the safety was superior to that of HRT（RR=0.18, 95%CI [0.08,0.41]）, indicating that the differences were statistically significant（Z=4.08, P〈0.000 1）. Forty-two direct comparisons and 110 indirect comparisons were generated according to network Meta-analysis, among which, 38 comparisons were statistically significant. Network Metaanalysis results with HRT as control showed： the therapeutic measures ranking top 3 according to the curative effect sequence were catgut embedment in acupoint, moxibustion and warming-needle moxibustion, successively, and all the 3 measures were monotherapies without reflecting the advantages of comprehensive therapy. HRT ranked 17 th among the 18 included therapeutic measures. Conclusion On the basis of current evidences, acupoint stimulation therapy has a better clinical efficacy and safety for treatment of POI when compared with HRT. The acupoint stimulation therapies ranking the top 3 have more significant curative effects, but the long-term efficacy and the effect on the ovarian function still need to be further explored. In addition, the conclusion of this study still needs to be verified through a large number of RCTs with reasonable designs and appropriate methods.

Effect of electric acupoint stimulation on gastrointestinal hormones and motility among geriatric postoperative patients with gastrointestinal tumors

OBJECTIVE:To evaluate the effects of electric acupoint stimulation on gastrointestinal hormones and motility among geriatric postoperative patients with gastrointestinal tumors,and to explore an efficient and noninvasive method for postoperative recovery of bowel functions.METHODS:Forty patients were randomly and evenly assigned into a regular nursing care group(RNC) and an acupoint electric stimulation group(AES).Patients in the RNC group received regular nursing care and patients in the AES group received regular nursing care plus electric stimulation of acupoints.The serum levels of gastrin(GAS),motilin(MOT),and cholecystokinin(CCK),and an electrogastrogram(EGG) of all the patients were evaluated on the first,third,and fifth day after surgery.The time to first flatus after surgery and the number of patients with side effects such as abdominal pain,abdominal distention,and diarrhea were recorded.RESULTS:There were significant differences between the two groups in GAS,MOT,EGG,time to first flatus,abdominal pain,abdominal distention,and diarrhea(P < 0.05).CONCLUSION:Electric stimulation on acupoints could increase levels of GAS and MOT,promote the recovery of gastrointestinal functions,and decrease complications among postoperative senile patients with gastrointestinal tumors.

Effect of acupuncture plus medium-frequency electric stimulation on bladder function after radical hysterectomy for cervical cancer

Objective： To observe the effect of acupuncture plus medium-frequency electric stimulation on bladder function after radical hysterectomy for cervical cancer. Methods： A total of 170 patients confirmed by biopsy and surgical pathology and treated with radical hysterectomy for cervical cancer were randomly divided into an acupuncture group, an observation group and a control group by random digital table. Fifty-six cases in the acupuncture group were treated with acupuncture after surgery, one session each day, till the extubation day; 58 cases in the observation group were treated with acupuncture plus medium-frequency electric stimulation after surgery, one session each day, till the extubation day; and 56 cases in the control group didn＇t receive any intervention, and the catheter was retained till the extubation day. On the postoperative day 14, all groups were dealt with catheterization to determine the residual urine volume, in order to observe the occurrence rate of urinary retention and the recovery of bladder function and to compare the differences of the therapeutic effects among the groups. Results： The occurrence rates of urinary retention were respectively 16.1%, 20.7% and 46.4% in the acupuncture group, observation group and control group, with significant differences （P〈0.05）. When comparing the acupuncture group and the observation group with the control group, there were significant differences （both P〈0.05）. In comparison between the acupuncture group and the observation group, there was no significant difference （P〉0.05）. The recovery rates of bladder function in the three group were respectively 42.9%, 60.3% and 41.1% without significant differences （P〉0.05）. Moreover, there were no significant between-group differences （P〉0.05）, but acupuncture plus medium-frequency electric stimulation showed a better tendency. Conclusion： The single application of acupuncture therapy is effective and able to prevent urinary retention after radical hysterectomy for cervical cancer. Acupuncture plus medium-frequency electric stimulation can effectively enhance the recovery of bladder function and reduce the residual urine volume in the bladder to the maximum.

Clinical study on acupuncture combined with low-frequency electric stimulation for scissor gait in children with spastic cerebral palsy

Objective：To observe the clinical effect of acupuncture combined with low-frequency electric stimulation on scissor gait in children with spastic cerebral palsy. Methods：A total of 60 spastic cerebral palsy kids were allocated into two groups by random number table, 30 in each group. Cases in the control group were treated with physical exercise therapy, massage and hydrotherapy. Based on the therapies given to the control group, cases in the observation group were supplemented with acupuncture combined with low-frequency electric stimulation. Selected points included Zusanli （ST 36）, Sanyinjiao （SP 6）, Yanglingquan （GB 34）, Jiexi （ST 41）, Chengshan （BL 57）, Naoqing [Extra, locates at 2 cun directly above Jiexi （ST 41）] and Genping （Extra, locates at the midpoint of the line connecting medial and lateral malleolus）. The treatment was done once every other day and 10 d made up a treatment course. The low-frequency electric stimulation was applied to anterior tibia, 6 times a week and 20 times made up a treatment course. Cases were treated for a total of 3 courses and there was a 15-20 d interval between two courses. The low limb functions were assessed before and after treatment using the modified Ashworth scale （MAS） and composite spasticity scale （CSS）. In addition, the ankle dorsiflexion angles were measured before and after treatment. Results：After treatment, the ankle dorsiflexion angles and CSS scores in the observation group were better than those in the control group, showing statistical significances （P〈0.05）; the effective rate in the observation group calculated by MAS and ankle dorsiflexion angle were both higher than that in the control group, showing a statistical significance （P〈0.05）. Conclusion：Rehabilitation training combined with acupuncture and low-frequency electric stimulation can achieve better effect than rehabilitation training alone in improving scissor gait in kids with spastic cerebral palsy.

Clinical observation on acupoint massage plus Vitalstim electrical stimulation for deglutition disorder after stroke

Objective:To observe the effect of acupoint massage plus Vitalstim electrical stimulation on deglutition function and surface electromyography(SEMG)of deglutition muscle groups.Methods:A total of 60 patients with deglutition disorder after stroke were selected and divided into an electrical stimulation group,a massage group and an integrated group according to the random number table method,with 20 cases in each group.Patients in these three groups were given the same routine rehabilitation training for deglutition.In addition,patients in the electrical stimulation group were given extra Vitalstim electrical stimulation,patients in the massage group were given extra acupoint massage on the head,face and neck,and patients in the integrated group were given extra acupoint massage plus Vitalstim electrical stimulation.Fujishima Ichiro food intake level scale(FILS)was scored before and after treatment.The swallowing duration and maximal amplitude of masseter muscle in SEMG were evaluated before and after treatment.Results:After treatment,the FILS score and the maximal amplitude of recruitment potential generated by muscular contraction of masseter muscle group in the three groups were higher than those before treatment(all P<0.05),and the swallowing duration of masseter muscle group was shortened compared with that in the same group before treatment(all P<0.05).After treatment,the FILS score in the integrated group was higher than that in the electrical stimulation group and the massage group(both P<0.05).The swallowing duration of masseter muscle group measured by SEMG was lower than that in the electrical stimulation group and the massage group(both P<0.05),while the maximal amplitude was higher than that of the electrical stimulation group and the massage group(P<0.05).After treatment,there were no significant differences in the FILS score,swallowing duration and maximal amplitude of masseter muscle group between the electrical stimulation group and the massage group(all P>0.05).Conclusion:Both acupoint massage and electrical stimulation can improve the deglutition function in patients with deglutition disorder after stroke,and improve the coordination and flexibility of masseter muscle.The integration of the two is more effective.

Music electric stimulation of points for anxiety:a multi-center randomized controlled clinical trial

To observe the therapeutic efficacy of music electric stimulation of points in treating anxiety. Methods： By adopting a design of multi-centered randomized controlled trial （RCT）, a total of 270 patients with anxiety were randomized into a treatment group and a medication group. The treatment group was intervened by music electric stimulation of points, while the medication group was intervened by oral administration of doxepin. The two groups were evaluated by using Hamilton anxiety rating scale （HAMA） and Chinese revised edition of self-rating anxiety scale （SAS-CR） before and after the intervention. The therapeutic efficacies were also compared. Results： The total effective rate was 93.6% in the treatment group versus 92.3% in the medication group, and the between-group difference was statistically insignificant （P〉O.05）. After the treatment, the aggregate scores of HAMA and SAS-CR were significantly changed in both groups （both P〈0.001）, and the inter-group differences were statistically insignificant （P〉O.05）. Conclusion： Music electric stimulation of points can produce equivalent efficacy in treating anxiety compared to doxepin. Thus, it can be taken as a choice in the treatment of anxiety.

Electrophysiological monitoring and identification of neural roots during somatic-autonomic reflex pathway procedure for neurogenic bladder

OBJECTIVE: To identify and separate the ventral root from dorsal root, which is the key for success of the artificial somatic-autonomic reflex pathway procedure for neurogenic bladder after spinal cord injury (SCI). Here we report the results of intra-operating room monitoring with 10 paralyzed patients. METHODS: Ten male volunteers with complete suprasacral SCI underwent the artificial somatic-autonomic procedure under general anesthesia. Vastus medialis, tibialis anticus and gastrocnemius medialis of the left lower limb were monitored for electromyogram (EMG) activities resulted from L4, L5, and S1 stimulation respectively to differentiate the ventral root from dorsal root. A Laborie Urodynamics system was connected with a three channel urodynamic catheter inserted into the bladder. The L2 and L3 roots were stimulated separately while the intravesical pressure was monitored to evaluate the function of each root. RESULTS: The thresholds of stimulation on ventral root were 0.02 ms duration, 0.2-0.4 mA, (mean 0.3 mA+/-0.07 mA), compared with 0.2-0.4 ms duration, 1.5-3 mA (mean 2.3 mA+/-0.5 mA) for dorsal root (P

压力性尿失禁诊疗135例临床分析(英文)

Objective The purpose of this study is to evaluate and compare the two different treatments by researching 135 cases with stress urinary incontinence.Methods From June 2006 to June 2010,135 patients with stress urinary incontinence were treated in Department of Gynecology and Obstetrics of Peking University Shenzhen Hospital.91 cases of them were treated with low frequency electric stimulation and biofeedback therapy (Group A),and the other 44 cases were treated by improved transobturaor tension-free vaginal tape(TVT-O) and TVT-O (Group B).Then,we compared these two groups by whole recovery rate,recovery rate of patients with urge incontinence,charge of treatment and complication,respectively.Results Group B's recovery rate for stress urinary incontinence was 100%.Ⅰ degree stress urinary incontinence in Group A's recovery rate was higher;Ⅱ degree patients' recovery rate for stress urinary incontinence was lower;Ⅲ degree patients' recovery rate was 0%.Only 1 case showed abnormal urine stream;2 cases showed urinary retention,but the symptoms disappeared after the treatment.No significant complication in Group A.There were huge differences of the expense between the two groups.The effect in Group A for patients with urge incontinence was good,but there was no effect shown in Group B.Conclusions The two treatments are safe and effective for stress urinary incontinence,but there are existed prominent differences of the therapeutic efficacy between the two groups.

Satellite cell proliferation and myofiber cross-section area increase after electrical stimulation following sciatic nerve crush injury in rats

Background:Electrical stimulation has been recommended as an effective therapy to prevent muscle atrophy after nerve injury.However,the effect of electrical stimulation on the proliferation of satellite cells in denervated muscles has not yet been fully elucidated.This study was aimed to evaluate the changes in satellite cell proliferation after electrical stimulation in nerve injury and to determine whether these changes are related to the restoration of myofiber cross-section area(CSA).Methods:Sciatic nerve crush injury was performed in 48 male Sprague-Dawley rats.In half(24/48)of the rats,the gastrocnemius was electrically stimulated transcutaneously on a daily basis after injury,while the other half were not stimulated.Another group of 24 male Sprague-Dawley rats were used as sham operation controls without injury or stimulation.The rats were euthanized 2,4,and 6 weeks later.After 5-bromo-2’-deoxyuridine(BrdU)labeling,the gastrocnemia were harvested for the detection of paired box protein 7(Pax7),BrdU,myofiber CSA,and myonuclei number per fiber.All data were analyzed using two-way analysis of variance and Bonferroni post-hoc test.Results:The percentages of Pax7-positive nuclei(10.81±0.56%)and BrdU-positive nuclei(34.29±3.87%)in stimulated muscles were significantly higher compared to those in non-stimulated muscles(2.58±0.33%and 1.30±0.09%,respectively,Bonferroni t=15.91 and 18.14,P<0.05).The numbers of myonuclei per fiber(2.19±0.24)and myofiber CSA(1906.86±116.51 mm2)were also increased in the stimulated muscles(Bonferroni t=3.57 and 2.73,P<0.05),and both were positively correlated with the Pax7-positive satellite cell content(R2=0.52 and 0.60,P<0.01).There was no significant difference in the ratio of myofiber CSA/myonuclei number per fiber among the three groups.Conclusions:Our results indicate that satellite cell proliferation is promoted by electrical stimulation after nerve injury,which may be correlated with an increase in myonuclei number and myofiber CSA.

Case studies of Chinese acupuncture's comprehensive effectiveness on knee pain

Conventional Western medicine（CWM） and traditional Chinese medicine（TCM） have different approaches and lead to different practices in experimental design, research methodology, regulation, and standards. TCM emphasizes on the optimal or holistic health. In contrast, CWM is an allopathic medicine primarily based on anatomy, biology, biochemistry,molecular biology and modern technology, and rejects the concept of invisible substances and quantum entanglement.Consequently, CWM emphasizes on abnormal lab tests or obvious diseases. In the early 1970 s, TCM and acupuncture quickly emerged as an alternative to CWM as Westerners explored new TCM concepts while questioning the side effects of CWM. Many countries accept traditional acupuncture as a legal alternative medical practice. Some CWM physicians nowadays are more enthusiastic and are receptive to learning and practicing acupuncture. The common goal of CWM and TCM is to enhance human health, but problems arise over differences in approach. As a response to some Western journal papers that failed to validate the real acupuncture effect because of their incorrect methodologies and their ignorance of the holistic acupuncture approaches, the authors hereby present a group of case studies to demonstrate the real and unique effects of genuine acupuncture. The objective was to explore the clinical effects of acupuncture for knee pain.Thirty-six patients with knee pain were divided into five groups based on age. Holistic TCM diagnosis was performed at the beginning of each case and then made a personalized acupuncture treatment prescription according to the root of illness found by the diagnosis. The symptoms and signs were recorded before and after every treatment, and the treatment effects were assessed based upon the self-reported feeling and the observed changes of the patient following the numeric rating scale（NRS）. The results were summarized after the completion of the minimal 5 acupuncture treatments or the standard 10 acupuncture treatments. Among the 36 patients who participated in the cases studies, 17 patients reported a complete healing for knee pain（47.2%）. About 60 kinds of illness other than knee pain were improved（98.9%） and the complete healing rate was about 44.2%. This leads to the conclusion that TCM acupuncture is remarkably effective in treating knee pain. TCM and CWM share a common goal in promoting the health of human being. The efficacy of TCM acupuncture in treating knee pain shouldn＇t be denied or distorted.

Use of a self-designed bladder controller for restoring bladder function in paraplegic dogs

Objective: To evaluate the results of a self-designed bladder controller for restoring micturition function in paraplegic dogs.Methods: The spinal cords of 4 dogs were transected above the cone. Electrodes were implanted in S2 bilaterally and connected to the subcutaneous receivers for external activation. Microsurgical technique was employed to perform dorsal rhizotomy of S1-3 intradurally. The dogs were stimulated daily to observe micturition. Urodynamic testing and vesicography were performed. Results: All the dogs acquired micturition under the control of electric stimulation, with urine volume 80-140 ml per time. The mode of micturition was post-stimulus voiding. Vesicography revealed that the bladder was filled well and the bladder neck was open in the micturition course of electric stimulation. Residual urine volume was 15-20 ml. Urodynamic testing found that the bladder pressure and intraurethral pressure increased simultaneously, but when the intraurethral pressure was greater than the bladder pressure, no micturition occurred. The pressure decreased to baseline rapidly and the bladder pressure decreased slowly between two bursts. Micturition occurred when the bladder pressure was greater than the intraurethral pressure.Conclusions: The self-designed bladder controller together with a sacral deafferentation procedure can restore micturition function of paraplegic dogs.