66 In summary, the immunomodulatory potency of SP may be a releva

66 In summary, the immunomodulatory potency of SP may be a relevant component in the pathophysiology of major depression. Neurokinin receptor antagonists

The first peptidergic NK1 receptor antagonists were synthesized in the early 1980s as useful tools for the investigation of the endogenous NK1 ligands.67 Ten years later, Snider and colleagues established the first nonpeptide NK1 receptor antagonist.68 It was the first step in the race for a pharmacological compound to antagonize the SP signal. It was only 2 years later that the binding epitopes of SP and the new antagonist were detected69: the tachykinin binds to the extracellular loops of the receptor, while the nonpeptide Inhibitors,research,lifescience,medical antagonists bind more deeply in the transmembrane segments of the receptor molecule. In the meantime, a great variety of nonpeptide antagonists for the NK1, NK2, and NK3 done receptors have become available. Basic pharmacological studies on Inhibitors,research,lifescience,medical neurokinin receptor antagonists The important

modulating and enhancing role of SP in nociception led to the idea of introducing NK1 receptor antagonists as antinociceptive drugs. A lot of effort was made toward the development of NK1 receptor antagonists for the treatment of pain. Although NK1 receptor antagonists appeared to act synergistically to inhibit NMDA receptors on second-order Inhibitors,research,lifescience,medical sensory neurons, they exhibited only weak potency in acute pain.70 However, antinociceptive inhibitor Erlotinib efficacy could be observed in nociceptive models of chronic pain. This may be relevant to the treatment of the fibromyalgia syndrome (FM), a syndrome, characterized by chronic widespread pain and depression-like symptoms. Serum Inhibitors,research,lifescience,medical Inhibitors,research,lifescience,medical and cerebrospinal fluid (CSF) levels of SP are increased in FM, suggesting its probable role in the pathophysiology of FM.71 We were able to demonstrate a relationship between

SP levels and intensity of pain perception in FM patients.72 Thus, the therapeutic use of NK1 receptor Carfilzomib antagonists in FM may be a successful treatment strategy in FM, although they have failed to show antinociceptive efficacy in other chronic pain syndromes like peripheral neuropathy, osteoarthritis, or migraine.73 Since central administration of SP was shown to induce depression-like and anxious behavior (see above), the NK1 receptor antagonists were tested in several animal models of depression and anxiety. Vocalization evoked in guinea-pig pups or neonatal mice by transient maternal separation could be attenuated by systemic administration of several NK1 receptor antagonists, such as CP99994, L760735, or L733060.2,74 This effect was comparable to that of clinically used antidepressants (phenelzine, imipramine, fluoxetine) and anxiolytics (diazepam, buspirone).

Finally, the INSTINCT trial required the recruitment of a local <

Finally, the INSTINCT trial required the recruitment of a local stroke champion at each site to serve as the local principal investigator and to act as a liaison between the INSTINCT trial clinical coordinating center and the health care providers at each site. Figure 1 Overview of INSTINCT trial. Process of barrier assessments and interventions at INSTINCT hospitals. Study Setting Twenty-four hospitals were randomly selected from the population of Michigan

acute care hospitals and matched into 12 pairs based on emergency department volume and number of stroke patients (See Figure ​Figure1).1). Inhibitors,research,lifescience,medical Hospitals that were established academic comprehensive stroke centers were excluded. Primary stroke centers were not excluded, but were relatively uncommon in the hospital sample at the time of randomization. Each pair contained an intervention site and a control site, randomly assigned. Inhibitors,research,lifescience,medical Intervention group hospitals were 25% urban with a total aggregate annual emergency department volume of 397,193 in 2007. Rationale for qualitative inquiry An

overall goal of the qualitative inquiry was to design a process which would complement existing quality improvement Inhibitors,research,lifescience,medical programs, such as Get With the Guidelines (GWTG)- Stroke[12]. While GWTG-Stroke provides important tools for measuring progress, it is limited in its specific ability to encourage clinicians to comply with guidelines Inhibitors,research,lifescience,medical recommending intravenous tPA to eligible stroke patients. This is of particular importance in the United States, where emergency physicians (EPs) are typically the frontline of acute stroke care. In most U.S. practice settings, immediate namely access to a neurologist or stroke specialist does not exist[13]. Many decisions regarding stroke treatment, up to and Inhibitors,research,lifescience,medical including thrombolytic use, are made by EPs. Even in settings with access to acute stroke teams, the emergency care providers (physicians and nurses) need to recognize that the patient is having a stroke and alert the stroke team. In both instances, clinician beliefs about

the inhibitor Pacritinib relative efficacy of stroke thrombolysis, physician expertise, past experience, and concern about adverse effects influence the efficiency and overall tone of the decision-making process. Thus, the initial relationship at the bedside between clinician and decision maker (patient or family member) considering thrombolysis for stroke is both complex and ill-defined[14]. In a large proportion of community hospitals in the United Batimastat States this role is most commonly filled by EPs. Overview of data collection process The qualitative data collection and analysis methods have been described in detail previously and are summarized below[15]. During design, data collection, and analysis, we adhered to the consolidated criteria for reporting qualitative research (COREQ) when possible as outlined in Table ​Table11[16]. The qualitative inquiry occurred in two phases.

Epidural

anesthesia is an effective pain management optio

Epidural

anesthesia is an effective pain management option and adjunct to intravenous opioids for large abdominal operations. It helps to reduce the pulmonary complications, duration of ileus and provides better pain control than opioids alone (36,37). Risks associated with epidural catheter placement include epidural hematoma, epidural abscess, and spinal cord injury. These risks are increased post hepatectomy due to alterations in coagulation profile. Postoperative coagulopathy is at its peak 2-5 days post surgery. This time frame coincides with the recommended time of removal Inhibitors,research,lifescience,medical for epidural catheters and may necessitate transfusion of fresh frozen plasma and/or platelets (32,38-40). Due to these risks, the role of single dose epidural shots has been examined. Inhibitors,research,lifescience,medical Ko et al. reported that the combination of single

intrathecal injection of morphine combined with postoperative patient controlled analgesia (PCA) resulted in improved pain control in the early postoperative period than PCA alone (41). Epidural catheter use in hepatic resection has also been associated with greater transfusion requirement (see Page and Kooby, this issue). There are other drugs that may be useful as adjuncts to opioid administration. Intravenous acetaminophen has recently become available in the United States. The recommended maximal dose Inhibitors,research,lifescience,medical is 2 g/day in patients with hepatic impairment (35). NSAID Inhibitors,research,lifescience,medical use is generally not

recommended post hepatectomy, in cirrhotic patients, or in patients with renal scientific study insufficiency due to the risks of bleeding and hepatorenal syndrome (35,42). Other non-opioid analgesics such as nefopam is widely used in European countries but is Inhibitors,research,lifescience,medical not currently FDA (Food and Drug Administration) approved for routine use in United States. The use of local anesthetic infusions via the On-Q Pain Buster system placed in the musculofascial layer of the subcostal wound combined with PCA decreased total morphine consumption and improved pain at rest and after spirometry when compared to PCA alone in patients who underwent open hepatic resection (43). An infusion of no more than 0.25% ropivacaine or duration of infusion of less than 2 days is recommended due to increased plasma levels post hepatectomy. There are also case reports Dacomitinib of the use of paravertebral infusion of local anesthetic with PCA. However comparative studies are needed prior to routine use of this technique (44). There are many options available for post hepatectomy pain control. A multimodal approach specifically chosen for an individual patient is recommended and may consist of intravenous opioids, non-opioid injectables, continuous or single dose epidural anesthesia, and local anesthetic infusions with the transition to oral opioids as tolerated.

Last, our study concentrated on the concept of morphinofobia and

Last, our study concentrated on the concept of morphinofobia and should not be generalized for other opioids. Conclusion This study contributes to a better understanding

of “the myths of morphine” among the general population and health professionals in the region of Beira Interior. It suggests that efficient pain management is not limited to the prescription of an adequate analgesic according to « the golden standard ». The success of a morphine prescription is influenced by a multitude of other factors. Our results are in accordance with the results of the study by Musi et al. [26] done in a similar regional setting. Inhibitors,research,lifescience,medical There seems to be quite a misunderstanding of “morphine” as well among GP as HP in North-Eastern Portugal. Such a misunderstanding might well end up in straight forward

morphinofobia, thus ultimately Inhibitors,research,lifescience,medical compromising an appropriate pain management strategy as recommended by W.H.O. guidelines and EAPC recommendations. This leads us to suggest that there is a need for information campaigns selleck bio targeting the general population and for better training programs targeting health care professionals based on the theory of planned clinical behaviour [14] in order to improve acceptance and efficacy of pain management. Competing interests The authors declare that they have no competing interests. Authors’ contributions HV carried out the study concept, drafted the manuscript, the data analysing Inhibitors,research,lifescience,medical and interpretation, Inhibitors,research,lifescience,medical the follow-up and participated in the questionnaire design and data collection. EKM carried

out the design of the questionnaire, the study concept and participated in the draft of the manuscript. MF carried out the design and the translation of the questionnaires, survey and data collection and contributed in the data analysis and interpretation. CHR conceived the study, participated in the questionnaire design, data analysis and interpretation and Inhibitors,research,lifescience,medical the draft of the manuscript. PC carried out the draft of the manuscript and participated in the data analysis and interpretation. All the authors approved the final manuscript. Pre-publication history The pre-publication history for this paper can be accessed here: http://www.biomedcentral.com/1472-684X/9/15/prepub Acknowledgements The delay between the survey and this reporting was caused by the absence of financial support and the suddenly death of our dear colleague Prof. C-H Rapin. The authors thank GSK-3 the hospitals and the community home care centres of Beira Interior for their collaboration. In Ganetespib memoriam of Professor Charles-Henri Rapin, co-author, who died on the 10th of July 2008 in Sion, Switzerland.
Opioids are increasingly used for the treatment of chronic malignant and nonmalignant pain [1,2] and systematic reviews of randomized controlled trials have confirmed their short-term efficacy for the treatment of neuropathic pain, back pain, ostearthritis, cancer pain, and fibromyalgia [3-8].

However, as only about 10 out of 50 studies assessed the relation

However, as only about 10 out of 50 studies assessed the relationship of symptomatic remission to functional outcome and cognition, the hope of the RSWG that the availability of a validated remission measure would stimulate new studies on cognition and functional outcomes has only partly been fulfilled. This also holds true for studies on the association of symptomatic remission with quality of life. It is further Inhibitors,research,lifescience,medical important to know

that none of the 50 studies to date have assessed the influence of differing clinical services or different type of interventions on the proposed remission criteria. Finally, only one study to date has assessed the congruence between RSWG remission and remission as perceived by patients, relatives, and professionals. This is surprising considering the hope of the RSWG was that the development of remission selleck chemicals criteria should facilitate the dialogue on treatment expectations among physicians, patients and carers, health care administrators, and policy makers. Inhibitors,research,lifescience,medical The authors hope that the present article supports future research in this area. Footnotes Declaration

of interest: Professor Martin Lambert has received educational selleck grants from AstraZeneca Inhibitors,research,lifescience,medical and Eli Lilly Company and has received fees as speaker from AstraZeneca, Bristol Myers Squibb, Eli Lilly Company, Janssen Cilag, Pfizer, and Sanofi Aventis. Associate Professor Anne Karow has received educational grants from Bristol Myers Squibb and has received fees as speaker from AstraZeneca, Bristol Myers Squibb, Eli Lilly Company, Janssen Inhibitors,research,lifescience,medical Cilag, Pfizer, undbeck, and Essex Pharma. Professor Stefan

Leucht has received peaker/consultancy/advisory board honoraria from SanofiAventis, BMS, EliLilly, Essex Pharma, AstraZeneca, GlaxoSmithKline, Jans-sen/Johnson and Johnson, Lundbeck and Pfizer. SanofiAventis, and EliLilly supported Inhibitors,research,lifescience,medical research projects by Stefan Leucht. Professor Benno G. Schimmelmann has received educational grants from AstraZeneca and Novartis and has received speaker/consultancy/advisory board honoraria from AstraZeneca, Novartis, Bristol Myers Squibb, Eli Lilly Company, Janssen Cilag and Sanofi Aventis. Prof Dieter Naber has received speaker/consultancy/advisory board Cilengitide honoraria from AstraZeneca, BMS, Janssen-Cilag, Lilly, Lundbeck, Pfizer, Servier, and Wyeth.
The use of medication in the acute and long-term treatment of schizophrenia remains the cornerstone of disease management. This paper will attempt to review and highlight recent developments and current controversies in the pharmacologic treatment of schizophrenia. In that context, we will highlight areas where gaps in our knowledge continue to exist, and discuss the types of research ideally suited to fill these gaps.

40 Thompson and colleagues41 have also reported an accelerated de

40 Thompson and colleagues41 have also reported an accelerated decrease in gray matter volume in early-onset schizophrenia. Of particular note, in a recent review of the literature, DeLisi et al42 reviewed evidence for progressive changes in both chronic and first-episode patients. They concluded that progressive changes over time in chronic

patients are far less than what is observed in first-episode patients, again underscoring the Inhibitors,research,lifescience,medical fact that progressive changes in the early stages of illness may be more dramatic than changes observed later in the course of the illness. Another recent review43 sheds further light on the issue of progressive changes following first episode. Inhibitors,research,lifescience,medical This review found that progressive changes following first episode were more pronounced in the first 20 years and less pronounced after this time period compared with healthy controls. Of further note, the changes observed included gray matter volume reductions in the frontal and temporal lobes,

as well as increased lateral ventricles. In addition, these changes were associated with more progressive changes associated with poor outcome, more negative symptoms, and poor performance on neurocognitive measures. A review by Pantelis and coworkers17 of longitudinal MRI studies of first-episode patients, prodromal patients, and high-risk individuals also suggests an acceleration of gray matter Inhibitors,research,lifescience,medical reduction early in the course of illness. Specifically, there is gray matter reduction in prefrontal regions, which these investigators believe leads to further progressive changes in medial temporal and Inhibitors,research,lifescience,medical orbitofrontal brain regions. These investigators also interpret findings, to date, as

indicative of an early neurodevelopmental insult or lesion that likely “renders the brain vulnerable to later brain maturation processes” and which takes place during adolescence or early adulthood. These interpretations are reminiscent of Mednick and McNeil’s 1968 two-hit theory of schizophrenia,33 and order inhibitor Feinberg’s Inhibitors,research,lifescience,medical 198232 theory that schizophrenia results from abnormal synaptic pruning. The number of first-episode studies is, however, relatively small compared with Dacomitinib the number of chronic studies. Additionally, the selection of patients differs in that some studies make it clear include patients that have been ill for several years, and, while they may not be chronic per se, they might be better classified as reflecting “early schizophrenia” rather than as first-episode schizophrenia. Having said this, however, there are a number of highresolution longitudinal studies that have investigated brain abnormalities at first episode of illness. Some, including Gur and coworkers,37 and Kasai and coworkers,39 are noted above. Another study by Lieberman et al44 reported larger lateral ventricles and reduced volume of the hippocampus at baseline, but only increased lateral ventricles at follow-up 1 year later.

A compromise that is sometimes used is randomized, open treatment

A compromise that is sometimes used is randomized, open treatment with utilization of masked raters, but care needs to be taken to maintain the masking. Treatment selection The choice of treatment and control(s) will, of course, be heavily influenced by the basic question that the RCT is intended to address. The choice of active control and the target dose(s)

of both the investigational medicine and the control agent are important. Estimates of therapeutic equivalence and comparative adverse effect profiles are affected by these choices. Inhibitors,research,lifescience,medical If a dose is too low, efficacy may be suboptimal, but if a dose is too high it might inflate the incidence of adverse effects. Titration schedules can also be important Inhibitors,research,lifescience,medical for some drugs as well as bioavailability

towards issues related to food ingestion, or metabolic issues related to smoking, body weight, concomitant medications, etc. The side effect profiles of the experimental drug and comparator can also lead to functional unblinding and should be considered from that standpoint as well, or methods can be used to reduce the likelihood of such effects by using an ineffective low dose of the experimental drug as a pseudoplacebo, or separating the ratings of efficacy from those of tolerability, or using centralized raters who do not follow the same patient Inhibitors,research,lifescience,medical through a trial. An important and potentially difficult issue is the Inhibitors,research,lifescience,medical extent to which and what kind of “rescue” medication should be made available to those individuals who might otherwise drop out of the trial due

to lack of efficacy- and need for further treatment. This selleck possibility can complicate the assessment of the therapeutic agent. However, in some settings it is difficult to conduct a controlled trial without such a provision. As will be discussed Inhibitors,research,lifescience,medical subsequently, the possibility of treating all patients initially with active agents, identifying those with a clear early response and then enrolling only the latter subjects in a double -blind, placebo controlled discontinuation study could be a powerful strategy to detect a true drug effect Entinostat while exposing a minimal number of patients to placebo. Comedications The permission, timing, and dosing of comedications also requires consideration. Comedications are useful to limit adverse effect burden and dropouts, but can obscure true treatment effects. Moreover, differential washout of comedications in treatment groups prior to randomization can create confounds, whereas overly limited use of comedications might limit the feasibility of the trial and not match clinical reality. Placebo controls Recent discussion regarding placebo controlled clinical trials in schizophrenia has largely focused on ethical issues.

105 Overall, miR-195, -212, -132, -27b emerge as potent inducers

105 Overall, miR-195, -212, -132, -27b emerge as potent inducers of cardiac hypertrophy, while miR-23a appears to serve Bcl-2 lymphoma as a contributive factor to the establishment of this pathology. In addition to upregulated pro-hypertrophic miRNAs, disruption of anti-hypertrophic miRNAs expression has also been reported in the hypertrophied and failing myocardium. A representative example is miR-1, which was downregulated

in a series of studies in rodent models of hypertrophy, HCM and HF (TAC, AKT overexpression, MHCα-CN mice, cardiac specific Dicer deletion, and DBL transgenic mice). Ikeda et al demonstrated that the size of miR-1 deficient neonatal rat CMCs was significantly increased at baseline and after treatment with pro-hypetrophic stimulus (ET), indicating that miR-1 downregulation promotes hypertrophic growth. According to further studies in CMCs, miR-1 inhibits cell growth-related targets (RasGAP, Cdk9, fibronectin, Rheb), reduces protein synthesis and cell size, and its downregulation promotes hypertrophy. 74 In addition, in vitro experiments in a series of studies revealed multiple putative mechanisms of action for mir-1-mediated hypertrophy suppression, 76,71–75 including targeting of Igf-1 and Igf1-r,

71 calmodulin, Mef2a and Gata4. 72 These data indicate that miR-1 targets key regulators of hypertrophic growth, and may thus act as a central suppressor of hypertrophy via a range of downstream effectors in the failing myocardium. Similarly, the newly described miR-378 has been shown to be down-regulated during hypertrophic growth and HF. Studies in rat CMCs have shown that deficiency of this

miRNA is sufficient to induce fetal gene expression, thereby suggesting an anti-hypertrophic role in HF. MiR-378 seemingly acts by negatively regulating the MAPKs pathway. In specific, multiple components of this pathway have been identified as miR-378 targets (Mapk1, Igfr1, Grb2, Ksr1) by Ganesan et al. 108 In addition, recent experiments in rat CMCs showed that miR-378 directly targets Cilengitide Grb2 and blocks Ras activation, resulting in negative regulation of fetal gene expression and cardiac hypertrophy. 106,107 MiR-9 is also downregulated following hypertrophic treatments, and confers anti-hypertrophic effects in the murine heart. Wang et al utilized the isoproterenol and aldosterone-induced mouse models of hypertrophy to demonstrate that NFATc3 can promote hypertrophy via induction of myocardin expression, while miR-9 targets and suppresses myocardin. 109 Whether miR-9 is also underexpressed in human HF and may thus provide a target towards pathological hypertrophy HF inhibition, is yet to be determined. miRNAs impact on ECM remodeling and fibrosis Besides the establishment of hypertrophy and/or dilatation, the failing myocardium is often accompanied by structural remodeling.

Although the accuracy of waiting time duration is uncertain, perc

Although the accuracy of waiting time duration is uncertain, percentages have been described in other studies [17,22,27,29,37,43-45]. Probable reasons could be either patients got tired of waiting, seek advice in another healthcare facility or they felt better and left [15,20,46,47]. The contributory factors for LWBS are overcrowding due to high patient influx and boarded patients in ED, lack of awareness among general population regarding ED utilization as well as inefficient primary health care facilities [20,39,48-52]. This crowding result into prolong waiting hours and ultimately increased rate of LWBS. In our institution because of lack of availability of inpatient beds in high acuity areas these

patients who are Inhibitors,research,lifescience,medical either critically ill or intubated have to stay in the ED at times for more than 24–48 hours before Inhibitors,research,lifescience,medical their final disposition. The situation further worsen when more and more critical patients continue to land in the emergency department with limited resources like nursing staff and beds available. It is a proven phenomenon that when ED was crowded and on diversion there was 2.26 times risk of leaving the ED. Similar Inhibitors,research,lifescience,medical results have been reported by TL Viet and K V Rhodes that ED crowding increases the LWBS rate [21]. Increased percentages of LWBS during weekend or

night shift and seasonal variations gives insight into epidemics such as dengue fever, inadequate http://www.selleckchem.com/products/azd9291.html outpatient services on the weekends and after hour’s utilization of ED services for minor illnesses [16,21,51,53-56]. Our data had demonstrated a sudden increase in LWBS patients in the third quarter that coincide with the dengue epidemic of 2010 in Pakistan [57,58]. Inhibitors,research,lifescience,medical A strong seasonal variation with highest LWBS (up to 70%) in winters is also found in other studies [45]. There are certain limitations of this study. First

data were collected retrospectively. Secondly the study was conducted in a single tertiary care private hospital therefore results may not be generalized. Our department is the first in Pakistan to practice Inhibitors,research,lifescience,medical a defined triage system which started recently. Very little is known about the reliability and validity of the triage at our institute. This is the first ever analyzed data from AKUH-ED. Follow up studies are needed to address this issue in detail. The cross sectional design Brefeldin_A of study did not enable us to follow the clinical outcome of LWBS patients in detail. Additional studies are required to determine subsequent morbidity and mortality as well as other hospital factors affecting the percentage of LWBS. As all the patients are not the registered patients at AKUH, so the return visit of all the patients who had been triaged cannot be traced for any adverse outcome. This was the first reported data so we haven’t studied the different age group characteristics separately. Subsequent studies on pediatric, adult and geriatric patients are needed to further elaborate their characteristics and factors affecting their decision of leaving.

The electrostatic force balance technology is adopted in the circ

The electrostatic force balance technology is adopted in the circuit, and the application range of vacuum microelectronic http://www.selleckchem.com/products/Tipifarnib(R115777).html accelerometer is greatly extended.2.?Structure and Working PrincipleThe structure diagram of a vacuum microelectronic accelerometer is illustrated in Figure 1. The mechanical components comprise four cantilever beams, a proof mass and a micro-silicon field emission tip array. The electrodes include a cathode, an anode and a feedback electrode. Meanwhile, the protecting chain is designed. It will prevent the damage of the tip array and realize over loading self-protection. When the acceleration exceeds the measurement range, the anode will contact with the protecting chain, and avoid the collision between the anode and the tip array.Figure 1.Structure diagram of vacuum microelectronic accelerometer.This accelerometer has been designed and fabricated. The dimensions of the accelerometer are obtained. Figure 2 is the SEM diagram of single tip. The bottom pyramid is the tip, and the top plate is the SiO2/Si3N4 cap protecting the tip from being eroded. Finally, the cap will be removed after the tip acuity. When a big enough DC voltage is added between the tip and the anode electrode, the tip will emit electrons under high electric field.Figure 2.The SEM diagram of the single tip.The vacuum microelectronic accelerometer works in electrostatic force balance mode. The working principle is that by applying a forward bias voltage between the anode and cathode, when the bias voltage is large enough, the tip array begins to emit electrons under high electric field, and then the electrons form a diode forward current. When the bias voltage is constant and there is an acceleration acting on the accelerometer, the proof mass will produce a displacement, and result in the change of emission current. Using current detecting circuit and electrostatic negative feedback system can make the proof mass maintain the balance position, and then the acceleration is obtained by measuring the output voltage.3.?Mathematical Model and System-Level Analysis3.1. The Mathematical ModelMatlab was used to build the mathematical model of the vacuum microelectronic accelerometer. The model is composed of different function blocks based on Laplace transforms. In general, a vacuum microelectronic accelerometer with a feedback control system is not a linear system. Assumptions and approximations are used to linearize the system.3.1.1. The Sensing PartThe proof mass is the sensing part of the accelerometer. It can be considered as a suspended mass-spring-damping system [10]. Using Laplace transforms, the dynamic performance of the proof mass can be expressed as:G1(s)=��xm��a=1ms2+bs+k(1)where m, b, and k represent the mass, damping coefficient, and spring constant of the proof mass, respectively. ��a is the external acceleration, and ��x is the displacement of the proof mass.