Why are pitfall traps so rare in the natural world?

Prey capture by trapping is uncommon taxonomically, and generally requires highly evolved cognitive powers (humans) or specialist self-secreted materials (for example, spiders and caddisfly larvae). The most notable exception to this is the conical traps dug by antlion larvae. The relative uncommonness (taxonomically and ecologically) of such pitfall traps has been described as an unexplained mystery in recent publications. Here we suggest some potential routes that might lead to resolution to this mystery. We argue that although such pitfall traps have numerous benefits and are relatively cheap and easy to construct, they may suffer two significant disadvantages relative to, for example, spiders’ webs. First, pitfall traps may require a quite specialist microhabitat. Second, antlion pitfall traps may only work to retain all but the smallest prey if the antlion is present at the bottom of the pit. Thus, antlion may be more functionally tied to their trap than spiders and (since traps are much more visually conspicuous than their owners) this may make them vulnerable to predators and parasitoids that cue on the traps. Both these hypothesised drawbacks are speculative in the absence of a strong body of data and so we discuss how both potential costs could be explored empirically.     

Neuroendocrine tumor in gastric adenoma: a diagnostic pitfall mimicking invasive adenocarcinoma

ABSTRACT: Neuroendocrine tumor (NET) in adenoma of the gastrointestinal tract is a rare mixed glandular-endocrine neoplasm and has uncommonly been described mostly in the colon. Histologically, this tumor is composed of a predominant proportion of benign adenomatous component and a small portion of well-differentiated NE component. Only three cases of NET in gastric adenoma have been reported in the literature. We present 4 cases of NET in gastric adenoma mimicking invasive adenocarcinoma. The NETs were 0.62 mm to 4.1 mm in size and located at the basal lamina propria, muscularis mucosa and submucosa. Histologically, NETs consisted of nests, cords, tubules, and clusters of cells that predominantly interposed between the foveolar base without disturbing the overall polyp architecture. The lesions were completely removed by endoscopic submucosal dissection in three cases and in one case, subtotal gastrectomy was performed because endoscopic biopsy was invasive adenocarcinoma. The patients' clinical course was uneventful without an evidence of recurrence or metastasis. The recognition of NET in gastric adenoma will help avoid potential diagnostic pitfalls masquerading as invasvie adenocarcinomas posed by their infiltrative pattern into submucosa.Virtual slidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1688552293761001.     

Medical and minimally invasive treatment of urinary incontinence

Newer agents and procedures give urologists more options in treating patients who have urinary incontinence related to such etiologies as an ineffective sphincter, detrusor hypersensitivity, obstruction, or a combination of these. Abolition of the involuntary contractions characteristic of detrusor instability can be accomplished pharmacologically or surgically. First-line anticholinergic agents are tolterodine and oxybutynin XL, given orally. Alternatively, intravesical administration provides a high concentration of drug, such as capsaicin or resiniferatoxin, at the detrusor muscle level. However, this commits the patient to intermittent self-catheterization. Surgery is reserved for those who have failed prolonged trials of conservative therapies. For patients with intractable urge incontinence, urologists have the new technique of sacral nerve stimulation.     

Brow suspension,a minimally invasive technique in facial rejuvenation

People tend to prefer noninvasive or minimally invasive methods of facial rejuvenation, especially when it involves their face, which is the hallmark of a person's identity and impossible to hide. It is widely known that brow ptosis gives the face a "tired look" and also accentuates deformities of the upper eyelid. Most people who are interested in facial rejuvenation may not accept even a minor surgery, such as an endoscopic surgery. The senior author has developed a minimally invasive method of suspending the brow at a higher position. In this technique, there is neither surgical dissection nor a surgical incision except for four stab incisions and suture insertion, which is why we refer to it as a nonsurgical brow suspension. It is done under local anesthesia, and the brows are fixed in the position that they assume when the patient is supine. In the past 6 years, we performed 387 brow suspensions on 324 female and 63 male patients. The youngest patient was 19 years old, and the oldest was 74 years old. A retrospective chart review was done. These 387 cases were reviewed by comparison of preoperative and postoperative photographs. This approach was not only used for patients who were not interested in surgical rejuvenation but was also combined with lipofilling, laser resurfacing, and/or upper blepharoplasty. This technique is useful for correcting postsurgical brow asymmetry. We present this technique as an adjunct to the established techniques of facial rejuvenation. Despite the high patient acceptance and technical ease, it is not a replacement for the established techniques of facial rejuvenation.     

Technological advances in minimally invasive radiofrequency ablation of cardiac tissues

Ablative techniques have been sought in many circumstances as alternatives to surgical resection/incision. Besides being minimally invasive, potential benefits of ablation include greater speed and improved access to target tissue compared with other surgical techniques. There is a wide variety of ablation technologies currently in use for medical treatment. These include but are not limited to tissue heating by radiofrequency (RF) current, microwaves, laser, and high intensity ultrasound. RF is among the most heavily used because of its relatively low complexity and cost. Ablative techniques have proven to be viable alternatives to surgical resection/incision of tissue. Although there are other means of tissue heating besides RF, RF is the most commonly used technique in operating rooms because of the reliability of transmural lesions and the low complexity of the system. Optimal systems account for the heterogeneous nature of tissue and variations in tissue property through the ablation cycle. It is important to monitor and assure adequate energy delivery by selecting the appropriate configuration of devices. Energy delivery varies between the various generators and systems, some more responsive than others with relative to changes in tissue impedance that will affect the end results of the operation.     

A minimally invasive approach for correction of chin ptosis

Although ptosis of the tip of the chin is common and can be seen in persons of any age, it is frequently seen in older patients seeking facial rejuvenation. A variety of techniques have been described to correct ptosis of the chin. The authors describe a minimally invasive method that can be used correct chin ptosis. This technique uses a small intraoral incision to place a U-shaped Prolene suture that gathers the soft tissue of the chin and elevates it above the lower border of the mandibular symphysis. A retrospective review of 314 cases performed in conjunction with face lifts between January of 1994 and January of 2000 was performed to evaluate this technique. There were no significant complications, and long-term results have been very satisfactory and lasting.     

全髋置换术中后外侧微创小切口的应用分析

目的探讨后外侧微创小切口全髋置换术在临床的应用价值。方法将我科收治的64例全髋关节置换患者随机分为两组。治疗组32例,采用后外侧微创小切口全髋置换术;对照组32例,采用常规全髋置换术。记录两组患者的手术时间、术中术后失血量、切口长度、术后开始功能锻炼时间、术后Harris评分、并发症等。结果随访时间为3个月～2年,平均12个月。两组患者术后切口均为Ⅰ级切口甲级愈合,无1例发生切口及深部感染,两组患者术后Harris评分、术后并发症等无显著性差异。但治疗组(后外侧微创切口全髋置换术)在手术时间、术中术后失血量、手术切口长度、术后开始功能锻炼时间均显著低于常规全髋置换术,差异有统计学意义(P<0.05)。结论后外侧微创小切口行人工全髋置换术可明显缩短手术时间和降低术后并发症及假体位置不当的风险,具有手术创伤小、失血量少、可早期进行关节功能锻炼等优点。     

Design of a multifunctional compliant instrument for minimally invasive surgery

A new multifunctional compliant instrument has been designed for use in minimally invasive surgery. The instrument combines scissors and forceps into a single multifunctional device. The main advantage of using multifunctional instruments for minimally invasive surgery is that instrument exchanges can be reduced, thus reducing procedure time and risk of inadvertent tissue injury during instrument exchanges. In this paper, the length, width, and thickness of the multifunctional compliant mechanism tool tip is optimized to maximize the jaw opening and the grasping force. The optimized design is then modeled to simulate the stresses encountered in the scissors mode. A 5.0 mm diameter stainless steel prototype is fabricated using electro-discharge machining and is shown to grasp and cut successfully.